Terahertz Device

Abstract

This terahertz device includes an antenna base (70) including reflective films (82A, 82B), wherein: the reflective films (82A, 82B) are curved to be recessed; the reflective film (82A) and the reflective film (82B) are arranged to be adjacent to each other in a y direction; and when viewed from a z direction, the sizes of the reflective film (82A) and the reflective film (82B) along an x direction are smaller than the sizes of the reflective film (82A) and the reflective film (82B) along the y direction.

Description

[Technical Field]

[0001] The present disclosure relates to terahertz devices. [Background technology]

[0002] In recent years, as electronic devices such as transistors have become increasingly miniaturized and their size has reached nanoscale, a phenomenon known as the quantum effect has become observable. Development is underway to utilize this quantum effect to realize ultrafast devices and devices with new functions.

[0003] In such an environment, attempts are being made to utilize electromagnetic waves in the frequency range known as the terahertz band, which has a frequency range of 0.1 THz to 10 THz, to perform high-capacity communication, information processing, imaging, measurement, etc. This frequency range combines the properties of both light and radio waves, and if devices operating in this frequency band can be realized, they could be used for a wide range of applications, including the aforementioned imaging, high-capacity communication, and information processing, as well as measurements in various fields such as physical properties, astronomy, and biology.

[0004] As an element for generating or receiving electromagnetic waves in the terahertz band, for example, an element having a structure in which a resonant tunneling diode and a fine slot antenna are integrated is known (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-111542 Summary of the Invention [Problem to be solved by the invention]

[0006] Terahertz devices are used as light sources that output electromagnetic waves with frequencies in the terahertz band and as detectors that detect electromagnetic waves with frequencies in the terahertz band, and there is a demand for higher output and improved resolution in such terahertz devices.

[0007] An object of the present disclosure is to provide a terahertz device that can achieve higher output or improved resolution. [Means for solving the problem]

[0008] A terahertz device that solves the above-described problems includes a plurality of terahertz elements including a first terahertz element and a second terahertz element that receive electromagnetic waves, and a plurality of reflecting surfaces including a first reflecting surface that faces the first terahertz element in a thickness direction of the first terahertz element and reflects the incident electromagnetic waves toward the first terahertz element, and a second reflecting surface that faces the second terahertz element in a thickness direction of the second terahertz element and reflects the incident electromagnetic waves toward the second terahertz element, wherein the first reflecting surface is open toward the first terahertz element and reflects the incident electromagnetic waves from the first terahertz element. the first reflective surface is curved so as to be concave in a direction away from the first terahertz element, the second reflective surface opens toward the second terahertz element and is curved so as to be concave in a direction away from the second terahertz element, the first reflective surface and the second reflective surface are arranged adjacent to each other in a first direction, and when a direction parallel to a thickness direction of the first terahertz element is defined as a height direction of the terahertz device, at least one of the sizes of the first reflective surface and the second reflective surface along the first direction is smaller than the sizes of the first reflective surface and the second reflective surface along a second direction that is different from the first direction, as viewed from the height direction of the terahertz device.

[0009] According to this configuration, the distance between the first terahertz element and the second terahertz element that are adjacent to each other in the first direction can be reduced, thereby improving the resolution of the terahertz device in the electromagnetic wave detection range.

[0010] A terahertz device that solves the above problem includes a plurality of terahertz elements including a first terahertz element and a second terahertz element that generate electromagnetic waves, and a plurality of reflecting surfaces including a first reflecting surface that faces the first terahertz element in a thickness direction of the first terahertz element and reflects the electromagnetic waves generated from the first terahertz element in one direction, and a second reflecting surface that faces the second terahertz element in a thickness direction of the second terahertz element and reflects the electromagnetic waves generated from the second terahertz element in one direction, wherein the first reflecting surface is open toward the first terahertz element and the first reflective surface is curved so as to be concave in a direction away from the second terahertz element, the second reflective surface opens toward the second terahertz element and is curved so as to be concave in a direction away from the second terahertz element, the first reflective surface and the second reflective surface are arranged adjacent to each other in a first direction, and when a direction parallel to a thickness direction of the first terahertz element is defined as a height direction of the terahertz device, at least one of the sizes of the first reflective surface and the second reflective surface along the first direction is smaller than the sizes of the first reflective surface and the second reflective surface along a second direction which is different from the first direction, as viewed from the height direction of the terahertz device.

[0011] According to this configuration, by providing multiple terahertz elements, when the terahertz device is used as a light source that outputs electromagnetic waves in the terahertz band, it is possible to increase the output of the light source. In addition, since the distance between the first terahertz element and the second terahertz element in the first direction can be reduced, the multiple electromagnetic waves output in one direction from the multiple terahertz elements via the multiple reflecting surfaces are not spaced apart in the first direction or the space can be reduced, so that the electromagnetic waves output by the terahertz device can be made uniform in the first direction. [Effects of the Invention]

[0012] The terahertz device described above can achieve higher output or improved resolution. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 2 is a perspective view of the terahertz device according to the first embodiment, viewed from above. [Figure 2] FIG. 2 is a perspective view of the terahertz device of FIG. 1 as viewed from below. [Figure 3] Back view of the terahertz device in Figure 1. [Figure 4] 4 is an end view of the terahertz device of FIG. 3, line 4-4. [Figure 5] 5 is an end view of the terahertz device of FIG. 3, line 5-5. [Figure 6] FIG. [Figure 7] FIG. 2 is an end view schematically showing an active element and its periphery. [Figure 8] Enlarged view of a portion of Figure 7. [Figure 9] 2 is a perspective view of the antenna base of the terahertz device of FIG. 1 as viewed from above. [Figure 10] FIG. 10 is a plan view of the antenna base of FIG. [Figure 11] 11-11 is a cross-sectional view of the antenna base of FIG. 10 . [Figure 12] 12-12 is a cross-sectional view of the terahertz device of FIG. 3. [Figure 13] 13 is a cross-sectional view of the terahertz device of FIG. 12 taken along line 13-13. [Figure 14] FIG. 14 is a partially enlarged view of the conductive portion and its surroundings in FIG. 13 . [Figure 15] FIG. 15 is a partially enlarged view of the conductive portion and its surroundings in FIG. 14 . [Figure 16] FIG. 3 is an explanatory diagram for explaining an example of one step of the manufacturing method of the terahertz device according to the first embodiment. [Figure 17] 17 is a cross-sectional view of the support substrate and its periphery taken along line 17-17 in FIG. 16. [Figure 18] FIG. 2 is an explanatory diagram for explaining an example of a step in a method for manufacturing a terahertz device. [Figure 19] (a) is a cross-sectional view of the support substrate and its periphery taken along line 19-19 in FIG. 18, and (b) is an enlarged view of a portion of (a). [Figure 20] FIG. 2 is an explanatory diagram for explaining an example of a step in a method for manufacturing a terahertz device. [Figure 21] 21 is a cross-sectional view of the support substrate and its surroundings taken along line 21-21 in FIG. 20. [Figure 22] FIG. 2 is an explanatory diagram for explaining an example of a step in a method for manufacturing a terahertz device. [Figure 23] 23 is a cross-sectional view of the support substrate and its surroundings taken along line 23-23 in FIG. 22. [Figure 24] FIG. 2 is an explanatory diagram for explaining an example of a step in a method for manufacturing a terahertz device. [Figure 25] FIG. 2 is an explanatory diagram for explaining an example of a step in a method for manufacturing a terahertz device. [Figure 26] FIG. 2 is an explanatory diagram for explaining an example of a step in a method for manufacturing a terahertz device. [Figure 27] FIG. 2 is an explanatory diagram for explaining an example of a step in a method for manufacturing a terahertz device. [Figure 28] FIG. 2 is an explanatory diagram for explaining an example of a step in a method for manufacturing a terahertz device. [Figure 29] FIG. 2 is an explanatory diagram for explaining an example of a step in a method for manufacturing a terahertz device. [Figure 30] FIG. 2 is an explanatory diagram for explaining an example of a step in a method for manufacturing a terahertz device. [Figure 31] (a) Schematic diagram of a terahertz element surrounded by gas, (b) graph showing the change in refractive index in the case of (a). [Figure 32] (a) Schematic diagram of a terahertz device surrounded by a dielectric and a gas, (b) graph showing the change in refractive index in the case of (a). [Figure 33] FIG. 10 is a schematic cross-sectional view showing the inter-element distance between adjacent terahertz elements in a terahertz device of a comparative example. [Figure 34] 3 is a schematic cross-sectional view showing the distance between adjacent terahertz elements in the terahertz device according to the first embodiment. FIG. [Figure 35] FIG. 10 is a plan view of a terahertz device according to a second embodiment. [Figure 36]FIG. 36 is a perspective view of the antenna base of the terahertz device of FIG. 35 viewed from above. [Figure 37] 37 is a plan view of the antenna base of FIG. 36. [Figure 38] FIG. 38 is a plan view showing one type of individual antenna base that constitutes the antenna base of FIG. 37. [Figure 39] 38 is a plan view of another type of individual antenna base that constitutes the antenna base of FIG. 37. [Figure 40] 38 is a plan view of yet another type of individual antenna base that constitutes the antenna base of FIG. 37; [Figure 41] 36 is a cross-sectional view of the terahertz device of FIG. 35 taken along line 41-41. [Figure 42] 32 is a cross-sectional view of the terahertz device of FIG. 35 taken along line 42-42. [Figure 43] 36 is a cross-sectional view of the terahertz device of FIG. 35 taken along line 43-43. [Figure 44] 36 is a cross-sectional view for explaining the arrangement of the conductive parts of the terahertz device of FIG. 35. [Figure 45] Enlarged view of the antenna base. [Figure 46] FIG. 10 is a plan view of a terahertz device according to a third embodiment. [Figure 47] FIG. 47 is a perspective view of the antenna base of the terahertz device of FIG. 46 viewed from above. [Figure 48] 48 is a plan view of the antenna base of FIG. 47. [Figure 49] FIG. 49 is a plan view showing one type of individual antenna base that constitutes the antenna base of FIG. 48. [Figure 50] 49 is a plan view of another type of individual antenna base that constitutes the antenna base of FIG. 48. [Figure 51] 49 is a plan view of yet another type of individual antenna base that constitutes the antenna base of FIG. 48; [Figure 52] A cross-sectional view of the terahertz device of Figure 46 taken along line 52-52. [Figure 53] A cross-sectional view of the terahertz device of Figure 46 taken along line 53-53. [Figure 54] 47 is a cross-sectional view for explaining the arrangement of the conductive parts of the terahertz device of FIG. 46. [Figure 55] A partially enlarged view of the conductive part of Figure 54. [Figure 56] Enlarged view of the antenna base. [Figure 57] FIG. 4 is a cross-sectional view showing a modification of the terahertz device of the first embodiment. [Figure 58] FIG. 10 is a cross-sectional view showing a modification of the terahertz device according to the second embodiment. [Figure 59] FIG. 10 is a cross-sectional view showing a modification of the terahertz device according to the second embodiment. [Figure 60] FIG. 10 is a cross-sectional view showing a modification of the terahertz device according to the second embodiment. [Figure 61] FIG. 10 is a cross-sectional view showing a modification of the terahertz device according to the second embodiment. [Figure 62] FIG. 4 is a circuit diagram showing an outline of a modification of the terahertz device of the first embodiment. [Figure 63] FIG. 4 is an enlarged cross-sectional view showing a part of a modified example of the terahertz device according to the first embodiment. [Figure 64] FIG. 10 is an enlarged cross-sectional view showing a part of a modified example of the terahertz device according to the second embodiment. [Figure 65] FIG. 10 is an enlarged cross-sectional view showing a part of a modified example of the terahertz device according to the second embodiment. [Figure 66] FIG. 10 is a front view schematically showing a terahertz element according to a modified example. [Figure 67] FIG. 10 is a plan view of an antenna base in a modified example of the terahertz device of the first embodiment. [Figure 68] A cross section of the antenna base taken along line 68-68 in Figure 67. [Figure 69] FIG. 10 is a plan view of an antenna base in a modified example of the terahertz device of the first embodiment. [Figure 70] A cross section of the antenna base taken along line 70-70 in Figure 69. [Figure 71] FIG. 10 is a plan view of an antenna base in a modified example of the terahertz device according to the second embodiment. [Figure 72] FIG. 10 is a plan view of an antenna base in a modified example of the terahertz device of the third embodiment. [Figure 73] FIG. 10 is a plan view of an antenna base of a modified terahertz device. [Figure 74] FIG. 74 is a plan view of a modified terahertz device having the antenna base of FIG. 73. [Figure 75] FIG. 4 is a cross-sectional view of a modified example of the terahertz device of the first embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, embodiments of the terahertz device will be described with reference to the drawings. Each of the embodiments shown below exemplifies a configuration and method for embodying the technical idea, and the material, shape, structure, arrangement, dimensions, etc. of each component are not limited to those described below. Various modifications can be made to each of the following embodiments. Furthermore, the drawings are partially schematic for convenience of illustration.

[0015] In the present disclosure, unless otherwise specified, the phrase "A is formed on B" includes a configuration in which A is formed directly on B and a configuration in which A is formed on B via an intervening object provided between A and B. Similarly, the phrase "A is disposed on B" includes a configuration in which A is disposed directly on B and a configuration in which A is disposed on B via an intervening object provided between A and B, unless otherwise specified. Furthermore, the phrase "A overlaps with B when viewed from a certain direction" includes a configuration in which all of A overlaps with B and a configuration in which part of A overlaps with B, unless otherwise specified.

[0016] [First embodiment] (Configuration of terahertz device) The configuration of a terahertz device 10 according to a first embodiment of the present disclosure will be described with reference to FIGS.

[0017] As shown in FIGS. 1 and 2, the terahertz device 10 of this embodiment is formed in the overall shape of a long, narrow rectangular parallelepiped. The terahertz device 10 has a device main surface 11, a device back surface 12 opposite to the device main surface 11, and four device side surfaces 13 to 16. The device main surface 11 is an elongated rectangle with a long side direction and a short side direction that are perpendicular to each other. The terahertz device 10 of this embodiment receives electromagnetic waves from outside the device. Note that the term "electromagnetic waves" includes the concepts of either light or radio waves, or both.

[0018] For convenience of explanation, in this embodiment, the longitudinal direction of the device principal surface 11 is defined as the x direction, and the lateral direction of the device principal surface 11 is defined as the y direction. The direction perpendicular to both the x direction and the y direction is defined as the z direction. The z direction can also be said to be the height direction of the terahertz device 10.

[0019] The device principal surface 11 and the device rear surface 12 are surfaces that intersect with the z direction, and in this embodiment, are perpendicular to the z direction. The device rear surface 12 is a surface that faces the opposite side of the device principal surface 11 in the z direction. In other words, the device principal surface 11 and the device rear surface 12 can be said to be both end surfaces of the terahertz device 10 in the height direction.

[0020] For ease of explanation, the direction in the z direction from the device back surface 12 toward the device main surface 11 is referred to as "upward." Upward can also be said to be a direction perpendicular to the device main surface 11 and away from the device main surface 11 to the side opposite the device back surface 12. The four device side surfaces 13 to 16 may also be referred to as the first device side surface 13, the second device side surface 14, the third device side surface 15, and the fourth device side surface 16.

[0021] The first device side surface 13 and the second device side surface 14 are both end surfaces of the terahertz device 10 in the x direction and intersect with the x direction. In this embodiment, the first device side surface 13 and the second device side surface 14 are each perpendicular to the x direction and extend along the y direction and the z direction. In this embodiment, the first device side surface 13 and the second device side surface 14 are each formed in a stepped shape. This point will be described later.

[0022] The third device side surface 15 and the fourth device side surface 16 are both end surfaces of the terahertz device 10 in the y direction and intersect with the y direction. In this embodiment, the third device side surface 15 and the fourth device side surface 16 are orthogonal to the y direction and extend along the x direction and the z direction, respectively.

[0023] As shown in FIG. 3, the terahertz device 10 includes a plurality of terahertz elements 20. The plurality of terahertz elements 20 include a terahertz element 20A, a terahertz element 20B, and a terahertz element 20C. The terahertz elements 20A to 20C have the same configuration. In this embodiment, the terahertz elements 20A to 20C are aligned with each other in the x direction and spaced apart from each other in the y direction. The terahertz element 20A is disposed closer to the third device side surface 15 than the center of the terahertz device 10 in the y direction, and the terahertz element 20C is disposed closer to the fourth device side surface 16 than the center of the terahertz device 10 in the y direction. The terahertz element 20B is disposed between the terahertz element 20A and the terahertz element 20C in the y direction. In this embodiment, the terahertz element 20B is disposed at the center of the terahertz device 10 in the y direction. In this embodiment, each of the terahertz elements 20A to 20C is disposed at the center of the terahertz device 10 in the x direction.

[0024] For convenience of explanation, when the terahertz elements 20A to 20C are commonly described below, they will simply be described as the terahertz element 20. When there is no need to distinguish between the terahertz elements 20A to 20C, they will be described as a plurality of terahertz elements 20.

[0025] The terahertz element 20 is an element that converts electromagnetic waves in the terahertz band into electrical energy. The terahertz element 20 receives electromagnetic waves in the terahertz band (in other words, terahertz waves). The frequency of such electromagnetic waves in the terahertz band is, for example, 0.1 Thz to 10 Thz.

[0026] As shown in FIGS. 4 to 6, the terahertz element 20 has a plate shape with the thickness direction being the z direction. In this embodiment, the terahertz element 20 has a rectangular plate shape as a whole. In this embodiment, as shown in FIG. 6, the terahertz element 20 is square when viewed from the z direction. The shape of the terahertz element 20 when viewed from the z direction is not limited to a square, and may be rectangular, circular, elliptical, or polygonal. Note that, given that the z direction and the thickness direction of the terahertz element 20 coincide with each other, "viewed from the z direction" can also be referred to as "viewed from the thickness direction of the terahertz element 20." Furthermore, since the z direction can be referred to as the height direction of the terahertz device 10, "viewed from the z direction" can also be referred to as "viewed from the height direction of the terahertz device 10."

[0027] 4 and 5, the element thickness D1, which is the dimension in the z direction of the terahertz element 20, is set based on, for example, the frequency of the electromagnetic wave to be received. As an example, the element thickness D1 may be thinner as the frequency of the electromagnetic wave increases, and may be thicker as the frequency of the electromagnetic wave decreases.

[0028] The terahertz element 20 has an element principal surface 21 and an element rear surface 22 as surfaces intersecting the thickness direction of the terahertz element 20. The element principal surface 21 and the element rear surface 22 are surfaces intersecting the z direction, and are orthogonal to the z direction in this embodiment. Therefore, the z direction can also be said to be a direction orthogonal to the element principal surface 21.

[0029] The element principal surface 21 and the element rear surface 22 each have a rectangular shape, for example a square shape, when viewed from the z direction. However, the shapes of the element principal surface 21 and the element rear surface 22 when viewed from the z direction are not limited to this and can be changed as desired.

[0030] 4 and 5, the terahertz element 20 of this embodiment is disposed with the element back surface 22 facing upward (in other words, with the element main surface 21 facing downward). The element main surface 21 is disposed closer to the device back surface 12 than the element back surface 22, and the element back surface 22 is disposed closer to the device main surface 11 than the element main surface 21.

[0031] As shown in Fig. 6, the terahertz element 20 has a first element side surface 23 and a second element side surface 24, which are end surfaces in the x direction, and a third element side surface 25 and a fourth element side surface 26, which are end surfaces in the y direction. The first element side surface 23 and the second element side surface 24 are each planes that intersect with the x direction and are orthogonal to the x direction in this embodiment. The third element side surface 25 and the fourth element side surface 26 are each planes that intersect with the y direction and are orthogonal to the y direction in this embodiment. The first element side surface 23 and the second element side surface 24 are orthogonal to the third element side surface 25 and the fourth element side surface 26.

[0032] As shown in FIGS. 4 to 6, there is a receiving point P1 that receives electromagnetic waves. This receiving point P1 can also be said to be a resonance point that resonates with electromagnetic waves in the terahertz band. In this embodiment, the receiving point P1 is a point (in other words, an area) that receives electromagnetic waves. The receiving point P1 is formed on the element principal surface 21. The element principal surface 21 on which the receiving point P1 is located constitutes an active surface that receives electromagnetic waves. The z direction (in other words, the thickness direction of the terahertz element 20 or the height direction of the terahertz device 10) can also be said to be a direction perpendicular to the surface on which the receiving point P1 is provided.

[0033] The reception point P1 in this embodiment is disposed at the center of the element principal surface 21. However, the position of the reception point P1 is not limited to the center of the element principal surface 21 and can be any position. As shown in FIG. 6, in this embodiment, the first vertical distance x1 between the second element side surface 24 (or the first element side surface 23) and the reception point P1 is, for example, (λ' InP / 2)+((λ´ InP / 2)×N) (N is an integer equal to or greater than 0: N=0, 1, 2, . . .).

[0034] where λ' InP is the effective wavelength of the electromagnetic wave propagating inside the terahertz element 20. When the refractive index of the terahertz element 20 is n1, c is the speed of light, and fc is the center frequency of the electromagnetic wave, λ' InPis (1 / n1)×(c / fc). fc can also be said to be the target frequency of the terahertz element 20. Furthermore, fc may be the frequency at which the output of the electromagnetic waves received by the terahertz element 20 is greatest.

[0035] Although details will be described later, the element refractive index n1 is higher than the dielectric refractive index n2, which is the refractive index of the dielectric 50 surrounding the terahertz element 20, and therefore the electromagnetic wave received by the terahertz element 20 is reflected at the free end by the second element side surface 24. Therefore, by setting the first perpendicular distance x1 as described above, the terahertz element 20 itself is designed as a resonator (first-order resonator) in the terahertz device 10.

[0036] Similarly, the second vertical distance y1 between the fourth element side surface 26 (or the third element side surface 25) and the reception point P1 is, for example, (λ' InP / 2)+((λ´ InP / 2)×N) (N is an integer equal to or greater than 0: N=0, 1, 2, . . .).

[0037] Note that the vertical distances x1 and y1 may be different values ​​for each of the element side surfaces 23, 24, 25, and 26, as long as they are each calculated using the above formula. For example, the first vertical distance x1 between the second element side surface 24 and reception point P1 may be different from the first vertical distance between the first element side surface 23 and reception point P1. Similarly, the second vertical distance y1 between the fourth element side surface 26 and reception point P1 may be different from the second vertical distance between the third element side surface 25 and reception point P1.

[0038] As shown in FIGS. 7 and 8, the terahertz device 20 includes an element substrate 31, an active element 32, a first element conductive layer 33, and a second element conductive layer . The element substrate 31 is made of a semiconductor and has semi-insulating properties. The semiconductor that constitutes the element substrate 31 is, for example, InP (indium phosphide).

[0039] The element refractive index n1 is the refractive index (absolute refractive index) of the element substrate 31. When the element substrate 31 is made of InP, the element refractive index n1 is approximately 3.4. In this embodiment, the element substrate 31 has a rectangular plate shape, for example, a square shape when viewed from the z direction. The element main surface 21 and the element back surface 22 are the main surface and back surface of the element substrate 31, and the element side surfaces 23 to 26 are side surfaces of the element substrate 31.

[0040] The active element 32 converts electromagnetic waves in the terahertz band into electrical energy. The active element 32 is formed on the element substrate 31. In this embodiment, the active element 32 is provided at the center of the element main surface 21. The reception point P1 can also be said to be the position where the active element 32 is provided.

[0041] The active element 32 is typically a resonant tunneling diode (RTD). However, the active element 32 is not limited to this, and may be, for example, a tunnel injection transit time (TUNNETT) diode, an impact ionization avalanche transit time (IMPATT) diode, a GaAs-based field effect transistor (FET), a GAN-based FET, a high electron mobility transistor (HEMT), or a heterojunction bipolar transistor (HBT).

[0042] An example for realizing the active element 32 will now be described. 8, a semiconductor layer 41a is formed on the element substrate 31. The semiconductor layer 41a is made of, for example, GaInAs. The semiconductor layer 41a is doped with a high concentration of n-type impurities.

[0043] A GaInAs layer 42a is stacked on the semiconductor layer 41a. The GaInAs layer 42a is doped with n-type impurities. For example, the impurity concentration of the GaInAs layer 42a is lower than the impurity concentration of the semiconductor layer 41a.

[0044] A GaInAs layer 43a is stacked on the GaInAs layer 42a. The GaInAs layer 43a is not doped with impurities. An AlAs layer 44a is stacked on the GaInAs layer 43a, an InGaAs layer 45 is stacked on the AlAs layer 44a, and an AlAs layer 44b is stacked on the InGaAs layer 45. The AlAs layer 44a, the InGaAs layer 45, and the AlAs layer 44b form an RTD section.

[0045] A GaInAs layer 43b that is not doped with impurities is stacked on the AlAs layer 44b. A GaInAs layer 42b that is doped with n-type impurities is stacked on the GaInAs layer 43b. A GaInAs layer 41b is stacked on the GaInAs layer 42b. The GaInAs layer 41b is doped with a high concentration of n-type impurities. For example, the impurity concentration of the GaInAs layer 41b is higher than the impurity concentration of the GaInAs layer 42b.

[0046] The active element 32 may have any specific configuration as long as it can receive (or generate, or both) electromagnetic waves. In other words, the active element 32 may be anything that can receive electromagnetic waves in the terahertz band.

[0047] 4 and 5, an element reflecting layer 35 that reflects electromagnetic waves is formed on the element back surface 22 of the present embodiment. Electromagnetic waves that are incident on a portion of the terahertz element 20 above the reception point P1 (active element 32) are reflected by the element reflecting layer 35 and directed downward.

[0048] Here, the element thickness D1 may be set so that the resonance condition of the electromagnetic wave is established. Specifically, when the element reflecting layer 35 is formed, the electromagnetic wave undergoes fixed end reflection at the interface between the element rear surface 22 and the element reflecting layer 35, resulting in a phase shift of π. Taking this into consideration, the element thickness D1 in this embodiment is set to (λ' InP / 4)+(λ´ InP / 4)×N (N is an integer equal to or greater than 0: N=0, 1, 2, . . .). By setting the element thickness D1 as described above, it is possible to excite standing waves inside the terahertz element 20. However, the element thickness D1 is not limited to the above and can be changed arbitrarily.

[0049] As shown in FIG. 7, the first element conductive layer 33 and the second element conductive layer 34 are each formed on the element principal surface 21. The first element conductive layer 33 and the second element conductive layer 34 each have a metal laminate structure. The laminate structure of each of the first element conductive layer 33 and the second element conductive layer 34 is, for example, a structure in which Au (gold), Pd (palladium), and Ti (titanium) are laminated. Alternatively, the laminate structure of each of the first element conductive layer 33 and the second element conductive layer 34 is a structure in which Au and Ti are laminated. Both the first element conductive layer 33 and the second element conductive layer 34 are formed by vacuum deposition, sputtering, or the like.

[0050] 6, the element conductive layers 33, 34 include pads 33a, 34a arranged opposite to each other and spaced apart in a predetermined direction (the y direction in this embodiment) with the receiving point P1 (active element 32) in between, and element conduction portions 33b, 34b extending from the pads 33a, 34a toward the active element 32. In the following description, the pad 33a may be referred to as the first pad 33a, the pad 34a as the second pad 34a, the element conduction portion 33b as the first element conduction portion 33b, and the element conduction portion 34b as the second element conduction portion 34b.

[0051] The pads 33a and 34a extend, for example, in a direction (x direction in this embodiment) perpendicular to the opposing direction of the pads 33a and 34a. When viewed, for example, from the z direction, the pads 33a and 34a each have a rectangular shape with a long side and a short side in the x direction. Specifically, the pads 33a and 34a each have a rectangular shape with a long side in the x direction and a short side in the y direction.

[0052] The pads 33a and 34a are arranged at positions that do not overlap with the reception point P1 when viewed from the z direction. For example, the pads 33a and 34a are arranged on both sides of the reception point P1 (in other words, the active element 32) in the y direction, and in this embodiment, are arranged closer to the element side surfaces 25 and 26 than the reception point P1.

[0053] The element conduction parts 33b and 34b each have an elongated shape extending in the y direction, for example. The length of the element conduction parts 33b and 33b in the x direction is shorter than the length of the pads 33a and 34a in the x direction.

[0054] 8, tip portions 33ba, 34ba of element conduction portions 33b, 34b overlap with active element 32 when viewed from the z direction and are electrically connected to active element 32. Specifically, tip portion 33ba of first element conduction portion 33b is located on GaInAs layer 41b and is in contact with GaInAs layer 41b.

[0055] Furthermore, the semiconductor layer 41a extends further in the y direction toward the second pad 34a (see FIG. 6) than other layers, such as the GaInAs layer 42a. The tip portion 34ba of the second element conduction portion 34b is laminated on a portion of the semiconductor layer 41a where the GaInAs layer 42a, etc. are not laminated. This establishes electrical continuity between the active element 32 and both element conductive layers 33 and 34 (in other words, both pads 33a and 34a). The second element conduction portion 34b and other layers, such as the GaInAs layer 42a, are spaced apart in the x direction.

[0056] Although not shown, a GaInAs layer heavily doped with n-type impurities may be interposed between the GaInAs layer 41b and the tip portion 33ba of the first element conductive portion 33b, unlike in Fig. 8. This can improve contact between the first element conductive layer 33 and the GaInAs layer 41b.

[0057] As shown in FIGS. 4 and 5, the terahertz device 10 includes a dielectric 50 which is an example of a holding member, an antenna base 70, a reflective film 82 which is an example of a reflector, and a gas space 92.

[0058] The dielectric 50 is made of a dielectric material that transmits the electromagnetic waves received by the terahertz element 20. In this embodiment, the dielectric 50 is made of a resin material, and as an example, it is made of epoxy resin (e.g., glass epoxy resin). The dielectric 50 has insulating properties. The color of the dielectric 50 can be any color, such as black.

[0059] The dielectric refractive index n2, which is the refractive index (absolute refractive index) of the dielectric 50, is lower than the element refractive index n1. For example, the dielectric refractive index n2 is 1.55. The dielectric 50 may have a single-layer structure or a multi-layer structure. In other words, one or more interfaces may be formed within the dielectric 50.

[0060] 3 to 5, the dielectric 50 surrounds each of the multiple terahertz elements 20. In this embodiment, the dielectric 50 surrounds the entirety of each of the terahertz elements 20A, 20B, and 20C, and covers the element main surface 21, element back surface 22, and element side surfaces 23 to 26 (see FIG. 6) of each of the terahertz elements 20A, 20B, and 20C.

[0061] The element main surface 21, element back surface 22, and element side surfaces 23 to 26 of each of the terahertz elements 20A, 20B, and 20C are in contact with the dielectric 50. That is, the dielectric 50 of this embodiment surrounds each of the terahertz elements 20A, 20B, and 20C so that no gap is generated between the dielectric 50 and each of the terahertz elements 20A, 20B, and 20C. In other words, the dielectric 50 seals each of the terahertz elements 20A, 20B, and 20C.

[0062] The dielectric 50 is formed in the shape of a plate with its thickness direction in the z direction, for example. Specifically, as shown in Fig. 3, the dielectric 50 is in the shape of a rectangular plate with its length direction in the y direction and its width direction in the x direction.

[0063] As shown in Figures 4 and 5, the dielectric 50 has a dielectric principal surface 51 and a dielectric back surface 52 that intersect with the z direction. The dielectric principal surface 51 and the dielectric back surface 52 are each perpendicular to the z direction, for example. The dielectric principal surface 51 faces downward. The dielectric back surface 52 is the surface opposite to the dielectric principal surface 51 and faces upward. In this embodiment, the dielectric back surface 52 constitutes the device principal surface 11.

[0064] 3, the dielectric 50 has a first dielectric side surface 53 and a second dielectric side surface 54, which are both end surfaces in the x direction, and a third dielectric side surface 55 and a fourth dielectric side surface 56, which are both end surfaces in the y direction. Each of the dielectric side surfaces 53 to 56 constitutes a part of the device side surfaces 13 to 16. In this embodiment, the first dielectric side surface 53 and the second dielectric side surface 54 are perpendicular to the third dielectric side surface 55 and the fourth dielectric side surface 56.

[0065] As shown in FIGS. 4 and 5, the terahertz element 20 is provided in the dielectric 50 with the element main surface 21 facing the dielectric main surface 51. The terahertz element 20 is disposed between the dielectric main surface 51 and the dielectric back surface 52. In this embodiment, the dielectric thickness D2, which is the length of the dielectric 50 in the z direction, is set so as to satisfy the resonance condition of the electromagnetic wave received by the terahertz element 20. More specifically, the dielectric thickness D2 is determined by the following equation: (λ' R / 2)+(λ′ R / 2) × N (N is an integer equal to or greater than 0: N = 0, 1, 2, . . .). R is the effective wavelength of the electromagnetic wave propagating through the dielectric 50, and is, for example, (1 / n2) × (c / fc). Note that the dielectric thickness D2 can also be said to be the distance between the dielectric main surface 51 and the dielectric back surface 52 in the z direction.

[0066] In this embodiment, the dielectric 50 and the antenna base 70 are separate bodies. In other words, the dielectric 50 and the antenna base 70 are formed separately. The antenna base 70 may be made of the same material as the dielectric 50, or may be made of a different material.

[0067] 4 and 5, the antenna base 70 is provided on the dielectric main surface 51 side of the dielectric 50. The antenna base 70 is provided at a position facing the dielectric 50 in the z direction. The z direction can also be said to be the facing direction between the antenna base 70 and the dielectric 50.

[0068] Here, the dielectric 50 has protrusions 61 and 62 that protrude laterally beyond the antenna base 70 when viewed from the z direction. Specifically, the dielectric 50 of this embodiment is formed to be longer in the x direction than the antenna base 70. Therefore, the protrusions 61 and 62 protrude on both sides in the x direction relative to the antenna base 70. When viewed from the z direction, the protrusions 61 and 62 are provided on both sides in the x direction relative to the antenna base 70, and are spaced apart in the x direction. The terahertz element 20 is disposed between the protrusions 61 and 62.

[0069] In this embodiment, the length of the dielectric 50 in the y direction is set to be the same as the length of the antenna base 70 in the y direction. That is, the dielectric 50 does not protrude in the y direction relative to the antenna base 70. In addition, the length of the antenna base 70 in the z direction is set to be longer than the dielectric thickness D2.

[0070] Next, the antenna base 70 will be described. 9, the antenna base 70 of this embodiment has, for example, an elongated rectangular parallelepiped shape as a whole. The longitudinal direction of the antenna base 70 is the same as the longitudinal direction of the terahertz device 10, and the lateral direction of the antenna base 70 is the same as the lateral direction of the terahertz device 10.

[0071] The antenna base 70 is formed of, for example, an insulating material. Specifically, the antenna base 70 is formed of a dielectric material, for example, a synthetic resin such as epoxy resin. An example of the epoxy resin is glass epoxy resin. However, the material of the antenna base 70 is not limited to this and may be any material, such as Si, Teflon (registered trademark), or glass. The color of the antenna base 70 may be any color, such as black.

[0072] The antenna base 70 has a base main surface 71T, a base back surface 72T opposite the base main surface 71T, and four base side surfaces 73T to 76T. The base main surface 71T and the base back surface 72T are each an elongated rectangle with a longitudinal direction and a lateral direction that are perpendicular to each other. In this embodiment, the antenna base 70 is arranged such that the longitudinal direction of the base main surface 71T and the base back surface 72T is aligned with the y direction and the lateral direction is aligned with the x direction. Here, the four base side surfaces 73T to 76T may be referred to as a first base side surface 73T, a second base side surface 74T, a third base side surface 75T, and a fourth base side surface 76T.

[0073] The base main surface 71T and the base back surface 72T are each surfaces that intersect with the z direction, and in this embodiment, are perpendicular to the z direction. The base back surface 72T is a surface that faces the opposite side to the base main surface 71T in the z direction. As shown in FIGS. 4 and 5 , the base main surface 71T faces the same side as the device main surface 11, and the base back surface 72T faces the same side as the device back surface 12. The base main surface 71T faces the dielectric main surface 51. The base back surface 72T constitutes the device back surface 12. In this embodiment, the base main surface 71T and the base back surface 72T have, for example, the same shape. However, this is not limited thereto, and the base main surface 71T and the base back surface 72T may have different shapes.

[0074] As shown in FIGS. 4 and 5, the dielectric 50 is placed on the base principal surface 71T. In other words, the base principal surface 71T is the surface facing the dielectric principal surface 51 of the dielectric 50, and can also be said to be the surface on which the dielectric 50 is placed. The base principal surface 71T is formed smaller in the x direction than the dielectric principal surface 51. Therefore, a portion of the dielectric principal surface 51 protrudes in the x direction beyond the base principal surface 71T. Meanwhile, the length in the y direction of the base principal surface 71T and the length in the y direction of the dielectric principal surface 51 are set to be the same.

[0075] The first base side surface 73T and the second base side surface 74T are both end surfaces in the x direction. The first base side surface 73T and the second base side surface 74T are surfaces that intersect with the x direction, and in this embodiment, are perpendicular to the x direction.

[0076] The first base side surface 73T constitutes the first device side surface 13. Specifically, the first device side surface 13 is constituted by the first dielectric side surface 53 and the first base side surface 73T. The first dielectric side surface 53 is disposed laterally of the first base side surface 73T, in other words, in a direction away from the terahertz element 20. Therefore, the first device side surface 13 has a stepped shape, and a part of the dielectric principal surface 51 is exposed as a stepped surface between the first dielectric side surface 53 and the first base side surface 73T. That is, the dielectric principal surface 51 has a first protruding surface 51a that protrudes laterally from the antenna base 70 (in other words, the first base side surface 73T). The first protruding surface 51a is a portion of the dielectric principal surface 51 that corresponds to the first protrusion 61.

[0077] The second base side surface 74T constitutes the second device side surface 14. Specifically, the second device side surface 14 is constituted by the second dielectric side surface 54 and the second base side surface 74T. The second dielectric side surface 54 is disposed laterally of the second base side surface 74T, in other words, in a direction away from the terahertz element 20. Therefore, the second device side surface 14 has a stepped shape, and a part of the dielectric principal surface 51 is exposed as a stepped surface between the second dielectric side surface 54 and the second base side surface 74T. That is, the dielectric principal surface 51 has a second protruding surface 51b that protrudes laterally from the antenna base 70 (in other words, the second base side surface 74T). The second protruding surface 51b is a portion of the dielectric principal surface 51 that corresponds to the second protrusion 62.

[0078] 9 and 10, the third base side surface 75T and the fourth base side surface 76T are both end surfaces in the y direction. The third base side surface 75T and the fourth base side surface 76T are surfaces that intersect with the y direction and are perpendicular to the y direction in this embodiment.

[0079] As shown in FIG. 12, the third base side surface 75T constitutes the third device side surface 15. Specifically, the third device side surface 15 is constituted by the third dielectric side surface 55 and the third base side surface 75T. In this embodiment, the third dielectric side surface 55 and the third base side surface 75T are flush with each other. Therefore, the third device side surface 15 is a flat surface with no steps formed thereon.

[0080] The fourth base side surface 76T constitutes the fourth device side surface 16. Specifically, the fourth device side surface 16 is constituted by the fourth dielectric side surface 56 and the fourth base side surface 76T. In this embodiment, the fourth dielectric side surface 56 and the fourth base side surface 76T are flush with each other. Therefore, the fourth device side surface 16 is a flat surface with no steps formed thereon.

[0081] As shown in Figures 9 and 10, the antenna base 70 is formed by combining a plurality of individual antenna bases. The antenna base 70 of this embodiment is formed by combining three individual antenna bases 70A, 70B, and 70C. In this embodiment, as shown in Figures 9 and 10, the individual antenna bases 70A, 70B, and 70C are combined to form a line in the y direction. Also, as shown in Figure 10, the individual antenna base 70A and the individual antenna base 70C have the same configuration, and the individual antenna base 70B has a different configuration from the individual antenna bases 70A and 70C. In other words, the antenna base 70 is formed by combining antenna bases of two different configurations.

[0082] 12, the individual antenna base 70A is arranged to face the terahertz element 20A in the thickness direction (z direction) of the terahertz element 20A. The individual antenna base 70B is arranged to face the terahertz element 20B in the thickness direction (z direction) of the terahertz element 20B. The individual antenna base 70C is arranged to face the terahertz element 20C in the thickness direction (z direction) of the terahertz element 20C. In this embodiment, the individual antenna bases 70A to 70C are arranged below the terahertz elements 20A to 20C.

[0083] As shown in FIG. 9, each of the individual antenna bases 70A to 70C has a base main surface 71 and a base back surface 72 as surfaces that intersect with the z direction. The base main surface 71 and the base back surface 72 are each surfaces that intersect with the z direction and are perpendicular to the z direction in this embodiment. The base main surface 71 and the base back surface 72 are each, for example, rectangular (e.g., square). When the individual antenna bases 70A to 70C are combined, the base main surface 71 and the base back surface 72 of the individual antenna bases 70A to 70C form the base main surface 71T and the base back surface 72T of the antenna base 70. In this embodiment, the base main surface 71 and the base back surface 72 have, for example, the same shape. However, this is not limiting, and the base main surface 71 and the base back surface 72 may have different shapes.

[0084] As shown in FIG. 10, each of the individual antenna bases 70A to 70C has a first base side surface 73, a second base side surface 74, a third base side surface 75, and a fourth base side surface 76. These base side surfaces 73 to 76 are surfaces facing laterally in the terahertz device 10 (antenna base 70). Each of the base side surfaces 73 to 76 is a surface perpendicular to the opposing direction of the base main surface 71 and the base back surface 72. Each of the base side surfaces 73 to 76 connects the base main surface 71 and the base back surface 72 (see FIG. 9). The base side surfaces 73 to 76 of the individual antenna bases 70A to 70C are determined to correspond to the base side surfaces 73T to 76T of the antenna base 70 when the individual antenna bases 70A to 70C are combined. In other words, the individual antenna base 70A and the individual antenna base 70C have the same shape, but the positions of the base side surfaces 73 and 74 are opposite, and the positions of the base side surfaces 75 and 76 are opposite.

[0085] The first base side surface 73 and the second base side surface 74 of each of the individual antenna bases 70A to 70C are the end surfaces in the x direction of the individual antenna bases 70A to 70C, respectively. These first base side surfaces 73 and second base side surfaces 74 are surfaces that intersect with the x direction and are orthogonal to the x direction in this embodiment. The first base side surfaces 73 and second base side surfaces 74 of each of the individual antenna bases 70A to 70C constitute the first base side surfaces 73T and second base side surfaces 74T of the antenna base 70.

[0086] The third base side surface 75 and the fourth base side surface 76 of each of the individual antenna bases 70A to 70C are both end surfaces in the y direction of the individual antenna bases 70A to 70C. Each of the third base side surface 75 and the fourth base side surface 76 is a surface that intersects with the y direction and is perpendicular to the y direction in this embodiment.

[0087] When viewed from the z direction, the individual antenna bases 70A to 70C are rectangular with a longitudinal direction and a lateral direction. The individual antenna bases 70A to 70C are each arranged so that the longitudinal direction is aligned with the x direction and the lateral direction is aligned with the y direction. In this embodiment, the lengths of the individual antenna bases 70A to 70C in the x direction are equal to each other. The length of the individual antenna base 70B in the y direction is shorter than the lengths of the individual antenna bases 70A and 70B in the y direction.

[0088] In this embodiment, the individual antenna bases 70A to 70C are arranged so that the fourth base side surface 76 of the individual antenna base 70A faces the third base side surface 75 of the individual antenna base 70B in the y direction, and the fourth base side surface 76 of the individual antenna base 70B faces the third base side surface 75 of the individual antenna base 70C in the y direction. That is, the third base side surface 75 of the individual antenna base 70A and the fourth base side surface 76 of the individual antenna base 70C form both end surfaces of the antenna base 70 in the y direction. In other words, the third base side surface 75 of the individual antenna base 70A forms the third base side surface 75T of the antenna base 70, and the fourth base side surface 76 of the individual antenna base 70C forms the fourth base side surface 76T of the antenna base 70. In this embodiment, the individual antenna bases 70A and 70B are fixed together, for example, by adhesive, and the individual antenna bases 70B and 70C are fixed together, for example, by adhesive. In other words, the fourth base side surface 76 of the individual antenna base 70A and the third base side surface 75 of the individual antenna base 70B are joined by adhesive, and the fourth base side surface 76 of the individual antenna base 70B and the third base side surface 75 of the individual antenna base 70C are joined by adhesive.

[0089] As shown in FIG. 9, the antenna base 70 has a plurality of antenna recesses 80. In this embodiment, the individual antenna base 70A has the antenna recess 80A, the individual antenna base 70B has the antenna recess 80B, and the individual antenna base 70C has the antenna recess 80C. In other words, the antenna base 70 has one antenna recess 80 for each individual antenna base. As can be seen from FIG. 9, the shapes of the antenna recesses 80A and 80C are different from the shape of the antenna recess 80B. In the following description, the antenna recess 80 will be used to describe matters common to the antenna recesses 80A, 80B, and 80C, that is, when it is not necessary to distinguish between the antenna recesses 80A, 80B, and 80C.

[0090] 4 and 5, the antenna recess 80 is recessed in a direction from the base main surface 71T toward the base back surface 72T, i.e., downward. In other words, the antenna recess 80 can be said to be recessed in a direction away from the base main surface 71T to the dielectric 50 (or the dielectric main surface 51), or in a direction away from the terahertz element 20. As shown in FIGS. 4 and 5, in this embodiment, in a cross-sectional view of the antenna base 70 cut along a plane along the x and z directions, the antenna recess 80 is curved so as to be convex toward the device back surface 12. The antenna recess 80 opens upward.

[0091] As shown in FIGS. 4 and 5, the antenna recess 80 has an antenna surface 81 facing the terahertz element 20 via the dielectric 50 and the gas space 92. In this embodiment, as shown in FIG. 11, the antenna recess 80A has an antenna surface 81A, the antenna recess 80B has an antenna surface 81B, and the antenna recess 80C has an antenna surface 81C. The antenna surfaces 81A to 81C are each formed to correspond to the antenna shape. Specifically, as shown in FIG. 12, the antenna surface 81A is curved so as to be concave in a direction away from the terahertz element 20A, the antenna surface 81B is curved so as to be concave in a direction away from the terahertz element 20B, and the antenna surface 81C is curved so as to be concave in a direction away from the terahertz element 20C. As shown in FIG. 9, the antenna surfaces 81A to 81C are each curved, for example, in a cone shape, and as one example, are curved so as to form part of a parabolic antenna shape. In the following description, matters common to the antenna surfaces 81A to 81C will be described using the antenna surface 81, that is, when it is not necessary to distinguish between the antenna surfaces 81A to 81C.

[0092] 10, the openings of the antenna recesses 80A to 80C are each circular with a portion missing when viewed from above. That is, the openings of the antenna surfaces 81A to 81C are each circular with a portion missing when viewed from above. More specifically, in this embodiment, the openings of the antenna surfaces 81A to 81C are each circular with at least one of both opening ends missing in the arrangement direction of the antenna surfaces 81A to 81C.

[0093] When viewed from above, the opening of the antenna surface 81A is missing an opening end 81Aa near the fourth base side surface 76 of both opening ends in the y direction. When viewed from above, the opening end 81Aa is formed in the same position as the fourth base side surface 76 of the individual antenna base 70A. When viewed from above, the opening end 81Aa is linear and extends along the x direction.

[0094] When viewed from above, the opening of the antenna surface 81B is missing both of its opening ends 81Ba, 81Bb in the y direction. The opening end 81Ba is the end closest to the third base side surface 75 of both ends of the opening of the antenna surface 81B in the y direction, and the opening end 81Bb is the end closest to the fourth base side surface 76 of both ends of the opening of the antenna surface 81B in the y direction. When viewed from above, the opening end 81Ba is formed in the same position as the third base side surface 75 of the individual antenna base 70B, and the opening end 81Bb is formed in the same position as the fourth base side surface 76 of the individual antenna base 70B. When viewed from above, both opening ends 81Ba, 81Bb are linear and extend along the x direction.

[0095] When viewed from above, the opening of the antenna surface 81C is missing an opening end 81Ca near the third base side surface 75 of both opening ends in the y direction. When viewed from above, the opening end 81Ca is formed in the same position as the third base side surface 75 of the individual antenna base 70C. When viewed from above, the opening end 81Ca is linear and extends along the x direction.

[0096] As shown in FIG. 10, when viewed from above, the diameter of antenna surface 81A, the diameter of antenna surface 81B, and the diameter of antenna surface 81C are equal to each other. Opening end 81Aa of antenna surface 81A is connected to opening end 81Ba of antenna surface 81B, and opening end 81Bb of antenna surface 81B is connected to opening end 81Ca of antenna surface 81C. In this embodiment, the length in the x direction of opening end 81Aa is equal to the length in the x direction of opening end 81Ba, and the length in the x direction of opening end 81Bb is equal to the length in the x direction of opening end 81Ca. Furthermore, the length in the x direction of opening end 81Ba and the length in the x direction of opening end 81Bb are equal to each other. In other words, in this embodiment, the length in the x direction of opening end 81Aa and the length in the x direction of opening end 81Ca are equal to each other.

[0097] As shown in FIG. 11 , the opening end 81Aa of the antenna surface 81A is located below the base main surface 71 of the individual antenna base 70A (the base main surface 71T of the antenna base 70). In the z direction, the opening end 81Aa of the antenna surface 81A is aligned with the opening end 81Ba of the antenna surface 81B. The opening end 81Ca of the antenna surface 81C is located below the base main surface 71 of the individual antenna base 70C (the base main surface 71T of the antenna base 70). In the z direction, the opening end 81Ca of the antenna surface 81C is aligned with the opening end 81Bb of the antenna surface 81B. Furthermore, in the z direction, the opening end 81Ba of the antenna surface 81B is aligned with the opening end 81Bb. That is, in the z direction, the opening end 81Aa of the antenna surface 81A is aligned with the opening end 81Ca of the antenna surface 81C.

[0098] Next, the reflective film 82 will be described. The reflective film 82 reflects the electromagnetic waves propagated to the antenna recess 80 toward the terahertz element 20 corresponding to the antenna recess 80 .

[0099] As shown in FIG. 11 , the reflective film 82 is formed on the antenna surface 81. The reflective film 82 is made of a material that reflects electromagnetic waves, for example, a metal such as Cu or an alloy. The reflective film 82 may have a single-layer structure or a multi-layer structure. In this embodiment, the reflective film 82 is formed over the entire antenna surface 81. On the other hand, the reflective film 82 is not formed on the base main surface 71T.

[0100] In this embodiment, the reflective film 82 has a reflective film 82A formed on the antenna surface 81A, a reflective film 82B formed on the antenna surface 81B, and a reflective film 82C formed on the antenna surface 81C. In this embodiment, the reflective films 82A to 82C are an integrally formed single component. In the following explanation, the reflective film 82 will be used to explain matters common to the reflective films 82A to 82C, that is, when it is not necessary to distinguish between the reflective films 82A to 82C.

[0101] In this embodiment, the reflective film 82 is formed on the antenna surface 81, and therefore the reflective film 82 has substantially the same shape as the antenna surface 81. That is, the reflective film 82A has substantially the same shape as the antenna surface 81A, the reflective film 82B has substantially the same shape as the antenna surface 81B, and the reflective film 82C has substantially the same shape as the antenna surface 81C. In other words, the reflective films 82A to 82C are each a parabolic mirror of revolution, and are curved in a cone shape. In this embodiment, the surface of the reflective film 82A opposite to the surface that contacts the antenna surface 81A, i.e., the surface of the reflective film 82A facing the terahertz element 20A, corresponds to the "first reflective surface." The surface of the reflective film 82B opposite to the surface that contacts the antenna surface 81B, i.e., the surface of the reflective film 82B facing the terahertz element 20B, corresponds to the "second reflective surface." The surface of the reflective film 82C opposite to the surface in contact with the antenna surface 81C, that is, the surface of the reflective film 82C facing the terahertz element 20C, corresponds to the "third reflective surface."

[0102] The reflective films 82A to 82C are each curved so as to be convex toward the rear surface 12 of the device (the rear surface 72 of the individual antenna bases 70A to 70C). Each of the reflective films 82A to 82C is open in one direction (upward in this embodiment).

[0103] 12, the reflective film 82 and the dielectric 50 face each other in the z direction. In other words, the reflective film 82 is provided at a position facing the dielectric 50. The electromagnetic waves reflected by the reflective film 82 are output toward the reception point P1. Specifically, the electromagnetic waves reflected by the reflective film 82A are output toward the reception point P1 of the terahertz element 20A. The electromagnetic waves reflected by the reflective film 82B are output toward the reception point P1 of the terahertz element 20B. The electromagnetic waves reflected by the reflective film 82C are output toward the reception point P1 of the terahertz element 20C.

[0104] The reflective film 82 is disposed on the element principal surface 21 side where the reception point P1 is present, rather than on the element rear surface 22, and faces the terahertz element 20 (the element principal surface 21 in this embodiment). In other words, the terahertz element 20 is disposed in the dielectric 50 with the element principal surface 21 facing the reflective film 82. Note that, when attention is paid to the positional relationship between the pads 33a, 34a and the reflective film 82, it can also be said that the pads 33a, 34a face the reflective film 82.

[0105] The reflective film 82 is disposed such that the focal point of the reflective film 82 is at a reception point P1. More specifically, as shown in FIG. 12, the plurality of terahertz elements 20 are disposed corresponding to the antenna surfaces 81A to 81C (reflective films 82A to 82C). The terahertz element 20A is disposed corresponding to the antenna surface 81A (reflective film 82A), the terahertz element 20B is disposed corresponding to the antenna surface 81B (reflective film 82B), and the terahertz element 20C is disposed corresponding to the antenna surface 81C (reflective film 82C). In this case, the reflective film 82A is disposed such that the focal point of the reflective film 82A is at a reception point P1 of the terahertz element 20A. The reflective film 82B is disposed such that the focal point of the reflective film 82B is at a reception point P1 of the terahertz element 20B. The reflective film 82C is disposed such that the focal point of the reflective film 82C is at a reception point P1 of the terahertz element 20C. In this embodiment, when viewed from the z direction, the center point P2 of the reflective film 82A and the reception point P1 of the terahertz element 20A coincide with each other, the center point P2 of the reflective film 82B and the reception point P1 of the terahertz element 20B coincide with each other, and the center point P2 of the reflective film 82C and the reception point P1 of the terahertz element 20C coincide with each other. In this embodiment, since the reception points P1 of the terahertz elements 20A to 20C are aligned in the z direction, the center points P2 of the reflective films 82A to 82C are aligned in the z direction.

[0106] Furthermore, if the vertical distance from the reception point P1 to the reflective film 82 is a specified distance z1, the z-coordinate of the reflective film 82 is Z, and the position of the reflective film 82 in the x-direction is X, then Z=(1 / (4z1))X 2It is preferable that the reflective film 82 be curved so as to satisfy the condition above. Note that X is set to "0" at the center point P2. The same applies to the position of the reflective film 82 in the y direction. However, the curvature of the reflective film 82 is not limited to this and can be changed as desired.

[0107] The z direction can also be said to be the opposing direction between the reflective film 82 and the terahertz element 20 (element principal surface 21). The z direction can also be said to be the opposing direction between the center point P2 of the reflective film 82 and the receiving point P1. The specified distance z1 can also be said to be the distance between the receiving point P1 and the position of the reflective film 82 that corresponds to the center point P2.

[0108] Furthermore, the reflective film 82 may be disposed at a position corresponding to the frequency of the electromagnetic wave so as to resonate with the electromagnetic wave received by the terahertz element 20. Specifically, the specified distance z1 may be set so as to satisfy the resonance condition of the electromagnetic wave received by the terahertz element 20.

[0109] 10, when viewed from above, the openings of the reflective films 82A to 82C have the same shape as the openings of the antenna surfaces 81A to 81C. That is, when viewed from above, the openings of the reflective films 82A to 82C have a circular shape with at least one of both opening edges of the reflective films 82A to 82C missing in the arrangement direction of the reflective films 82A to 82C.

[0110] When viewed from above, the opening of the reflective film 82A is missing an opening edge 82Aa at a position that overlaps with an opening edge 81Aa of the antenna surface 81 A. When viewed from above, the opening edge 82Aa is linear and extends along the x direction.

[0111] When viewed from above, the opening of the reflective film 82B is missing opening edges 82Ba and 82Bb at positions that overlap with opening edges 81Ba and 81Bb of the antenna surface 81B. When viewed from above, both opening edges 82Ba and 82Bb are linear and extend along the x direction.

[0112] When viewed from above, the opening of the reflective film 82C has an opening edge 82Ca missing at a position that overlaps with the opening edge 81Ca of the antenna surface 81C. When viewed from above, the opening edge 82Ca is linear and extends along the x direction.

[0113] Similar to the antenna surfaces 81A to 81C, the diameter of the reflective film 82A, the diameter of the reflective film 82B, and the diameter of the reflective film 82C are all equal when viewed from above. Opening end 82Aa of reflective film 82A is connected to opening end 82Ba of reflective film 82B, and opening end 82Bb of reflective film 82B is connected to opening end 82Ca of reflective film 82C. In this embodiment, the length in the x direction of opening end 82Aa is equal to the length in the x direction of opening end 82Ba. Furthermore, the length in the x direction of opening end 82Ba is equal to the length in the x direction of opening end 82Ca. Furthermore, the length in the x direction of opening end 82Ba is equal to the length in the x direction of opening end 82Bb. In other words, in this embodiment, the length in the x direction of opening end 81Aa is equal to the length in the x direction of opening end 82Ca.

[0114] As shown in FIG. 11 , the opening end 82Aa of the reflective film 82A is located below the base main surface 71 of the individual antenna base 70A (the base main surface 71T of the antenna base 70). The position of the opening end 82Aa of the reflective film 82A in the z direction is aligned with the position of the opening end 82Ba of the reflective film 82B in the z direction. The opening end 82Ca of the reflective film 82C is located below the base main surface 71 of the individual antenna base 70C (the base main surface 71T of the antenna base 70). In the z direction, the opening end 82Ca of the reflective film 82C is aligned with the opening end 82Bb of the reflective film 82B. Furthermore, in the z direction, the opening end 82Ba of the reflective film 82B is aligned with the opening end 82Bb. That is, in the z direction, the opening end 82Aa of the reflective film 82A is aligned with the opening end 82Ca of the reflective film 82C.

[0115] As shown in FIG. 10 , when viewed from above, the reflective film 82A is formed so that its center point P2 is at a position different from the center of the individual antenna base 70A. In this embodiment, when viewed from above, the center point P2 of the reflective film 82A is the center of the circular reflective film 82A with a portion missing, and coincides with the center point of the antenna surface 81A. More specifically, when viewed from above, the reflective film 82A is formed so that its center point P2 is at the center of the individual antenna base 70A in the x direction. When viewed from above, the reflective film 82A is formed so that its center point P2 is closer to the fourth base side surface 76 of the individual antenna base 70A in the y direction. In other words, when viewed from above, the center point P2 of the reflective film 82A is located closer to the individual antenna base 70B than the center of the individual antenna base 70A in the y direction.

[0116] When viewed from above, the center point P2 of the reflective film 82A coincides with the center point of the antenna surface 81A, and the shape of the reflective film 82A and the shape of the antenna surface 81A are approximately identical, so when viewed from above, the antenna surface 81A is formed so that the center point of the antenna surface 81A is at a position different from the center of the individual antenna base 70A, just like the reflective film 82A.

[0117] When viewed from above, the arc-shaped outer periphery of the reflective film 82A, at a portion connecting both end edges in a first direction (the y direction in this embodiment), which is the direction in which the reflective films 82A to 82C are arranged, has an arc-shaped central angle of less than 180°. Here, the first direction is a direction intersecting with the height direction (the z direction) of the terahertz device 10. In this embodiment, the first direction is a direction perpendicular to the height direction of the terahertz device 10. In this embodiment, the arc-shaped outer periphery of the reflective film 82A, at a portion connecting the end edge near the third base side surface 75 in the y direction and the end edge of the opening end 82Aa that is closer to the first base side surface 73 in the x direction, has an arc-shaped central angle θa1 of less than 180°. The portion of the arc-shaped outer periphery of the reflective film 82A that connects the edge near the third base side surface 75 in the y direction with one of the two end edges of the opening end 82Aa in the x direction that is closer to the second base side surface 74 has an arc-like central angle θa2 of less than 180°. The central angles θa1 and θa2 are equal to each other. Because the reflective film 82A and the antenna surface 81A have substantially the same shape when viewed from above, similar to the reflective film 82A, the portion of the arc-shaped outer periphery of the antenna surface 81A that connects the two end edges in the first direction, which is the direction in which the antenna surfaces 81A to 81C are arranged, has an arc-like central angle of less than 180°.

[0118] When viewed from above, the size of the reflective film 82A along a first direction, which is the direction in which the reflective films 82A to 82C are arranged, is smaller than the size of the reflective film 82A along a second direction different from the first direction. More specifically, when viewed from above, the length of the reflective film 82A passing through the center point P2 in the first direction (the y direction in this embodiment) is shorter than the length of the reflective film 82A passing through the center point P2 in the second direction. Here, the second direction is, for example, a direction perpendicular to the first direction when viewed from above (the x direction in this embodiment). In this embodiment, when viewed from above, the length LAY of the reflective film 82A in the y direction passing through the center point P2 is shorter than the length LAX of the reflective film 82A in the y direction passing through the center point P2. Here, the length LAX of the reflective film 82A passing through the center point P2 can also be said to be the diameter of the reflective film 82A when viewed from above.

[0119] Because the reflective film 82A and the antenna surface 81A have substantially the same shape when viewed from above, the relationship between the length of the antenna surface 81A in the x direction and the length of the antenna surface 81A in the y direction is the same as the relationship between the lengths of the reflective film 82A described above. That is, when viewed from above, the length of the antenna surface 81A passing through the center point of the antenna surface 81A in a first direction, which is the direction in which the antenna surfaces 81A to 81C are arranged, is shorter than the length of the antenna surface 81A passing through the center point of the antenna surface 81A in a second direction different from the first direction. Here, the second direction is, for example, a direction perpendicular to the first direction when viewed from above (the x direction in this embodiment). In this case, the length of the antenna surface 81A passing through the center point of the antenna surface 81A in the second direction can also be considered the diameter of the antenna surface 81A when viewed from above.

[0120] 11, in a cross-sectional view of the individual antenna base 70A taken along a plane that passes through the center point P2 of the reflective film 82A and is aligned with the y and z directions, the portion connecting both end edges of the reflective film 82A is formed into an arc shape with a central angle θz1 of less than 180°. Similarly, in a cross-sectional view of the individual antenna base 70A taken along a plane that passes through the center point of the antenna surface 81A and is aligned with the y and z directions, the portion connecting both end edges of the antenna surface 81A is formed into an arc shape with a central angle of less than 180°.

[0121] 10, when viewed from above, the reflective film 82B is formed so that its center point P2 is aligned with the center of the individual antenna base 70B. In this embodiment, the center point P2 of the reflective film 82B is the center of the partially missing circular reflective film 82B when viewed from above, and coincides with the center point of the antenna surface 81B.

[0122] When viewed from above, the center point P2 of the reflective film 82B coincides with the center point of the antenna surface 81B, and the shape of the reflective film 82B and the shape of the antenna surface 81B are approximately identical, so when viewed from above, the antenna surface 81B is formed so that the center point of the antenna surface 81B is aligned with the center of the individual antenna base 70B, just like the reflective film 82B.

[0123] When viewed from above, a portion of the arc-shaped outer periphery of the reflective film 82B connecting both end edges in a first direction (the y direction in this embodiment), which is the direction in which the reflective films 82A to 82C are arranged, has an arc shape with a central angle of less than 180°. In this embodiment, a portion of the arc-shaped outer periphery of the reflective film 82B connecting one of both end edges of the opening end 82Ba in the x direction that is closer to the first base side surface 73 and one of both end edges of the opening end 82Bb in the x direction that is closer to the first base side surface 73 has an arc shape with a central angle θb1 of less than 180°. A portion of the arc-shaped outer periphery of the reflective film 82B connecting one of both end edges of the opening end 82Ba in the x direction that is closer to the second base side surface 74 and one of both end edges of the opening end 82Bb in the x direction that is closer to the second base side surface 74 has an arc shape with a central angle θb2 of less than 180°. The central angles θb1 and θb2 are equal to each other. Furthermore, the central angles θb1 and θb2 are smaller than the central angles θa1 and θa2. Because the reflective film 82B and the antenna surface 81B have substantially the same shape when viewed from above, the arc-shaped outer edge of the antenna surface 81A, in the first direction (the y direction in this embodiment), in which the antenna surfaces 81A to 81C are arranged, has an arc shape with a central angle of less than 180°, similar to the reflective film 82B.

[0124] When viewed from above, the size of the reflective film 82B along a first direction, which is the direction in which the reflective films 82A to 82C are arranged, is smaller than the size of the reflective film 82B along a second direction, which is a direction different from the first direction. More specifically, when viewed from above, the length of the reflective film 82B passing through the center point P2 in the first direction (the y direction in this embodiment) is shorter than the length of the reflective film 82B passing through the center point P2 in the second direction. Here, the second direction is, for example, a direction perpendicular to the first direction when viewed from above (the x direction in this embodiment). In this embodiment, when viewed from above, the length LBY of the reflective film 82B passing through the center point P2 in the y direction is shorter than the length LBX of the reflective film 82B passing through the center point P2 in the y direction. Here, the length LBX of the reflective film 82B passing through the center point P2 can also be said to be the diameter of the reflective film 82A when viewed from above. That is, when viewed from above, the length LBX of the reflective film 82B passing through the center point P2 is equal to the length LAX of the reflective film 82A passing through the center point P2.

[0125] Because the reflective film 82B and the antenna surface 81B have substantially the same shape when viewed from above, the relationship between the length of the antenna surface 81B in the x direction and the length of the antenna surface 81B in the y direction is the same as the relationship between the lengths of the reflective film 82B described above. That is, when viewed from above, the length of the antenna surface 81B passing through the center point of the antenna surface 81B in a first direction (the y direction in this embodiment), which is the direction in which the antenna surfaces 81A to 81C are arranged, is shorter than the length of the antenna surface 81B passing through the center point of the antenna surface 81B in a second direction different from the first direction. Here, the second direction is, for example, a direction perpendicular to the first direction when viewed from above (the x direction in this embodiment). In this case, the length of the antenna surface 81B passing through the center point of the antenna surface 81B in the second direction can also be considered the diameter of the antenna surface 81B when viewed from above. That is, when viewed from above, the length of the antenna surface 81B passing through the center point of the antenna surface 81B in the second direction is equal to the length of the antenna surface 81A passing through the center point of the antenna surface 81A in the second direction.

[0126] 11 , in a cross-sectional view of the individual antenna base 70B taken along a plane that passes through the center point P2 of the reflective film 82B and that is aligned with the y and z directions, the portion connecting both end edges of the reflective film 82B is formed into an arc shape with a central angle θz2 of less than 180°. In this embodiment, the central angle θz2 is smaller than the central angle θz1 of the reflective film 82A. Similarly, in a cross-sectional view of the individual antenna base 70B taken along a plane that passes through the center point of the antenna surface 81B and that is aligned with the y and z directions, the portion connecting both end edges of the antenna surface 81B is formed into an arc shape with a central angle of less than 180°.

[0127] As shown in FIG. 10 , when viewed from above, the reflective film 82C is formed so that its center point P2 is at a position different from the center of the individual antenna base 70C. In this embodiment, when viewed from above, the center point P2 of the reflective film 82C is the center of the circular reflective film 82C with a missing portion, and coincides with the center point of the antenna surface 81C. More specifically, when viewed from above, the reflective film 82C is formed so that its center point P2 is at the center of the individual antenna base 70C in the x direction. When viewed from above, the reflective film 82C is formed so that its center point P2 is closer to the third base side surface 75 of the individual antenna base 70C in the y direction. In other words, when viewed from above, the center point P2 of the reflective film 82C is located closer to the individual antenna base 70B than the center of the individual antenna base 70C in the y direction.

[0128] When viewed from above, the center point P2 of the reflective film 82C coincides with the center point of the antenna surface 81C, and the shape of the reflective film 82C and the shape of the antenna surface 81C are approximately identical, so when viewed from above, the antenna surface 81C is formed so that the center point of the antenna surface 81C is at a position different from the center of the individual antenna base 70C, just like the reflective film 82C.

[0129] When viewed from above, the arc-shaped outer periphery of the reflective film 82C, at a portion connecting both end edges in a first direction (the y direction in this embodiment), which is the direction in which the reflective films 82A to 82C are arranged, has an arc-shaped central angle of less than 180°. In this embodiment, the arc-shaped outer periphery of the reflective film 82C, at a portion connecting the end edge near the fourth base side surface 76 in the y direction with one of both end edges of the opening end 82Ca in the x direction that is closer to the first base side surface 73, has an arc-shaped central angle θc1 of less than 180°. The arc-shaped outer periphery of the reflective film 82C, at a portion connecting the end edge near the fourth base side surface 76 in the y direction with one of both end edges of the opening end 82Ca in the x direction that is closer to the second base side surface 74, has an arc-shaped central angle θc2 of less than 180°. The central angles θc1 and θc2 are equal to each other. In this embodiment, the central angles θc1 and θc2 are equal to the central angles θa1 and θa2 of the reflective film 82A. Because the reflective film 82C and the antenna surface 81C have substantially the same shape when viewed from above, similar to the reflective film 82C, the portion of the arc-shaped outer edge of the antenna surface 81C that connects both end edges in the first direction (the y direction in this embodiment), which is the direction in which the antenna surfaces 81A to 81C are arranged, has an arc shape with a central angle of less than 180°.

[0130] When viewed from above, the size of the reflective film 82C along a first direction, which is the direction in which the reflective films 82A to 82C are arranged, is smaller than the size of the reflective film 82B along a second direction different from the first direction. More specifically, when viewed from above, the length of the reflective film 82C passing through the center point P2 in the first direction is shorter than the length of the reflective film 82C passing through the center point P2 in the second direction. Here, the second direction is, for example, a direction perpendicular to the first direction when viewed from above (the x direction in this embodiment). In this embodiment, when viewed from above, the length LCY of the reflective film 82C passing through the center point P2 in the y direction is shorter than the length LCX of the reflective film 82C passing through the center point P2 in the x direction. Here, the length LCX of the reflective film 82C passing through the center point P2 can also be considered the diameter of the reflective film 82C when viewed from above. In other words, the length LCX of the reflective film 82C passing through the center point P2 is equal to the length LAX of the reflective film 82A passing through the center point P2. Furthermore, the length LCY of the reflective film 82C is longer than the length LBY of the reflective film 82B. That is, the length LBY of the reflective film 82B is shorter than both the length LAY of the reflective film 82A and the length LCY of the reflective film 82B.

[0131] In this way, the lengths LAY to LCY of the reflective films 82A to 82C are shorter than the lengths LAX to LCX of the reflective films 82A to 82C. For this reason, it can be said that the size of the reflective films 82A to 82C along the first direction is smaller than the size of the reflective films 82A to 82C along the second direction.

[0132] Because the reflective film 82C and the antenna surface 81C have substantially the same shape when viewed from above, the relationship between the length of the antenna surface 81C in the x direction and the length of the antenna surface 81C in the y direction is the same as the relationship between the lengths of the reflective film 82C described above. That is, when viewed from above, the length of the antenna surface 81C passing through the center point of the antenna surface 81C in a first direction (the y direction in this embodiment), which is the direction in which the antenna surfaces 81A to 81C are arranged, is shorter than the length of the antenna surface 81C passing through the center point of the antenna surface 81C in a second direction different from the first direction. Here, the second direction is, for example, a direction perpendicular to the first direction when viewed from above (the x direction in this embodiment). In this case, the length of the antenna surface 81C passing through the center point of the antenna surface 81C in the second direction can also be considered the diameter of the antenna surface 81C when viewed from above. That is, the length of the antenna surface 81C passing through the center point of the antenna surface 81C in the second direction is equal to the length of the antenna surface 81A passing through the center point of the antenna surface 81A in the second direction.

[0133] 11 , in a cross-sectional view of the individual antenna base 70C taken along a plane that passes through the center point P2 of the reflective film 82C and is aligned with the y and z directions, the portion connecting both end edges of the reflective film 82C is formed into an arc shape with a central angle θz3 of less than 180°. In this embodiment, the central angle θz3 is equal to the central angle θz1 of the individual antenna base 70A. Similarly, in a cross-sectional view of the individual antenna base 70C taken along a plane that passes through the center point of the antenna surface 81C and is aligned with the y and z directions, the portion connecting both end edges of the antenna surface 81C is formed into an arc shape with a central angle of less than 180°.

[0134] 3 and 12, the reflective film 82A is formed to be larger than the terahertz element 20A when viewed from the z direction. Specifically, the reflective film 82A is formed to be larger than the terahertz element 20A in both the x direction and the y direction. The length LAX of the reflective film 82A is set to be longer than the length of the terahertz element 20A in the x direction, and the length LAY of the reflective film 82A is set to be longer than the length of the terahertz element 20A in the y direction.

[0135] The reflective film 82B is formed to be larger than the terahertz element 20B when viewed from the z direction. Specifically, the reflective film 82B is formed to be larger than the terahertz element 20B in both the x direction and the y direction. The length LBX of the reflective film 82B is set to be longer than the length of the terahertz element 20B in the x direction, and the length LBY of the reflective film 82B is set to be longer than the length of the terahertz element 20B in the y direction.

[0136] The reflective film 82C is formed to be larger than the terahertz element 20C when viewed from the z direction. Specifically, the reflective film 82C is formed to be larger than the terahertz element 20C in both the x direction and the y direction. The length LCX of the reflective film 82C is set to be longer than the length of the terahertz element 20C in the x direction, and the length LCY of the reflective film 82C is set to be longer than the length of the terahertz element 20C in the y direction.

[0137] 10, when viewed from above, the individual antenna base 70A has a peripheral wall 78A that surrounds the opening of the antenna recess 80A except for the missing portions that contact the antenna recess 80B. When viewed from above, the individual antenna base 70B has a peripheral wall 78B that surrounds the opening of the antenna recess 80B except for the missing portions that contact the antenna recesses 80A and 80C. When viewed from above, the individual antenna base 70C has a peripheral wall 78C that surrounds the opening of the antenna recess 80C except for the missing portions that contact the antenna recess 80B.

[0138] 3, inter-element distance DE1, which is the distance in the y direction between reception point P1 of terahertz element 20A and reception point P1 of terahertz element 20B, is smaller than lengths LAX and LBX, which are diameters along the x direction on antenna surfaces 81A and 81B. Also, inter-element distance DE2, which is the distance in the y direction between reception point P1 of terahertz element 20B and reception point P1 of terahertz element 20C, is smaller than lengths LBX and LCX, which are diameters along the x direction on antenna surfaces 81B and 81C.

[0139] As shown in FIGS. 4, 5, and 12, in this embodiment, the antenna base 70 and the dielectric 50 are separate bodies that are assembled and fixed in the z direction. Specifically, the terahertz device 10 includes an adhesive layer 91 as a fixing portion that fixes the dielectric 50 and the antenna base 70. The adhesive layer 91 is formed of, for example, an insulating material, such as a resin-based adhesive. The adhesive layer 91 is provided between the base main surface 71T and the dielectric main surface 51, and is provided along the periphery of the opening of the antenna recess 80A, the periphery of the opening of the antenna recess 80B, and the periphery of the opening of the antenna recess 80C.

[0140] The adhesive layer 91 bonds and fixes the dielectric 50 and the antenna base 70 together. That is, the dielectric 50 and the antenna base 70 are assembled from the z direction via the adhesive layer 91. This unitizes the dielectric 50 and the antenna base 70. As a result, the adhesive layer 91 restricts misalignment between the dielectric 50 and the antenna base 70 in a direction perpendicular to the z direction, making it difficult for the relative positions of the terahertz elements 20A, 20B, and 20C in the dielectric 50 and the reflective films 82A, 82B, and 82C of the antenna base 70 to shift.

[0141] In particular, in this embodiment, the inner peripheral edge of the adhesive layer 91 is disposed in a position flush with the surface of the reflective film 82, and is formed across the base main surface 71T and the edge of the reflective film 82. In other words, the adhesive layer 91 is configured not to protrude inward beyond the reflective film 82 (in other words, toward the terahertz element 20).

[0142] The inner peripheral end of the adhesive layer 91 can be considered to be the end of the adhesive layer 91 on the terahertz element 20 side. In other words, the inner peripheral end of the adhesive layer 91 formed on the base main surface 71 of the individual antenna base 70A can be considered to be the end of the adhesive layer 91 on the terahertz element 20A side. This inner peripheral end of the adhesive layer 91 has a circular shape with a portion missing when viewed from the z direction, corresponding to, for example, the antenna recess 80A. The inner peripheral end of the adhesive layer 91 formed on the base main surface 71 of the individual antenna base 70B can be considered to be the end of the adhesive layer 91 on the terahertz element 20B side. This inner peripheral end of the adhesive layer 91 has a circular shape with a portion missing when viewed from the z direction, corresponding to, for example, the antenna recess 80B. The inner peripheral end of the adhesive layer 91 formed on the base main surface 71 of the individual antenna base 70C can be considered to be the end of the adhesive layer 91 on the terahertz element 20C side. This inner peripheral end of the adhesive layer 91 has a circular shape with a portion missing when viewed from the z direction, corresponding to, for example, the antenna recess 80C. However, the shape of the inner peripheral edge of the adhesive layer 91 can be changed arbitrarily.

[0143] Next, the gas space 92 will be described. As shown in FIGS. 4, 5, and 12, the gas space 92 in this embodiment is defined by the dielectric principal surface 51 and the antenna surface 81. Specifically, the opening of the antenna recess 80 is blocked by the dielectric principal surface 51. As a result, the gas space 92 is defined by the dielectric principal surface 51 and the antenna surface 81, which is the inner surface of the antenna recess 80. More specifically, the gas space 92 is defined by the dielectric principal surface 51 and the antenna surfaces 81A to 81C. Specifically, the openings of the antenna recesses 80A to 80C are each blocked by the dielectric principal surface 51. In this embodiment, the adhesive layer 91 is provided along the periphery of the opening of each of the antenna recesses 80A to 80C, so that the gas space 92 is sealed. That is, the gas space 92 is sealed by the adhesive layer 91. The reflective films 82A to 82C are each provided in the gas space 92.

[0144] 12, the gas space 92 includes a gas space 92A defined by the antenna recess 80A and the dielectric principal surface 51, a gas space 92B defined by the antenna recess 80B and the dielectric principal surface 51, and a gas space 92C defined by the antenna recess 80C and the dielectric principal surface 51. In this embodiment, the gas spaces 92A, 92B, and 92C are in communication with each other. More specifically, the gas spaces 92A and 92B are in communication with each other at an opening end 81Aa of the antenna surface 81A (opening end 82Aa of the reflective film 82A) and an opening end 81Ba of the antenna surface 81B (opening end 82Ba of the reflective film 82B). The gas space 92B and the gas space 92C communicate with each other at an opening end 81Bb of the antenna surface 81B (opening end 82Bb of the reflective film 82B) and an opening end 81Ca of the antenna surface 81C (opening end 82Ca of the reflective film 82C).

[0145] The gas spaces 92A to 92C are each formed in a substantially hemispherical shape. When viewed from the z direction, the gas space 92A is formed to be larger than the terahertz element 20A in a direction perpendicular to the z direction. When viewed from the z direction, the length of the gas space 92A in the x direction is longer than the length of the terahertz element 20A in the x direction, and the length of the gas space 92A in the y direction is longer than the length of the terahertz element 20A in the y direction. When viewed from the z direction, the gas space 92B is formed to be larger than the terahertz element 20B in a direction perpendicular to the z direction. When viewed from the z direction, the length of the gas space 92B in the x direction is longer than the length of the terahertz element 20B in the x direction, and the length of the gas space 92B in the y direction is longer than the length of the terahertz element 20B in the y direction. When viewed from the z direction, the gas space 92C is formed to be larger than the terahertz element 20C in a direction perpendicular to the z direction. When viewed from the z direction, the length of the gas space 92C in the x direction is longer than the length of the terahertz element 20C in the x direction, and the length of the gas space 92C in the y direction is longer than the length of the terahertz element 20C in the y direction.

[0146] Gas exists in each of the gas spaces 92A to 92C. The gas refractive index n3, which is the refractive index of the gas existing in each of the gas spaces 92A to 92C, is set to be lower than the dielectric refractive index n2. That is, each of the gas spaces 92A to 92C contains gas with a refractive index lower than the dielectric refractive index n2. For example, the gas existing in each of the gas spaces 92A to 92C is air. In this case, the gas refractive index n3 is approximately 1. Note that the gas existing in each of the gas spaces 92A to 92C is not limited to air, and may be any gas as long as it has a lower dielectric refractive index than n2.

[0147] The reflective film 82A has a portion facing the terahertz element 20A across the dielectric 50 and the gas space 92A. In this embodiment, the entire reflective film 82A faces the terahertz element 20A across the dielectric 50 and the gas space 92A.

[0148] In this embodiment, the reflective film 82A reflects the electromagnetic wave, which has passed through the dielectric 50 and propagated through the gas space 92A, toward the reception point P1 of the terahertz element 20A. In other words, the reflective film 82A can be said to guide the electromagnetic wave, which has passed through the dielectric 50 and propagated through the gas space 92A, toward the reception point P1 of the terahertz element 20A.

[0149] The reflective film 82B has a portion facing the terahertz element 20B across the dielectric 50 and the gas space 92B. In this embodiment, the entire reflective film 82B faces the terahertz element 20B across the dielectric 50 and the gas space 92B.

[0150] In the present embodiment, the reflective film 82B reflects the electromagnetic wave, which has passed through the dielectric 50 and propagated through the gas space 92B, toward the reception point P1 of the terahertz element 20B. In other words, the reflective film 82B can be said to guide the electromagnetic wave, which has passed through the dielectric 50 and propagated through the gas space 92B, toward the reception point P1 of the terahertz element 20B.

[0151] The reflective film 82C has a portion that faces the terahertz element 20C across the dielectric 50 and the gas space 92C. In this embodiment, the entire reflective film 82C faces the terahertz element 20C across the dielectric 50 and the gas space 92C.

[0152] In the present embodiment, the reflective film 82C reflects the electromagnetic wave, which has passed through the dielectric 50 and propagated through the gas space 92C, toward the reception point P1 of the terahertz element 20C. In other words, the reflective film 82C can be said to guide the electromagnetic wave, which has passed through the dielectric 50 and propagated through the gas space 92C, toward the reception point P1 of the terahertz element 20C.

[0153] 13, the terahertz device 10 includes a first electrode 101 and a second electrode 102 used for electrical connection with the outside, and a first conductive portion 110 and a second conductive portion 120 provided within the dielectric 50 and electrically connected to the terahertz element 20. In this embodiment, the electrodes 101 and 102 are provided individually for the individual antenna bases 70A to 70C. That is, the electrodes 101 and 102 include a first electrode 101A and a second electrode 102A provided on the individual antenna base 70A, a first electrode 101B and a second electrode 102B provided on the individual antenna base 70B, and a first electrode 101C and a second electrode 102C provided on the individual antenna base 70C. In this embodiment, the conductive portions 110 and 120 are provided individually for the terahertz elements 20A to 20C. In other words, both conductive parts 110, 120 have a first conductive part 110A and a second conductive part 120A electrically connected to terahertz element 20A, a first conductive part 110B and a second conductive part 120B electrically connected to terahertz element 20B, and a first conductive part 110C and a second conductive part 120C electrically connected to terahertz element 20C.

[0154] In this embodiment, the electrodes 101A and 102A are formed in a portion of the dielectric 50 that does not overlap with the reflective film 82A when viewed from the z direction, and in a portion of the dielectric 50 that overlaps with the reflective film 82A when viewed from the x direction. In other words, the electrodes 101A and 102A are disposed on one side of the reflective film 82A in the x direction in the dielectric 50.

[0155] In this embodiment, both electrodes 101A, 102A are provided laterally with respect to the antenna base 70 (individual antenna base 70A). Specifically, both electrodes 101A, 102A are formed on a portion of the dielectric principal surface 51 corresponding to the first protrusion 61, i.e., on the first protruding surface 51a (see FIGS. 4 and 5). Both electrodes 101A, 102A are aligned with each other in the x direction and arranged side by side in the y direction. Both electrodes 101A, 102A face downward.

[0156] In this embodiment, the electrodes 101B and 102B are formed in a portion of the dielectric 50 that does not overlap with the reflective film 82B when viewed from the z direction, and in a portion of the dielectric 50 that overlaps with the reflective film 82B when viewed from the x direction. In other words, the electrodes 101B and 102B are disposed on one side of the reflective film 82B in the x direction of the dielectric 50.

[0157] In this embodiment, both electrodes 101B, 102B are provided laterally with respect to the antenna base 70 (individual antenna base 70B). Specifically, both electrodes 101B, 102B are formed on a portion of the dielectric principal surface 51 corresponding to the first protrusion 61, i.e., on the first protruding surface 51a. Both electrodes 101B, 102B are aligned with each other in the x direction and arranged side by side in the y direction. Both electrodes 101B, 102B face downward.

[0158] In this embodiment, the electrodes 101C and 102C are formed in a portion of the dielectric 50 that does not overlap with the reflective film 82C when viewed from the z direction, and in a portion of the dielectric 50 that overlaps with the reflective film 82C when viewed from the x direction. In other words, the electrodes 101C and 102C are disposed on one side of the reflective film 82C in the x direction in the dielectric 50.

[0159] In this embodiment, both electrodes 101C and 102C are provided laterally with respect to the antenna base 70 (individual antenna base 70C). Specifically, both electrodes 101C and 102C are formed on a portion of the dielectric principal surface 51 corresponding to the first protrusion 61, i.e., on the first protruding surface 51a. Both electrodes 101C and 102C are aligned with each other in the x direction and arranged side by side in the y direction. Both electrodes 101C and 102C face downward.

[0160] In this embodiment, the electrodes 101A and 102A, the electrodes 101B and 102B, and the electrodes 101C and 102C are arranged so as to be aligned with each other in the x direction and spaced apart from each other in the y direction.

[0161] In this embodiment, each of the electrodes 101A, 102A, 101B, 102B, 101C, and 102C has a laminated structure including, for example, a Ni layer and an Au layer. However, the structure of each of the electrodes 101A, 102A, 101B, 102B, 101C, and 102C is not limited to this and may be any structure, such as a structure including a Pd layer or a structure including an Sn layer. Furthermore, the shape of each of the electrodes 101A, 102A, 101B, 102B, 101C, and 102C as viewed from the z direction may be any shape, such as a rectangle with its longer side aligned in the y direction and its shorter side aligned in the x direction. The shapes of the electrodes 101A and 102A as viewed from the z direction, the shapes of the electrodes 101B and 102B as viewed from the z direction, and the shapes of the electrodes 101C and 102C as viewed from the z direction may be different from each other.

[0162] 12, the length in the z direction of the antenna base 70 (individual antenna bases 70A, 70B, 70C) is greater than the thickness of the dielectric 50. Therefore, each of the electrodes 101A, 102A, 101B, 102B, 101C, 102C is biased toward the upper side (in other words, toward the device principal surface 11) relative to the center in the z direction of the terahertz device 10.

[0163] Each of the conductive portions 110A, 110B, 110C, 120A, 120B, and 120C is entirely provided within the dielectric 50. That is, the dielectric 50 seals the terahertz elements 20A to 20C together with each of the conductive portions 110A, 110B, 110C, 120A, 120B, and 120C. This prevents the conductive portions 110A, 110B, 110C, 120A, 120B, and 120C located within the dielectric 50 from contacting the reflective films 82A to 82C located outside the dielectric 50. That is, the dielectric 50 functions to insulate the conductive portions 110A, 110B, 110C, 120A, 120B, and 120C from the reflective films 82A to 82C.

[0164] 13, both conductive portions 110A and 120A extend in the x direction, which is the protruding direction of first protrusion 61, so as to overlap with both terahertz element 20A and electrodes 101A and 102A when viewed from the z direction. Both conductive portions 110B and 120B extend in the x direction so as to overlap with both terahertz element 20B and electrodes 101B and 102B when viewed from the z direction. Both conductive portions 110C and 120C extend in the x direction so as to overlap with both terahertz element 20C and electrodes 101C and 102C when viewed from the z direction.

[0165] In this embodiment, each of the conductive portions 110A, 120A, 110B, 120B, 110C, and 120C has a strip shape extending in the x direction and with the y direction as its width direction. In this embodiment, each of the conductive portions 110A, 120A, 110B, 120B, 110C, and 120C is a thin film with its thickness in the z direction. However, the specific shape of each of the conductive portions 110A, 120A, 110B, 120B, 110C, and 120C is arbitrary, and may be a plate-like shape with a predetermined thickness. In this embodiment, the terahertz element 20A is flip-chip mounted to both conductive portions 110A and 120A, the terahertz element 20B is flip-chip mounted to both conductive portions 110B and 120B, and the terahertz element 20C is flip-chip mounted to both conductive portions 110C and 120C.

[0166] 14, the first conductive part 110A electrically connects the terahertz element 20A and the first electrode 101A. The first conductive part 110A extends in the x-direction, which is the protruding direction of the first protrusion part 61, so as to face both the first pad 33a of the terahertz element 20A and the first electrode 101A.

[0167] 4, the first conductive unit 110A includes a first element facing unit 111 facing the first pad 33a of the terahertz element 20A in the z direction, a first electrode facing unit 112 facing the first electrode 101A in the z direction, a first connection unit 113 connecting the first element facing unit 111 and the first electrode facing unit 112, and a first columnar unit 115 connecting the first electrode facing unit 112 and the first electrode 101A. In this embodiment, the first element facing unit 111 and the first electrode facing unit 112 form both end units of the first conductive unit 110A in the x direction.

[0168] 14 and 15, the first element facing portion 111 is provided between the terahertz element 20A and the reflective film 82A in the z direction, and is formed so that at least a portion of the first element facing portion 111 overlaps with the first pad 33a of the terahertz element 20A when viewed from the z direction. The first element facing portion 111 faces the reflective film 82A in the z direction. The first pad 33a of the terahertz element 20A extends in the x direction, so that the first element facing portion 111 extends in the x direction. For example, the shape of the first element facing portion 111 when viewed from the z direction is rectangular with the long side extending in the x direction and the short side extending in the y direction.

[0169] The first conductive portion 110A includes a first bump 114 provided between the first element facing portion 111 and the first pad 33a of the terahertz element 20A. The terahertz element 20A is flip-chip mounted to the first element facing portion 111 via the first bump 114. The first pad 33a and the first element facing portion 111 are electrically connected by the first bump 114.

[0170] In this embodiment, a plurality of first bumps 114 are provided. For example, in response to the fact that the first pad 33a and the first element facing portion 111 of the terahertz element 20A extend in the x direction, a plurality of first bumps 114 (two in this embodiment) are arranged in the x direction. The first element facing portion 111 and the first bumps 114 are arranged at positions that do not overlap with the reception point P1 when viewed from the z direction. The shape of the first bumps 114 is, for example, a quadrangular prism. However, the shape of the first bumps 114 is not limited to this and may be any shape.

[0171] The first bump 114 may have a single layer structure or a multi-layer structure. As an example, the first bump 114 may have a multi-layer structure of a metal layer containing Cu, a metal layer containing Ti, and an alloy layer containing Sn. The alloy layer containing Sn is, for example, an Sn—Sb-based alloy layer or an Sn—Ag-based alloy layer.

[0172] A first insulating layer surrounding the first bump 114 may be formed on the first element facing portion 111. The first insulating layer may be formed in a frame shape that is open upward, and the first bump 114 may be housed within the first insulating layer. This can prevent the first bump 114 from sagging sideways. However, the first insulating layer is not essential.

[0173] The first electrode opposing portion 112 is formed so that at least a portion thereof overlaps with the first electrode 101A when viewed from the z direction. For example, the first electrode opposing portion 112 is formed at a position protruding laterally from the antenna base 70 (individual antenna base 70A), and specifically, is formed within the first protruding portion 61. Therefore, the first electrode opposing portion 112 is disposed at a position that does not overlap with the reflective film 82A when viewed from the z direction.

[0174] In this embodiment, the first electrode opposing portion 112 has a rectangular shape extending in the x and y directions when viewed from the z direction. The first electrode 101A is formed wider than the first electrode opposing portion 112 when viewed from the z direction. However, the shape and size of the first electrode 101A are not limited to this, and the first electrode 101A may be formed smaller than the first electrode opposing portion 112 or may have the same shape as the first electrode opposing portion 112.

[0175] 13 and 14, the first connection portion 113 is provided between the first element opposing portion 111 and the first electrode opposing portion 112, and extends in the x direction with the y direction as its width direction. A portion of the first connection portion 113 faces the reflective film 82A in the z direction. That is, a portion of the first connection portion 113 is provided at a position overlapping with the reflective film 82A. In other words, the first connection portion 113 has a portion that overlaps with the reflective film 82A and a portion that does not overlap with the reflective film 82A when viewed from the z direction.

[0176] The first connection portion 113 of this embodiment is formed to be narrower than the first element opposing portion 111. Specifically, the width (length in the y direction) of the first connection portion 113 is set to be shorter than the width (length in the y direction) of the first element opposing portion 111. The first connection portion 113 of this embodiment is formed to be narrower than, for example, the first electrode opposing portion 112. In other words, the first electrode opposing portion 112 extends longer in the y direction than the first connection portion 113.

[0177] The first connection portion 113 has a first connection main body portion 113a formed narrower than the first element facing portion 111 and the first electrode facing portion 112, and a first element side tapered portion 113b and a first electrode side tapered portion 113c on both sides of the first connection main body portion 113a in the longitudinal direction.

[0178] The first connection main body 113a extends with the x direction as its longitudinal direction and has a constant width in the y direction. When viewed from the z direction, the first connection main body 113a overlaps with the reflective film 82A. It can also be said that the first connection main body 113a connects the first element facing portion 111 and the first electrode facing portion 112. As shown in FIG. 15, the width W1 of the first connection main body 113a is shorter than the width W2 of the first element facing portion 111.

[0179] The first element side tapered portion 113b connects the first connection main body portion 113a and the first element facing portion 111. When viewed from the z direction, for example, the first element side tapered portion 113b is formed at a position adjacent to the terahertz element 20A in the x direction, and overlaps with the reflective film 82A when viewed from the z direction.

[0180] The first element side tapered portion 113b is formed to gradually widen from the first connection main body portion 113a toward the first element facing portion 111. In this embodiment, the first element side tapered portion 113b has a pair of first element side inclined surfaces 113ba that are inclined so as to gradually move away from each other as they move from the first connection main body portion 113a toward the first element facing portion 111.

[0181] 13, the first electrode side tapered portion 113c connects the first connection main body portion 113a and the first electrode opposing portion 112. The first electrode side tapered portion 113c is formed in a portion that does not overlap with the reflective film 82A when viewed from the z direction, for example, and is formed within the first protrusion 61, for example.

[0182] The first electrode side tapered portion 113c is formed so as to gradually increase in width from the first connection main body 113a toward the first electrode opposing portion 112. In this embodiment, the first electrode side tapered portion 113c has a pair of first electrode side inclined surfaces 113ca that are inclined so as to gradually move away from each other from the first connection main body 113a toward the first electrode opposing portion 112.

[0183] 4, the first columnar portion 115 is provided between the first electrode 101A and the first electrode opposing portion 112. The first columnar portion 115 extends with its height in the z direction, and is connected to the first electrode 101A and the first electrode opposing portion 112.

[0184] The first pillar portion 115 is formed, for example, in a cylindrical shape. However, the specific shape of the first pillar portion 115 is arbitrary, and it may be, for example, a rectangular pillar shape. In this embodiment, a first recess 112a is formed in the first electrode opposing portion 112 at a position overlapping with the first pillar portion 115. Note that the first recess 112a does not necessarily have to be provided.

[0185] According to this configuration, the first pad 33a of the terahertz element 20A and the first electrode 101A are electrically connected via the first bump 114, the first element opposing portion 111, the first connection portion 113, the first electrode opposing portion 112 and the first column portion 115.

[0186] The shapes of the first conductive parts 110B and 110C when viewed from the z direction are the same as the shape of the first conductive part 110A when viewed from the z direction. That is, like the first conductive part 110A, the first conductive parts 110B and 110C include a first element facing part 111, a first electrode facing part 112, a first connecting part 113, a first bump 114, and a first pillar part 115. Therefore, the first pad 33a of the terahertz element 20B and the first electrode 101B are electrically connected via the first bump 114, the first element facing part 111, the first connecting part 113, the first electrode facing part 112, and the first pillar part 115 of the first conductive part 110B. Therefore, it can be said that the first conductive part 110B electrically connects the terahertz element 20B and the first electrode 101B. Furthermore, the first pad 33a of the terahertz element 20C and the first electrode 101C are electrically connected via the first bump 114 of the first conductive portion 110C, the first element facing portion 111, the first connection portion 113, the first electrode facing portion 112, and the first pillar portion 115. For this reason, it can be said that the first conductive portion 110C electrically connects the terahertz element 20C and the first electrode 101C.

[0187] 5 and 13, the second conductive portion 120A electrically connects the terahertz element 20A and the second electrode 102A. As shown in Fig. 13 and 14, in this embodiment, the first conductive portion 110A and the second conductive portion 120A are arranged side by side in the y direction when viewed from the z direction. It can also be said that the two conductive portions 110A, 120A extend from the terahertz element 20A in one of the radial directions of the reflective film 82A when viewed from the z direction.

[0188] In particular, it can be said that the conductive portions 110A and 120A of this embodiment extend in a direction away from the terahertz element 20A when viewed from the z direction. Specifically, the conductive portions 110A and 120A extend in the x direction from the terahertz element 20A toward the first protrusion 61 when viewed from the z direction.

[0189] 5, the second conductive section 120A has a second element facing section 121 facing the second pad 34a of the terahertz element 20A in the z direction, a second electrode facing section 122 facing the second electrode 102A in the z direction, and a second column section 125 connecting the second element facing section 121 and the second electrode 102A. In this embodiment, the second element facing section 121 and the second electrode facing section 122 form both ends of the second conductive section 120A in the x direction.

[0190] The second element facing portion 121 is provided between the terahertz element 20A and the reflective film 82A in the z direction, and is formed so that at least a portion of it overlaps with the second pad 34a of the terahertz element 20A when viewed from the z direction. The second element facing portion 121 faces the reflective film 82A in the z direction. The second pad 34a of the terahertz element 20A extends in the x direction, so that the second element facing portion 121 extends in the x direction. For example, the second element facing portion 121 is formed in a rectangular shape with the x direction as the longitudinal direction and the y direction as the lateral direction.

[0191] In this embodiment, the pads 33a and 34a of the terahertz element 20A are spaced apart in the y direction, and accordingly, the element facing portions 111 and 121 are arranged side by side in the y direction. A dielectric 50 is present between the element facing portions 111 and 121, and the element facing portions 111 and 121 are insulated by the dielectric 50.

[0192] The second conductive portion 120A includes a second bump 124 provided between the second element facing portion 121 and the second pad 34a of the terahertz element 20A. The terahertz element 20A is flip-chip mounted to the second element facing portion 121 via the second bump 124. The second pad 34a of the terahertz element 20A and the second element facing portion 121 are electrically connected by the second bump 124.

[0193] 14 and 15, in this embodiment, a plurality of second bumps 124 are provided. For example, in response to the second pad 34a and the second element facing portion 121 of the terahertz element 20A extending in the x direction, a plurality of second bumps 124 (two in this embodiment) are arranged in the x direction. The second element facing portion 121 and the second bump 124 are arranged at positions that do not overlap with the reception point P1 when viewed from the z direction. The first bump 114 and the second bump 124 are arranged opposite to each other with a gap in the y direction and are aligned in the x direction. However, the arrangement of the first bump 114 and the second bump 124 is not limited thereto, and for example, the first bump 114 and the second bump 124 may be arranged with a shift in the y direction.

[0194] 14, the second electrode opposing portion 122 is formed so that at least a portion thereof overlaps with the second electrode 102A when viewed from the z direction. For example, the second electrode opposing portion 122 is formed at a position protruding laterally from the antenna base 70 (individual antenna base 70A), and specifically, is formed within the second protruding portion 62. Therefore, the second electrode opposing portion 122 is disposed at a position that does not overlap with the reflective film 82A when viewed from the z direction.

[0195] In this embodiment, the second electrode opposing portion 122 has a rectangular shape extending in the x and y directions when viewed from the z direction. When viewed from the z direction, the second electrode 102A is formed to be wider than the second electrode opposing portion 122. However, the size and shape of the second electrode 102A are not limited to this, and the second electrode 102A may be formed to be smaller than the second electrode opposing portion 122 or may have the same shape as the second electrode opposing portion 122.

[0196] The second connection portion 123 is provided between the second element opposing portion 121 and the second electrode opposing portion 122, and extends in the x direction with the y direction as its width direction. A portion of the second connection portion 123 faces the reflective film 82A in the z direction. That is, a portion of the second connection portion 123 is provided at a position overlapping with the reflective film 82A. In other words, the second connection portion 123 has a portion that overlaps with the reflective film 82A and a portion that does not overlap with the reflective film 82A when viewed from the z direction.

[0197] The second connection portion 123 of this embodiment is formed to be narrower than the second element opposing portion 121. Specifically, the width (length in the y direction) of the second connection portion 123 is set to be shorter than the width (length in the y direction) of the second element opposing portion 121. The second connection portion 123 of this embodiment is formed to be narrower than, for example, the second electrode opposing portion 122. In other words, the second electrode opposing portion 122 extends longer in the y direction than the second connection portion 123.

[0198] The second connection portion 123 has a second connection main body portion 123a formed narrower than the second element opposing portion 121 and the second electrode opposing portion 122, and a second element side tapered portion 123b and a second electrode side tapered portion 123c located at both ends of the second connection main body portion 123a in the longitudinal direction.

[0199] The second connection main body 123a extends with the x direction as its longitudinal direction and has a constant width in the y direction. When viewed from the z direction, the second connection main body 123a overlaps with the reflective film 82A. It can also be said that the second connection main body 123a connects the second element facing portion 121 and the second electrode facing portion 122. As shown in FIG. 15, the width W3 of the second connection main body 123a is shorter than the width W4 of the second element facing portion 121.

[0200] The second element side tapered portion 123b connects the second connection main body portion 123a and the second element facing portion 121. The second element side tapered portion 123b is formed at a position adjacent to the terahertz element 20A in the x direction when viewed from the z direction, for example, and overlaps with the reflective film 82A when viewed from the z direction.

[0201] 15, the second element side tapered portion 123b is formed so as to gradually increase in width from the second connection main body portion 123a toward the second element facing portion 121. In this embodiment, the second element side tapered portion 123b has a pair of second element side inclined surfaces 123ba that are inclined so as to gradually move away from each other from the second connection main body portion 123a toward the second element facing portion 121.

[0202] 14, the second electrode side tapered portion 123c connects the second connection main body portion 123a and the second electrode opposing portion 122. The second electrode side tapered portion 123c is formed in a portion that does not overlap with the reflective film 82A when viewed from the z direction, for example, and is formed within the second protrusion 62, for example.

[0203] The second electrode side tapered portion 123c is formed so as to gradually increase in width from the second connection main body 123a toward the second electrode opposing portion 122. In this embodiment, the second electrode side tapered portion 123c has a pair of second electrode side inclined surfaces 123ca that are inclined so as to gradually move away from each other from the second connection main body 123a toward the second electrode opposing portion 122.

[0204] 5, the second pillar portion 125 is provided between the second electrode 102A and the second electrode opposing portion 122. The second pillar portion 125 extends with its height in the z direction, and is connected to the second electrode 102A and the second electrode opposing portion 122.

[0205] The second pillar portion 125 is formed, for example, in a cylindrical shape. However, the specific shape of the second pillar portion 125 can be changed arbitrarily, and may be, for example, a rectangular pillar shape. In this embodiment, a second recess 122a is formed in the portion of the second electrode opposing portion 122 that overlaps with the second pillar portion 125. Note that the second recess 122a does not necessarily have to be provided.

[0206] According to this configuration, the second pad 34a of the terahertz element 20A and the second electrode 102A are electrically connected via the second bump 124, the second element opposing portion 121, the second connection portion 123, the second electrode opposing portion 122 and the second pillar portion 125.

[0207] The shapes of the second conductive portions 120B and 120C when viewed from the z direction are the same as the shape of the second conductive portion 120A when viewed from the z direction. That is, like the second conductive portion 120A, the second conductive portions 120B and 120C include a second element facing portion 121, a second electrode facing portion 122, a second connecting portion 123, a second bump 124, and a second pillar portion 125. Therefore, the second pad 34a of the terahertz element 20B and the second electrode 102B are electrically connected via the second bump 124, the second element facing portion 121, the second connecting portion 123, the second electrode facing portion 122, and the second pillar portion 125 of the second conductive portion 120B. Therefore, it can be said that the second conductive portion 120B electrically connects the terahertz element 20B and the second electrode 102B. Furthermore, the second pad 34a of the terahertz element 20C and the second electrode 102C are electrically connected via the second bump 124 of the second conductive portion 120C, the second element facing portion 121, the second connection portion 123, the second electrode facing portion 122, and the second pillar portion 125. For this reason, it can be said that the second conductive portion 120C electrically connects the terahertz element 20C and the second electrode 102C.

[0208] 13, in this embodiment, the first conductive portion 110B and the second conductive portion 120B are formed side by side in the y direction when viewed from the z direction. In other words, when viewed from the z direction, both conductive portions 110B, 120B extend from the terahertz element 20B in one radial direction of the reflective film 82B.

[0209] In particular, it can be said that the conductive portions 110B and 120B of this embodiment extend in a direction away from the terahertz element 20B when viewed from the z direction. Specifically, the conductive portions 110B and 120B extend in the x direction from the terahertz element 20B toward the first protrusion 61 when viewed from the z direction.

[0210] In this embodiment, the first conductive portion 110C and the second conductive portion 120C are arranged side by side in the y direction when viewed from the z direction. It can also be said that the two conductive portions 110C, 120C extend from the terahertz element 20C in one of the radial directions of the reflective film 82C when viewed from the z direction.

[0211] In particular, it can be said that the conductive portions 110C and 120C of this embodiment extend in a direction away from the terahertz element 20C when viewed from the z direction. Specifically, the conductive portions 110C and 120C extend in the x direction from the terahertz element 20C toward the first protrusion 61 when viewed from the z direction.

[0212] As shown in FIG. 13, in this embodiment, both conductive portions 110A, 120A, both conductive portions 110B, 120B, and both conductive portions 110C, 120C are aligned with each other in the x direction and spaced apart from each other in the y direction.

[0213] The reflective film 82A of this embodiment is in an electrically floating state. Specifically, the individual antenna base 70A on which the reflective film 82A is formed has insulating properties. Since both conductive portions 110A and 120A are provided within the dielectric 50, the reflective film 82A is insulated from both conductive portions 110A and 120A. Furthermore, the reflective film 82A is spaced apart from both electrodes 101A and 102A, and the individual antenna base 70A is interposed between them. Therefore, the reflective film 82A is insulated from both electrodes 101A and 102A. This maintains the floating state of the reflective film 82A. Note that the reflective films 82B and 82C are also in an electrically floating state, similar to the reflective film 82A.

[0214] (Method of manufacturing a terahertz device) Next, a method for manufacturing the terahertz device 10 of this embodiment will be described with reference to Figures 16 to 30. For convenience of explanation, a method for manufacturing one terahertz device 10 will be described.

[0215] The manufacturing method of the terahertz device 10 is roughly divided into the steps of forming a dielectric 50 that encapsulates the terahertz element 20, etc., forming an antenna base 70, and assembling the dielectric 50 and the antenna base 70.

[0216] First, the process of forming the dielectric 50 that seals the terahertz element 20 and the like will be described with reference to FIGS. As shown in FIGS. 16 and 17, the method for manufacturing the terahertz device 10 includes the step of forming the pillar portions 115 and 125 on the support substrate 130.

[0217] The support substrate 130 is made of a single-crystal semiconductor material, which is a single-crystal Si material in this embodiment. The thickness of the support substrate 130 in this embodiment is, for example, about 725 to 775 μm. Note that the support substrate 130 is not limited to a Si wafer and may be, for example, a glass substrate.

[0218] The process of forming the columnar portions 115, 125 includes, for example, a process of forming a base layer on the support substrate 130. This base layer is formed by sputtering. In this embodiment, a Ti layer is formed on the support substrate 130 as the base layer, and then a Cu layer is formed in contact with the Ti layer. In other words, the base layer is formed from a Ti layer and a Cu layer stacked on top of each other. In this embodiment, the thickness of the Ti layer is about 10 to 30 μm, and the thickness of the Cu layer is about 200 to 800 μm. Note that the constituent materials and thickness of the base layer are not limited to those described above.

[0219] Next, a plating layer is formed in contact with the base layer. The plating layer is formed by forming a resist pattern using photolithography and electroplating. Specifically, a photosensitive resist is applied to cover the entire surface of the base layer, and the photosensitive resist is then exposed and developed. This forms a patterned resist layer (hereinafter referred to as a "resist pattern"). The photosensitive resist is applied using, for example, a spin coater, but is not limited to this. At this time, a portion of the base layer is exposed from the resist pattern. Next, electroplating is performed using the base layer as a conductive path. As a result, a plating layer is laminated on the base layer exposed from the resist pattern. In this embodiment, the plating layer is made of, for example, Cu. After the plating layer is formed, the resist pattern is removed. Through the above steps, pillar portions 115, 125 are formed. The pillar portions 115, 125 stand upward from the support substrate 130.

[0220] 16 and 17, the manufacturing method of the terahertz device 10 includes a first sealing step of forming a first dielectric layer 131 that covers the columnar portions 115 and 125. In the first sealing step, the first dielectric layer 131 is formed by, for example, molding. In this embodiment, the first dielectric layer 131 has electrical insulation properties and is made of, for example, a synthetic resin whose main component is epoxy resin. The first dielectric layer 131 constitutes a part of the dielectric 50.

[0221] The specific process for forming the first dielectric layer 131 is arbitrary, but one possible process is to form the first dielectric layer 131 higher than the columnar portions 115, 125, and then polish the first dielectric layer 131 to expose the tip surfaces of the columnar portions 115, 125. In this case, polishing marks, which are traces of the polishing, are formed on the upper surface of the first dielectric layer 131.

[0222] Furthermore, the tip surfaces of the columnar portions 115, 125 may be polished when the first dielectric layer 131 is polished. In this case, burrs may be generated on the tip surfaces of the columnar portions 115, 125. For this reason, the manufacturing method of the terahertz device 10 may include a step of removing burrs from the columnar portions 115, 125. In this case, as shown in FIG. 17 , the tip surfaces of the columnar portions 115, 125 are positioned slightly recessed from the upper surface of the first dielectric layer 131.

[0223] 18 and 19(a), the method of manufacturing terahertz device 10 includes a step of forming both conductive portions 110A and 120A, a step of forming both conductive portions 110B and 120B, and a step of forming both conductive portions 110C and 120C. Because the steps of forming these conductive portions are common steps, only the step of forming both conductive portions 110A and 120A will be described, and descriptions of the step of forming both conductive portions 110B and 120B and the step of forming both conductive portions 110C and 120C will be omitted.

[0224] 18, the process of forming the conductive portions 110A and 120A includes the process of forming the element facing portions 111 and 121, the electrode facing portions 112 and 122, and the connecting portions 113 and 123. In this process, the element facing portions 111 and 121, the electrode facing portions 112 and 122, and the connecting portions 113 and 123 are formed by patterning the first dielectric layer 131. Note that the element facing portions 111 and 121, the electrode facing portions 112 and 122, and the connecting portions 113 and 123 may be composed of an underlayer and a plating layer.

[0225] 19(b), in both conductive portions 110A and 120A, the tip surfaces of the columnar portions 115 and 125 are recessed relative to the upper surface of the first dielectric layer 131, and therefore recesses 112a and 122a are formed in the electrode opposing portions 112 and 122 formed on the tip surfaces of the columnar portions 115 and 125. Note that, in both conductive portions 110B, 120B, 110C, and 120C, recesses 112a and 122a are formed in the electrode opposing portions 112 and 122, similar to both conductive portions 110A and 120A.

[0226] 20 to 23, the method for manufacturing the terahertz device 10 includes an element mounting step of mounting the terahertz element 20A, the terahertz element 20B, and the terahertz element 20C. The element mounting step is performed by flip-chip bonding, for example.

[0227] 20 and 21, the element mounting process includes a step of forming bumps 114, 124 on conductive portions 110A, 120A, 110B, 120B, 110C, and 120C. The step of forming bumps 114, 124 includes, for example, a step of forming a resist layer in areas other than the bump formation areas where bumps 114, 124 are to be formed, a step of stacking conductive layers that form bumps 114, 124 in the bump formation areas, and a step of removing the resist layer. The resist layer is formed of, for example, a photosensitive resist and is patterned by exposure and development.

[0228] If an unnecessary base layer is formed in the process of forming the conductive portions 110A, 120A, 110B, 120B, 110C, and 120C, the manufacturing method of the terahertz device 10 may include a process of removing the unnecessary base layer. The unnecessary base layer may be removed by wet etching using a mixed solution of H2SO4 (sulfuric acid) and H2O2 (hydrogen peroxide), for example.

[0229] 22 and 23, the element mounting process includes a step of bonding the terahertz element 20A to the conductive portions 110A and 120A using the bumps 114 and 124, a step of bonding the terahertz element 20B to the conductive portions 110B and 120B using the bumps 114 and 124, and a step of bonding the terahertz element 20C to the conductive portions 110C and 120C using the bumps 114 and 124. As a result, the terahertz element 20A is flip-chip mounted on both conductive portions 110A and 120A, thereby establishing electrical continuity between the terahertz element 20A and both conductive portions 110A and 120A. As the terahertz element 20B is flip-chip mounted on both conductive portions 110B and 120B, thereby establishing electrical continuity between the terahertz element 20B and both conductive portions 110B and 120B. Since the terahertz element 20C is flip-mounted on both conductive portions 110C and 120C, the terahertz element 20C and both conductive portions 110C and 120C are electrically connected to each other.

[0230] As shown in FIG. 24, the manufacturing method of the terahertz device 10 includes a second sealing step of forming a second dielectric layer 132 that seals the conductive portions 110A, 120A, 110B, 120B, 110C, and 120C and the terahertz elements 20A to 20C. The second dielectric layer 132 is laminated on the first dielectric layer 131. In this embodiment, the second dielectric layer 132 is formed of the same material as the first dielectric layer 131. That is, the second dielectric layer 132 has electrical insulation properties, and is, for example, a synthetic resin whose main component is epoxy resin. The dielectric 50 is composed of the first dielectric layer 131 and the second dielectric layer 132. The lower surface of the first dielectric layer 131 constitutes the dielectric principal surface 51, and the upper surface of the second dielectric layer 132 constitutes the dielectric rear surface 52. The terahertz elements 20A to 20C and the conductive portions 110A, 120A, 110B, 120B, 110C, and 120C are sealed by the dielectric layers 131 and 132.

[0231] Before forming the second dielectric layer 132, an underfill mainly composed of, for example, epoxy resin may be filled below each of the terahertz elements 20A to 20C (between the terahertz element 20A and the first dielectric layer 131 or both conductive portions 110A, 120A, between the terahertz element 20B and the first dielectric layer 131 or both conductive portions 110B, 120B, and between the terahertz element 20C and the first dielectric layer 131 or both conductive portions 110C, 120C).

[0232] In this embodiment, an interface 133 may be formed between the first dielectric layer 131 and the second dielectric layer 132. However, the dielectric layers 131 and 132 may be completely integrated together, and the interface 133 may not be formed.

[0233] 25, the manufacturing method of the terahertz device 10 includes a step of removing the support substrate 130 to expose the dielectric principal surface 51 of the dielectric 50 and the base end surfaces of the pillar portions 115, 125. The step of removing the support substrate 130 uses, for example, a mechanical grinder. However, the method of removing the support substrate 130 is not limited to the configuration using a mechanical grinder.

[0234] 26, the manufacturing method of the terahertz device 10 includes a step of forming the electrodes 101A, 102A, 101B, 102B, 101C, and 102C. The step of forming the electrodes 101A, 102A, 101B, 102B, 101C, and 102C is performed by, for example, electroless plating. In this embodiment, the electrodes 101A, 102A, 101B, 102B, 101C, and 102C are formed by stacking a Ni layer, a Pd layer, and an Au layer in this order by, for example, electroless plating.

[0235] The method for forming the electrodes 101A, 102A, 101B, 102B, 101C, and 102C is not limited to this, and a Ni layer and an Au layer may be laminated in this order, only an Au layer may be laminated, only Sn may be formed, or Sn may be formed on a Ni layer.

[0236] Next, the process of forming the antenna base 70 will be described with reference to FIGS. The manufacturing method of the terahertz device 10 includes a step of forming an antenna recess 80A in the individual antenna base 70A, a step of forming an antenna recess 80B in the individual antenna base 70B, and a step of forming an antenna recess 80C in the individual antenna base 70C. In this embodiment, since the individual antenna bases 70A and 70C have the same shape, the method of forming the individual antenna base 70A and the method of forming the individual antenna base 70B will be described together.

[0237] 27, in the step of forming antenna recesses 80A and 80C, molds DUA and DLA formed corresponding to antenna surfaces 81A and 81C are used to form antenna recess 80A having antenna surface 81A and antenna recess 80C having antenna surface 81C. In addition, in the step of forming antenna recess 80B, molds DUB and DLB formed corresponding to antenna surface 81B are used to form antenna recess 80B having antenna surface 81B.

[0238] The manufacturing method of the terahertz device 10 includes a step of forming the metal films 134A, 134B, and 134C that constitute the reflective films 82A, 82B, and 82C. This step is performed after the antenna recesses 80A to 80C are formed.

[0239] 28, in this step, metal films 134A and 134C are formed on both the base main surface 71 and the antenna surfaces 81A and 81C of the individual antenna bases 70A and 70C, respectively. Also, a metal film 134B is formed on both the base main surface 71 and the antenna surface 81B of the individual antenna base 70B.

[0240] 29, the metal films 134A and 134C formed on the base main surfaces 71 of the individual antenna bases 70A and 70C and the metal film 134B formed on the base main surface 71 of the individual antenna base 70B are removed. Any specific method may be used to remove the metal films 134A to 134C formed on each base main surface 71, and for example, they may be removed by patterning or polishing. As a result, a reflective film 82A is formed only on the antenna surface 81A, a reflective film 82B is formed only on the antenna surface 81B, and a reflective film 82C is formed only on the antenna surface 81C.

[0241] The process for forming the reflective films 82A-82C is not limited to the above process. For example, the method for manufacturing the terahertz device 10 may include a process for masking the base principal surfaces 71 of the individual antenna bases 70A-70C and a process for forming the reflective films 82A-82C on the antenna surfaces 81A-81C by evaporation using an electron beam or the like. In this case, the process for removing the reflective films 82A-82C formed on the base principal surfaces 71 is not necessary.

[0242] 30, the manufacturing method of the terahertz device 10 includes a step of forming the individual antenna bases 70A to 70C, and then assembling the individual antenna base 70A with the individual antenna base 70B, and assembling the individual antenna base 70B with the individual antenna base 70C. Specifically, in this step, an adhesive layer is used to bond the individual antenna base 70A with the individual antenna base 70B, and to bond the individual antenna base 70B with the individual antenna base 70C.

[0243] Next, the process of assembling the dielectric 50 and the antenna base 70 will be described. Although not shown, the manufacturing method of the terahertz device 10 includes a step of assembling the dielectric 50 and the antenna base 70 on which the reflective films 82A, 82B, and 82C are formed. In this step, the antenna base 70 and the dielectric 50 are bonded together using an adhesive layer 91. Through the above steps, the terahertz device 10 is manufactured.

[0244] (action) Next, the operation of the terahertz device 10 of this embodiment will be described with reference to FIGS.

[0245] Fig. 31(a) shows a schematic diagram of the terahertz element 20 surrounded by gas, and Fig. 31(b) is a graph showing the change in refractive index in the case of Fig. 31(a). Fig. 32(a) shows a schematic diagram of the terahertz element 20 surrounded by gas and a dielectric 50, and Fig. 32(b) is a graph showing the change in refractive index in the case of Fig. 32(a).

[0246] In this embodiment, electromagnetic waves propagating toward the terahertz device 10 propagate through the dielectric 50 and the gas space 92 to the reflective film 82, and are reflected by the reflective film 82 toward the terahertz element 20 (preferably, the receiving point P1). As a result, the terahertz element 20 receives the electromagnetic waves. In this configuration, the device principal surface 11 can be considered as an incident surface onto which the electromagnetic waves are incident, and the inner surface of the reflective film 82 can be considered as a reflecting surface that reflects the electromagnetic waves incident from the device principal surface 11 toward the terahertz element 20. Furthermore, the device principal surface 11 can be considered as an input surface onto which the electromagnetic waves are input, and the terahertz device 10 can be considered to receive the electromagnetic waves input from the device principal surface 11.

[0247] Here, we will explain the case where electromagnetic waves propagate from the reflective film 82 to the terahertz element 20 without passing through the dielectric 50, and the case where electromagnetic waves propagate from the reflective film 82 to the terahertz element 20 via the dielectric 50, by comparing them.

[0248] As shown in FIGS. 31(a) and 31(b), if there is no dielectric 50 and the terahertz element 20 is surrounded by gas, the refractive index changes significantly at the boundary between the inside and outside of the terahertz element 20, specifically, at the boundary between the terahertz element 20 and the gas. In this case, electromagnetic waves are likely to be reflected at the boundary between the inside and outside of the terahertz element 20, and the electromagnetic waves are likely to be trapped within the terahertz element 20. As a result, many resonance modes are likely to occur within the terahertz element 20. Therefore, there is a risk that electromagnetic waves of frequencies other than the target frequency will be generated within the terahertz element 20 and will be received.

[0249] 32(a) and 32(b), when the terahertz element 20 is surrounded by a dielectric 50 having a dielectric refractive index n2 lower than the element refractive index n1 and higher than the gas refractive index n3, the refractive index decreases stepwise with increasing distance from the terahertz element 20. Therefore, the change in refractive index at the boundary between the inside and outside of the terahertz element 20, specifically, at the boundary between the terahertz element 20 and the dielectric 50, is small. This makes it possible to suppress the reflection of electromagnetic waves at the boundary between the inside and outside of the terahertz element 20 to some extent, making it difficult for a large number of resonance modes to occur.

[0250] Fig. 33 schematically shows the cross-sectional structure of a terahertz device 10X of a comparative example, and Fig. 34 schematically shows the cross-sectional structure of the terahertz device 10 of this embodiment. Fig. 33 and Fig. 34 show cross-sectional structures taken along a plane along the arrangement direction of the antenna bases 70 (70X) and the height direction of the terahertz device 10 (10X) at the position where the terahertz element 20 is arranged.

[0251] As shown in Fig. 33, a terahertz device 10X of the comparative example includes an antenna base 70X. The antenna base 70X is configured by combining an individual antenna base 70P, an individual antenna base 70Q, and an individual antenna base 70R in a line. In the antenna base 70X shown in Fig. 33, the individual antenna base 70Q is sandwiched between the individual antenna base 70P and the individual antenna base 70R.

[0252] These individual antenna bases 70P, 70Q, and 70R have the same shape and are provided with a substantially hemispherical antenna recess 80X. The antenna recess 80X is recessed from the base main surface 71X of each individual antenna base 70P, 70Q, and 70R toward the base back surface 72X and opens at the base main surface 71X. That is, the opening end of the antenna recess 80X of each individual antenna base 70P, 70Q, and 70R is surrounded by the base main surface 71X along its entire periphery. Therefore, each of the individual antenna bases 70P, 70Q, and 70R has a peripheral wall 78X that includes the base main surface 71X and extends along the entire periphery of the opening end of the antenna recess 80X.

[0253] 33, the peripheral wall portion 78X of the individual antenna base 70P and the peripheral wall portion 78X of the individual antenna base 70Q are interposed between the antenna recess 80X of the individual antenna base 70P and the antenna recess 80X of the individual antenna base 70Q. Furthermore, the peripheral wall portion 78X of the individual antenna base 70Q and the peripheral wall portion 78X of the individual antenna base 70R are interposed between the antenna recess 80X of the individual antenna base 70Q and the antenna recess 80X of the individual antenna base 70R.

[0254] In this regard, in this embodiment, as shown in Fig. 34, the peripheral wall 78X is not provided between the individual antenna bases 70A and 70B, and the peripheral wall 78X is not provided between the individual antenna bases 70B and 70C. That is, adjacent antenna recesses 80A and 80B are in contact with each other in the arrangement direction (y direction) of the individual antenna bases 70A and 70B, and adjacent antenna recesses 80B and 80C are in contact with each other in the arrangement direction (y direction) of the individual antenna bases 70B and 70C. In addition, part of the antenna surfaces 81A to 81C of each antenna recess 80A to 80C is cut out in the arrangement direction (y direction in this embodiment) of the individual antenna bases 70A to 70C. 33 and 34, with this configuration, the inter-element distance DE1, which is the distance between the reception point P1 of terahertz element 20A of the present embodiment and the reception point P1 of terahertz element 20B, is smaller than the inter-element distance DEX1 between terahertz element 20A and terahertz element 20B of the comparative example. Furthermore, the inter-element distance DE2 between the reception point P1 of terahertz element 20B of the present embodiment and the reception point P1 of terahertz element 20C is smaller than the inter-element distance DEX2 between terahertz element 20B and terahertz element 20C of the comparative example. That is, in terahertz device 10 of the present embodiment, adjacent terahertz elements 20A and 20B can be brought closer to each other, and adjacent terahertz elements 20B and 20C can be brought closer to each other, compared to terahertz device 10X of the comparative example.

[0255] (effect) The terahertz device 10 of this embodiment provides the following effects. (1-1) When viewed from the z direction, the size of each of the reflective films 82A and 82B along a first direction, which is the arrangement direction of the antenna surfaces 81A to 81C, in other words, the arrangement direction of the reflective films 82A to 82C, is smaller than the size of each of the reflective films 82A and 82B along a second direction, which is a direction different from the first direction, when viewed from the z direction. In this embodiment, the length LAY of the reflective film 82A and the length LBY of the reflective film 82B in the y direction, which is the arrangement direction of the reflective films 82A to 82C, are each shorter than the length LAX of the reflective film 82A and the length LBX of the reflective film 82B in the x direction, which is a direction different from the y direction.

[0256] According to this configuration, the inter-element distance DE1, which is the distance between the reception point P1 of the terahertz element 20A and the reception point P1 of the terahertz element 20B that are adjacent in the first direction (the y direction in this embodiment), can be made smaller than when the length LAY of the reflective film 82A and the length LBY of the reflective film 82B are equal to the length LAX of the reflective film 82A and the length LBX of the reflective film 82B, respectively. Therefore, the resolution in the detection range for detecting electromagnetic waves of the terahertz device 10 can be improved.

[0257] (1-2) When viewed from above, the portion of the arc-shaped outer periphery of the reflective film 82A connecting both end edges in the first direction (the y direction in this embodiment) is formed into an arc shape with central angles θa1, θa2 of less than 180°. When viewed from above, the portion of the arc-shaped outer periphery of the reflective film 82B connecting both end edges in the first direction is formed into an arc shape with central angles θb1, θb2 of less than 180°.

[0258] According to this configuration, the reflective films 82A and 82B can be formed so that the length LAY of the reflective film 82A and the length LBY of the reflective film 82B are shorter than the length LAX of the reflective film 82A and the length LBY of the reflective film 82B, respectively, while maintaining a spherical shape formed with a constant curvature.

[0259] (1-3) The gas space 92A partitioned by the antenna surface 81A and the dielectric 50 and the gas space 92B partitioned by the antenna surface 81B and the dielectric 50 are connected in the first direction (the y direction in this embodiment) at the boundary between the reflective film 82A (antenna surface 81A) and the reflective film 82B (antenna surface 81B). This configuration can obtain the effect of (1-1) above.

[0260] (1-4) In a cross-sectional view of the individual antenna base 70A taken along a plane passing through the center point P2 of the reflective film 82A and the center point P2 of the reflective film 82B and running along the y and z directions, the portion connecting both end edges of the reflective film 82A in the y direction and the portion connecting both end edges of the reflective film 82B in the y direction are each formed as an arc with central angles θz1, θz2 of less than 180°.

[0261] According to this configuration, the reflective films 82A and 82B can be formed such that the length LAY of the reflective film 82A and the length LBY of the reflective film 82B are shorter than the length LAX of the reflective film 82A and the length LBY of the reflective film 82B, respectively, while maintaining a spherical shape formed with a constant curvature.

[0262] (1-5) When viewed from the z direction, an opening edge 82Aa of the reflective film 82A and an opening edge 82Ba of the reflective film 82B, which are the boundaries between the reflective film 82A and the reflective film 82B, are each formed in a straight line.

[0263] According to this configuration, the reflective films 82A and 82B can be formed such that the length LAY of the reflective film 82A and the length LBY of the reflective film 82B are shorter than the length LAX of the reflective film 82A and the length LBY of the reflective film 82B, respectively, while maintaining a spherical shape formed with a constant curvature.

[0264] (1-6) When viewed from the z direction, the sizes of the reflective films 82B and 82C along the first direction are smaller than the sizes of the reflective films 82B and 82C along the second direction. In this embodiment, the length LBY of the reflective film 82B and the length LCY of the reflective film 82C in the y direction, which is the arrangement direction of the reflective films 82A to 82C, are each shorter than the length LBX of the reflective film 82B and the length LCX of the reflective film 82C in the x direction, which is a direction different from the y direction.

[0265] According to this configuration, the inter-element distance DE2, which is the distance between the reception point P1 of the terahertz element 20B and the reception point P1 of the terahertz element 20C that are adjacent in the first direction (the y direction in this embodiment), can be made smaller than when the length LBY of the reflective film 82B and the length LCY of the reflective film 82C are equal to the length LBX of the reflective film 82B and the length LCX of the reflective film 82C, respectively. Therefore, the resolution in the detection range for detecting electromagnetic waves of the terahertz device 10 can be improved.

[0266] (1-7) In a cross-sectional view of the individual antenna base 70C cut by a plane passing through the center point P2 of the reflective film 82C and along the y and z directions, the portion of the reflective film 82C connecting both end edges in the y direction is formed in an arc shape with a central angle θz3 of less than 180°.

[0267] According to this configuration, the reflective film 82C can be formed such that the length LCY of the reflective film 82C is shorter than the length LCX of the reflective film 82C while maintaining the spherical shape formed with a constant curvature.

[0268] (1-8) When viewed from the z direction, an opening edge 82Bb of the reflective film 82B, which is the boundary between the reflective film 82B and the reflective film 82C, and an opening edge 82Ca of the reflective film 82C are each formed in a straight line.

[0269] According to this configuration, the reflective film 82C can be formed such that the length LCY of the reflective film 82C is shorter than the length LCX of the reflective film 82C while maintaining the spherical shape formed with a constant curvature.

[0270] (1-9) The terahertz device 10 includes a dielectric 50 as a holding member attached to the base main surface 71 of each of the individual antenna bases 70A to 70C. The dielectric 50 holds each of the terahertz elements 20A to 20C.

[0271] According to this configuration, each terahertz element 20A to 20C is held by a common holding member, dielectric 50, and therefore the number of steps required for assembling dielectric 50 and antenna base 70 can be reduced compared to a configuration in which a separate holding member, dielectric, is provided for each terahertz element 20A to 20C.

[0272] (1-10) The terahertz device 10 includes a plurality of terahertz elements 20A-20C that receive electromagnetic waves, a dielectric 50 made of a dielectric material and surrounding each of the terahertz elements 20A-20C, gas spaces 92A-92C in which gas exists, and reflective films 82A-82C that form first, second, and third reflective surfaces. The reflective film 82A has a portion that faces the terahertz element 20A across the dielectric 50 and the gas space 92A, and reflects the electromagnetic waves that have propagated through the dielectric 50 and the gas space 92A toward a reception point P1 of the terahertz element 20A. The reflective film 82B has a portion that faces the terahertz element 20B across the dielectric 50 and the gas space 92B, and reflects the electromagnetic waves that have propagated through the dielectric 50 and the gas space 92B toward a reception point P1 of the terahertz element 20B. The reflective film 82C has a portion facing the terahertz element 20C across the dielectric 50 and the gas space 92C, and reflects the electromagnetic waves propagating through the dielectric 50 and the gas space 92C toward the receiving point P1 of the terahertz element 20C. If the refractive index of each of the terahertz elements 20A to 20C is an element refractive index n1, the refractive index of the gas in the gas spaces 92A to 92C is a gas refractive index n3, and the refractive index of the dielectric 50 is a dielectric refractive index n2, then n1>n2>n3.

[0273] According to this configuration, the terahertz elements 20A-20C are surrounded by the dielectric 50 having a refractive index between the element refractive index n1 and the gas refractive index n3, so that the change in refractive index at the inner and outer boundaries of the terahertz elements 20A-20C can be reduced. This makes it possible to suppress excessive reflection of electromagnetic waves at the inner and outer boundaries of the terahertz elements 20A-20C, thereby suppressing the generation of multiple resonance modes within the terahertz elements 20A-20C. Therefore, it is possible to suppress the generation of electromagnetic waves of frequencies other than the target frequency.

[0274] (1-11) The dielectric 50 has a dielectric principal surface 51 facing the reflective films 82A-82C and a dielectric back surface 52 opposite the dielectric principal surface 51. The terahertz device 10 has an individual antenna base 70A having an antenna surface 81A curved so as to be concave in a direction away from the terahertz element 20A, an individual antenna base 70B having an antenna surface 81B curved so as to be concave in a direction away from the terahertz element 20B, and an individual antenna base 70C having an antenna surface 81C curved so as to be concave in a direction away from the terahertz element 20C. The reflective films 82A-82C are films formed on the antenna surfaces 81A-81C, and gas spaces 92A-92C are partitioned by the dielectric principal surface 51 and the antenna surfaces 81A-81C.

[0275] According to this configuration, the gas spaces 92A to 92C are partitioned by the dielectric principal surface 51 and the antenna surfaces 81A to 81C, so that the electromagnetic waves emitted from the dielectric principal surface 51 reach the reflective films 82A to 82C through the gas spaces 92A to 92C, thereby achieving the effect of (1-10).

[0276] (1-12) The dielectric 50 and the antenna base 70 are separate bodies, and the terahertz device 10 includes an adhesive layer 91 as a fixing portion that fixes the dielectric 50 and the antenna base 70. According to this configuration, the adhesive layer 91 can suppress misalignment between the dielectric 50 and the antenna base 70, thereby suppressing misalignment between the terahertz element 20A and the reflective film 82A, between the terahertz element 20B and the reflective film 82B, and between the terahertz element 20C and the reflective film 82C.

[0277] (1-13) The reflective film 82A is formed on the antenna surface 81A, but is not formed on the base main surface 71 of the individual antenna base 70A. The reflective film 82B is formed on the antenna surface 81B, but is not formed on the base main surface 71 of the individual antenna base 70B. The reflective film 82C is formed on the antenna surface 81C, but is not formed on the base main surface 71 of the individual antenna base 70C.

[0278] This configuration makes it possible to prevent electromagnetic waves from being reflected by the reflective films 82A to 82C formed on the base main surfaces 71 of the individual antenna bases 70A to 70C, thereby suppressing problems caused by unwanted reflected waves, such as the generation of unwanted standing waves.

[0279] (1-14) The reflective films 82A to 82C are each shaped like a parabolic antenna. This configuration allows the electromagnetic waves to be suitably reflected toward the receiving points P1 of the terahertz elements 20A to 20C.

[0280] (1-15) Each of the reflective films 82A to 82C is in an electrically floating state. This configuration can prevent problems such as the reflective films 82A to 82C absorbing electromagnetic waves.

[0281] (1-16) The individual antenna bases 70A to 70C are each made of an insulating material. This configuration can prevent the reflective films 82A to 82C from being electrically connected to any member via the individual antenna bases 70A to 70C.

[0282] (1-17) The terahertz device 10 includes conductive parts 110A, 120A, 110B, 120B, 110C, and 120C that are provided in the dielectric 50 and electrically connected to the terahertz elements 20. With this configuration, the conductive parts 110A, 120A, 110B, 120B, 110C, and 120C are less likely to come into contact with the reflective films 82A to 82C that are located outside the dielectric 50. This can prevent electrical connection between the conductive parts 110A, 120A, 110B, 120B, 110C, and 120C and the reflective films 82A to 82C.

[0283] (1-18) When viewed from the z direction, the dielectric 50 has protrusions 61 and 62 that protrude laterally beyond the antenna base 70. Electrodes 101A, 102A, 101B, 102B, 101C, and 102C electrically connected to the conductive portions 110A, 120A, 110B, 120B, 110C, and 120C are formed on protruding surfaces 51a and 51b, which are portions of the dielectric main surface 51 that correspond to the protrusions 61 and 62. According to this configuration, the electrodes 101A, 102A, 101B, 102B, 101C, and 102C and the conductive portions 110A, 120A, 110B, 120B, 110C, and 120C can be used to electrically connect the terahertz elements 20A to 20C to the outside.

[0284] (1-19) The terahertz elements 20A to 20C each include pads 33a and 34a formed on the element main surface 21. The conductive portions 110A, 120A, 110B, 120B, 110C, and 120C extend in the x direction, which is the protruding direction of the protruding portions 61 and 62, so as to overlap with both the terahertz elements 20A to 20C and the electrodes 101A, 102A, 101B, 102B, 101C, and 102C when viewed from the z direction, and include element facing portions 111 and 121 facing the pads 33a and 34a in the z direction. The terahertz elements 20A to 20C are flip-chip mounted on the element facing portions 111 and 121 via bumps 114 and 124 provided between the pads 33a and 34a and the element facing portions 111 and 121 of the conductive portions 110A, 120A, 110B, 120B, 110C and 120C, respectively. This allows electrical connection between the terahertz elements 20A to 20C and both electrodes 101A, 102A, 101B, 102B, 101C and 102C.

[0285] In particular, flip-chip mounting is used as the mounting method for the terahertz elements 20A to 20C, which allows for faster signal transmission compared to mounting using wire bonding. In other words, mounting using wire bonding in the high-frequency band of terahertz electromagnetic waves can be problematic in that the signal transmission speed is limited by the wire. In this regard, flip-chip mounting, which does not use wires, does not cause this problem. This allows for faster signal transmission.

[0286] (1-20) The conductive parts 110A, 120A include electrode facing parts 112, 122 that face the electrodes 101A, 102A, and connection parts 113, 123 that extend in the x direction and connect the element facing parts 111, 121 to the electrode facing parts 112, 122. If the y direction of the conductive parts 110A, 120A is the width direction, at least a portion of the connection parts 113, 123 is formed to be narrower than the element facing parts 111, 121. With this configuration, because part or all of the connection parts 113, 123 overlap with the reflective film 82A, there is a concern that the connection parts 113, 123 may block electromagnetic waves (hereinafter referred to as blocking).

[0287] In this regard, in this embodiment, the area that is blocked can be reduced because at least a portion of the connecting portions 113, 123 is formed narrower than the element facing portions 111, 121. This reduces blocking.

[0288] Furthermore, the contact area can be increased because the element facing portions 111, 121 are wider than the connection portions 113, 123. This allows suitable electrical connection between the pads 33a, 34a and the element facing portions 111, 121 using the bumps 114, 124.

[0289] Similarly to the conductive parts 110A and 120A, the conductive parts 110B, 120B, 110C, and 120C also include electrode facing parts 112 and 122 and connection parts 113 and 123. This, similar to the conductive parts 110A and 120A, can reduce blocking and allow suitable electrical connection between the pads 33a and 34a and the element facing parts 111 and 121 using the bumps 114 and 124.

[0290] (1-21) The electrode facing portions 112, 122 of the conductive portions 110A, 120A are formed wider than the connecting portions 113, 123. This configuration allows for a larger contact area, thereby enabling favorable electrical connection between the electrode facing portions 112, 122 and the electrodes 101A, 102A. Furthermore, the electrode facing portions 112, 122 of the conductive portions 110B, 120B, 110C, 120C are also formed wider than the connecting portions 113, 123, thereby achieving the above-mentioned effect.

[0291] (1-22) The first connection portion 113 has a first connection main body portion 113a formed narrower than the first element facing portion 111, and a first element side tapered portion 113b connecting the first connection main body portion 113a and the first element facing portion 111. The first element side tapered portion 113b is formed so as to gradually increase in width from the first connection main body portion 113a toward the first element facing portion 111. This configuration can reduce reflected waves generated within the first conductive portions 110A to 110C. The same applies to the second connection portion 123.

[0292] (1-23) The first connection main body 113a is formed to be narrower than the first electrode opposing portion 112. The first connection portion 113 includes a first electrode side tapered portion 113c that connects the first connection main body 113a and the first electrode opposing portion 112, and the first electrode side tapered portion 113c is formed to gradually increase in width from the first connection main body 113a toward the first electrode opposing portion 112. This configuration can reduce reflected waves generated within the first conductive portions 110A to 110C. The same applies to the second connection portion 123.

[0293] (1-24) The first pad 33a and the first element facing portion 111 extend in the x direction, and a plurality of first bumps 114 are arranged in the x direction. Similarly, the second pad 34a and the second element facing portion 121 extend in the x direction, and a plurality of second bumps 124 are arranged in the x direction. This allows the contact area to be increased, and the contact resistance to be reduced.

[0294] In a configuration in which the pads 33a and 34a are spaced apart in the y direction, if the pads 33a and 34a were extended in the y direction, the distance between the pads 33a and 34a would be shortened, which could result in a short circuit or interference between the receiving point P1 and the pads 33a and 34a, which could impede the propagation of electromagnetic waves. In this embodiment, however, the pads 33a and 34a extend in the x direction, which is perpendicular to the opposing direction of the pads 33a and 34a, and therefore the above-mentioned problems can be suppressed.

[0295] [Second embodiment] A terahertz device 10 according to a second embodiment will be described with reference to Figs. 35 to 45. The terahertz device 10 according to this embodiment differs from the terahertz device 10 according to the first embodiment mainly in the configuration of the antenna base 70. In the following description, components common to the terahertz device 10 according to the first embodiment are given the same reference numerals, and their description may be omitted. Furthermore, in this embodiment, although the configuration of the antenna base 70 differs from that of the antenna base 70 according to the first embodiment, the multiple individual antenna bases are identified by sequentially designating them as 70A, 70B, 70C, and so on.

[0296] As shown in Figures 35 and 41, the terahertz device 10 includes multiple (eight in this embodiment) terahertz elements 20, a dielectric 50 which is an example of a holding member, an antenna base 70, a reflective film 82, and a gas space 92.

[0297] 35, the plurality of terahertz elements 20 include terahertz element 20A, terahertz element 20B, terahertz element 20C, terahertz element 20D, terahertz element 20E, terahertz element 20F, terahertz element 20G, and terahertz element 20H. The terahertz elements 20A to 20H have the same configuration as each other and the same configuration as the terahertz element 20 of the first embodiment.

[0298] Dielectric 50 surrounds each of the multiple terahertz elements 20. As shown in Fig. 41 and Fig. 42, dielectric 50 surrounds the entire terahertz element 20E, and covers element main surface 21, element back surface 22, and element side surfaces 23 to 26 of terahertz element 20E.

[0299] The element main surface 21, element back surface 22, and element side surfaces 23 to 26 of the terahertz element 20E are in contact with the dielectric 50. That is, similar to the first embodiment, the dielectric 50 of this embodiment surrounds the terahertz element 20E so that no gap is generated between the dielectric 50 and the terahertz element 20E. In other words, the dielectric 50 seals the terahertz element 20E.

[0300] Although not shown, the dielectric 50 surrounds the entirety of each of the terahertz elements 20A to 20D and 20F to 20H, similarly to the terahertz element 20E, and covers the element main surface 21, element back surface 22 and element side surfaces 23 to 26 of each of the terahertz elements 20A to 20D and 20F to 20H. In other words, the dielectric 50 seals each of the terahertz elements 20A to 20D and 20F to 20H.

[0301] 35, the dielectric 50 is formed in the shape of a plate with its thickness direction in the z direction. Specifically, the dielectric 50 is a rectangular plate with its longitudinal direction in the y direction and its lateral direction in the x direction. The dielectric 50 is configured to cover the entire antenna base 70 from above. In this embodiment, the dielectric 50 is configured to protrude from both sides of the antenna base 70 in the x direction and to protrude from both sides of the antenna base 70 in the y direction.

[0302] As shown in Figures 41 and 42, the dielectric 50 has a dielectric principal surface 51 and a dielectric back surface 52 that intersect with the z direction. The dielectric principal surface 51 and the dielectric back surface 52 are each perpendicular to the z direction, for example. The dielectric principal surface 51 faces downward. The dielectric back surface 52 is the surface opposite to the dielectric principal surface 51 and faces upward. In this embodiment, the dielectric back surface 52 constitutes the device principal surface 11.

[0303] 35, dielectric 50 has first dielectric side surface 53 and second dielectric side surface 54, which are end surfaces in the x direction, and third dielectric side surface 55 and fourth dielectric side surface 56, which are end surfaces in the y direction. Each of dielectric side surfaces 53 to 56 constitutes a part of device side surfaces 13 to 16. In this embodiment, first dielectric side surface 53 and second dielectric side surface 54 are orthogonal to third dielectric side surface 55 and fourth dielectric side surface 56.

[0304] 41 and 42, the terahertz element 20E is provided in the dielectric 50 with the element main surface 21 facing the dielectric main surface 51, as in the first embodiment. The terahertz element 20E is disposed between the dielectric main surface 51 and the dielectric back surface 52. In this embodiment, as in the first embodiment, the dielectric thickness D2, which is the length of the dielectric 50 in the z direction, is set so as to satisfy the resonance condition of the electromagnetic wave received by the terahertz element 20E. Note that the terahertz elements 20A to 20D and 20F to 20H are also provided in the dielectric 50, as in the terahertz element 20E.

[0305] As shown in FIG. 35, the terahertz element 20A, the terahertz element 20B, the terahertz element 20C, and the terahertz element 20D are arranged aligned with one another in the x direction and spaced apart from one another in the y direction.

[0306] Terahertz element 20E, terahertz element 20F, terahertz element 20G, and terahertz element 20H are arranged aligned in the x direction and spaced apart in the y direction. In this embodiment, the pitch (inter-element distance) of each of terahertz elements 20E to 20H in the y direction is equal to the pitch (inter-element distance) of each of terahertz elements 20A to 20D in the y direction. Here, for example, if the difference between the average value of the pitch of each of terahertz elements 20E to 20H in the y direction and the average value of the pitch of each of terahertz elements 20A to 20D in the y direction is within 5% of the average value of the pitch of each of terahertz elements 20A to 20D in the y direction, it can be said that the pitch of each of terahertz elements 20E to 20H in the y direction is equal to the pitch of each of terahertz elements 20A to 20D in the y direction. Here, the pitch in the y direction (the distance between elements) is the distance between the reception points P1 of the terahertz elements 20 adjacent to each other in the y direction.

[0307] The terahertz elements 20A to 20D and the terahertz elements 20E to 20H are arranged to be spaced apart in the x direction. In this embodiment, the terahertz elements 20A to 20D are arranged closer to the first dielectric side surface 53 than the terahertz elements 20E to 20H.

[0308] The terahertz elements 20A to 20D and the terahertz elements 20E to 20H are arranged spaced apart in the x direction while being shifted in the y direction. In this embodiment, when viewed from above, the terahertz elements 20A to 20D and the terahertz elements 20E to 20H are arranged alternately in the y direction. The terahertz elements 20A to 20D are arranged closer to the third dielectric side surface 55 than the terahertz elements 20E to 20H. More specifically, the terahertz element 20A is arranged closer to the third dielectric side surface 55 than the terahertz element 20E in the y direction. The terahertz element 20B is arranged between the terahertz element 20E and the terahertz element 20F in the y direction. The terahertz element 20C is arranged between the terahertz element 20F and the terahertz element 20G in the y direction. The terahertz element 20D is disposed between the terahertz element 20G and the terahertz element 20H in the y direction.

[0309] As shown in FIGS. 36 and 37 , in this embodiment, the antenna base 70 has a generally rectangular shape when viewed from above, with its longer side oriented in the y direction and its shorter side oriented in the x direction. More specifically, a first step portion 79A and a second step portion 79B are provided at both ends of the antenna base 70 in the y direction. The first step portion 79A is provided on the third base side surface 75T of the antenna base 70, and the second step portion 79B is provided on the fourth base side surface 76T of the antenna base 70. The first step portion 79A is provided such that a portion of the third base side surface 75T closer to the first base side surface 73T is closer to the first dielectric side surface 53 of the dielectric 50 than a portion of the third base side surface 75T closer to the first base side surface 73T. The second step portion 79B is provided such that a portion of the fourth base side surface 76T closer to the first base side surface 73T is closer to the first dielectric side surface 53 than a portion of the fourth base side surface 76T closer to the second base side surface 74T. Therefore, the first base side surface 73T of the antenna base 70 is formed to be shifted closer to the first dielectric side surface 53 in the y direction with respect to the second base side surface 74T.

[0310] The antenna base 70 of this embodiment is formed of, for example, an insulating material, similar to the antenna base 70 of the first embodiment. Specifically, the antenna base 70 is formed of a dielectric material, for example, a synthetic resin such as epoxy resin. An example of the epoxy resin is glass epoxy resin. However, the material of the antenna base 70 is not limited to this and may be any material, such as Si, Teflon, or glass. The color of the antenna base 70 may be any color, such as black.

[0311] The antenna base 70 of this embodiment is made up of a combination of a plurality of (eight in this embodiment) individual antenna bases 70A to 70H. More specifically, the antenna base 70 has a row of individual antenna bases 70A to 70D and a row of individual antenna bases 70E to 70H.

[0312] The individual antenna bases 70A to 70D constitute a first base side surface 73T and are arranged along the y direction. The individual antenna base 70A constitutes a third base side surface 75T, and the individual antenna base 70D constitutes a fourth base side surface 76T. The individual antenna base 70B is adjacent to the individual antenna base 70A and the individual antenna base 70C. That is, the individual antenna base 70B is sandwiched between the individual antenna base 70A and the individual antenna base 70C. The individual antenna base 70C is adjacent to the individual antenna base 70B and the individual antenna base 70D. That is, the individual antenna base 70C is sandwiched between the individual antenna base 70B and the individual antenna base 70D.

[0313] The individual antenna bases 70E to 70H constitute the second base side surface 74T and are arranged along the y direction. The individual antenna base 70E constitutes the third base side surface 75T. That is, the third base side surface 75T is made up of the individual antenna base 70A and the individual antenna base 70E. The individual antenna base 70H constitutes the fourth base side surface 76T. That is, the fourth base side surface 76T is made up of the individual antenna base 70D and the individual antenna base 70H. The individual antenna base 70F is adjacent to the individual antenna base 70E and the individual antenna base 70G. That is, the individual antenna base 70F is sandwiched between the individual antenna base 70E and the individual antenna base 70G. The individual antenna base 70G is adjacent to the individual antenna base 70F and the individual antenna base 70H. That is, the individual antenna base 70G is sandwiched between the individual antenna base 70F and the individual antenna base 70H.

[0314] In this embodiment, the individual antenna bases 70A to 70D and the individual antenna bases 70E to 70H are arranged with a shift in the y direction. More specifically, when viewed from the x direction, the individual antenna base 70A overlaps with both the individual antenna bases 70E and 70F, the individual antenna base 70B overlaps with both the individual antenna bases 70F and 70G, and the individual antenna base 70C overlaps with both the individual antenna bases 70G and 70H. Specifically, in the y direction, the individual antenna base 70A is arranged closer to the third base side surface 75T than the individual antenna base 70E and closer to the fourth base side surface 76T than the individual antenna base 70F. The individual antenna base 70A is in contact with the individual antenna base 70E. The individual antenna base 70B is arranged closer to the third base side surface 75T than the individual antenna base 70F and closer to the fourth base side surface 76T than the individual antenna base 70G. The individual antenna base 70B is in contact with both the individual antenna bases 70E and 70F. The individual antenna base 70C is positioned closer to the third base side surface 75T than the individual antenna base 70G and closer to the fourth base side surface 76T than the individual antenna base 70H. The individual antenna base 70C is in contact with both the individual antenna bases 70F and 70G. The individual antenna base 70H is positioned closer to the third base side surface 75T than the individual antenna base 70D. The individual antenna base 70D is in contact with both the individual antenna bases 70G and 70H.

[0315] As shown in FIG. 35, the individual antenna base 70A is arranged to face the terahertz element 20A in the thickness direction (z direction) of the terahertz element 20A. The individual antenna base 70B is arranged to face the terahertz element 20B in the thickness direction (z direction) of the terahertz element 20B. The individual antenna base 70C is arranged to face the terahertz element 20C in the thickness direction (z direction) of the terahertz element 20C. The individual antenna base 70D is arranged to face the terahertz element 20D in the thickness direction (z direction) of the terahertz element 20D. The individual antenna base 70E is arranged to face the terahertz element 20E in the thickness direction (z direction) of the terahertz element 20E. The individual antenna base 70F is arranged to face the terahertz element 20F in the thickness direction (z direction) of the terahertz element 20F. The individual antenna base 70G is arranged to face the terahertz element 20G in the thickness direction (z direction) of the terahertz element 20G. The individual antenna base 70H is arranged to face the terahertz element 20H in the thickness direction (z direction) of the terahertz element 20H. In this embodiment, the individual antenna bases 70A to 70H are arranged below the terahertz elements 20A to 20H, respectively.

[0316] As shown in Figures 41 to 43, the antenna base 70 has a plurality of antenna recesses 80 recessed from the base main surface 71T toward the base back surface 72T, as in the first embodiment. Specifically, as shown in Figures 36 and 37, in this embodiment, the individual antenna base 70A has the antenna recess 80A, the individual antenna base 70B has the antenna recess 80B, the individual antenna base 70C has the antenna recess 80C, the individual antenna base 70D has the antenna recess 80D, the individual antenna base 70E has the antenna recess 80E, the individual antenna base 70F has the antenna recess 80F, the individual antenna base 70G has the antenna recess 80G, and the individual antenna base 70H has the antenna recess 80H. In other words, the antenna base 70 has one antenna recess 80 for each individual antenna base.

[0317] As shown in FIGS. 41 to 43, the antenna recess 80 has an antenna surface 81 facing the terahertz element 20 across the dielectric 50 and the gas space 92, as in the first embodiment. Specifically, as shown in FIGS. 36 and 37, in this embodiment, the antenna recess 80A has an antenna surface 81A, the antenna recess 80B has an antenna surface 81B, the antenna recess 80C has an antenna surface 81C, and the antenna recess 80D has an antenna surface 81D. Furthermore, the antenna recess 80E has an antenna surface 81E, the antenna recess 80F has an antenna surface 81F, the antenna recess 80G has an antenna surface 81G, and the antenna recess 80H has an antenna surface 81H. When viewed from above, these antenna surfaces 81A to 81H have the same shape as the openings of the corresponding antenna recesses 80A to 80H.

[0318] As shown in FIGS. 41 to 43, similarly to the first embodiment, the reflective film 82 is formed on the antenna surface 81. The reflective film 82 is formed over the entire antenna surface 81. On the other hand, the reflective film 82 is not formed on the base main surface 71T. In other words, the reflective film 82 has substantially the same shape as the antenna surface 81. The reflective film 82 is formed from the same material as the reflective film 82 of the first embodiment.

[0319] The reflective film 82 includes a reflective film 82A formed on the antenna surface 81A, a reflective film 82B formed on the antenna surface 81B, a reflective film 82C formed on the antenna surface 81C, a reflective film 82D formed on the antenna surface 81D, a reflective film 82E formed on the antenna surface 81E, a reflective film 82F formed on the antenna surface 81F, a reflective film 82G formed on the antenna surface 81G, and a reflective film 82H formed on the antenna surface 81H. In this embodiment, the reflective films 82A to 82H are an integrally formed single component.

[0320] The reflective film 82A has approximately the same shape as the antenna surface 81A, the reflective film 82B has approximately the same shape as the antenna surface 81B, the reflective film 82C has approximately the same shape as the antenna surface 81C, the reflective film 82D has approximately the same shape as the antenna surface 81D, the reflective film 82E has approximately the same shape as the antenna surface 81E, the reflective film 82F has approximately the same shape as the antenna surface 81F, the reflective film 82G has approximately the same shape as the antenna surface 81G, and the reflective film 82H has approximately the same shape as the antenna surface 81H. In other words, the reflective films 82A to 82H are each a parabolic mirror of revolution and are curved in a cone shape. When viewed from above, the reflective films 82A to 82H each have a circular shape with a missing portion. The reflective films 82A to 82H are each curved so as to be convex toward the rear surface 12 of the device. The reflective film 82 is open in one direction (upward in this embodiment).

[0321] 41 to 43, the reflective film 82 and the dielectric 50 face each other in the z direction. In other words, the reflective film 82 is provided at a position facing the dielectric 50. The electromagnetic waves reflected by the reflective film 82 are output toward the reception point P1. Specifically, the electromagnetic waves reflected by the reflective film 82A are output toward the reception point P1 of the terahertz element 20A. The electromagnetic waves reflected by the reflective film 82B are output toward the reception point P1 of the terahertz element 20B. The electromagnetic waves reflected by the reflective film 82C are output toward the reception point P1 of the terahertz element 20C. The electromagnetic waves reflected by the reflective film 82D are output toward the reception point P1 of the terahertz element 20D. The electromagnetic waves reflected by the reflective film 82E are output toward the reception point P1 of the terahertz element 20E. The electromagnetic waves reflected by the reflective film 82F are output toward the reception point P1 of the terahertz element 20F. The electromagnetic waves reflected by the reflective film 82G are output toward the reception point P1 of the terahertz element 20G. The electromagnetic wave reflected by the reflective film 82H is output toward the receiving point P1 of the terahertz device 20H.

[0322] The positional relationship between the reflective film 82 and the terahertz element 20 is the same as in the first embodiment. The size relationship between the reflective film 82 and the terahertz element 20 is also the same as in the first embodiment. That is, when viewed from above, the reflective films 82A to 82H are each formed larger than the terahertz elements 20A to 20H.

[0323] As in the first embodiment, the antenna base 70 and the dielectric 50 are fixed via an adhesive layer 91. The adhesive layer 91 is configured so as not to protrude inward from the reflective film 82 (in other words, toward the terahertz element 20).

[0324] As shown in FIGS. 38 to 40, in this embodiment, the antenna base 70 uses three types of individual antenna bases. As shown in FIG. 38, the individual antenna base 70E has a base main surface 71 and a base back surface 72 as surfaces that intersect with the z direction. The base main surface 71 and the base back surface 72 are each surfaces that intersect with the z direction and are perpendicular to the z direction in this embodiment. The base main surface 71 and the base back surface 72 each have a pentagonal shape when viewed from the z direction. In this embodiment, the base main surface 71 and the base back surface 72 have, for example, the same shape. However, this is not a limitation, and the base main surface 71 and the base back surface 72 may have different shapes.

[0325] The individual antenna base 70E has base side surfaces, which are a first base side surface 73, a second base side surface 74, a third base side surface 75, and a fourth base side surface 76. These base side surfaces 73 to 76 are surfaces that face laterally in the terahertz device 10 (antenna base 70). Each of the base side surfaces 73 to 76 is a surface that is perpendicular to the opposing direction between the base main surface 71 and the base back surface 72. Each of the base side surfaces 73 to 76 connects the base main surface 71 and the base back surface 72.

[0326] The third base side surface 75 and the fourth base side surface 76 are both end surfaces in the y direction of the individual antenna base 70E. The third base side surface 75 forms a part of the third base side surface 75T of the antenna base 70. When viewed from the z direction, the third base side surface 75 and the fourth base side surface 76 each extend along the x direction.

[0327] The first base side surface 73 and the second base side surface 74 are the two end surfaces of the individual antenna base 70E in the x direction, respectively. The first base side surface 73 is a surface of the individual antenna base 70E near the first base side surface 73T (see FIG. 37) of the antenna base 70, and extends in a direction intersecting both the x and y directions when viewed from the z direction. Specifically, when viewed from above, the first base side surface 73 is formed in a V shape. The first base side surface 73 has a base side surface portion 73a, which is a portion of the first base side surface 73 closer to the third base side surface 75, and a base side surface portion 73b, which is a portion of the first base side surface 73 closer to the fourth base side surface 76. The base side surface portion 73a is a surface that slopes toward the third base side surface 75 as it approaches the second base side surface 74. The base side surface portion 73b is a surface that slopes toward the fourth base side surface 76 as it approaches the second base side surface 74.

[0328] The second base side surface 74 constitutes a part of a second base side surface 74T of the antenna base 70. When viewed from the z direction, the second base side surface 74 extends along the y direction. The antenna surface 81E of the antenna recess 80E is recessed from the base main surface 71 of the individual antenna base 70E toward the base back surface 72. In this embodiment, in a cross-sectional view of the individual antenna base 70E cut along a plane along the x and z directions, the antenna surface 81E is curved so as to be convex toward the base back surface 72. The antenna surface 81E is open at the base main surface 71. In other words, the antenna surface 81E is open upward.

[0329] The opening of the antenna surface 81E has a circular shape with a portion missing when viewed from above. Specifically, the opening of the antenna surface 81E is missing at an opening end 81Ea, which is the end of the opening of the antenna surface 81E on the base side surface portion 73a side, an opening end 81Eb, which is the end of the opening of the antenna surface 81E on the base side surface portion 73b side, and an opening end 81Ec, which is the end on the fourth base side surface 76 side. Each of these opening ends 81Ea to 81Ec is formed in a straight line when viewed from above.

[0330] When viewed from above, the opening end 81Ea of the antenna surface 81E is formed at a position overlapping with the base side portion 73a, the opening end 81Eb is formed at a position overlapping with the base side portion 73b, and the opening end 81Ec is formed at a position overlapping with the fourth base side surface 76.

[0331] The reflective film 82E is formed on the antenna surface 81E. The reflective film 82E is formed over the entire antenna surface 81E. On the other hand, the reflective film 82E is not formed on the base main surface 71 of the individual antenna base 70E.

[0332] When viewed from above, the opening of the reflective film 82E has the same shape as the opening of the antenna surface 81E. That is, when viewed from above, the opening of the reflective film 82E has an opening edge 82Ea that overlaps with an opening edge 81Ea of the antenna surface 81E, an opening edge 82Eb that overlaps with an opening edge 81Eb of the antenna surface 81E, and an opening edge 82Ec that overlaps with an opening edge 81Ec of the antenna surface 81E. When viewed from above, the opening edges 82Ea to 82Ec are each formed in a straight line.

[0333] When viewed from above, the reflective film 82E is formed so that its center point P2 is at a position different from the center of the individual antenna base 70E in the x and y directions. In this embodiment, when viewed from above, the reflective film 82E is formed so that its center point P2 is closer to the first base side surface 73 in the x direction than the center of the individual antenna base 70E in the x direction. When viewed from above, the reflective film 82E is formed so that its center point P2 is closer to the fourth base side surface 76 in the y direction than the center of the individual antenna base 70E in the y direction.

[0334] When viewed from above, the center point P2 of the reflective film 82E coincides with the center point of the antenna surface 81E, and the shape of the reflective film 82E and the shape of the antenna surface 81E are approximately identical, so when viewed from above, the antenna surface 81E is formed so that the center point of the antenna surface 81E is at a position different from the center of the individual antenna base 70E in the x and y directions, just like the reflective film 82E.

[0335] When viewed from above, the portion of the arc-shaped outer periphery of reflective film 82E that connects both end edges in a first direction, which is the arrangement direction of reflective film 82E and reflective film 82F, is formed into an arc shape with a central angle θe1 ​​of less than 180°. In this embodiment, when viewed from above, the portion of the arc-shaped outer periphery of reflective film 82E that connects both end edges in the first direction (y direction in this embodiment) is formed into an arc shape with a central angle θe1 ​​of less than 180°.

[0336] When viewed from above, the arc-shaped outer periphery of the reflective film 82E, at a portion connecting both end edges in the third direction, which is the arrangement direction of the reflective film 82E and the reflective film 82A, is formed in an arc shape with a central angle of less than 180°. Here, the third direction is a direction different from both the x direction and the y direction when viewed from the z direction. In one example, the third direction is a direction intersecting both the x direction and the y direction when viewed from the z direction. In this embodiment, the third direction is a direction extending obliquely from the base side surface 75T to the base side surface 76T as it moves from the base side surface 73T to the base side surface 74T of the antenna base 70.

[0337] In this embodiment, when viewed from above, the portion of the arc-shaped outer peripheral edge of the reflective film 82E that connects both end edges in the third direction (in this embodiment, a direction perpendicular to the direction in which the base side portion 73a extends when viewed from above) is formed in an arc shape with a central angle θe2 of less than 180°.

[0338] When viewed from above, the arc-shaped outer periphery of the reflective film 82E, at a portion connecting both end edges in a fourth direction, which is the arrangement direction of the reflective film 82E and the reflective film 82B, is formed in an arc shape with a central angle of less than 180°. Here, the fourth direction is a direction different from the x direction, the y direction, and the third direction when viewed from the z direction. In one example, the fourth direction is a direction intersecting each of the x direction, the y direction, and the third direction when viewed from the z direction. In this embodiment, the fourth direction is a direction extending obliquely from the base side surface 76T to the base side surface 75T as it moves from the base side surface 73T to the base side surface 74T of the antenna base 70.

[0339] In this embodiment, when viewed from above, the portion of the arc-shaped outer peripheral edge of the reflective film 82E that connects both end edges in the fourth direction (in this embodiment, a direction perpendicular to the direction in which the base side portion 73b extends when viewed from above) is formed in an arc shape with a central angle θe3 of less than 180°.

[0340] Because the reflective film 82E and the antenna surface 81E have substantially the same shape when viewed from above, similarly to the reflective film 82E, the portion of the arc-shaped outer periphery of the antenna surface 81E connecting both edges in the first direction, which is the arrangement direction of the antenna surface 81E and the antenna surface 81F, is formed in an arc shape with a central angle of less than 180°. The portion of the arc-shaped outer periphery of the antenna surface 81E connecting both edges in the third direction, which is the arrangement direction of the antenna surface 81E and the antenna surface 81A (in this embodiment, the direction perpendicular to the extension direction of the base side surface portion 73a when viewed from above), is formed in an arc shape with a central angle of less than 180°. The portion of the arc-shaped outer periphery of the antenna surface 81E connecting both edges in the fourth direction, which is the arrangement direction of the antenna surface 81E and the antenna surface 81B (in this embodiment, the direction perpendicular to the extension direction of the base side surface portion 73b when viewed from above), is formed in an arc shape with a central angle of less than 180°.

[0341] When viewed from above, the length LR1 of a perpendicular line to the opening edge 82Ea of the reflective film 82E that passes through the center point P2 of the reflective film 82E is smaller than the radius RE of the reflective film 82E. When viewed from above, the length LR2 of a perpendicular line to the opening edge 82Eb of the reflective film 82E that passes through the center point P2 of the reflective film 82E is smaller than the radius RE of the reflective film 82E. When viewed from above, the length LR3 of a perpendicular line to the opening edge 82Ec of the reflective film 82E that passes through the center point P2 of the reflective film 82E is smaller than the radius RE of the reflective film 82E. Note that when viewed from above, the perpendicular line to the opening edge 82Ec of the reflective film 82E that passes through the center point P2 of the reflective film 82E is a straight line extending along the y direction. Furthermore, the length LR1 can also be referred to as the length along the third direction, and the length LR2 can also be referred to as the length along the fourth direction. Therefore, the length (LR1+RE) of the reflective film 82E in the third direction is shorter than the diameter of the reflective film 82E, and the length (LR2+RE) of the reflective film 82E in the fourth direction is shorter than the diameter of the reflective film 82E. Furthermore, the length (LR3+RE) of the reflective film 82E in the first direction is shorter than the diameter of the reflective film 82E. Thus, when viewed from above, the size of the reflective film 82E along the first direction, which is the direction in which the reflective films 82E to 82H (see FIG. 37) are arranged, can be said to be smaller than the size of the reflective film 82E along the second direction, which is different from the first direction. Here, the second direction is a direction (the x direction in this embodiment) perpendicular to the first direction when viewed from above. Furthermore, when viewed from above, the size of the reflective film 82E along the third direction, which is the direction in which the reflective films 82E and 82A are arranged, can be said to be smaller than the size of the reflective film 82E along the second direction. Also, when viewed from above, the size of the reflective film 82E along the fourth direction, which is the direction in which the reflective films 82E and 82B are arranged, is smaller than the size of the reflective film 82E along the second direction.

[0342] Furthermore, since the reflective film 82E and the antenna surface 81E have approximately the same shape when viewed from above, the relationship between the length of the perpendicular line passing through the center point of the antenna surface 81E among the perpendicular lines to the opening ends 81Ea to 81Ec of the antenna surface 81E and the radius of the antenna surface 81E is the same as the relationship between the lengths LR1 to LR3 of the reflective film 82E and the radius RE of the reflective film 82E.

[0343] 41 , in a cross-sectional view of the individual antenna base 70E taken along a plane that passes through the center point P2 of the reflective film 82E and is aligned with the y and z directions, the portion connecting both end edges of the reflective film 82E in the y direction is formed into an arc shape with a central angle of less than 180°. Furthermore, although not shown, in a cross-sectional view of the individual antenna base 70E taken along a plane that passes through the center point P2 of the reflective film 82E and is aligned with the third direction and the z direction, the portion connecting both end edges of the reflective film 82E in the third direction is formed into an arc shape with a central angle of less than 180°. Furthermore, although not shown, in a cross-sectional view of the individual antenna base 70E taken along a plane that passes through the center point P2 of the reflective film 82E and is aligned with the fourth direction and the z direction, the portion connecting both end edges of the reflective film 82E in the fourth direction is formed into an arc shape with a central angle of less than 180°.

[0344] 41 , in a cross-sectional view of the individual antenna base 70E taken along a plane passing through the center of the antenna surface 81E and extending along the y and z directions, the portion connecting both end edges of the antenna surface 81E in the y direction is formed into an arc shape with a central angle of less than 180°. Furthermore, although not shown, in a cross-sectional view of the individual antenna base 70E taken along a plane passing through the center of the antenna surface 81E and extending along the third and z directions, the portion connecting both end edges of the antenna surface 81E in the third direction is formed into an arc shape with a central angle of less than 180°. Furthermore, although not shown, in a cross-sectional view of the individual antenna base 70E taken along a plane passing through the center of the antenna surface 81E and extending along the fourth and z directions, the portion connecting both end edges of the antenna surface 81E in the fourth direction is formed into an arc shape with a central angle of less than 180°.

[0345] When viewed from above, the individual antenna base 70E has a peripheral wall 78E that surrounds the opening of the antenna recess 80E except for the missing portion of the opening. The peripheral wall 78E constitutes the base main surface 71 of the individual antenna base 70E.

[0346] 39, like the individual antenna base 70E, the individual antenna base 70A has a base main surface 71 and a base back surface 72 as surfaces intersecting the z direction. When viewed from the z direction, the base main surface 71 and the base back surface 72 each have a substantially rectangular shape with one of four sides extending in a direction intersecting both the x direction and the y direction. In this embodiment, the base main surface 71 and the base back surface 72 have, for example, the same shape. However, this is not a limitation, and the base main surface 71 and the base back surface 72 may have different shapes.

[0347] The individual antenna base 70A has four base side surfaces, namely, a first base side surface 73, a second base side surface 74, a third base side surface 75, and a fourth base side surface 76. These base side surfaces 73 to 76 are surfaces facing laterally in the terahertz device 10 (antenna base 70). Each of the base side surfaces 73 to 76 is a surface perpendicular to the opposing direction of the base main surface 71 and the base back surface 72, and connects the base main surface 71 and the base back surface 72.

[0348] The third base side surface 75 and the fourth base side surface 76 constitute both end surfaces of the individual antenna base 70A in the y direction. The third base side surface 75 constitutes a part of the third base side surface 75T of the antenna base 70. The third base side surface 75 and the fourth base side surface 76 each extend along the x direction when viewed from above. When viewed from the z direction, the length in the x direction of the fourth base side surface 76 is shorter than the length in the x direction of the third base side surface 75.

[0349] The first base side surface 73 and the second base side surface 74 constitute both end surfaces of the individual antenna base 70A in the x direction. The first base side surface 73 constitutes a part of a first base side surface 73T of the antenna base 70. When viewed from above, the first base side surface 73 extends along the y direction.

[0350] The second base side surface 74 is a side surface of the individual antenna base 70A near the second base side surface 74T of the antenna base 70, and extends in a direction intersecting both the x direction and the y direction when viewed from above. Specifically, the second base side surface 74 has a base side surface portion 74a that is closer to the third base side surface 75 and a base side surface portion 74b that is closer to the fourth base side surface 76. When viewed from the z direction, the base side surface portion 74a extends along the y direction. When viewed from the z direction, the base side surface portion 74b is an inclined surface that slopes toward the first base side surface 73 as it approaches the fourth base side surface 76.

[0351] The antenna surface 81A of the antenna recess 80A is recessed from the base main surface 71 toward the base back surface 72 of the individual antenna base 70A. In this embodiment, in a cross-sectional view of the individual antenna base 70A cut along a plane along the x and z directions, the antenna surface 81A is curved so as to be convex toward the base back surface 72. The antenna surface 81A is open at the base main surface 71. In other words, the antenna surface 81A is open facing upward.

[0352] The opening of the antenna surface 81A has a circular shape with a portion missing when viewed from above. Specifically, the opening of the antenna surface 81A is missing at an opening end 81Aa on the second base side surface 74 side and an opening end 81Ab on the fourth base side surface 76 side. In other words, these opening ends 81Aa and 81Ab are each formed in a straight line when viewed from above. When viewed from above, the opening end 81Aa is formed at a position overlapping with the base side surface portion 74b, and the opening end 81Ab is formed at a position overlapping with the fourth base side surface 76.

[0353] When viewed from above, the reflective film 82A is formed so that its center point P2 is at a position different from the center of the individual antenna base 70A in the x and y directions. In this embodiment, the reflective film 82A is formed so that its center point P2 is closer to the base side surface portion 74b in the x direction than the center of the individual antenna base 70A in the x direction. When viewed from above, the reflective film 82A is formed so that its center point P2 is closer to the fourth base side surface 76 in the y direction than the center of the individual antenna base 70A in the y direction.

[0354] When viewed from above, the center point P2 of the reflective film 82A coincides with the center point of the antenna surface 81A, and the shape of the reflective film 82A and the shape of the antenna surface 81A are approximately identical, so when viewed from above, the antenna surface 81A is formed so that the center point of the antenna surface 81A is at a position different from the center of the individual antenna base 70A in the x and y directions, just like the reflective film 82A.

[0355] When viewed from above, the portion of the arc-shaped outer periphery of the reflective film 82A that connects both end edges in a first direction, which is the arrangement direction of the reflective film 82A and the reflective film 82B, is formed into an arc shape with a central angle θa1 of less than 180°. In this embodiment, when viewed from above, the portion of the arc-shaped outer periphery of the reflective film 82A that connects both end edges in the first direction (the y direction in this embodiment) is formed into an arc shape with a central angle θa1 of less than 180°.

[0356] When viewed from above, the portion of the arc-shaped outer periphery of reflective film 82A that connects both end edges in the third direction, which is the arrangement direction of reflective film 82A and reflective film 82E, is formed into an arc shape with a central angle θa2 of less than 180°. In this embodiment, when viewed from above, the portion of the arc-shaped outer periphery of reflective film 82A that connects both end edges in the third direction (in this embodiment, the direction perpendicular to the direction in which base side surface portion 74b extends when viewed from above) is formed into an arc shape with a central angle θa2 of less than 180°.

[0357] Because the reflective film 82A and the antenna surface 81A have substantially the same shape when viewed from above, similar to the reflective film 82A, the portion of the arc-shaped outer edge of the antenna surface 81A connecting both edges in the first direction, which is the arrangement direction of the antenna surfaces 81A and 81B, is formed in an arc shape with a central angle of less than 180°. When viewed from above, the portion of the arc-shaped outer edge of the antenna surface 81A connecting both edges in the third direction, which is the arrangement direction of the antenna surfaces 81A and 81E, is formed in an arc shape with a central angle of less than 180°.

[0358] When viewed from above, a length LR4 of a perpendicular line to the opening edge 82Aa of the reflective film 82A that passes through the center point P2 of the reflective film 82A is smaller than a radius RA of the reflective film 82A. When viewed from above, a length LR5 of a perpendicular line to the opening edge 82Ab of the reflective film 82A that passes through the center point P2 of the reflective film 82A is smaller than the radius RA of the reflective film 82A. Here, in this embodiment, the radius RA of the reflective film 82A is equal to the radius RE of the reflective film 82E. Furthermore, of the perpendicular lines to the opening edge 82Ab of the reflective film 82A, a perpendicular line that passes through the center point P2 of the reflective film 82A is a straight line extending along the y direction. Furthermore, the length LR4 is also referred to as the length along the third direction. Therefore, the length (LR3 + RA) of the reflective film 82A in the third direction is shorter than the diameter of the reflective film 82A. Furthermore, the length (LR5 + RA) of the reflective film 82A in the first direction is shorter than the diameter of the reflective film 82A. In this way, when viewed from above, it can be said that the size of the reflective film 82A along the first direction, which is the direction in which the reflective films 82A to 82D (see FIG. 37) are arranged, is smaller than the size of the reflective film 82A along the second direction, which is different from the first direction. Here, the second direction is a direction (the x direction in this embodiment) perpendicular to the first direction when viewed from above. Also, it can be said that the size of the reflective film 82A along the third direction, which is the direction in which the reflective films 82E and 82A are arranged, is smaller than the size of the reflective film 82A along the second direction when viewed from above.

[0359] Furthermore, since the reflective film 82A and the antenna surface 81A have approximately the same shape when viewed from above, the relationship between the length of the perpendicular line passing through the center point of the antenna surface 81A among the perpendicular lines to the opening ends 81Aa, 81Ab of the antenna surface 81A and the radius of the antenna surface 81A is the same as the relationship between the lengths LR4, LR5 of the reflective film 82A and the radius RA of the reflective film 82A.

[0360] Although not shown, in a cross-sectional view of the individual antenna base 70A taken along a plane that passes through the center point P2 of the reflective film 82A and extends along the y and z directions, the portion connecting both end edges of the reflective film 82A in the y direction is formed into an arc shape with a central angle of less than 180°. Also, in a cross-sectional view of the individual antenna base 70A taken along a plane that passes through the center point P2 of the reflective film 82A and extends along the third direction and the z direction, the portion connecting both end edges of the reflective film 82A in the third direction is formed into an arc shape with a central angle of less than 180°.

[0361] Although not shown, in a cross-sectional view of the individual antenna base 70A taken along a plane that passes through the center point of the antenna surface 81A and is aligned with the y and z directions, the portion connecting both end edges of the antenna surface 81A in the y direction is formed into an arc shape with a central angle of less than 180°. Also, in a cross-sectional view of the individual antenna base 70A taken along a plane that passes through the center point of the antenna surface 81A and is aligned with the third direction and z direction, the portion connecting both end edges of the antenna surface 81A in the third direction is formed into an arc shape with a central angle of less than 180°.

[0362] The individual antenna bases 70B, 70C, 70D, 70F, 70G, and 70H have the same shape. Therefore, as an example, the configuration of the individual antenna base 70B shown in Fig. 40 will be described, and descriptions of the configurations of the individual antenna bases 70C, 70D, and 70F to 70H will be omitted.

[0363] 40, like the individual antenna base 70A, the individual antenna base 70B has a base main surface 71 and a base back surface 72 as surfaces that intersect in the z direction. When viewed from the z direction, the base main surface 71 and the base back surface 72 each have a pentagonal shape. In this embodiment, the base main surface 71 and the base back surface 72 have, for example, the same shape. However, this is not limiting, and the base main surface 71 and the base back surface 72 may have different shapes.

[0364] The individual antenna base 70B has base side surfaces, which are a first base side surface 73, a second base side surface 74, a third base side surface 75, and a fourth base side surface 76. These base side surfaces 73 to 76 are surfaces that face laterally in the terahertz device 10 (antenna base 70). Each of the base side surfaces 73 to 76 is a surface that is perpendicular to the opposing direction of the base main surface 71 and the base back surface 72, and connects the base main surface 71 and the base back surface 72.

[0365] The third base side surface 75 and the fourth base side surface 76 are both end surfaces in the y direction of the individual antenna base 70B. When viewed from the z direction, the third base side surface 75 and the fourth base side surface 76 each extend along the x direction.

[0366] The first base side surface 73 and the second base side surface 74 are both end surfaces of the individual antenna base 70B in the x direction. When viewed from above, the first base side surface 73 extends along the y direction.

[0367] When viewed from above, the second base side surface 74 extends in a direction intersecting the x and y directions. Specifically, when viewed from above, the second base side surface 74 is formed in a V shape. The second base side surface 74 has a base side surface portion 74a that is a portion closer to the third base side surface 75 and a base side surface portion 74b that is a portion closer to the fourth base side surface 76. The base side surface portion 74a is a surface that slopes toward the third base side surface 75 as it approaches the first base side surface 73. The base side surface portion 74b is a surface that slopes toward the fourth base side surface 76 as it approaches the first base side surface 73.

[0368] The antenna surface 81B of the antenna recess 80B is recessed from the base main surface 71 of the individual antenna base 70B toward the base back surface 72. In this embodiment, in a cross-sectional view of the individual antenna base 70B cut along a plane along the x and z directions, the antenna surface 81B is curved so as to be convex toward the base back surface 72. The antenna surface 81B is open at the base main surface 71. In other words, the antenna surface 81B is open upward.

[0369] The opening of antenna surface 81B has a circular shape with a portion missing when viewed from above. Specifically, the opening of antenna surface 81B is missing at opening end 81Ba on the base side surface portion 74a side, opening end 81Bb on the base side surface portion 74b side, opening end 81Bc on the third base side surface 75 side, and opening end 81Bd on the fourth base side surface 76 side. Each of these opening ends 81Ba to 81Bd is formed linearly when viewed from above.

[0370] When viewed from above, opening end 81Ba is formed at a position overlapping with base side portion 74a, opening end 81Bb is formed at a position overlapping with base side portion 74b, opening end 81Bc is formed at a position overlapping with third base side portion 75, and opening end 81Bd is formed at a position overlapping with fourth base side portion 76.

[0371] When viewed from above, the opening of reflective film 82B has the same shape as the opening of antenna surface 81B. That is, when viewed from above, the opening of reflective film 82B has opening end 82Ba overlapping opening end 81Ba of antenna surface 81B, opening end 82Bb overlapping opening end 81Bb of antenna surface 81B, opening end 82Bc overlapping opening end 81Bc of antenna surface 81B, and opening end 82Bd overlapping opening end 81Bd of antenna surface 81B. When viewed from above, each of opening ends 82Ba to 82Bd is formed in a straight line.

[0372] When viewed from above, the reflective film 82B is formed so that its center point P2 is at a position different from the center in the x and y directions of the individual antenna base 70B. When viewed from above, the reflective film 82B is formed so that its center point P2 is closer to the first base side surface 73 in the x direction than the center in the x direction of the individual antenna base 70B. When viewed from above, the reflective film 82B is formed so that its center point P2 is at the center in the y direction of the individual antenna base 70B.

[0373] When viewed from above, the center point P2 of the reflective film 82B coincides with the center point of the antenna surface 81B, and the shape of the reflective film 82B and the shape of the antenna surface 81B are approximately identical, so when viewed from above, the antenna surface 81B is formed so that the center point of the antenna surface 81B is at a position different from the center of the individual antenna base 70B in the x and y directions, just like the reflective film 82B.

[0374] When viewed from above, the portion of the arc-shaped outer periphery of the reflective film 82B that connects both end edges in the first direction, which is the arrangement direction of the reflective film 82B and the reflective film 82A, is formed into an arc shape with a central angle θb1 of less than 180°. In this embodiment, when viewed from above, the portion of the arc-shaped outer periphery of the reflective film 82B that connects both end edges in the first direction (the y direction in this embodiment) is formed into an arc shape with a central angle θb1 of less than 180°.

[0375] When viewed from above, the portion of the arc-shaped outer periphery of reflective film 82B that connects both end edges in the fourth direction, which is the arrangement direction of reflective film 82B and reflective film 82E, is formed in an arc shape with a central angle θb2 of less than 180°. In this embodiment, when viewed from above, the portion of the arc-shaped outer periphery of reflective film 82B that connects both end edges in the fourth direction (in this embodiment, the direction perpendicular to the direction in which base side surface portion 74a extends when viewed from above) is formed in an arc shape with a central angle θb2 of less than 180°.

[0376] When viewed from above, the portion of the arc-shaped outer periphery of reflective film 82B that connects both end edges in the third direction, which is the arrangement direction of reflective film 82B and reflective film 82F, is formed into an arc shape with a central angle θb3 of less than 180°. In this embodiment, when viewed from above, the portion of the arc-shaped outer periphery of reflective film 82B that connects both end edges in the third direction (in this embodiment, the direction perpendicular to the direction in which base side surface portion 74b extends when viewed from above) is formed into an arc shape with a central angle θb3 of less than 180°.

[0377] Because the reflective film 82B and the antenna surface 81B have substantially the same shape when viewed from above, the portion of the arc-shaped outer periphery of the antenna surface 81B connecting both edges in the first direction, which is the arrangement direction of the antenna surface 81B and the antenna surface 81A, is formed into an arc shape with a central angle of less than 180°. The portion of the arc-shaped outer periphery of the antenna surface 81B connecting both edges in the fourth direction, which is the arrangement direction of the antenna surface 81B and the antenna surface 81E, is formed into an arc shape with a central angle of less than 180°. The portion of the arc-shaped outer periphery of the antenna surface 81B connecting both edges in the third direction, which is the arrangement direction of the antenna surface 81B and the antenna surface 81F, is formed into an arc shape with a central angle of less than 180°.

[0378] When viewed from above, the length LR6 of a perpendicular line to the opening edge 82Ba of the reflective film 82B that passes through the center point P2 of the reflective film 82B is smaller than the radius RB of the reflective film 82B. When viewed from above, the length LR7 of a perpendicular line to the opening edge 82Bb of the reflective film 82B that passes through the center point P2 of the reflective film 82B is smaller than the radius RB of the reflective film 82B. When viewed from above, the length LR8 of a perpendicular line to the opening edge 82Bc of the reflective film 82B that passes through the center point P2 of the reflective film 82B is smaller than the radius RB of the reflective film 82B. When viewed from above, the length LR9 of a perpendicular line to the opening edge 82Bd of the reflective film 82B that passes through the center point P2 of the reflective film 82B is smaller than the radius RB of the reflective film 82B. Here, in this embodiment, the radius RB of the reflective film 82B is equal to the radius RA of the reflective film 82A. Furthermore, among the perpendicular lines to the opening edge 82Bc of the reflective film 82B, the perpendicular line passing through the center point P2 of the reflective film 82B, and among the perpendicular lines to the opening edge 82Bd of the reflective film 82B, the perpendicular line passing through the center point P2 of the reflective film 82B, are each a straight line extending along the y direction. The sum of the lengths LR8 and LR9 (LR8 + LR9) of these perpendicular lines is equal to the length of the individual antenna base 70B in the y direction. Therefore, the length of the individual antenna base 70B in the y direction is shorter than the diameter of the reflective film 82B. Furthermore, the length LR7 can also be considered the length along the third direction, and the length LR6 can also be considered the length along the fourth direction. Therefore, the length of the reflective film 82B in the third direction (LR7 + RB) is shorter than the diameter of the reflective film 82B, and the length of the reflective film 82B in the fourth direction (LR6 + RB) is shorter than the diameter of the reflective film 82B. In this way, when viewed from above, it can be said that the size of the reflective film 82B along the first direction, which is the direction in which the reflective films 82A to 82D (see FIG. 37) are arranged, is smaller than the size of the reflective film 82B along the second direction, which is different from the first direction. Here, the second direction is a direction (the x direction in this embodiment) perpendicular to the first direction when viewed from above. Also, when viewed from above, it can be said that the size of the reflective film 82B along the third direction, which is the direction in which the reflective films 82B and 82F are arranged, is smaller than the size of the reflective film 82B along the second direction. Also, when viewed from above, it can be said that the size of the reflective film 82B along the fourth direction, which is the direction in which the reflective films 82E and 82B are arranged, is smaller than the size of the reflective film 82B along the second direction.

[0379] Furthermore, since the reflective film 82B and the antenna surface 81B have approximately the same shape when viewed from above, the relationship between the length of the perpendicular line passing through the center point of the antenna surface 81B among the perpendicular lines to the opening ends 81Ba to 81Bd of the antenna surface 81B and the radius of the antenna surface 81B is the same as the relationship between the lengths LR6 to LR9 of the reflective film 82B and the radius RB of the reflective film 82B.

[0380] Although not shown, in a cross-sectional view of the individual antenna base 70B taken along a plane that passes through the center point P2 of the reflective film 82B and that is aligned with the y and z directions, the portion connecting both end edges of the reflective film 82B in the y direction is formed into an arc shape with a central angle of less than 180°. Also, in a cross-sectional view of the individual antenna base 70B taken along a plane that passes through the center point P2 of the reflective film 82B and that is aligned with the third direction and the z direction, the portion connecting both end edges of the reflective film 82B in the third direction is formed into an arc shape with a central angle of less than 180°. Also, in a cross-sectional view of the individual antenna base 70B taken along a plane that passes through the center point P2 of the reflective film 82B and that is aligned with the third direction and the z direction, the portion connecting both end edges of the reflective film 82B in the fourth direction is formed into an arc shape with a central angle of less than 180°.

[0381] Although not shown, in a cross-sectional view of the individual antenna base 70B taken along a plane that passes through the center point of the antenna surface 81B and is aligned with the y and z directions, the portion connecting both end edges of the antenna surface 81B in the y direction is formed into an arc shape with a central angle of less than 180°. Also, in a cross-sectional view of the individual antenna base 70B taken along a plane that passes through the center point of the antenna surface 81B and is aligned with the third direction and the z direction, the portion connecting both end edges of the antenna surface 81B in the third direction is formed into an arc shape with a central angle of less than 180°. Also, in a cross-sectional view of the individual antenna base 70B taken along a plane that passes through the center point of the antenna surface 81B and is aligned with the third direction and the z direction, the portion connecting both end edges of the antenna surface 81B in the fourth direction is formed into an arc shape with a central angle of less than 180°.

[0382] When viewed from above, the individual antenna base 70B has a peripheral wall 78B that surrounds the opening of the antenna recess 80B except for the missing portion of the opening. The peripheral wall 78B forms the base main surface 71 of the individual antenna base 70B.

[0383] The antenna surface 81C of the antenna recess 80C of the individual antenna base 70C, the antenna surface 81D of the antenna recess 80D of the individual antenna base 70D, the antenna surface 81F of the antenna recess 80F of the individual antenna base 70F, the antenna surface 81G of the antenna recess 80G of the individual antenna base 70G, and the antenna surface 81H of the antenna recess 80H of the individual antenna base 70H each have the same shape as the antenna surface 81B of the antenna recess 80B. Furthermore, the reflective films 82C, 82D, 82F, 82G, and 82H each have the same shape as the reflective film 82B.

[0384] As shown in Figure 37, the base side surface portion 74b of the individual antenna base 70A and the base side surface portion 73a of the individual antenna base 70E are in contact with each other. That is, the individual antenna bases 70A and 70E are arranged in the third direction. Similarly, the base side surface portion 74b of the individual antenna base 70B and the base side surface portion 74b of the individual antenna base 70F are in contact with each other, the base side surface portion 74b of the individual antenna base 70C and the base side surface portion 74b of the individual antenna base 70G are in contact with each other, and the base side surface portion 74b of the individual antenna base 70D and the base side surface portion 74b of the individual antenna base 70H are in contact with each other. That is, the individual antenna bases 70B and 70F are arranged in the third direction, the individual antenna bases 70C and 70G are arranged in the third direction, and the individual antenna bases 70D and 70H are arranged in the third direction.

[0385] The base side surface portion 74a of the individual antenna base 70B and the base side surface portion 73b of the individual antenna base 70E are in contact. That is, the individual antenna base 70B and the individual antenna base 70E are arranged in the fourth direction. Similarly, the base side surface portion 74a of the individual antenna base 70C and the base side surface portion 74a of the individual antenna base 70F are in contact, and the base side surface portion 74a of the individual antenna base 70D and the base side surface portion 74a of the individual antenna base 70G are in contact. That is, the individual antenna base 70C and the individual antenna base 70F are arranged in the fourth direction, and the individual antenna base 70D and the individual antenna base 70G are arranged in the fourth direction.

[0386] Next, the gas space 92 will be described. As shown in FIGS. 41 to 43, the gas space 92 is defined by the dielectric main surface 51 and the antenna surface 81, as in the first embodiment. Specifically, the opening of the antenna recess 80 is covered by the dielectric main surface 51. Specifically, the openings of the antenna recesses 80A to 80H are each covered by the dielectric main surface 51. In this embodiment, the gas space 92 communicates with the outside of the device at the antenna recesses 80D, 80H of the individual antenna bases 70D, 70H. In other words, the gas space 92 in this embodiment is not sealed. Note that the gas space 92 may be sealed by changing the configuration of the individual antenna base 70H to that of the individual antenna base 70A, and by changing the configuration of the individual antenna base 70D to that of the individual antenna base 70E.

[0387] A gas space 92 is defined by the dielectric main surface 51 and the antenna surface 81, which is the inner surface of the antenna recess 80. More specifically, the gas space 92 is defined by the dielectric main surface 51 and the antenna surfaces 81A-81H. The reflective films 82A-82H are each provided within the gas space 92. The gas space 92 includes a plurality of gas spaces 92 defined by the antenna recesses 80A-80H and the dielectric main surface 51. In this embodiment, the gas spaces corresponding to adjacent individual antenna bases among the individual antenna bases 70A-70H communicate with each other. 41 and 42, a gas space 92E defined by the dielectric principal surface 51 and the antenna surface 81E, a gas space 92F defined by the dielectric principal surface 51 and the antenna surface 81F, and a gas space 92G defined by the dielectric principal surface 51 and the antenna surface 81G are interconnected in a first direction (the y direction in this embodiment), which is the arrangement direction of the reflective film 82F and the reflective film 82G. As shown in FIG. 42, the gas space 92E is interconnected with a gas space 92B defined by the dielectric principal surface 51 and the antenna surface 81B. That is, the gas space 92B and the gas space 92E are interconnected in a fourth direction, which is the arrangement direction of the reflective film 82B and the reflective film 82E. As shown in FIG. 43, the gas space 92G is interconnected with a gas space 92C defined by the dielectric principal surface 51 and the antenna surface 81C. That is, gas space 92C and gas space 92G communicate with each other in the third direction, which is the arrangement direction of reflective film 82C and reflective film 82G. Because gas is present in gas space 92, the relationships between the refractive indexes of dielectric 50, gas space 92, and terahertz element 20 and the propagation path of the electromagnetic waves are the same as those in the first embodiment. As described above, with respect to the gas spaces 92 corresponding to individual antenna bases 70A to 70H, the gas spaces 92 of the individual antenna bases arranged in the first direction (the y direction in this embodiment) communicate with each other in the first direction, the gas spaces 92 of the individual antenna bases arranged in the third direction communicate with each other in the third direction, and the gas spaces 92 of the individual antenna bases arranged in the fourth direction communicate with each other in the fourth direction.

[0388] 44, the terahertz device 10 includes a first electrode 101, a second electrode 102, a first conductive portion 110, and a second conductive portion 120, similar to the first embodiment. In this embodiment, the electrodes 101, 102 are provided individually according to the terahertz elements 20A to 20H. The configurations of the electrodes 101, 102 and the conductive portions 110, 120 are similar to those of the first embodiment. The conductive portions 110, 120 are sealed in a dielectric 50, similar to the first embodiment. For convenience, the first electrodes 101 and second electrodes 102 corresponding to the terahertz elements 20A to 20H are referred to as first electrodes 101A to 101H and second electrodes 102A to 102H, respectively, and the first conductive portions 110 and second conductive portions 120 corresponding to the terahertz elements 20A to 20H are referred to as first conductive portions 110A to 110H and second conductive portions 120A to 120H.

[0389] The first conductive portion 110A and the second conductive portion 120A connected to the terahertz element 20A, the first conductive portion 110B and the second conductive portion 120B connected to the terahertz element 20B, the first conductive portion 110C and the second conductive portion 120C connected to the terahertz element 20C, and the first conductive portion 110D and the second conductive portion 120D connected to the terahertz element 20D each extend in the x direction toward the first protrusion 61. Therefore, the first electrode 101A and the second electrode 102A connected to the first conductive portion 110A and the second conductive portion 120A, the first electrode 101B and the second electrode 102B connected to the first conductive portion 110B and the second conductive portion 120B, the first electrode 101C and the second electrode 102C connected to the first conductive portion 110C and the second conductive portion 120C, and the first electrode 101D and the second electrode 102D connected to the first conductive portion 110D and the second conductive portion 120D are each provided on the first protrusion 61. That is, the conductive portions 110A-110D, 120A-120D connected to the terahertz elements 20A-20D arranged corresponding to the individual antenna bases 70A-70D closer to the first protrusion 61 of the antenna base 70 extend toward the first protrusion 61 which is closer to the individual antenna bases 70A-70D than the second protrusion 62. The electrodes 101A-101D, 102A-102D are provided on the first protrusion 61 which is closer to the individual antenna bases 70A-70D than the second protrusion 62.

[0390] The electrodes 101A to 101D and 102A to 102D are aligned in the x direction and spaced apart from each other in the y direction, and the conductive portions 110A to 110D and 120A to 120D are aligned in the x direction and spaced apart from each other in the y direction.

[0391] The first conductive portion 110E and the second conductive portion 120E connected to the terahertz element 20E, the first conductive portion 110F and the second conductive portion 120F connected to the terahertz element 20F, the first conductive portion 110G and the second conductive portion 120G connected to the terahertz element 20G, and the first conductive portion 110H and the second conductive portion 120H connected to the terahertz element 20H each extend in the x-direction toward the second protrusion 62. Therefore, the first electrode 101E and the second electrode 102E connected to the first conductive portion 110E and the second conductive portion 120E, the first electrode 101F and the second electrode 102F connected to the first conductive portion 110F and the second conductive portion 120F, the first electrode 101G and the second electrode 102G connected to the first conductive portion 110G and the second conductive portion 120G, and the first electrode 101H and the second electrode 102H connected to the first conductive portion 110H and the second conductive portion 120H are each provided on the second protrusion 62. That is, the conductive portions 110E-110H and 120E-120H connected to the terahertz elements 20E-20H arranged corresponding to the individual antenna bases 70E-70H closer to the second protrusion 62 of the antenna base 70 extend toward the second protrusion 62 which is closer to the individual antenna bases 70E-70H than the first protrusion 61. The electrodes 101E-101H and 102E-102H are provided on the second protrusion 62 which is closer to the individual antenna bases 70E-70H than the first protrusion 61.

[0392] The electrodes 101E-101H and 102E-102H are aligned in the x direction and spaced apart from each other in the y direction. The conductive portions 110E-110H and 120E-120H are aligned in the x direction and spaced apart from each other in the y direction.

[0393] In this embodiment, the reflective films 82A to 82H are each in an electrically floating state. More specifically, the reflective film 82A is electrically insulated from both electrodes 101A and 102A and both conductive portions 110A and 120A. The reflective film 82B is electrically insulated from both electrodes 101B and 102B and both conductive portions 110B and 120B. The reflective film 82C is electrically insulated from both electrodes 101C and 102C and both conductive portions 110C and 120C. The reflective film 82D is electrically insulated from both electrodes 101D and 102D and both conductive portions 110D and 120D. The reflective film 82E is electrically insulated from both electrodes 101E and 102E and both conductive portions 110E and 120E. Reflective film 82F is electrically insulated from both electrodes 101F, 102F and both conductive portions 110F, 120F. Reflective film 82G is electrically insulated from both electrodes 101G, 102G and both conductive portions 110G, 120G. Reflective film 82H is electrically insulated from both electrodes 101H, 102H and both conductive portions 110H, 120H.

[0394] (action) The operation of the terahertz device 10 of this embodiment will be described with reference to FIG. FIG. 45 is an enlarged view of the individual antenna bases 70B, 70C, 70E to 70G and their surrounding areas.

[0395] 45, in a first direction (y direction in this embodiment) which is the arrangement direction of the reflective films 82E and 82F, the inter-element distance Lef, which is the distance between the reception point P1 of the terahertz element 20E and the reception point P1 of the terahertz element 20F, is smaller than the diameter of the reflective film 82E (the radius RE of the reflective film 82E × 2). The inter-element distance Lef is also smaller than the diameter of the reflective film 82F (the radius RF of the reflective film 82F × 2).

[0396] In the fourth direction, which is the arrangement direction of the reflective films 82E and 82B, an inter-element distance Lbe, which is the distance between the reception point P1 of the terahertz element 20E and the reception point P1 of the terahertz element 20B, is smaller than the diameter of the reflective film 82E. The inter-element distance Lbe is also smaller than the diameter of the reflective film 82B (the radius RB of the reflective film 82B × 2).

[0397] In the third direction, which is the arrangement direction of the reflective films 82B and 82F, an inter-element distance Lbf, which is the distance between the reception point P1 of the terahertz element 20B and the reception point P1 of the terahertz element 20F, is smaller than the diameter of the reflective film 82B. The inter-element distance Lbf is also smaller than the diameter of the reflective film 82F.

[0398] In a first direction which is the arrangement direction of the reflective films 82B and 82C, an inter-element distance Lbc between the reception point P1 of the terahertz element 20B and the reception point P1 of the terahertz element 20C is smaller than the diameter of the reflective film 82B. The inter-element distance Lbc is also smaller than the diameter of the reflective film 82C (the radius RC of the reflective film 82C × 2).

[0399] In the fourth direction, which is the arrangement direction of the reflective films 82C and 82F, the inter-element distance Lcf, which is the distance between the reception point P1 of the terahertz element 20C and the reception point P1 of the terahertz element 20F, is smaller than the diameter of the reflective film 82C. The inter-element distance Lcf is also smaller than the diameter of the reflective film 82F.

[0400] In the first direction, which is the arrangement direction of the reflective films 82F and 82G, an inter-element distance Lfg, which is the distance between the reception point P1 of the terahertz element 20F and the reception point P1 of the terahertz element 20G, is smaller than the diameter of the reflective film 82F. The inter-element distance Lfg is also smaller than the diameter of the reflective film 82G (the radius RG of the reflective film 82G × 2).

[0401] In the third direction, which is the arrangement direction of the reflective films 82C and 82G, an inter-element distance Lcg, which is the distance between the reception point P1 of the terahertz element 20C and the reception point P1 of the terahertz element 20G, is smaller than the diameter of the reflective film 82C. The inter-element distance Lcg is also smaller than the diameter of the reflective film 82G.

[0402] Although not shown, the inter-element distances of terahertz elements 20A, 20B, and 20C, the inter-element distances of terahertz elements 20C, 20D, and 20G, and the inter-element distances of terahertz elements 20D, 20G, and 20H are similar to the inter-element distances of terahertz elements 20B, 20C, 20E to 20G described above.

[0403] In this way, the inter-element distance, which is the distance connecting the reception points P1 of adjacent terahertz elements 20 in the arrangement direction of the plurality of reflective films 82, is smaller than the diameter of the reflective film 82. Therefore, the adjacent terahertz elements 20 in the arrangement direction can be brought closer to each other.

[0404] (effect) According to the terahertz device 10 of this embodiment, in addition to the effects according to the first embodiment, the following effects can be obtained.

[0405] (2-1) When viewed from the z direction, the row of terahertz elements 20A to 20D aligned in the y direction and the row of terahertz elements 20E to 20H aligned in the y direction are spaced apart in the x direction. This configuration can widen the detection range of the terahertz device 10 in the x direction.

[0406] (2-2) When viewed from the z direction, the row of terahertz elements 20A to 20D and the row of terahertz elements 20E to 20H are arranged so as to be offset in the y direction. That is, in the y direction, from the third base side surface 75T to the fourth base side surface 76T of the antenna base 70, terahertz element 20A, terahertz element 20E, terahertz element 20B, terahertz element 20F, terahertz element 20C, terahertz element 20G, terahertz element 20D, and terahertz element 20H are arranged in this order.

[0407] According to this configuration, in a fourth direction which is the arrangement direction of reflective film 82E and reflective film 82B, the arrangement direction of reflective film 82F and reflective film 82C, and the arrangement direction of reflective film 82G and reflective film 82D, terahertz element 20E and terahertz element 20B can be brought closer to each other, terahertz element 20F and terahertz element 20C can be brought closer to each other, and terahertz element 20G and terahertz element 20D can be brought closer to each other.

[0408] Furthermore, in a third direction that is the arrangement direction of reflective film 82A and reflective film 82E, the arrangement direction of reflective film 82B and reflective film 82F, the arrangement direction of reflective film 82C and reflective film 82G, and the arrangement direction of reflective film 82D and reflective film 82H, terahertz element 20A and terahertz element 20E can be brought closer to each other, terahertz element 20B and terahertz element 20F can be brought closer to each other, terahertz element 20C and terahertz element 20G can be brought closer to each other, and terahertz element 20D and terahertz element 20H can be brought closer to each other. Therefore, the resolution in the detection range of terahertz device 10 can be improved.

[0409] (2-3) When viewed from the z direction, the size of the reflective film 82B along the fourth direction, which is the arrangement direction of the reflective film 82E and the reflective film 82B, and the size of the reflective film 82B along the third direction, which is the arrangement direction of the reflective film 82F and the reflective film 82B, are both smaller than the size of the reflective film 82B along the second direction (the x direction in this embodiment). The same is true for the other reflective films 82A, 82C, 82D, and 82F to 82G.

[0410] According to this configuration, the terahertz elements 20 adjacent to each other in the third direction and the fourth direction can be brought closer to each other, thereby improving the resolution in the detection range of the terahertz device 10.

[0411] (2-4) When viewed from above, the arc-shaped outer peripheral edge of reflective film 82B, including the portion connecting both edges in the fourth direction, which is the arrangement direction of reflective film 82E and reflective film 82B, and the portion connecting both edges in the third direction, which is the arrangement direction of reflective film 82F and reflective film 82B, are each formed in an arc shape with a central angle of less than 180°.

[0412] According to this configuration, the reflective film 82B can be formed such that the lengths LR6 and LR7 of the reflective film 82B are each shorter than the radius RB of the reflective film 82B while maintaining the reflective film 82B in a spherical shape formed with a constant curvature.

[0413] Like the reflective film 82B, the portions connecting both end edges in the third direction and the portions connecting both end edges in the fourth direction of each of the reflective films 82A, 82C to 82H are each formed in an arc shape with a central angle of less than 180°. With this configuration, the reflective films 82A, 82C to 82H can be formed so that the lengths of each of the reflective films 82A, 82C to 82H in the third direction and the fourth direction are shorter than the radii of the reflective films 82A, 82C to 82H while maintaining a spherical shape formed with a constant curvature.

[0414] (2-5) When viewed from above, the boundary between reflective film 82A and reflective film 82E, the boundary between reflective film 82B and reflective film 82E, the boundary between reflective film 82B and reflective film 82F, the boundary between reflective film 82C and reflective film 82F, the boundary between reflective film 82C and reflective film 82G, the boundary between reflective film 82D and reflective film 82G, and the boundary between reflective film 82D and reflective film 82H are each formed in a straight line.

[0415] According to this configuration, the reflective films 82A to 82H can be formed so that the lengths of the reflective films 82A to 82H in the third direction and the fourth direction are shorter than the radii of the reflective films 82A to 82H while maintaining a spherical shape formed with a constant curvature.

[0416] (2-6) The gas space 92B partitioned by the antenna surface 81B and the dielectric 50 and the gas space 92E partitioned by the antenna surface 81E and the dielectric 50 are connected in the third direction at the boundary between the reflective film 82B (antenna surface 81B) and the reflective film 82E (antenna surface 81E). The gas space 92C partitioned by the antenna surface 81C and the dielectric 50 and the gas space 92F partitioned by the antenna surface 81F and the dielectric 50 are connected in the third direction at the boundary between the reflective film 82C (antenna surface 81C) and the reflective film 82F (antenna surface 81F). The gas space partitioned by the antenna surface 81D and the dielectric 50 and the gas space partitioned by the antenna surface 81G and the dielectric 50 are connected in the third direction at the boundary between the reflective film 82D (antenna surface 81D) and the reflective film 82G (antenna surface 81G). According to this configuration, it is possible to obtain an effect similar to that described in (2-3) above.

[0417] (2-7) In a cross-sectional view of the antenna base 70 taken along a plane passing through the center point P2 of the reflective film 82B and the center point P2 of the reflective film 82E and aligned along the third direction and the z direction, which are the arrangement directions of the reflective film 82B and the reflective film 82E, the portion connecting both end edges of the reflective film 82B in the third direction and the portion connecting both end edges of the reflective film 82E in the third direction are each formed as an arc with a central angle of less than 180°.

[0418] According to this configuration, reflective films 82B and 82E can be formed such that the lengths in the third direction of reflective film 82B and reflective film 82E are shorter than the radii of reflective film 82B and reflective film 82E, respectively, while maintaining a spherical shape formed with a constant curvature.

[0419] The relationship between reflective film 82C and reflective film 82F and reflective film 82D and reflective film 82G is similar to the relationship between reflective film 82B and reflective film 82E. Therefore, the same effects as those described above can be obtained for reflective film 82C and reflective film 82F, and reflective film 82D and reflective film 82G, respectively.

[0420] (2-10) The gas space partitioned by the antenna surface 81A and the dielectric 50 and the gas space 92E partitioned by the antenna surface 81E and the dielectric 50 are connected in the fourth direction at the boundary between the reflective film 82A (antenna surface 81A) and the reflective film 82E (antenna surface 81E). The gas space 92B partitioned by the antenna surface 81B and the dielectric 50 and the gas space 92F partitioned by the antenna surface 81F and the dielectric 50 are connected in the fourth direction at the boundary between the reflective film 82B (antenna surface 81B) and the reflective film 82F (antenna surface 81F). The gas space 92C partitioned by the antenna surface 81C and the dielectric 50 and the gas space partitioned by the antenna surface 81G and the dielectric 50 are connected in the fourth direction at the boundary between the reflective film 82C (antenna surface 81C) and the reflective film 82G (antenna surface 81G). The gas space partitioned by the antenna surface 81D and the dielectric 50 and the gas space partitioned by the antenna surface 81H and the dielectric 50 are connected in the fourth direction at the boundary between the reflective film 82D (antenna surface 81D) and the reflective film 82H (antenna surface 81H). According to this configuration, an effect equivalent to the above (2-3) can be obtained.

[0421] (2-11) In a cross-sectional view of the antenna base 70 taken along a plane passing through the center point P2 of the reflective film 82B and the center point P2 of the reflective film 82F and aligned with the third direction and the z direction, which are the arrangement directions of the reflective film 82B and the reflective film 82F, the portion connecting both end edges in the third direction of the reflective film 82B and the portion connecting both end edges in the third direction of the reflective film 82F are each formed in an arc shape with a central angle of less than 180°.

[0422] According to this configuration, reflective films 82B and 82F can be formed such that the length in the third direction of reflective film 82B and the length in the third direction of reflective film 82F are shorter than the radius of reflective film 82B and the radius of reflective film 82F, respectively, while maintaining a spherical shape formed with a constant curvature.

[0423] The relationships between reflective films 82A and 82E, between reflective films 82C and 82G, and between reflective films 82D and 82H are similar to the relationship between reflective films 82B and 82F. Therefore, the same effects as those described above can be obtained for reflective films 82A and 82E, between reflective films 82C and 82G, and between reflective films 82D and 82H, respectively.

[0424] [Third embodiment] A terahertz device 10 according to a third embodiment will be described with reference to Figs. 46 to 56. The terahertz device 10 according to this embodiment differs from the terahertz device 10 according to the first embodiment mainly in the configuration of the antenna base 70. In the following description, components common to the terahertz device 10 according to the first embodiment are given the same reference numerals, and their description may be omitted. Furthermore, in this embodiment, although the configuration of the antenna base 70 differs from that of the antenna base 70 according to the first embodiment, the multiple individual antenna bases are identified by sequentially designating them as 70A, 70B, 70C, and so on.

[0425] As shown in FIGS. 46 and 52, the terahertz device 10 includes a plurality of terahertz elements 20, a dielectric 50 which is an example of a holding member, an antenna base 70, a reflective film 82, and a gas space 92.

[0426] 46, the plurality of terahertz elements 20 include terahertz element 20A, terahertz element 20B, terahertz element 20C, terahertz element 20D, terahertz element 20E, terahertz element 20F, terahertz element 20G, terahertz element 20H, and terahertz element 201. The terahertz elements 20A to 20I have the same configuration as each other and the same configuration as the terahertz element 20 of the first embodiment.

[0427] The dielectric 50 surrounds each of the multiple terahertz elements 20. In one example, as shown in Fig. 52 and Fig. 53, the dielectric 50 surrounds the entire terahertz element 20E, covering the element main surface 21, element back surface 22, and element side surfaces 23 to 26 of the terahertz element 20E. Similarly, the dielectric 50 surrounds the entire terahertz elements 20A to 20D and 20F to 20I, covering the element main surface 21, element back surface 22, and element side surfaces 23 to 26 of each of the terahertz elements 20A to 20D and 20F to 20I.

[0428] The element main surface 21, element back surface 22, and element side surfaces 23 to 26 of each of the terahertz elements 20A to 20I are in contact with the dielectric 50. That is, similar to the first embodiment, the dielectric 50 of this embodiment surrounds each of the terahertz elements 20A to 20I so that no gap is generated between the dielectric 50 and each of the terahertz elements 20A to 20I. In other words, the dielectric 50 seals each of the terahertz elements 20A to 20I.

[0429] 46, the dielectric 50 is formed, for example, in the shape of a plate with its thickness direction in the z direction. Specifically, the dielectric 50 is a square plate with the same length in the x direction and the y direction. When viewed from the z direction, the dielectric 50 is formed in the shape of a square that is slightly larger than the antenna base 70. In other words, the dielectric 50 protrudes from the antenna base 70 on both sides in the x direction and from the antenna base 70 on both sides in the y direction.

[0430] As shown in Figures 52 and 53, the dielectric 50 has a dielectric principal surface 51 and a dielectric back surface 52 as surfaces that intersect with the z direction. The dielectric principal surface 51 and the dielectric back surface 52 are each perpendicular to the z direction, for example. The dielectric principal surface 51 faces downward. The dielectric back surface 52 is the surface opposite to the dielectric principal surface 51 and faces upward. In this embodiment, the dielectric back surface 52 constitutes the device principal surface 11.

[0431] 46, dielectric 50 has first dielectric side surface 53 and second dielectric side surface 54, which are end surfaces in the x direction, and third dielectric side surface 55 and fourth dielectric side surface 56, which are end surfaces in the y direction. Each of dielectric side surfaces 53 to 56 constitutes a part of device side surfaces 13 to 16. In this embodiment, first dielectric side surface 53 and second dielectric side surface 54 are perpendicular to third dielectric side surface 55 and fourth dielectric side surface 56.

[0432] As in the first embodiment, the terahertz element 20 is provided in the dielectric 50 with the element main surface 21 facing the dielectric main surface 51. In one example, as shown in FIGS. 52 and 53, the terahertz elements 20B, 20D to 20F, and 20H are each disposed between the dielectric main surface 51 and the dielectric back surface 52. Although not shown, the terahertz elements 20A, 20C, 20G, and 20I are also each disposed between the dielectric main surface 51 and the dielectric back surface 52. In this embodiment, as in the first embodiment, the dielectric thickness D2, which is the length of the dielectric 50 in the z direction, is set so as to satisfy the resonance condition of the electromagnetic wave received by the terahertz element 20.

[0433] 46, when viewed from the z direction, the terahertz elements 20A to 20I are arranged in a lattice pattern. More specifically, the terahertz elements 20A to 20C are arranged aligned with each other in the x direction but spaced apart from each other in the y direction. The terahertz elements 20D to 20F are arranged aligned with each other in the x direction but spaced apart from each other in the y direction. The terahertz elements 20G to 20I are arranged aligned with each other in the x direction but spaced apart from each other in the y direction. The rows of the terahertz elements 20A to 20C, the rows of the terahertz elements 20D to 20F, and the rows of the terahertz elements 20G to 20I are arranged aligned with each other in the y direction but spaced apart from each other in the x direction. That is, the terahertz element 20A, the terahertz element 20D, and the terahertz element 20G are arranged aligned with each other in the y direction but spaced apart from each other in the x direction. Terahertz element 20B, terahertz element 20E, and terahertz element 20H are arranged spaced apart from one another in the x direction while being aligned with one another in the y direction. Terahertz element 20C, terahertz element 20F, and terahertz element 20I are arranged spaced apart from one another in the x direction while being aligned with one another in the y direction. In this embodiment, the pitches (inter-element distances) of adjacent terahertz elements 20 in the x direction and y direction are equal to one another. Here, if the maximum amount of deviation between adjacent terahertz elements 20 in the x direction and y direction is within 5% of the average value of the pitches of adjacent terahertz elements 20 in the x direction and y direction, it can be said that the pitches (inter-element distances) of adjacent terahertz elements 20 in the x direction and y direction are equal to one another. Here, the pitch in the x direction (inter-element distance) is the distance connecting the receiving points P1 of the terahertz elements 20 adjacent to each other in the x direction, and the pitch in the y direction (inter-element distance) is the distance connecting the receiving points P1 of the terahertz elements 20 adjacent to each other in the y direction.

[0434] As shown in Figures 46 to 48, in this embodiment, the antenna base 70 has a square shape when viewed from above. More specifically, the first base side surface 73T and the second base side surface 74T face each other in the x direction and extend along the y direction. The third base side surface 75T and the fourth base side surface 76T face each other in the y direction and extend along the x direction. The material of the antenna base 70 is the same as the material of the antenna base 70 of the first embodiment.

[0435] The antenna base 70 of this embodiment is made up of a combination of multiple (nine in this embodiment) individual antenna bases 70A, 70B, 70C, 70D, 70E, 70F, 70G, 70H, and 70I. More specifically, the antenna base 70 has a row of individual antenna bases 70A, 70B, and 70C, a row of individual antenna bases 70D, 70E, and 70F, and a row of individual antenna bases 70G, 70H, and 70I. These rows of individual antenna bases 70A to 70C, 70D to 70F, and 70G to 70I extend along the y direction.

[0436] The individual antenna bases 70A to 70C form a first base side surface 73T, the individual antenna bases 70G to 70I form a second base side surface 74T, the individual antenna bases 70A, 70D, and 70G form a third base side surface 75T, and the individual antenna bases 70C, 70F, and 70I form a fourth base side surface 76T. In other words, the individual antenna bases 70A, 70C, 70G, and 70H form the four corners of the antenna base 70.

[0437] In this embodiment, the individual antenna base 70B is sandwiched between the individual antenna base 70A and the individual antenna base 70C in the y direction. The individual antenna base 70E is sandwiched between the individual antenna base 70D and the individual antenna base 70F in the y direction. The individual antenna base 70H is sandwiched between the individual antenna base 70G and the individual antenna base 70I in the y direction. The individual antenna base 70D is sandwiched between the individual antenna base 70A and the individual antenna base 70G in the x direction. The individual antenna base 70E is sandwiched between the individual antenna base 70B and the individual antenna base 70H in the x direction. The individual antenna base 70F is sandwiched between the individual antenna base 70C and the individual antenna base 70I in the x direction.

[0438] As shown in FIG. 46, the individual antenna base 70A is arranged to face the terahertz element 20A in the thickness direction (z direction) of the terahertz element 20A. The individual antenna base 70B is arranged to face the terahertz element 20B in the thickness direction (z direction) of the terahertz element 20B. The individual antenna base 70C is arranged to face the terahertz element 20C in the thickness direction (z direction) of the terahertz element 20C. The individual antenna base 70D is arranged to face the terahertz element 20D in the thickness direction (z direction) of the terahertz element 20D. The individual antenna base 70E is arranged to face the terahertz element 20E in the thickness direction (z direction) of the terahertz element 20E. The individual antenna base 70F is arranged to face the terahertz element 20F in the thickness direction (z direction) of the terahertz element 20F. The individual antenna base 70G is arranged to face the terahertz element 20G in the thickness direction (z direction) of the terahertz element 20G. The individual antenna base 70H is arranged to face the terahertz element 20H in the thickness direction (z direction) of the terahertz element 20H. The individual antenna base 70I is arranged to face the terahertz element 20I in the thickness direction (z direction) of the terahertz element 20I. In this embodiment, the individual antenna bases 70A to 70I are arranged below the terahertz elements 20A to 20I, respectively.

[0439] As shown in Fig. 47, the antenna base 70 has an antenna recess 80 recessed from the base main surface 71T toward the base back surface 72T, similar to the first embodiment. Specifically, as shown in Fig. 47 and Fig. 48, in this embodiment, the individual antenna base 70A has the antenna recess 80A, the individual antenna base 70B has the antenna recess 80B, the individual antenna base 70C has the antenna recess 80C, the individual antenna base 70D has the antenna recess 80D, the individual antenna base 70E has the antenna recess 80E, the individual antenna base 70F has the antenna recess 80F, the individual antenna base 70G has the antenna recess 80G, the individual antenna base 70H has the antenna recess 80H, and the individual antenna base 70I has the antenna recess 80I.

[0440] As shown in FIGS. 52 and 53, the antenna recess 80 has an antenna surface 81 facing the terahertz element 20 across the dielectric 50 and the gas space 92, as in the first embodiment. Specifically, as shown in FIGS. 47 and 48, in this embodiment, the antenna recess 80A has an antenna surface 81A, the antenna recess 80B has an antenna surface 81B, the antenna recess 80C has an antenna surface 81C, and the antenna recess 80D has an antenna surface 81D. Furthermore, the antenna recess 80E has an antenna surface 81E, the antenna recess 80F has an antenna surface 81F, the antenna recess 80G has an antenna surface 81G, the antenna recess 80H has an antenna surface 81H, and the antenna recess 80I has an antenna surface 81I. When viewed from above, these antenna surfaces 81A to 81I have the same shape as the openings of the corresponding antenna recesses 80A to 80I.

[0441] 52 and 53, similarly to the first embodiment, the reflective film 82 is formed on the antenna surface 81. The reflective film 82 is formed over the entire antenna surface 81. On the other hand, the reflective film 82 is not formed on the base main surface 71T. In other words, the reflective film 82 has substantially the same shape as the antenna surface 81. The reflective film 82 is formed of the same material as the reflective film 82 of the first embodiment.

[0442] 47 and 48, the reflective film 82 includes a reflective film 82A formed on the antenna surface 81A, a reflective film 82B formed on the antenna surface 81B, a reflective film 82C formed on the antenna surface 81C, a reflective film 82D formed on the antenna surface 81D, a reflective film 82E formed on the antenna surface 81E, a reflective film 82F formed on the antenna surface 81F, a reflective film 82G formed on the antenna surface 81G, a reflective film 82H formed on the antenna surface 81H, and a reflective film 82I formed on the antenna surface 81I. In this embodiment, the reflective films 82A to 82I are an integrally formed single component.

[0443] The reflective film 82A has approximately the same shape as the antenna surface 81A, the reflective film 82B has approximately the same shape as the antenna surface 81B, the reflective film 82C has approximately the same shape as the antenna surface 81C, the reflective film 82D has approximately the same shape as the antenna surface 81D, the reflective film 82E has approximately the same shape as the antenna surface 81E, the reflective film 82F has approximately the same shape as the antenna surface 81F, the reflective film 82G has approximately the same shape as the antenna surface 81G, the reflective film 82H has approximately the same shape as the antenna surface 81H, and the reflective film 82I has approximately the same shape as the antenna surface 81I. In other words, the reflective films 82A to 82I are each a parabolic mirror of revolution and are curved in a cone shape. When viewed from above, the reflective films 82A to 82I each have a circular shape with a missing portion. The reflective films 82A to 82I each curve convexly toward the device back surface 12 (base back surface 72). Each of the reflective films 82A to 82I has an opening facing in one direction (upward in this embodiment).

[0444] 52 and 53, the reflective films 82A to 82I and the dielectric 50 face each other in the z direction. In other words, the reflective films 82A to 82I are provided at positions facing the dielectric 50.

[0445] The electromagnetic waves reflected by the reflective film 82 are output toward the reception point P1. In one example, as shown in FIG. 52, the electromagnetic waves reflected by the reflective film 82D are output toward the reception point P1 of the terahertz element 20D. The electromagnetic waves reflected by the reflective film 82E are output toward the reception point P1 of the terahertz element 20E. The electromagnetic waves reflected by the reflective film 82F are output toward the reception point P1 of the terahertz element 20F. As shown in FIG. 53, the electromagnetic waves reflected by the reflective film 82B are output toward the reception point P1 of the terahertz element 20B. The electromagnetic waves reflected by the reflective film 82H are output toward the reception point P1 of the terahertz element 20H. Although not shown, the electromagnetic waves reflected by the reflective film 82A are output toward the reception point P1 of the terahertz element 20A. The electromagnetic waves reflected by the reflective film 82C are output toward the reception point P1 of the terahertz element 20C. The electromagnetic wave reflected by the reflective film 82G is output toward the reception point P1 of the terahertz element 20G. The electromagnetic wave reflected by the reflective film 82I is output toward the reception point P1 of the terahertz element 20I.

[0446] The positional relationship between the reflective film 82 and the terahertz element 20 is the same as in the first embodiment. The size relationship between the reflective film 82 and the terahertz element 20 is also the same as in the first embodiment. That is, when viewed from above, the reflective films 82A to 82I are formed larger than the terahertz elements 20A to 20I, respectively.

[0447] 52 and 53, similarly to the first embodiment, the antenna base 70 and the dielectric 50 are fixed via an adhesive layer 91. The adhesive layer 91 is configured so as not to protrude inward beyond the reflective film 82 (in other words, toward the terahertz element 20).

[0448] As shown in FIGS. 49 to 51, in this embodiment, the antenna base 70 uses three types of individual antenna bases. As shown in FIG. 49, the individual antenna base 70G has a base main surface 71 and a base back surface 72 as surfaces that intersect with the z direction. The base main surface 71 and the base back surface 72 are each surfaces that intersect with the z direction and are perpendicular to the z direction in this embodiment. The base main surface 71 and the base back surface 72 each have a square shape when viewed from the z direction. In this embodiment, the base main surface 71 and the base back surface 72 have, for example, the same shape. However, this is not a limitation, and the base main surface 71 and the base back surface 72 may have different shapes.

[0449] The individual antenna base 70G has four base side surfaces, namely, a first base side surface 73, a second base side surface 74, a third base side surface 75, and a fourth base side surface 76. These base side surfaces 73 to 76 are surfaces facing laterally in the terahertz device 10 (antenna base 70). Each of the base side surfaces 73 to 76 is a surface perpendicular to the opposing direction of the base main surface 71 and the base back surface 72, and connects the base main surface 71 and the base back surface 72.

[0450] The first base side surface 73 and the second base side surface 74 are surfaces facing each other in the x direction. When viewed from the z direction, each of the base side surfaces 73 and 74 extends along the y direction. The second base side surface 74 forms a part of the second base side surface 74T (see FIG. 48) of the antenna base 70.

[0451] The third base side surface 75 and the fourth base side surface 76 are surfaces that face each other in the y direction. When viewed from the z direction, each of the base side surfaces 75, 76 extends along the x direction. The third base side surface 75 forms a part of a third base side surface 75T of the antenna base 70.

[0452] The antenna surface 81G of the antenna recess 80G is recessed from the base main surface 71 of the individual antenna base 70G toward the base back surface 72. In this embodiment, the antenna surface 81G is recessed in a substantially spherical shape. In a cross-sectional view of the individual antenna base 70G cut along a plane along the x and z directions, the antenna surface 81G is curved so as to be convex toward the base back surface 72. In a cross-sectional view of the individual antenna base 70G cut along a plane along the y and z directions, the antenna surface 81G is curved so as to be convex toward the base back surface 72. The antenna surface 81G is open at the base main surface 71. In other words, the antenna surface 81G is open upward.

[0453] The opening of the antenna surface 81G has a circular shape with a portion missing when viewed from above. Specifically, the opening of the antenna surface 81G is missing at an opening end 81Ga, which is the end of the antenna surface 81G on the first base side surface 73 side, and an opening end 81Gb, which is the end on the fourth base side surface 76 side. These opening ends 81Ga and 81Gb are each formed in a straight line when viewed from above.

[0454] When viewed from above, an opening end 81Ga of the antenna surface 81G is formed at a position overlapping with the first base side surface 73, and an opening end 81Gb is formed at a position overlapping with the fourth base side surface .

[0455] The reflective film 82G is formed on the antenna surface 81 G. The reflective film 82G is formed over the entire antenna surface 81 G. On the other hand, the reflective film 82G is not formed on the base main surface 71.

[0456] When viewed from above, the opening of the reflective film 82G has the same shape as the opening of the antenna surface 81G. That is, when viewed from above, the opening of the reflective film 82G has an opening edge 82Ga that overlaps with an opening edge 81Ga of the antenna surface 81G, and an opening edge 82Gb that overlaps with an opening edge 81Gb of the antenna surface 81G. When viewed from above, both opening edges 81Ga and 81Gb are formed in a straight line.

[0457] When viewed from above, the reflective film 82G is formed so that its center point P2 is different from the center of the individual antenna base 70G in the x and y directions. In this embodiment, when viewed from above, the reflective film 82G is disposed closer to the first base side surface 73 and the fourth base side surface 76 than the center of the individual antenna base 70G in the x and y directions. More specifically, when viewed from above, the reflective film 82G is formed so that its center point P2 is closer to the first base side surface 73 in the x direction than the center of the individual antenna base 70G in the x direction. Furthermore, when viewed from above, the reflective film 82G is formed so that its center point P2 is closer to the fourth base side surface 76 in the y direction than the center of the individual antenna base 70G in the y direction.

[0458] When viewed from above, the center point P2 of the reflective film 82G coincides with the center point of the antenna surface 81E, and the shape of the reflective film 82G and the shape of the antenna surface 81G are approximately identical, so when viewed from above, the antenna surface 81G is formed so that the center point of the antenna surface 81G is at a position different from the center of the individual antenna base 70G in the x and y directions, just like the reflective film 82G.

[0459] When viewed from above, the portion of the arc-shaped outer periphery of the reflective film 82G that connects both end edges in the first direction, which is the arrangement direction of the reflective film 82G and the reflective film 82H, is formed into an arc shape with a central angle θg1 of less than 180°. In this embodiment, when viewed from above, the portion of the arc-shaped outer periphery of the reflective film 82G that connects both end edges in the first direction (the y direction in this embodiment) is formed into an arc shape with a central angle θg1 of less than 180°.

[0460] When viewed from above, the portion of the arc-shaped outer periphery of the reflective film 82G that connects both end edges in the second direction, which is the arrangement direction of the reflective film 82G and the reflective film 82D, is formed into an arc shape with a central angle θg2 of less than 180°. In this embodiment, when viewed from above, the portion of the arc-shaped outer periphery of the reflective film 82G that connects both end edges in the second direction (x direction in this embodiment) is formed into an arc shape with a central angle θg2 of less than 180°.

[0461] Because the reflective film 82G and the antenna surface 81G have substantially the same shape when viewed from above, similar to the reflective film 82G, the portion of the arc-shaped outer periphery of the antenna surface 81G connecting both end edges in a first direction (the y direction in this embodiment), which is the arrangement direction of the antenna surfaces 81G and 81H, is formed into an arc shape with a central angle of less than 180°. When viewed from above, the portion of the arc-shaped outer periphery of the antenna surface 81G connecting both end edges in a second direction (the x direction in this embodiment), which is the arrangement direction of the antenna surfaces 81G and 81D, is formed into an arc shape with a central angle of less than 180°.

[0462] When viewed from above, the length LS1 of a perpendicular line to the opening edge 82Ga of the reflective film 82G that passes through the center point P2 of the reflective film 82G is smaller than the radius RG of the reflective film 82G. When viewed from above, the length LS2 of a perpendicular line to the opening edge 82Gb of the reflective film 82G that passes through the center point P2 of the reflective film 82G is smaller than the radius RG of the reflective film 82G. When viewed from above, the perpendicular line to the opening edge 82Ga of the reflective film 82G is a straight line extending along the x direction, and the perpendicular line to the opening edge 82Gb of the reflective film 82G is a straight line extending along the y direction. Furthermore, the length LS1 is the length along the second direction (the x direction in this embodiment), and the length LS2 is the length along the first direction (the y direction in this embodiment). Therefore, the length (LS1+RG) of the reflective film 82G in the first direction is shorter than the diameter (RG×2) of the reflective film 82G, and the length (LS2+RG) of the reflective film 82G in the second direction is shorter than the diameter of the reflective film 82G. Thus, when viewed from above, the size of the reflective film 82G along the first direction, which is the direction in which the reflective films 82G-82I (see FIG. 37) are arranged, can also be said to be smaller than the size of the reflective film 82G along the second direction, which is the direction in which the reflective films 82G, 82D, and 82A are arranged, and along a third direction that is different from both the first direction and the third direction. Here, the third direction is a direction that intersects with both the first direction and the second direction when viewed from above. Furthermore, when viewed from above, the size of the reflective film 82G along the second direction can also be said to be smaller than the size of the reflective film 82G along the third direction.

[0463] Furthermore, since the reflective film 82G and the antenna surface 81G have the same shape when viewed from above, the relationship between the length of the perpendicular line passing through the center point of the antenna surface 81G among the perpendicular lines to the opening ends 81Ga, 81Gb of the antenna surface 81G and the radius of the antenna surface 81G is the same as the relationship between the lengths LS1, LS2 of the reflective film 82G and the radius RG of the reflective film 82G.

[0464] Although not shown, in a cross-sectional view of the individual antenna base 70G taken along a plane that passes through the center point P2 of the reflective film 82G and extends along the y and z directions, the portion connecting both end edges of the reflective film 82G in the y direction is formed into an arc shape with a central angle of less than 180°. Also, in a cross-sectional view of the individual antenna base 70G taken along a plane that passes through the center point P2 of the reflective film 82G and extends along the x and z directions, the portion connecting both end edges of the reflective film 82G in the x direction is formed into an arc shape with a central angle of less than 180°.

[0465] Although not shown, in a cross-sectional view of the individual antenna base 70G taken along a plane that passes through the center point of the antenna surface 81G and is aligned with the y and z directions, the portion connecting both end edges of the antenna surface 81G in the y direction is formed into an arc shape with a central angle of less than 180°. Also, in a cross-sectional view of the individual antenna base 70G taken along a plane that passes through the center point of the antenna surface 81G and is aligned with the x and z directions, the portion connecting both end edges of the antenna surface 81G in the x direction is formed into an arc shape with a central angle of less than 180°.

[0466] When viewed from above, the individual antenna base 70G has a peripheral wall 78G that surrounds the opening of the antenna recess 80G except for the missing portion of the opening. The peripheral wall 78G forms the base main surface 71 of the individual antenna base 70G.

[0467] As shown in Fig. 48, the individual antenna bases 70A, 70D, 70H, and 70I have the same shape. Therefore, as an example, the configuration of the individual antenna base 70H shown in Fig. 50 will be described, and a description of the configurations of the individual antenna bases 70A, 70D, and 70I will be omitted.

[0468] 50, the individual antenna base 70H, like the individual antenna base 70G, has a base main surface 71 and a base back surfac...

Claims

1. a plurality of terahertz elements including a first terahertz element, a second terahertz element, and a third terahertz element for receiving electromagnetic waves; a first reflecting surface facing the first terahertz element in a thickness direction of the first terahertz element and reflecting an incident electromagnetic wave toward the first terahertz element, a second reflecting surface facing the second terahertz element in a thickness direction of the second terahertz element and reflecting an incident electromagnetic wave toward the second terahertz element, and a third reflecting surface facing the third terahertz element in a thickness direction of the third terahertz element and reflecting an incident electromagnetic wave toward the third terahertz element, the first reflecting surface is open toward the first terahertz element and curved to be concave in a direction away from the first terahertz element, the second reflecting surface is open toward the second terahertz element and curved to be concave in a direction away from the second terahertz element, the third reflecting surface is open toward the third terahertz element and curved to be concave in a direction away from the third terahertz element, If the direction parallel to the thickness direction of each of the terahertz elements is the height direction of the terahertz device, the first reflecting surface and the second reflecting surface are arranged adjacent to each other in a first direction intersecting a height direction of the terahertz device, and the third reflecting surface is arranged adjacent to the second reflecting surface on an opposite side to the first reflecting surface in the first direction, When viewed from a height direction of the terahertz device, at least one of the sizes of the first reflecting surface and the second reflecting surface along the first direction is smaller than the sizes of the first reflecting surface and the second reflecting surface along a second direction that is different from the first direction, and the size of the third reflecting surface along the first direction is smaller than the size of the third reflecting surface along the second direction. Terahertz device.

2. the first reflecting surface and the second reflecting surface each have a spherical shape, When viewed from a height direction of the terahertz device, at least one of a portion of an outer periphery of the first reflecting surface connecting both ends in the first direction and a portion of an outer periphery of the second reflecting surface connecting both ends in the first direction is formed into an arc shape with a central angle of less than 180°. The terahertz device according to claim 1 .

3. the third reflecting surface has a spherical shape, When viewed from the height direction of the terahertz device, a portion of the outer periphery of the third reflecting surface connecting both end edges in the first direction is formed into an arc shape with a central angle of less than 180°.

3. The terahertz device according to claim 1 or 2.

4. The second reflecting surface has a spherical shape, When viewed from the height direction of the terahertz device, a portion of the outer periphery of the second reflecting surface connecting both end edges in the first direction is formed into an arc shape with a central angle of less than 90°. The terahertz device according to any one of claims 1 to 3.

5. a plurality of terahertz elements including a first terahertz element, a second terahertz element, and a third terahertz element for receiving electromagnetic waves; a first reflecting surface facing the first terahertz element in a thickness direction of the first terahertz element and reflecting an incident electromagnetic wave toward the first terahertz element, a second reflecting surface facing the second terahertz element in a thickness direction of the second terahertz element and reflecting an incident electromagnetic wave toward the second terahertz element, and a third reflecting surface facing the third terahertz element in a thickness direction of the third terahertz element and reflecting an incident electromagnetic wave toward the third terahertz element, the first reflecting surface is open toward the first terahertz element and curved to be concave in a direction away from the first terahertz element, the second reflecting surface is open toward the second terahertz element and curved to be concave in a direction away from the second terahertz element, the third reflecting surface is open toward the third terahertz element and curved to be concave in a direction away from the third terahertz element, If the direction parallel to the thickness direction of each of the terahertz elements is the height direction of the terahertz device, A direction intersecting with the height direction of the terahertz device is defined as a first direction, a direction intersecting with the height direction of the terahertz device and different from the first direction is defined as a second direction, a direction intersecting with the height direction of the terahertz device and different from the first direction and the second direction is defined as a third direction, and a direction intersecting with the height direction of the terahertz device and different from the first direction, the second direction, and the third direction is defined as a fourth direction. the first reflecting surface and the second reflecting surface are arranged adjacent to each other in the first direction, the third reflecting surface is arranged adjacent to the first reflecting surface in the third direction, and is arranged adjacent to the second reflecting surface in the fourth direction, When viewed from a height direction of the terahertz device, at least one of the sizes of the first reflecting surface and the second reflecting surface along the first direction is smaller than the sizes of the first reflecting surface and the second reflecting surface along the second direction, and at least one of the sizes of the third reflecting surface along the third direction and the size of the third reflecting surface along the fourth direction is smaller than the size of the third reflecting surface along the second direction. Terahertz device.

6. The third terahertz element is disposed at a position different from the first terahertz element and the second terahertz element in the second direction and at a position between the first terahertz element and the second terahertz element in the first direction. The terahertz device according to claim 5 .

7. the third reflecting surface has a spherical shape, When viewed from the height direction of the terahertz device, at least one of a portion of an outer periphery of the third reflecting surface connecting both ends in the third direction and a portion of an outer periphery of the third reflecting surface connecting both ends in the fourth direction is formed in an arc shape with a central angle of less than 180°.

7. The terahertz device according to claim 5 or 6.

8. When viewed from a height direction of the terahertz device, a size of the first reflecting surface along the third direction is smaller than a size of the first reflecting surface along the second direction. The terahertz device according to any one of claims 5 to 7.

9. When viewed from a height direction of the terahertz device, a size of the second reflecting surface along the fourth direction is smaller than a size of the second reflecting surface along the second direction. The terahertz device according to any one of claims 5 to 8.

10. a plurality of terahertz elements including a first terahertz element, a second terahertz element, a third terahertz element, and a fourth terahertz element for receiving electromagnetic waves; a first reflecting surface facing the first terahertz element in a thickness direction of the first terahertz element and reflecting an incident electromagnetic wave toward the first terahertz element, a second reflecting surface facing the second terahertz element in a thickness direction of the second terahertz element and reflecting the incident electromagnetic wave toward the second terahertz element, a third reflecting surface facing the third terahertz element in a thickness direction of the third terahertz element and reflecting the incident electromagnetic wave toward the third terahertz element, and a fourth reflecting surface facing the fourth terahertz element in a thickness direction of the fourth terahertz element and reflecting the incident electromagnetic wave toward the fourth terahertz element, the first reflecting surface is open toward the first terahertz element and curved to be concave in a direction away from the first terahertz element, the second reflecting surface is open toward the second terahertz element and curved to be concave in a direction away from the second terahertz element, the third reflecting surface is open toward the third terahertz element and curved to be concave in a direction away from the third terahertz element, the fourth reflecting surface is open toward the fourth terahertz element and curved to be concave in a direction away from the fourth terahertz element, A direction parallel to a thickness direction of each of the terahertz elements is defined as a height direction of the terahertz device, a direction intersecting the height direction of the terahertz device as viewed from the height direction of the terahertz device is defined as a first direction, and a direction perpendicular to the first direction is defined as a second direction. the first reflecting surface and the second reflecting surface are arranged adjacent to each other in the first direction, the third reflecting surface is arranged adjacent to the first reflecting surface in the second direction, the fourth reflecting surface is arranged adjacent to the second reflecting surface in the second direction, and the third reflecting surface and the fourth reflecting surface are arranged adjacent to each other in the first direction, When viewed from a height direction of the terahertz device, at least one of the sizes of the first reflecting surface and the second reflecting surface along the first direction is smaller than the sizes of the first reflecting surface and the second reflecting surface along the second direction, and at least one of the sizes of the third reflecting surface and the fourth reflecting surface along the first direction is smaller than the sizes of the third reflecting surface and the fourth reflecting surface along a third direction different from the first direction and the second direction. Terahertz device.

11. When viewed from a height direction of the terahertz device, at least one of a size of the third reflecting surface and a size of the fourth reflecting surface along the second direction is smaller than a size of the third reflecting surface and a size of the fourth reflecting surface along the third direction, respectively. The terahertz device according to claim 10.

12. the third reflecting surface and the fourth reflecting surface each have a spherical shape, When viewed from a height direction of the terahertz device, at least one of a portion of an outer periphery of the third reflecting surface connecting both ends in the second direction and a portion of an outer periphery of the fourth reflecting surface connecting both ends in the second direction is formed into an arc shape with a central angle of less than 180°.

12. The terahertz device according to claim 10 or 11.

13. a plurality of terahertz elements including a first terahertz element and a second terahertz element for receiving electromagnetic waves; a first reflecting surface facing the first terahertz element in a thickness direction of the first terahertz element and reflecting an incident electromagnetic wave toward the first terahertz element, and a second reflecting surface facing the second terahertz element in a thickness direction of the second terahertz element and reflecting an incident electromagnetic wave toward the second terahertz element; an antenna base having a plurality of antenna surfaces facing the plurality of terahertz elements in a thickness direction of the terahertz element, the first reflecting surface is open toward the first terahertz element and curved to be concave in a direction away from the first terahertz element, the second reflecting surface is open toward the second terahertz element and curved to be concave in a direction away from the second terahertz element, If the direction parallel to the thickness direction of both the terahertz elements is the height direction of the terahertz device, the first reflecting surface and the second reflecting surface are arranged adjacent to each other in a first direction intersecting a height direction of the terahertz device, When viewed from a height direction of the terahertz device, at least one of the sizes of the first reflecting surface and the second reflecting surface along the first direction is smaller than the sizes of the first reflecting surface and the second reflecting surface along a second direction that is different from the first direction, The plurality of reflecting surfaces are formed of reflecting films formed on the respective antenna surfaces. Terahertz device.

14. a plurality of terahertz elements including a first terahertz element and a second terahertz element for receiving electromagnetic waves; a first reflecting surface facing the first terahertz element in a thickness direction of the first terahertz element and reflecting an incident electromagnetic wave toward the first terahertz element, and a second reflecting surface facing the second terahertz element in a thickness direction of the second terahertz element and reflecting an incident electromagnetic wave toward the second terahertz element; an antenna base having a plurality of antenna surfaces facing the plurality of terahertz elements in a thickness direction of the terahertz element, the first reflecting surface is open toward the first terahertz element and curved to be concave in a direction away from the first terahertz element, the second reflecting surface is open toward the second terahertz element and curved to be concave in a direction away from the second terahertz element, If the direction parallel to the thickness direction of both the terahertz elements is the height direction of the terahertz device, the first reflecting surface and the second reflecting surface are arranged adjacent to each other in a first direction intersecting a height direction of the terahertz device, When viewed from a height direction of the terahertz device, at least one of the sizes of the first reflecting surface and the second reflecting surface along the first direction is smaller than the sizes of the first reflecting surface and the second reflecting surface along a second direction that is different from the first direction, The antenna base is made of metal. The plurality of reflecting surfaces are made up of the plurality of antenna surfaces. Terahertz device.

15. a plurality of terahertz elements including a first terahertz element and a second terahertz element for generating electromagnetic waves; a first reflecting surface facing the first terahertz element in a thickness direction of the first terahertz element and reflecting an electromagnetic wave generated from the first terahertz element in one direction, and a second reflecting surface facing the second terahertz element in a thickness direction of the second terahertz element and reflecting an electromagnetic wave generated from the second terahertz element in one direction; an antenna base having a plurality of antenna surfaces facing the plurality of terahertz elements in a thickness direction of the terahertz element, the first reflecting surface is open toward the first terahertz element and curved to be concave in a direction away from the first terahertz element, the second reflecting surface is open toward the second terahertz element and curved to be concave in a direction away from the second terahertz element, If the direction parallel to the thickness direction of both the terahertz elements is the height direction of the terahertz device, the first reflecting surface and the second reflecting surface are arranged adjacent to each other in a first direction intersecting a height direction of the terahertz device, When viewed from a height direction of the terahertz device, at least one of the sizes of the first reflecting surface and the second reflecting surface along the first direction is smaller than the sizes of the first reflecting surface and the second reflecting surface along a second direction that is different from the first direction, The plurality of reflecting surfaces are formed of reflecting films formed on the respective antenna surfaces. Terahertz device.

16. a plurality of terahertz elements including a first terahertz element and a second terahertz element for generating electromagnetic waves; a first reflecting surface facing the first terahertz element in a thickness direction of the first terahertz element and reflecting an electromagnetic wave generated from the first terahertz element in one direction, and a second reflecting surface facing the second terahertz element in a thickness direction of the second terahertz element and reflecting an electromagnetic wave generated from the second terahertz element in one direction; an antenna base having a plurality of antenna surfaces facing the plurality of terahertz elements in a thickness direction of the terahertz element, the first reflecting surface is open toward the first terahertz element and curved to be concave in a direction away from the first terahertz element, the second reflecting surface is open toward the second terahertz element and curved to be concave in a direction away from the second terahertz element, If the direction parallel to the thickness direction of both the terahertz elements is the height direction of the terahertz device, the first reflecting surface and the second reflecting surface are arranged adjacent to each other in a first direction intersecting a height direction of the terahertz device, When viewed from a height direction of the terahertz device, at least one of the sizes of the first reflecting surface and the second reflecting surface along the first direction is smaller than the sizes of the first reflecting surface and the second reflecting surface along a second direction that is different from the first direction, The antenna base is made of metal. The plurality of reflecting surfaces are made up of the plurality of antenna surfaces. Terahertz device.

17. a holding member attached to the antenna base and holding each of the plurality of terahertz elements; The holding member covers the plurality of reflecting surfaces. The terahertz device according to any one of claims 13 to 16.

18. A partition wall is provided at a boundary between adjacent reflecting surfaces among the plurality of reflecting surfaces, the partition wall being in contact with the holding member to separate the adjacent reflecting surfaces.

18. The terahertz device of claim 17.

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