Antenna Device

Abstract

To provide an antenna device which allows reduction in loss while improving its gain.SOLUTION: An antenna device 10 comprises: a substrate 20 which has a base material 21 containing a dielectric and a conductor 22; and a waveguide 30, an antenna 40, and a matching part 50 which are disposed, as part of the conductor, on the base material. The antenna has: a plurality of patch parts 41 which face an upper wall part and are disposed in an array; a plurality of power feeding lines 42 which extend from the patch parts in a Z-direction, and which are provided individually for the patch parts; and a plurality of short-circuiting parts 43 which are provided individually for the patch parts, and which electrically connect the patch parts to the upper wall part. The upper wall part has a plurality of openings 34 which are formed individually for the power feeding lines. Each of the power feeding lines extends into the waveguide through a corresponding one of the openings.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The disclosure herein relates to an antenna device. [Background technology]

[0002] Patent Document 1 discloses an antenna device in which an array antenna and a waveguide are formed on the same substrate. A strip line is used to feed the array antenna. The contents of the prior art document are incorporated by reference as an explanation of the technical elements in this specification. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2008-5164 A Summary of the Invention [Problem to be solved by the invention]

[0004] As the frequency band becomes higher, such as the millimeter wave band, the amount of radiation from the stripline increases, resulting in increased radiation loss. Also, the amount of the electric field formed in the thickness direction of the board due to radio wave propagation in the stripline that spreads into the board increases, resulting in increased dielectric loss. In the above respects, or in other respects not mentioned, further improvements in the antenna device are required.

[0005] One disclosed object is to provide an antenna device capable of improving gain while reducing loss. [Means for solving the problem]

[0006] The antenna device disclosed herein comprises: A substrate (20) having a substrate (21) including a dielectric and a conductor (22) disposed on the substrate; a waveguide (30) disposed on the substrate as a part of a conductor, the waveguide having an upper wall portion (31), a lower wall portion (32) facing the upper wall portion in the thickness direction of the substrate, and a side wall portion (33) connected to the upper wall portion and the lower wall portion; an antenna (40) having a plurality of patch sections (41) arranged on a substrate as a part of a conductor and arranged in an array so as to face the upper wall section in the plate thickness direction, a plurality of feed lines (42) extending from the patch sections in the plate thickness direction and provided individually for the patch sections, and a plurality of short-circuit sections (43) provided individually for the patch sections and electrically connecting the patch sections and the upper wall section; a matching section (50) that is disposed on the substrate as a part of the conductor and is provided separately from the patch section in order to match the impedance of the waveguide with the impedance of the antenna; The upper wall portion has a plurality of openings (34) formed individually for the power supply lines; Each of the feed lines is extended through a corresponding opening into the inside of the waveguide. And, The matching section includes an inner layer pattern (51, 52, 53) connected to the feed line at a position away from the patch section so as to face the lower wall section. In one disclosure, the inner layer pattern includes a first inner layer pattern (51) disposed between the upper wall portion and the lower wall portion in the plate thickness direction, The matching portion includes a first inner layer pattern and a second via conductor (55) disposed within the waveguide and connected to the inner layer pattern, and is connected to the inner surface of the lower wall portion and has a predetermined height from the inner surface. In another embodiment of the disclosure, the inner layer pattern includes a second inner layer pattern (52) disposed in the opening. In another embodiment of the present disclosure, the inner layer pattern includes a third inner layer pattern (53) disposed between the patch portion and the upper wall portion in the plate thickness direction.

[0007] According to the disclosed antenna device, a waveguide, an antenna, and a matching section are formed on a substrate. The antenna has a plurality of patch sections arranged in an array, and the gain can be improved. The feed line extends from the patch section through an opening to the inside of the waveguide. The feed line does not extend in a direction perpendicular to the plate thickness direction as in the strip line, but extends from the patch section in the plate thickness direction. Therefore, even in high frequency bands such as the millimeter wave band, radiation from the feed line can be suppressed, that is, radiation loss can be suppressed. Furthermore, since the feed is not based on the formation of an electric field in the plate thickness direction for radio wave propagation as in the microstrip line, the amount of electric field spreading in the substrate is small, and dielectric loss due to the feed line can be suppressed. As a result, an antenna device capable of reducing loss can be provided.

[0008] The various aspects disclosed in this specification adopt different technical means to achieve their respective objectives. The claims and the parenthetical symbols described in this section are merely illustrative of the corresponding relationship with the embodiments described below, and are not intended to limit the technical scope. The objectives, features, and effects disclosed in this specification will become clearer with reference to the following detailed description and the accompanying drawings. [Brief description of the drawings]

[0009] [Figure 1] 1 is a perspective view showing an example of an antenna device according to a first embodiment. [Diagram 2] FIG. 2 is a cross-sectional view taken along line II-II in FIG. [Diagram 3] FIG. 2 is a cross-sectional view taken along line III-III in FIG. [Figure 4] FIG. 4 is an enlarged view of region IV in FIG. [Diagram 5] FIG. 13 is a perspective view showing an example of four elements. [Figure 6] FIG. 6 is an exploded perspective view of the antenna device shown in FIG. [Figure 7] FIG. 13 is a diagram showing radiation characteristics of four elements. [Figure 8] FIG. 13 is a diagram showing radiation characteristics of two elements. [Figure 9] FIG. 11 is a cross-sectional view showing a modified example. [Figure 10] FIG. 11 is a cross-sectional view showing an antenna device according to a second embodiment. [Figure 11] FIG. 11 is a cross-sectional view showing an antenna device according to a third embodiment. [Figure 12] FIG. 11 is a cross-sectional view showing an antenna device according to a fourth embodiment. [Figure 13] FIG. 13 is a perspective view showing an antenna device according to a fifth embodiment. [Figure 14] FIG. [Figure 15] FIG. 13 is a perspective view showing an antenna device according to a sixth embodiment. [Figure 16]FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, several embodiments will be described with reference to the drawings. In addition, by assigning the same reference numerals to corresponding components in each embodiment, duplicated explanations may be omitted. When only a part of the configuration is described in each embodiment, the configuration of the other embodiment described above can be applied to the other parts of the configuration. In addition to the combination of configurations explicitly stated in the description of each embodiment, configurations of several embodiments can be partially combined together even if not explicitly stated, as long as there is no particular problem with the combination.

[0011] (First embodiment) The antenna device is configured to transmit and / or receive radio waves at a predetermined operating frequency, and is used, for example, in a high-speed wireless transmission system in the 80 GHz band.

[0012] <Antenna device> First, an antenna device will be described with reference to Figs. 1 to 4. Fig. 1 is a perspective view showing a schematic configuration of an example of an antenna device. Fig. 2 is a cross-sectional view taken along line II-II in Fig. 1. Fig. 3 is a cross-sectional view taken along line III-III in Fig. 1. Fig. 4 is an enlarged view of region IV shown by a dashed line in Fig. 3 to show the configuration of the matching section. That is, Figs. 1 to 3 show a simplified view of the matching section 50. The outline arrows shown in Figs. 1 and 2 indicate the power feeding direction. Note that the power feeding direction is also indicated by an outline arrow in other figures.

[0013] As shown in Figs. 1 to 4, the antenna device 10 includes a substrate 20, a waveguide 30, an antenna 40, and a matching section 50. In the following, the thickness direction of the substrate 20 is defined as the Z direction, and one direction perpendicular to the Z direction is defined as the X direction. The direction perpendicular to the Z direction and the X direction is defined as the Y direction. Unless otherwise specified, a shape viewed from the Z direction, that is, a shape along the XY plane defined by the X direction and the Y direction, is referred to as a planar shape. The planar view from the Z direction may be simply referred to as a planar view.

[0014] The substrate 20 has a base material 21 and a conductor 22. The substrate 20 may be referred to as a printed circuit board or a wiring board. The substrate 20 has one surface 20a and a back surface 20b that is the surface opposite to the surface 20a in the Z direction. The base material 21 includes a dielectric material such as a resin. The substrate 21 is expected to have a wavelength shortening effect due to the dielectric material. The substrate 21 may be made of, for example, only a resin, a combination of a resin and a glass cloth or a nonwoven cloth, or a ceramic. The substrate 21 may be referred to as an insulating substrate. The substrate 21 may be formed by stacking insulating layers including a dielectric material in multiple layers, for example.

[0015] The conductor 22 is disposed on the substrate 21. The conductor 22 is formed in a printed circuit board using a general wiring technique. The conductor 22 includes a conductor pattern and a via conductor. The conductor pattern is sometimes referred to as a conductor layer. The conductor pattern is disposed in multiple layers on the substrate 21. In other words, the substrate 20 is a multi-layer substrate. The conductor pattern is formed by patterning a metal foil such as a copper foil. The via conductor is formed by disposing a conductor such as a plating in a through hole (via) formed in an insulating layer constituting the substrate 21.

[0016] In the antenna device 10, elements other than the substrate 20 are disposed on the base material 21 as parts of the conductor 22. The waveguide 30, the antenna 40, and the matching unit 50 are configured using the conductor 22. That is, the waveguide 30, the antenna 40, and the matching unit 50 are formed on the substrate 20. The substrate 20 may include only the components of the waveguide 30, the antenna 40, and the matching unit 50 as the conductor 22, or may include circuit elements other than the above-mentioned components.

[0017] The waveguide 30 is a transmission path for feeding power to the antenna 40. Radio waves propagate through the waveguide 30. As described above, the waveguide 30 is disposed on the substrate 21 as a part of the conductor 22. The waveguide 30 has an upper wall portion 31, a lower wall portion 32, and a side wall portion 33. The upper wall portion 31, the lower wall portion 32, and the side wall portion 33 are parts of the conductor 22 disposed on the substrate 21. The upper wall portion 31 and the lower wall portion 32 are disposed opposite each other with a predetermined gap therebetween in the Z direction.

[0018] In this embodiment, the lower wall portion 32 is configured by a surface layer pattern on the back surface 20b side of the substrate 20. The surface layer pattern is a conductor pattern arranged on the surface (front surface) of the base material 21. On the other hand, an inner layer pattern described later is a conductor pattern arranged inside the base material 21. The upper wall portion 31 is located between the lower wall portion 32 and a patch portion 41 described later in the Z direction. That is, the upper wall portion 31 is located closer to the patch portion 41 than the lower wall portion 32. The side wall portion 33 is connected to the upper wall portion 31 and the lower wall portion 32. In this way, the waveguide 30 is a transmission path with a tunnel structure surrounded by the upper wall portion 31, the lower wall portion 32, and the side wall portion 33. The waveguide 30 extends in the X direction, and power is supplied to the waveguide 30 from one end side in the X direction.

[0019] The waveguide 30 has a substantially rectangular ring shape. Such a waveguide 30 may be referred to as a rectangular waveguide. The substrate 21 is disposed inside the waveguide 30. In the waveguide 30, the width, which is the opening length in the Y direction, is longer than the height, which is the opening length in the Z direction. The width of the waveguide 30 is set within a range of 0.5×λε or more and 1×λε or less, that is, within a range of 1 / 2 wavelength or more and 1 wavelength or less, with respect to the wavelength λε of the radio wave of the operating frequency. The wavelength λε is a wavelength taking into consideration the dielectric (relative dielectric constant). The wavelength λε is calculated by (300 [mm / s] / operating frequency [GHz]) / square root of the dielectric constant of the substrate 21. The height of the waveguide 30 is set to about 1 / 2 wavelength, for example, within a range of 0.4×λε to 0.6×λε. With such a length setting, radio waves propagate through the waveguide 30.

[0020] The waveguide 30 has an opening 34. The opening 34 is formed in the upper wall portion 31. The opening 34 penetrates the upper wall portion 31 in the Z direction. The opening 34 is formed so that a power feed line 42, which will be described later, can be extended to the inside of the waveguide 30. The opening 34 is formed separately for the power feed line 42. The opening 34 is formed so as to overlap a part of the corresponding patch portion 41 in a plan view. The opening 34 is formed not to contact the power feed line 42 and is sized so as to prevent radio waves from leaking out of the waveguide 30.

[0021] The opening 34 has a substantially circular shape in plan view. The diameter D of the opening 34 can be calculated by the following formula (1). Here, d is the diameter of the feed line 42, ε is the relative dielectric constant of the substrate 21, and Zo is the impedance converted by the matching section 50.

number

[0022] The antenna 40 has a patch section 41, a power feed line 42, and a short circuit section 43. The antenna 40 uses the upper wall section 31 (waveguide 30) as the ground plate of the antenna 40. The upper wall section 31 functions as the ground plate of the antenna 40. The ground plate is connected to a power feed circuit (not shown) to provide a ground potential (earth potential) in the antenna device 10. The upper wall section 31 provides a ground potential by providing an opening in the lower wall section 32 of the waveguide 30 and electrically connecting, for example, a standard waveguide or an outer conductor of a coaxial cable. The direction perpendicular to the plate surface of the ground plate is also approximately parallel to the Z direction. In a plan view, the area of ​​the ground plate is larger than the area of ​​the patch section 41. The ground plate has a size that includes the patch section 41. It is preferable that the ground plate has a size necessary for stable operation of the antenna 40.

[0023] The patch section 41 is disposed on the substrate 21 as a part of the conductor 22 so as to function as a radiating element. The patch section 41 includes the above-mentioned conductor pattern. The arrangement of the conductor pattern constituting the patch section 41 in the Z direction is not particularly limited. It may be a surface layer pattern or an inner layer pattern. The patch section 41 is disposed facing the upper wall section 31 so as to have a predetermined distance between the patch section 41 and the ground plate, i.e., the upper wall section 31, in the Z direction. The patch section 41 may be referred to as a radiating element or an antenna element. In a plan view, the entire patch section 41 overlaps with the upper wall section 31. That is, the entire plate surface (lower surface) of the patch section 41 faces the upper wall section 31 in the Z direction. The patch section 41 is disposed substantially parallel to the upper wall section 31. "Substantially parallel" does not necessarily mean completely parallel.

[0024] The patch portion 41 of this embodiment is disposed on one surface 20a of the substrate 20. The patch portion 41 is a surface layer pattern on the one surface 20a side of the substrate 20. The basic shape of the patch portion 41 is a substantially square shape in plan view. The basic shape is the outer contour of the patch portion 41 in plan view. The patch portion 41 has four sides that define the outer contour in plan view. The patch portion 41 may have a slit on at least one of the four sides.

[0025] The patch section 41 is disposed opposite the upper wall section 31, which is the ground plane, to form a capacitor according to the area of ​​the patch section 41 and the distance from the ground plane. The patch section 41 is formed to a size that forms a capacitor that resonates in parallel at a target frequency with the inductor provided in the short-circuit section 43. The area of ​​the patch section 41 is appropriately designed so as to provide a desired capacitor and, ultimately, so as to operate at the operating frequency.

[0026] In the present embodiment, the basic shape (outer contour) of the patch section 41 is a square shape as an example, but the planar shape of the patch section 41 may be a circle, a regular octagon, a regular hexagon, or the like as another configuration. The basic shape of the patch section 41 is preferably a shape that is line-symmetrical with respect to two mutually orthogonal straight lines as axes of symmetry, that is, a two-way line-symmetrical shape. A two-way line-symmetrical shape refers to a shape that is line-symmetrical with respect to a certain straight line as an axis of symmetry, and is also line-symmetrical with respect to another straight line that is orthogonal to the straight line. Examples of two-way line-symmetrical shapes include an ellipse, a rectangle, a circle (a perfect circle), a square, a regular hexagon, a regular octagon, and a rhombus. In addition, it is more preferable that the patch section 41 is a point-symmetrical shape such as a circle, a square, a rectangle, or a parallelogram.

[0027] The feed line 42 is disposed on the substrate 21 as a part of the conductor 22 in order to feed power to the patch unit 41. The feed line 42 is electrically connected to the patch unit 41. The feed line 42 includes the above-mentioned via conductor. The power supply method is not limited to the direct power supply method. A power supply method in which the feed line 42 and the patch unit 41 are electromagnetically coupled may be adopted. One of the ends of the feed line 42 is electrically connected to the patch unit 41. The electrical connection portion between the patch unit 41 and the feed line 42 is the power supply point. The feed line 42 extends in the Z direction. The other end of the feed line 42 is disposed inside the waveguide 30. The feed line 42 extends from the patch unit 41 (power supply point) to the inside of the waveguide 30 through the opening 34 formed in the upper wall portion 31. The current input to the feed line 42 from the waveguide 30 propagates to the patch unit 41 and excites the patch unit 41. The power supply line 42 of the present embodiment is composed of a plurality of via conductors arranged side by side in the Z direction.

[0028] The short-circuiting portion 43 is disposed on the substrate 21 as a part of the conductor 22 in order to electrically connect, i.e., short-circuit, the upper wall portion 31, which is the ground plane, and the patch portion 41. The short-circuiting portion 43 includes the above-mentioned via conductor. One end of the short-circuiting portion 43 is connected to the upper wall portion 31, and the other end is connected to the patch portion 41. The short-circuiting portion 43 has, for example, a substantially circular shape in plan. By adjusting the diameter and length of the short-circuiting portion 43, the inductor value (inductance) of the short-circuiting portion 43 can be adjusted. The short-circuiting portion 43 is connected to the substantial center of the patch portion 41 in a plan view. The center of the patch portion 41 corresponds to the center of gravity of the patch portion 41.

[0029] Since the patch portion 41 in this embodiment has a substantially square shape in plan view, the center corresponds to the intersection of two diagonals of the patch portion 41. The number of via conductors constituting the short-circuit portion 43 is not particularly limited. In this embodiment, one via conductor constitutes the short-circuit portion 43. The short-circuit portion 43 may be constituted by a plurality of via conductors arranged in parallel between the upper wall portion 31 and the patch portion 41.

[0030] The antenna 40 has a plurality of patch sections 41, feed lines 42, and short-circuit sections 43 each having the above-mentioned configuration. The plurality of patch sections 41 are arranged to face a common (single) upper wall section 31. The plurality of patch sections 41 are arranged in an array in a plan view. In the example shown in Figs. 1 to 4, the plurality of patch sections 41 are arranged along the X direction. Specifically, three patch sections 41 are lined up in a row. The spacing between the centers of the patch sections 41 arranged in a row is set within a range of 0.25 x λε or more and 1 x λε or less, that is, within a range of ¼ wavelength or more and 1 wavelength or less.

[0031] In the following, the number of elements may be indicated by the number of patch units 41. In Figs. 1 to 4, an example of three elements is shown. A plurality of feed lines 42 are provided for each patch unit 41. The feed lines 42 are configured to be able to feed power to the plurality of patch units 41 individually. A plurality of short-circuit units 43 are also provided for each patch unit 41 individually. That is, a feed line 42 and a short-circuit unit 43 are provided for each patch unit 41.

[0032] The matching section 50 matches the impedance of the waveguide 30 with the impedance of the antenna 40. The matching section 50 is sometimes called a conversion section because it converts the impedance between the waveguide 30 and the antenna 40. For example, the impedance of the waveguide 30 is 100Ω or more, and the impedance of the antenna 40 is 50 to 75Ω. The matching section 50 converts, for example, the impedance to an intermediate value between the impedance of the waveguide 30 and the antenna 40. The matching section 50 may convert the impedance of the waveguide 30 to a value approximately equal to the impedance of the antenna 40.

[0033] The matching section 50 is also disposed on the substrate 21 as a part of the conductor 22. The matching section 50 is provided individually for the patch section 41, i.e., the radiating element. The matching section 50 of this embodiment is disposed inside the waveguide 30. As shown in FIG. 4, the matching section 50 includes an inner layer pattern 51 and a via conductor 55. The inner layer pattern 51 corresponds to a first inner layer pattern, and the via conductor 55 corresponds to a second via conductor.

[0034] The inner layer pattern 51 is connected to the feed line 42 at a position away from the patch portion 41 so as to face the lower wall portion 32. The inner layer pattern 51 is disposed inside the waveguide 30. The inner layer pattern 51 is located between the upper wall portion 31 and the lower wall portion 32 in the Z direction. One end of the via conductor 55 is connected to the conductor pattern constituting the lower wall portion 32, and the other end is connected to the inner layer pattern 51. In this manner, the matching portion 50 is connected to the inner surface 32a of the lower wall portion 32, and has a predetermined height from the inner surface 32a. The number of via conductors 55 interposed between the inner layer pattern 51 and the lower wall portion 32 is not particularly limited. Only one may be disposed, or a plurality of via conductors 55 may be disposed. In this embodiment, three or more via conductors 55 are disposed for one inner layer pattern 51.

[0035] The matching section 50 is connected to the tip of the feed line 42. The conductor 22 constituting the matching section 50 is electrically connected to the conductor 22 constituting the feed line 42. The feed line 42 and / or the feed line 42 including the matching section 50 is extended to a position below the center of the height of the waveguide 30. In other words, the feed line 42 and / or the feed line 42 including the matching section 50 arranged inside the waveguide 30 has a length of ¼ wavelength or more.

[0036] 5 and 6 show a more specific example of the configuration of the antenna device 10. FIG. 5 is a perspective view of the antenna device 10. In FIG. 5, the matching section 50 is illustrated in a simplified manner. FIG. 6 is an exploded perspective view. In FIG. 5 and FIG. 6, an example of four elements is shown. The four patch sections 41 are arranged in a row in the X direction. The base material 21 is formed by laminating three insulating layers 210, 211, and 212. The conductor pattern has the patch section 41 and the lower wall section 32, which are surface layer patterns, and the upper wall section 31 and the inner layer pattern 51, which are inner layer patterns. That is, four layers of conductor patterns are arranged on the base material 21.

[0037] The side wall portion 33 of the waveguide 30 is composed of a plurality of via conductors 330. The plurality of via conductors 330 are arranged at intervals such that radio waves do not leak out. The plurality of via conductors 330 are arranged such that one end side in the X direction is open to allow power supply and the other end side is closed. The plurality of via conductors 330 are arranged in a substantially U-shape in plan view. The via conductors 330 are sometimes referred to as posts. The side wall portion 33 composed of the plurality of via conductors 330 are sometimes referred to as post walls. The waveguide 30 having the side wall portion 33 composed of the via conductors 330 is sometimes referred to as a post wall waveguide.

[0038] The power supply line 42 is composed of via conductors 420. The via conductors 420 correspond to a first via conductor. The multiple via conductors 420 are connected to each other through the openings 34 to form the power supply line 42. The short circuit portion 43 is composed of via conductors 430. One end of the via conductor 430 is connected to the patch portion 41, and the other end is connected to the upper wall portion 31. The matching portion 50 is composed of the inner layer pattern 51 and the via conductors 55, as described above. Four via conductors 55 are interposed between the lower wall portion 32 and one inner layer pattern 51.

[0039] <Antenna operation> Next, the operation of the antenna 40 will be described. As described above, the antenna 40 has a structure in which the opposing ground plate (upper wall portion 31) and patch portion 41 are connected by the short circuit portion 43. This structure is a so-called mushroom structure, which is the same as the basic structure of a metamaterial. The antenna 40 is an antenna that applies metamaterial technology, and is therefore sometimes called a metamaterial antenna.

[0040] The antenna 40 of this embodiment is designed to operate in a zeroth-order resonance mode at a desired operating frequency, and is therefore sometimes referred to as a zeroth-order resonance antenna. The zeroth-order resonance is a phenomenon in which a metamaterial resonates at a frequency where the phase constant β of the dispersion characteristics of the metamaterial is zero (0). The phase constant β is the imaginary part of the propagation coefficient γ of a wave propagating through a transmission line. The antenna 40 can effectively transmit and / or receive radio waves in a predetermined band including the frequency at which the zeroth-order resonance occurs.

[0041] Schematically, the antenna 40 operates by LC parallel resonance between a capacitor formed between the ground plane and the patch unit 41 and an inductor included in the short circuit unit 43. The patch unit 41 is shorted to the ground plane by the short circuit unit 43 provided in its central region. The area of ​​the patch unit 41 is set to an area that forms a capacitor that resonates in parallel with the inductor included in the short circuit unit 43 at a desired frequency (operating frequency). The value of the inductor (inductance) is determined according to the dimensions of each part of the short circuit unit 43, for example, the diameter and the length in the Z direction.

[0042] Therefore, when power of the operating frequency is supplied, parallel resonance occurs due to energy exchange between the inductor and the capacitor, and an electric field perpendicular to the ground plane is generated between the ground plane and the patch unit 41. That is, an electric field in the Z direction is generated. This perpendicular electric field propagates from the short circuit portion 43 toward the edge of the patch unit 41, and becomes a vertically polarized wave at the edge of the patch unit 41 and propagates through space. Note that the vertically polarized wave here refers to a radio wave whose electric field vibration direction is perpendicular to the ground plane and the patch unit 41. Furthermore, the antenna device 10 receives a vertically polarized wave arriving from outside the antenna device 10 by LC parallel resonance.

[0043] In addition, the resonant frequency of the zero-order resonance does not depend on the antenna size. Therefore, the length of one side of the patch section 41 can be made shorter than 1 / 2 wavelength of the zero-order resonance frequency. For example, the zero-order resonance can be generated even if the length of one side is equivalent to 1 / 4 wavelength. It is also possible to make one side shorter than 1 / 4 wavelength, but for example, the gain (antenna gain) will decrease.

[0044] <Directivity and Antenna Gain> Figures 7 and 8 show the results of an electromagnetic field simulation of the antenna device 10 having the above-mentioned configuration. Figure 7 shows an example of two elements. Figure 8 shows an example of four elements, similar to Figures 5 and 6. Note that, except for the difference in the number of elements, the other conditions are the same in Figures 7 and 8. For example, the operating frequency is 82.3 GHz, and the dielectric constant is 3.6.

[0045] As shown in Fig. 7, in the case of two elements, the maximum gain was 5.9 dBi. As shown in Fig. 8, in the case of four elements, the maximum gain was 8.6 dBi. In this way, by increasing the number of elements, the maximum gain of the antenna 40 was improved. In addition, for both two elements and four elements, directivity was shown in the X direction, which is the arrangement direction of the elements (patch portions 41).

[0046] <Summary of the First Embodiment> A metamaterial antenna has a low gain per unit. Therefore, in order to improve the gain, it is necessary to make it into an array. A metamaterial antenna is configured with a short circuit part (via conductor) that constitutes an inductor, and a ground plate and a patch part that constitute a capacitor on a substrate containing a dielectric. To make an array of metamaterial antennas with such a structure, a stripline is generally used. However, the stripline is extended from the power supply point of the patch part on the same plane as the patch part, and faces the ground plate in the thickness direction of the substrate. Therefore, when the frequency band becomes high, such as the millimeter wave band, the amount of radiation from the stripline increases, and the radiation loss increases. In addition, the amount of the electric field formed in the thickness direction of the substrate due to the radio wave propagation of the stripline spreads in the substrate, and the dielectric loss increases. In this way, the loss tends to increase.

[0047] In this embodiment, the waveguide 30, the antenna 40, and the matching section 50 are formed on the substrate 20. The antenna 40 has a plurality of patch sections 41 arranged in an array. The array can improve the gain. The feed line 42 extends from the patch section 41 to the inside of the waveguide 30 through the opening 34 formed in the upper wall section 31. The feed line 42 does not extend in a direction perpendicular to the Z direction like the strip line, but extends from the patch section 41 in the Z direction. Therefore, even in high frequency bands such as the millimeter wave band, radiation from the feed line 42 can be suppressed, that is, radiation loss can be suppressed. In addition, since the feed is not based on the formation of an electric field in the Z direction for radio wave propagation like the microstrip line, the amount of electric field spreading in the substrate 20 is small, and the dielectric loss due to the feed line 42 can be suppressed. As a result, it is possible to provide an antenna device 10 that can reduce loss.

[0048] Moreover, in this embodiment, each of the power supply lines 42 includes a via conductor 420. This makes it possible to realize the power supply lines 42 extending in the Z direction on the substrate 20. Furthermore, the configuration of the power supply lines 42 can be simplified.

[0049] Moreover, in this embodiment, the matching section 50 includes an inner layer pattern 51 and a via conductor 55 disposed inside the waveguide 30. The inner layer pattern 51 is connected to the feeder line 42 at a position away from the patch section 41 so as to face the lower wall section 32. The via conductor 55 is connected to the inner layer pattern 51. The matching section 50 is connected to the inner surface 32a of the lower wall section 32 and has a predetermined height from the inner surface 32a.

[0050] In this way, by providing the matching section 50 having a predetermined height from the inner surface 32a of the lower wall section 32, the opening area of ​​the waveguide 30 becomes narrower at the portion where the matching section 50 is provided than at the portion where the matching section 50 is not provided. Therefore, the impedance of the waveguide 30 can be converted to a value close to the impedance of the antenna 40 or a value equal to the impedance of the antenna 40. For example, if the impedance of the waveguide 30 is 100Ω and the impedance of the antenna 40 is 50Ω, the impedance of the matching section 50 can be set to 75Ω or 50Ω. Since the matching section 50 can be formed by a part of the conductor 22 of the substrate 20, the configuration can be simplified. Since the matching section 50 is provided on each of the feeder lines 42, the impedance can be matched between each of the elements and the waveguide 30.

[0051] The configuration of the matching section 50 is not limited to the above example. In the modified example shown in FIG. 9, the matching section 50 is disposed inside the waveguide 30, similarly to FIG. 4. The matching section 50 is configured by inner layer patterns 51 and via conductors 55 arranged in multiple stages. Specifically, compared to the matching section 50 shown in FIG. 4, one stage of via conductors 55 and inner layer patterns 51 is added, resulting in a two-stage structure. This allows the height of the matching section 50 to be increased, and the opening area of ​​the waveguide 30 to be reduced.

[0052] In FIG. 9, the area of ​​the inner layer pattern 51 in the upper stage close to the patch portion 41 is smaller than the area of ​​the inner layer pattern 51 in the lower stage. This makes it possible to widen the band. Note that the area is the area when viewed in a plan view, that is, the area facing the lower wall portion 32. The relationship in size between the upper stage and the lower stage is not limited to the above example. For example, the upper stage may have the same configuration as the lower stage. Furthermore, the number of stages of the matching section 50 is not limited to two. It may be three or more stages.

[0053] Second embodiment This embodiment is a modification based on the previous embodiment, and the description of the previous embodiment can be used. In the previous embodiment, the matching portion is formed by the inner layer pattern and the via conductor located between the upper wall portion and the lower wall portion. Instead of this, the matching portion may be formed by the inner layer pattern located in the opening portion.

[0054] FIG. 10 is a cross-sectional view showing the antenna device 10 according to this embodiment. FIG. 10 corresponds to FIG. 2. As shown in FIG. 10, the matching section 50 includes an inner layer pattern 52 arranged in the opening 34. The inner layer pattern 52 is also connected to the feed line 42 at a position away from the patch section 41 so as to face the lower wall section 32. The inner layer pattern 52 is connected to the middle of the feed line 42, not to the tip of the feed line 42. The inner layer pattern 52 is arranged on the same plane as the upper wall section 31 on the substrate 20. The inner layer pattern 52 corresponds to a second inner layer pattern. The other configurations are the same as those described in the preceding embodiment.

[0055] <Summary of the second embodiment> As described above, the matching section 50 of the present embodiment includes the inner layer pattern 52. By providing the inner layer pattern 52, a capacitor is connected in parallel and an inductor is connected in series to the impedance of the waveguide 30. This makes it possible to make the impedance of the matching section 50 smaller than that of the waveguide 30, and to match the impedance of the waveguide 30 and the impedance of the antenna 40.

[0056] Furthermore, since the inner layer pattern 52 is disposed on the same plane as the upper wall portion 31, it can be formed in the same process as the upper wall portion 31. In other words, the manufacturing process can be simplified.

[0057] Third embodiment This embodiment is a modification based on the previous embodiment, and the description of the previous embodiment can be used. In the previous embodiment, the matching section is formed by an inner layer pattern located inside the waveguide. Instead of this, the matching section may be formed by an inner layer pattern located outside the waveguide.

[0058] FIG. 11 is a cross-sectional view showing the antenna device 10 according to this embodiment. FIG. 11 corresponds to FIG. 2. As shown in FIG. 11, the matching section 50 includes an inner layer pattern 53 arranged between the patch section 41 and the upper wall section 31 in the Z direction. The inner layer pattern 53 is also connected to the feed line 42 at a position away from the patch section 41 so as to face the lower wall section 32. The inner layer pattern 53 is connected to the feed line 42 not at the tip thereof but in the middle thereof. The inner layer pattern 53 may be smaller than the opening 34 in a plan view, or may have a size that matches the opening 34. It may also be larger than the opening 34. The inner layer pattern 53 corresponds to a third inner layer pattern. The other configurations are the same as those described in the preceding embodiment.

[0059] <Summary of the third embodiment> As described above, the matching section 50 of this embodiment includes the inner layer pattern 53. By providing the matching section 50 at a position away from the bottom wall section 32, a capacitor is connected in parallel and an inductor is connected in series to the impedance of the waveguide 30, similar to the configuration of the second embodiment. This makes it possible to make the impedance of the matching section 50 smaller than that of the waveguide 30, and to match the impedance of the waveguide 30 with that of the antenna 40.

[0060] (Fourth embodiment) This embodiment is a modification based on the preceding embodiment, and the description of the preceding embodiment can be used as the basis for this embodiment. The matching unit can be variously combined as shown in the preceding embodiment.

[0061] Fig. 12 is a cross-sectional view showing the antenna device 10 according to this embodiment. Fig. 12 corresponds to Fig. 2. As shown in Fig. 12, the matching section 50 is a combination of the configuration shown in Fig. 4 and the configuration shown in Fig. 11. That is, the matching section 50 includes an inner layer pattern 51 and a via conductor 55 arranged inside the waveguide 30, and an inner layer pattern 53 arranged outside the waveguide 30. The other configurations are similar to those described in the preceding embodiments.

[0062] <Summary of the Fourth Embodiment> 12, the inner layer pattern 51 and the via conductor 55 of the matching section 50 reduce the opening area of ​​the waveguide 30. Furthermore, the inner layer pattern 53 of the matching section 50 connects a capacitor and an inductor to the impedance of the waveguide 30. These two actions make it possible to make the impedance of the matching section 50 smaller than that of the waveguide 30, and to match the impedance of the waveguide 30 with that of the antenna 40.

[0063] Note that the matching unit 50 can be combined in various ways other than the example shown in Fig. 12. For example, the matching unit 50 may adopt a combination of the configuration shown in Fig. 4 and the configuration shown in Fig. 10. It goes without saying that in the combination with Fig. 10 or Fig. 11, the configuration shown in Fig. 9 may be adopted instead of the configuration shown in Fig. 4.

[0064] Fifth embodiment This embodiment is a modified example based on the preceding embodiment, and the description of the preceding embodiment can be used. In the preceding embodiment, the patch units are arranged in a single row. Instead of this, the patch units may be arranged in multiple rows.

[0065] FIG. 13 is a perspective view showing the antenna device 10 according to this embodiment. FIG. 13 corresponds to FIG. 5. As shown in FIG. 13, the antenna 40 includes a plurality of element rows 44. The element rows are sometimes referred to as array rows. Specifically, the antenna 40 includes four element rows 44. Each of the element rows 44 has six patch units 41. The six patch units 41 constituting one element row 44 are arranged side by side in the X direction with the above-mentioned predetermined intervals. The intervals between adjacent elements in the X direction are equal in each element row 44. The four element rows 44 are arranged side by side in the Y direction. The plurality of patch units 41 are arranged in a lattice pattern.

[0066] A plurality of waveguides 30 are provided on the substrate 20 corresponding to the element arrays 44. Specifically, four waveguides 30 are defined by via conductors 330 constituting the sidewall portion 33. Each of the waveguides 30 extends in the X direction. The four waveguides 30 are arranged side by side in the Y direction. The element arrays 44 are respectively arranged directly above the four waveguides 30. The other configurations are similar to those described in the preceding embodiment.

[0067] <Summary of the Fifth Embodiment> Figure 14 shows the results of an electromagnetic field simulation of the antenna device 10 shown in Figure 13. The simulation conditions were the same as those in Figures 7 and 8, except for the number of elements. Again, the operating frequency was 82.3 GHz and the dielectric constant was 3.6.

[0068] 14, the maximum gain was 13.3 dBi. In this way, by increasing the number of elements not only in the X direction but also in the Y direction, the maximum gain of antenna 40 was further improved. In addition, antenna 40 exhibited directivity in the X direction.

[0069] The number of patch units 41 constituting one element array 44 is not limited to six. In addition, the number of element arrays 44 is not limited to four.

[0070] Sixth embodiment This embodiment is a modification based on the preceding embodiment, and the description of the preceding embodiment can be used.

[0071] Fig. 15 is a perspective view showing the antenna device 10 according to this embodiment. Fig. 15 corresponds to Fig. 13. As shown in Fig. 15, the antenna device 10 includes a phase shifter 60. The phase shifter 60 is provided separately for the waveguide 30. The phase shifter 60 adjusts the phase of the current flowing through the element array 44 of the antenna 40. The antenna 40 including the phase shifter 60 is sometimes referred to as a phased array antenna.

[0072] The waveguide 30 is configured such that both ends in the X direction are closed by via conductors 330. In each waveguide 30, an opening 35 is formed in the bottom wall portion 32. The opening 35 is formed on one end side of the waveguide 30 in the X direction. The opening 35 penetrates the bottom wall portion 32 in the Z direction. The phase shifter 60 is connected to the waveguide 30 through the opening 35. The other configurations are similar to those described in the preceding embodiment.

[0073] <Summary of the Sixth Embodiment> Fig. 16 shows the results of an electromagnetic field simulation of the antenna device 10 shown in Fig. 15. Fig. 16 shows the radiation directivity along the XY plane. The simulation conditions were the same as those in Fig. 13. Fig. 16 shows the results when the phases of the four element arrays 44 are the same, when the phases are shifted by 15 degrees, and when the phases are shifted by -15 degrees.

[0074] As shown in Fig. 16, when the beams are in phase, the radiation direction of the main beam is the X direction. When the beams are shifted in phase, the radiation direction of the main beam can be shifted left or right based on the radiation direction when the beams are in phase. In this way, by adjusting the phase of the current flowing through each element row 44 of the antenna 40, the beam can be directed in any direction.

[0075] (Other embodiments) The disclosure in this specification and drawings, etc. is not limited to the exemplified embodiments. The disclosure includes the exemplified embodiments and modifications by those skilled in the art based thereon. For example, the disclosure is not limited to the combination of parts and / or elements shown in the embodiments. The disclosure can be implemented by various combinations. The disclosure can have additional parts that can be added to the embodiments. The disclosure includes the omission of parts and / or elements of the embodiments. The disclosure includes the substitution or combination of parts and / or elements between one embodiment and another embodiment. The disclosed technical scope is not limited to the description of the embodiments. Some disclosed technical scopes are indicated by the description of the claims, and should be interpreted as including all modifications within the meaning and scope equivalent to the description of the claims.

[0076] The disclosure in the specification and drawings is not limited by the claims. The disclosure in the specification and drawings includes the technical ideas described in the claims, and extends to more diverse and broader technical ideas than the technical ideas described in the claims. Therefore, various technical ideas can be extracted from the disclosure in the specification and drawings without being bound by the claims.

[0077] When an element or layer is referred to as being "on," "coupled," "connected," or "bonded," it may be directly coupled, connected, or bonded to another element or layer, and intervening elements or layers may be present. In contrast, when an element is referred to as being "directly on," "directly coupled," "directly connected," or "directly bonded" to another element or layer, there are no intervening elements or layers. Other words used to describe relationships between elements should be construed in a similar manner (e.g., "between" vs. "directly between," "adjacent" vs. "directly adjacent," etc.). As used in this specification, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0078] Spatially relative terms such as "inside," "outside," "back," "bottom," "low," "top," "top," and the like are utilized herein to facilitate the description of the relationship of one element or feature to another element or feature as depicted in the figures. Spatially relative terms may be intended to encompass different orientations of the device during use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as "below" or "directly below" other elements or features would be oriented "above" the other elements or features. Thus, the term "bottom" can encompass both an orientation of top and bottom. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used in this specification would be interpreted accordingly.

[0079] Although an example has been shown in which the matching portion 50 disposed between the upper wall portion 31 and the lower wall portion 32 includes the inner layer pattern 51 and the via conductor 55, the present invention is not limited to this. A configuration including only the inner layer pattern 51 is also possible. In other words, a configuration in which the matching portion 50 is disposed between the upper wall portion 31 and the lower wall portion 32 and is not connected to the lower wall portion 32 is also possible.

[0080] Although an example in which the power feed line 42 including the matching unit 50 is connected to the lower wall portion 32 has been described, the present invention is not limited to this. As described above, the power feed line 42 and / or the power feed line 42 including the matching unit 50 may be extended below the center of the height of the waveguide 30 in order to feed power from the waveguide 30. For example, in the configuration shown in FIG. 10, the power feed line 42 may not be connected to the lower wall portion 32. [Explanation of symbols]

[0081] 10...antenna device, 20...substrate, 20a...one side, 20b...rear side, 21...base material, 210, 211, 212...insulating layer, 22...conductor, 30...waveguide, 31...upper wall portion, 32...lower wall portion, 32a...inner surface, 33...side wall portion, 330...via conductor, 34...opening, 40...antenna, 41...patch portion, 42...feed line, 420...via conductor, 43...short circuit portion, 430...via conductor, 44...element array, 50...matching portion, 51, 52, 53...inner layer pattern, 55...via conductor, 60...phase shifter

Claims

1. A substrate (20) having a substrate (21) including a dielectric and a conductor (22) disposed on the substrate; a waveguide (30) disposed on the substrate as a part of the conductor, the waveguide having an upper wall portion (31), a lower wall portion (32) facing the upper wall portion in a plate thickness direction of the substrate, and a side wall portion (33) connected to the upper wall portion and the lower wall portion; an antenna (40) including: a plurality of patch sections (41) arranged on the substrate as a part of the conductor and arranged in an array so as to face the upper wall section in the plate thickness direction; a plurality of feed lines (42) extending from the patch sections in the plate thickness direction and provided individually for the patch sections; and a plurality of short-circuit sections (43) provided individually for the patch sections and electrically connecting the patch sections and the upper wall section; a matching section (50) disposed on the substrate as a part of the conductor and provided separately for the patch section in order to match an impedance of the waveguide with an impedance of the antenna; The upper wall portion has a plurality of openings (34) formed individually for the power supply lines; Each of the feed lines is extended through the corresponding opening into the waveguide, the matching portion includes an inner layer pattern (51, 52, 53) connected to the power supply line at a position away from the patch portion so as to face the lower wall portion, The inner layer pattern includes a first inner layer pattern (51) disposed between the upper wall portion and the lower wall portion in the plate thickness direction, The matching portion includes the first inner layer pattern and a second via conductor (55) arranged in the waveguide and connected to the inner layer pattern, and is connected to the inner surface of the lower wall portion and has a predetermined height from the inner surface.

2. A substrate (20) having a substrate (21) including a dielectric and a conductor (22) disposed on the substrate; a waveguide (30) disposed on the substrate as a part of the conductor, the waveguide having an upper wall portion (31), a lower wall portion (32) facing the upper wall portion in a plate thickness direction of the substrate, and a side wall portion (33) connected to the upper wall portion and the lower wall portion; an antenna (40) including: a plurality of patch sections (41) arranged on the substrate as a part of the conductor and arranged in an array so as to face the upper wall section in the plate thickness direction; a plurality of feed lines (42) extending from the patch sections in the plate thickness direction and provided individually for the patch sections; and a plurality of short-circuit sections (43) provided individually for the patch sections and electrically connecting the patch sections and the upper wall section; a matching section (50) disposed on the substrate as a part of the conductor and provided separately for the patch section in order to match an impedance of the waveguide with an impedance of the antenna; The upper wall portion has a plurality of openings (34) formed individually for the power supply lines; Each of the feed lines is extended through the corresponding opening into the waveguide, the matching portion includes an inner layer pattern (51, 52, 53) connected to the power supply line at a position away from the patch portion so as to face the lower wall portion, The antenna device, wherein the inner layer pattern includes a second inner layer pattern (52) disposed in the opening.

3. 3. The antenna device according to claim 2, wherein the inner layer pattern includes a third inner layer pattern (53) disposed between the patch portion and the upper wall portion in the plate thickness direction.

4. A substrate (20) having a substrate (21) including a dielectric and a conductor (22) disposed on the substrate; a waveguide (30) disposed on the substrate as a part of the conductor, the waveguide having an upper wall portion (31), a lower wall portion (32) facing the upper wall portion in a plate thickness direction of the substrate, and a side wall portion (33) connected to the upper wall portion and the lower wall portion; an antenna (40) including: a plurality of patch sections (41) arranged on the substrate as a part of the conductor and arranged in an array so as to face the upper wall section in the plate thickness direction; a plurality of feed lines (42) extending from the patch sections in the plate thickness direction and provided individually for the patch sections; and a plurality of short-circuit sections (43) provided individually for the patch sections and electrically connecting the patch sections and the upper wall section; a matching section (50) disposed on the substrate as a part of the conductor and provided separately for the patch section in order to match an impedance of the waveguide with an impedance of the antenna; The upper wall portion has a plurality of openings (34) formed individually for the power supply lines; Each of the feed lines is extended through the corresponding opening into the waveguide, the matching portion includes an inner layer pattern (51, 52, 53) connected to the power supply line at a position away from the patch portion so as to face the lower wall portion, The antenna device, wherein the inner layer pattern includes a third inner layer pattern (53) arranged between the patch portion and the upper wall portion in the plate thickness direction.

5. The antenna device according to any one of claims 2 to 4, wherein the inner layer pattern includes a first inner layer pattern (51) disposed between the upper wall portion and the lower wall portion in the plate thickness direction.

6. 6. The antenna device according to claim 5, wherein the matching portion includes the first inner layer pattern and a second via conductor (55) disposed in the waveguide and connected to the inner layer pattern, and is connected to an inner surface of the lower wall portion and has a predetermined height from the inner surface.

7. The antenna device according to any one of claims 1 to 6, wherein each of the feed lines includes a first via conductor (420).

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