Antenna device

Abstract

To provide a technique for efficiently generating or detecting an electromagnetic wave by efficiently arranging an antenna array.SOLUTION: An antenna device comprising an antenna array in which a plurality of active antennas each including an antenna and a semiconductor structure and configured to generate or detect an electromagnetic wave are arranged, wherein in the antenna array, a plurality of columns in each of which one or more active antennas are arranged in a first direction are arranged in a second direction intersecting the first direction, and each of the plurality of columns is arranged with an offset length in the first direction with respect to an adjacent column.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an antenna device. [Background technology]

[0002] As a current-injection type light source that generates electromagnetic waves in the frequency range of 30 GHz to 30 THz (hereinafter referred to as "terahertz waves"), oscillators that integrate a semiconductor element with a resonator and have electromagnetic wave gain for terahertz waves are known. Among these, oscillators that integrate a resonant tunneling diode (RTD) and an antenna are expected to operate at room temperature in the frequency range around 1 THz.

[0003] Patent Document 1 discloses a terahertz wave antenna array in which a plurality of oscillators, each of which integrates an RTD and an antenna, are arranged on the same substrate. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-32685 [Non-patent literature]

[0005] [Non-Patent Document 1] Jpn.J.Appl.Phys.,Vol.47,No.6(2008),pp.4375-4384 [Non-patent document 2] J.Appl.Phys.,Vol.103,124514(2008) Summary of the Invention [Problem to be solved by the invention]

[0006] In the antenna array disclosed in Patent Document 1, each antenna element is arranged in a square, adjacent to the other, at a pitch equal to or less than the wavelength of the terahertz waves to be detected or generated, or at an integer multiple of that wavelength. While a square arrangement allows for a high-density arrangement by narrowing the spacing between antenna elements, there is a possibility that mutual coupling between antennas will significantly reduce gain. Conversely, widening the spacing between antenna elements can narrow the beam width, but this may increase side lobes. There is a need to devise antenna element spacing and arrangement to achieve efficient generation or detection of electromagnetic waves.

[0007] In view of the above, an object of the present invention is to efficiently arrange an antenna array to realize efficient generation or detection of electromagnetic waves. [Means for solving the problem]

[0008] An antenna device according to a first aspect of the present invention comprises an antenna array in which a plurality of active antennas, each including an antenna and a semiconductor structure, are arranged to generate or detect electromagnetic waves, and the antenna array is characterized in that a plurality of rows in which one or more of the active antennas are arranged in a first direction are arranged in a second direction intersecting the first direction, and each of the plurality of rows is arranged with an offset length in the first direction relative to adjacent rows. [Effects of the Invention]

[0009] According to the present invention, the antenna array can be efficiently arranged to realize efficient generation or detection of electromagnetic waves. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a schematic diagram of an antenna array according to a first embodiment. [Figure 2] FIG. 1 is a top view of an antenna array according to a first embodiment. [Figure 3] FIG. 2 is a cross-sectional view of the antenna array according to the first embodiment. [Figure 4]FIG. 10 is a schematic diagram of an antenna array according to a second embodiment. [Figure 5] FIG. 10 is a top view of the antenna array according to the second embodiment. [Figure 6] FIG. 10 is a cross-sectional view of an antenna array according to a second embodiment. [Figure 7] FIG. 10 is a schematic diagram of an antenna array according to a third embodiment. [Figure 8] FIG. 10 is a top view of an antenna array according to a fourth embodiment. [Figure 9] FIG. 10 is a top view of an antenna array according to a fourth embodiment. [Figure 10] 4 is a graph showing the effect of the antenna array according to the first embodiment. [Figure 11] FIG. 10 is a schematic diagram of an antenna array according to a fifth embodiment. [Figure 12] FIG. 10 is a schematic diagram of an antenna array according to a fifth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] [Embodiment 1] The configuration of an antenna device 10 according to this embodiment that is applicable to electromagnetic waves (particularly terahertz waves) will be described with reference to Figures 1, 2, and 3. Note that, although the following description will be given particularly of the case where the antenna device 10 is used as a transmitter, the antenna device 10 can also be used as a receiver. Here, terahertz waves refer to electromagnetic waves within a frequency range of 10 GHz or higher and 100 THz or lower, and in one example, refer to electromagnetic waves within a frequency range of 30 GHz or higher and 30 THz or lower.

[0012] Fig. 1(a) shows a block diagram illustrating an example of the system configuration of an antenna device 10, and Fig. 1(b) shows a schematic top view of the antenna device 10 in one example, as viewed from above. The antenna device 10 includes an antenna array 11 consisting of multiple (n) active antennas AA1 to AAn arranged in an array, and a bias control unit 12. The bias control unit 12 may be provided outside the antenna array 11.

[0013] The active antenna AA1 integrates at least one antenna AN1 and a semiconductor RTD1 serving as an oscillation source, and is configured to emit terahertz waves TW with an oscillation frequency of fTHz. In this case, the active antenna AA1 may be configured to excite circularly polarized waves. Note that the components of the active antenna AA1 other than the semiconductor RTD1 serving as the oscillation member may be considered as the antenna AN1, and for example, only the antenna conductor or a combination of the antenna conductor and a ground (GND) conductor may be considered as the antenna AN1. The same applies to the other active antennas AA2 to AAn.

[0014] As shown in Figure 1(b), a square patch antenna can be used as an example of the antenna AN. However, this is just one example, and antennas of shapes other than a square patch antenna may be used as long as they can output electromagnetic waves in a predetermined frequency band, such as frequencies in the terahertz band (10 GHz or more and 100 THz or less).

[0015] Each of the semiconductors RTD1 to RTDn of the active antennas includes a semiconductor structure for generating or detecting terahertz waves. In this embodiment, an example will be described in which a resonant tunneling diode (RTD) is used as this semiconductor structure. Note that the semiconductor structure here is not limited to an RTD, and any semiconductor having electromagnetic wave gain or carrier nonlinearity (nonlinearity of current accompanying voltage change in current-voltage characteristics) for terahertz waves will suffice.

[0016] Therefore, in the following description, the semiconductors RTD1 to RTDn may be described as the semiconductor layer 100. In addition to the semiconductor structure described above, the semiconductor layer 100 may also include electrodes for forming ohmic junctions with the semiconductor structure and electrode layers for connecting to upper and lower wiring layers. The bias control unit 12 is a power supply for controlling bias signals applied to the semiconductors RTD1 to RTDn, and is electrically connected to the semiconductors RTD1 to RTDn.

[0017] FIG. 1(b) shows an example of the arrangement of nine active antennas. In the antenna array according to this embodiment, three active antennas each are arranged in a first direction, such as AA1 to AA3, AA4 to AA6, and AA7 to AA9, to form rows, and three rows are arranged in a second direction intersecting the first direction. The second direction is, for example, a direction substantially perpendicular to the first direction. Each row is arranged with an offset length in the first direction relative to adjacent rows. For example, each row is arranged with a substantially uniform offset length in the first direction relative to adjacent rows. In FIG. 1(b), the active antennas in the even-numbered rows are periodically arranged with an offset of 1 / 2 the wavelength of the terahertz waves to be detected or generated relative to the active antennas in the odd-numbered rows.

[0018] In antenna arrays, the spacing between antenna elements is an important parameter. Narrowing the spacing between antenna elements allows for a higher-density antenna array in a smaller area. However, this increases mutual coupling between antenna elements, reducing gain, and the high density places constraints on circuit configurations such as phase shifters. On the other hand, widening the spacing between antenna elements allows for a narrower main lobe beamwidth. This is advantageous in terms of mutual coupling between antenna elements, and also makes it easier to reduce the number of elements and configure circuits. However, widening the spacing between elements can generate radiation in unwanted directions, known as side lobes, which can cause problems with radio wave transmission and reception and reduce gain. For this reason, it is important to appropriately determine the spacing between antenna elements based on each design concept, such as whether to prioritize the desired radiation directivity or physical constraints such as board size.

[0019] A staggered arrangement, as shown in Figure 1(a), increases the degree of freedom in arrangement while maintaining antenna characteristics, making it possible to realize an antenna array with a more efficient arrangement. For example, the spacing between antenna elements can be widened to narrow the beam width of the main lobe or due to circuit configuration constraints such as phase shifters and wiring sections. In this case, compared to the previously mentioned square arrangement, which has a pitch of an integer multiple of the wavelength, it is possible to reduce side lobes while maintaining the main lobe characteristics. Furthermore, when constructing a higher-density antenna array, antenna elements can be arranged more flexibly, and depending on the arrangement method, it is expected that mutual coupling between each antenna element can be suppressed.

[0020] Note that the active antennas AA1 to AA9 each have the same configuration. Therefore, hereinafter, when there is no need to distinguish between the active antennas AA1 to AA9, the term "active antenna AA" will be used as a general term. In other words, the configuration of "active antenna AA" described below applies to each of the active antennas AA1 to AA9 that make up the antenna array 11.

[0021] Figure 10 shows the radiation patterns of a square arrangement (dashed line) and a staggered arrangement (solid line) using nine active antennas at an oscillation frequency of 450 GHz. As shown in Figure 10, the main lobe gain near 0 degrees, which is the front direction of the antenna, is equivalent for both arrangements. On the other hand, the side lobe gain near -30 to -120 degrees is about -5 to -10 dB lower for the staggered arrangement. As such, the antenna array of this embodiment can reduce the side lobes while maintaining the main lobe characteristics, confirming the superiority of the staggered arrangement over the square arrangement.

[0022] (Active antenna array configuration) Next, the structure and configuration of the antenna device 10 as described above will be explained with reference to Figs. 2 and 3. Fig. 2 shows a top view of an example configuration of the antenna array 11, and Fig. 3 shows its cross-sectional view. As shown in Fig. 3, the active antenna AA is configured to include a substrate 110, a conductor layer 109, a conductor layer 101, and dielectric layers 104 to 106. As shown in Fig. 3, the substrate 110, the conductor layer 109, and the conductor layer 101 are laminated in this order, and the dielectric layers 104 to 106 are located between the two conductor layers (wiring layers), the conductor layer 109 and the conductor layer 101. The dielectric layers 104 to 106 are arranged in the following order from the conductor layer 109 side: dielectric layer 106, dielectric layer 105, and dielectric layer 104.

[0023] The antenna configuration shown in Figures 2 and 3 is called a microstrip antenna that uses a microstrip line or the like of a finite length. Here, an example using a patch antenna, which is a microstrip resonator, will be described. Conductor layer 101 is a patch conductor (upper conductor of the patch antenna) of the active antenna AA, which is arranged so as to face conductor layer 109 via dielectric layers 104 to 106. Conductor layer 109 is a ground conductor (ground conductor, GND conductor) that is electrically grounded, and also serves as a reflector layer.

[0024] The active antenna AA has a width L of λ in the A-A' direction (resonance direction) of the conductor layer 101. TH z It is set to operate as a λ / 2 resonator. THz is the effective wavelength in the dielectric layers 104 to 106 of the terahertz wave that resonates in the active antenna AA. The wavelength of the terahertz wave in a vacuum is λ0, and the effective relative dielectric constant of the dielectric layer 104 is ε r Then, λ THz =λ0×ε r -1 / 2 It is expressed as:

[0025] The active antenna AA has a semiconductor structure that is a semiconductor layer 100. The semiconductor layer 100 corresponds to RTD1 to RTD9 in FIG. 1 and, as described above, is a resonant tunneling diode (RTD) in this embodiment. An RTD is a typical semiconductor structure that has electromagnetic wave gain in the terahertz wave frequency band, and is also called an active layer. For this reason, hereinafter, the semiconductor layer 100 may be referred to as an "RTD."

[0026] The RTD has a resonant tunneling structure layer including multiple tunnel barrier layers, with quantum well layers provided between the multiple tunnel barriers, and has a multiple quantum well structure that generates terahertz waves through intersubband transitions of carriers.The RTD has electromagnetic wave gain in the terahertz wave frequency range based on the photon-assisted tunneling phenomenon in the negative differential resistance region of the current-voltage characteristics, and exhibits self-oscillation in the negative differential resistance region.

[0027] The semiconductor layer 100 is electrically connected to the conductor layer 101. The semiconductor structure is, for example, a mesa-type structure, and the semiconductor layer 100 includes an electrode (Ohmic or Schottky) that contacts the semiconductor structure and an electrode layer for connecting to upper and lower wiring layers. The semiconductor layer 100 is located inside the active antenna AA and is configured to oscillate or detect terahertz waves. The semiconductor layer 100 is composed of a semiconductor layer that has electromagnetic wave gain or nonlinearity for terahertz waves.

[0028] The active antenna AA is an active antenna in which a semiconductor layer 100 and a patch antenna (antenna AN) are integrated. The frequency fTHz of the terahertz waves emitted from the active antenna AA alone is determined by the resonant frequency of the total parallel resonant circuit that combines the reactance of the patch antenna and the semiconductor layer 100.

[0029] Specifically, the equivalent circuit of the oscillator described in Non-Patent Document 1 is used to calculate the RTD and antenna. For a resonant circuit combining domitances (YRTD and Yaa), the frequency that satisfies the amplitude condition in equation (1) and the phase condition in equation (2) is determined as the oscillation frequency fTHz. Re[YRTD]+Re[Y11]≦0 (1) Im[YRTD]+Im[Y11]=0 (2)

[0030] Here, YRTD is the admittance of the semiconductor layer 100, Re is the real part, and Im is the imaginary part. Since the semiconductor layer 100 includes an RTD, which is a negative resistance element, Re[YRTD] has a negative value. Furthermore, Y11 represents the admittance of the entire structure of the active antenna AA1 as seen from the semiconductor layer 100.

[0031] A quantum cascade laser (QCL) structure having a multilayer structure of several hundred to several thousand semiconductor layers may be used as the semiconductor layer 100. In this case, the semiconductor layer 100 is a semiconductor layer including a QCL structure.

[0032] Furthermore, the semiconductor layer 100 may be a negative resistance element such as a Gunn diode or an IMPATT diode, which are often used in the millimeter wave band.

[0033] Furthermore, a high-frequency element such as a transistor with one terminal terminated may be used as the semiconductor layer 100, and a heterojunction bipolar transistor (HBT), a compound semiconductor layer-based FET, a high electron mobility transistor (HEMT), or the like may be used as the transistor.

[0034] Furthermore, a negative differential resistance of a Josephson device using a superconductor layer may be used as the semiconductor layer 100. In other words, the semiconductor layer 100 does not have to be an RTD, and any structure having similar characteristics may be used as long as it is a semiconductor structure for generating or detecting electromagnetic waves in a predetermined frequency band.

[0035] Although an RTD is used here as a configuration suitable for terahertz waves, an antenna array compatible with electromagnetic waves of any frequency band may be realized with the configuration described in this embodiment. That is, the semiconductor layer 100 in this embodiment is not limited to an RTD that outputs terahertz waves, and may be formed using a semiconductor that can output electromagnetic waves of any frequency band.

[0036] In microstrip resonators such as patch antennas, a thick dielectric layer reduces conductor loss and improves radiation efficiency. The dielectric layers 104-106 must be able to be formed into thick films (typically 3 μm or more), have low loss and a low dielectric constant in the terahertz band, and be easy to microfabricate (planarization and etching). The thicker the dielectric layer, the higher the radiation efficiency, but if it is too thick, multi-mode resonance may occur. Therefore, the upper limit of the dielectric layer thickness can be designed to be no more than 1 / 10 of the oscillation wavelength.

[0037] On the other hand, since miniaturization and high current density of diodes are necessary to increase the frequency and output of oscillators, the dielectric layer is also required to suppress leakage current and prevent migration as an insulating structure of the diode. To satisfy these two requirements, dielectric layers 104 to 106 may be made of different materials.

[0038] The dielectric layer 104 may be made of an organic dielectric material such as BCB (benzocyclobutene, manufactured by Dow Chemical Company, εr1=2), polytetrafluoroethylene, or polyimide, where εr1 is the relative dielectric constant of the first dielectric layer 104. Alternatively, the first dielectric layer 104 may be made of an inorganic dielectric material such as a TEOS oxide film or spin-on glass, which can be formed into a relatively thick film and has a low dielectric constant.

[0039] The dielectric layers 105 and 106 are required to have insulating properties (the ability to act as an insulator or high-resistance material that does not conduct electricity when subjected to DC voltage), barrier properties (the ability to prevent the diffusion of metal materials used in the electrodes), and processability (the ability to be processed with submicron precision). Materials that satisfy these requirements include inorganic insulating materials such as silicon oxide (εr2=4), silicon nitride (εr2=7), aluminum oxide, and aluminum nitride. εr2 is the relative permittivity of the dielectric layers 105 and 106.

[0040] Here, when the dielectric layers 104 to 106 have a multi-layer structure as in this embodiment, the relative dielectric constant εr of the dielectric layers 104 to 106 is an effective relative dielectric constant determined by the thickness and relative dielectric constant εr1 of the dielectric layer 104 and the thickness and relative dielectric constant εr2 of the dielectric layers 105 to 106.

[0041] From the viewpoint of impedance matching between the antenna and space, the dielectric layer 104 may be made of a material different from that of the dielectric layers 105 and 106, and may be made of a material with a low relative dielectric constant (εr1<εr2), in order to reduce the difference in dielectric constant between the antenna and air. Note that in the antenna device 10, the dielectric layer does not need to have a multi-layer structure, and may have a structure made of only one layer of the above-mentioned materials.

[0042] The semiconductor layer 100 is disposed on a conductor layer 109 formed on a substrate 110. The semiconductor layer 100 and the conductor layer 109 are electrically connected. Note that the semiconductor layer 100 and the conductor layer 109 can be connected with low resistance in order to reduce ohmic loss.

[0043] A via 103 is disposed on the semiconductor layer 100 on the side opposite to the side on which the conductor layer 109 is disposed, and the via 103 is electrically connected to the semiconductor layer 100. The semiconductor layer 100 is embedded in a dielectric layer 106, and is covered all around with the dielectric layer 106.

[0044] The semiconductor layer 100 includes an ohmic electrode, which is a conductor that forms an ohmic connection with the semiconductor to reduce ohmic loss and RC delay due to series resistance. Examples of materials that can be used for the ohmic electrode include Ti / Au, Ti / Pd / Au, Ti / Pt / Au, AuGe / Ni / Au, TiW, Mo, and ErAs. The materials are indicated by element symbols, and the substances represented by each symbol will not be described in detail here. This also applies to the following explanation.

[0045] Furthermore, by using a semiconductor in which the region where the semiconductor and ohmic electrode are in contact is heavily doped with impurities, the contact resistance can be reduced, thereby achieving higher output and higher frequencies. The absolute value of the negative resistance, which indicates the magnitude of the gain of an RTD used in the terahertz wave band, is generally on the order of 1 to 100 Ω, so the semiconductor layer 100 can be configured to suppress electromagnetic wave loss to 1% or less of that. Therefore, the contact resistance of the ohmic electrode can be suppressed to 1 Ω or less as a rough guide.

[0046] In order to operate in the terahertz wave band, the semiconductor layer 100 is formed so that its width is typically about 0.1 to 5 μm. Therefore, the contact resistance is set to a resistivity of 10 Ω·μm 2 The resistance is controlled to a range of 0.001 to several Ω or less.

[0047] Furthermore, the semiconductor layer 100 may be configured to include a metal (Schottky electrode) that forms a Schottky contact rather than an ohmic contact. In this case, the contact interface between the Schottky electrode and the semiconductor exhibits rectification, and the active antenna AA can be used as a terahertz wave detector. Note that the following describes a configuration using an ohmic electrode.

[0048] As shown in FIG. 3(a), the inside of the active antenna AA is made up of a substrate 110, a conductor layer 112, and a 109, a semiconductor layer 100, a via 103, and a conductor layer 101 are laminated in this order. The via 103 is formed inside the dielectric layers 104 to 106, and the conductor layer 101 and the semiconductor layer 100 are electrically connected to each other through the via 103.

[0049] Here, if the width of the via 103 is too large, the resonance characteristics of the patch antenna will deteriorate and the radiation efficiency will decrease due to an increase in parasitic capacitance. Therefore, the width of the via 103 can be configured to a dimension that does not interfere with the resonant electric field, typically, to be 1 / 10 or less of the effective wavelength λ of the terahertz wave of the standing oscillation frequency fTHz of the active antenna AA.

[0050] Furthermore, the width of the via 103 may be small enough not to increase the series resistance, and can be reduced to approximately twice the skin depth as a guideline. To reduce the series resistance to a level not exceeding 1 Ω, the width of the via 103 is typically in the range of 0.1 μm to 20 μm.

[0051] 3(b), the conductor layer 101 is electrically connected to the wiring layer 108 through a via, and the wiring layer 108 is electrically connected to the bias control unit 12 through a bias wiring layer 102, which is a common wiring formed within the chip. The bias control unit 12 may also be called a power supply circuit. The wiring layer 102 is disposed between the dielectric layer 104 and the dielectric layer 105. The wiring layer 108 is drawn out from each of the antennas.

[0052] The bias control unit 12 is a power supply for supplying a bias signal to the semiconductor layer 100 of the active antenna AA. Therefore, by connecting the wiring layer 102 and the wiring layers 108 drawn from each of the adjacent antennas, a bias signal is supplied to the semiconductor layer 100 of each antenna. The common bias wiring layer 102 ensures sufficient wiring width, reducing variations in operating voltage between antennas due to variations in wiring resistance, thereby stabilizing synchronization even when the number of arrays increases. In addition, it is possible to make the structure around the antennas symmetrical, preventing the radiation pattern from being distorted.

[0053] The vias 107 connecting the conductor layer 101 and the wiring layer 108 are connection parts for electrically and mechanically connecting the wiring layer 108 to the conductor layer 101. In this way, a structure for electrically connecting upper and lower layers is called a via. In addition to serving as components constituting the patch antenna, the conductor layers 109 and 101 also serve as electrodes for injecting current into the RTD, which is the semiconductor layer 100, by being connected to these vias. In this embodiment, the vias are formed of a material having a resistivity of 1×10 -6 Materials with a resistance of Ω·m or less can be used, such as metals and metal compounds such as Ag, Au, Cu, W, Ni, Cr, Ti, Al, AuIn alloys, and TiN.

[0054] The width of the via 107 connecting the conductor layer 101 and the wiring layer 108 is smaller than the width of the conductor layer 101. The width of the conductor layer 101 here is the width in the electromagnetic wave resonance direction (i.e., the A-A' direction) within the active antenna AA. Also, the portion of the wiring layer 108 connected to the via 107 The width of the portion (connection portion) is smaller (thinner) than the width of the conductor layer 101 (active antenna AA). Furthermore, these widths can be set to 1 / 10 or less (λ / 10 or less) of the effective wavelength λ of the terahertz wave with an oscillation frequency fTHz existing in the active antenna AA. By arranging the via 107 and the wiring layer 108 in a size and position that does not interfere with the resonant electric field within the active antenna AA, it is possible to improve the radiation efficiency.

[0055] The via 107 can be located at a node of the electric field of the terahertz wave with an oscillation frequency of fTHz standing in the active antenna AA. In this case, the via 107 and the wiring layer 108 are configured to have impedance sufficiently higher than the absolute value of the negative differential resistance of the RTD, which is the semiconductor layer 100, in a frequency band near the oscillation frequency of fTHz. In other words, the via 107 and the wiring layer 108 are configured to have impedance sufficiently higher than the absolute value of the negative differential resistance of the RTD, which is the semiconductor layer 100, in a frequency band near the oscillation frequency of fTHz. 08 is connected to the active antenna AA so that it has high impedance as seen from the RTD at the oscillation frequency fTHz. In this case, the active antenna AA is isolated at the frequency fTHz through the path via the wiring layer 102 for bias. This prevents the current of the oscillation frequency fTHz induced in each active antenna via the wiring layer 102 and the bias control unit 12 from affecting adjacent antennas. In addition, interference between the electric field of the oscillation frequency fTHz existing within the active antenna AA and these power supply members is suppressed.

[0056] The bias wiring layer 102 is a bias wiring common to multiple active antennas AA. The bias control unit 12 is arranged outside the chip to supply a bias signal to the semiconductor layer 100 of each antenna. The bias control unit 12 includes a stabilization circuit for suppressing low-frequency parasitic oscillation.

[0057] The stabilization circuit is set to have an impedance lower than the absolute value of the negative resistance corresponding to the gain of the semiconductor layer 100 in the frequency band from DC to 10 GHz. For stabilization at relatively high frequencies from 0.1 to 10 GHz, an AC short circuit is provided for each active antenna, in which a TiW resistive layer 116 and an MIM (Metal-Insulator-Metal) capacitor 115 are connected in series, as shown in FIG. 3(b). In this case, the MIM capacitor 115 has a large capacitance within the above-mentioned frequency range, for example, a capacitance of approximately several pF. The MIM capacitor 115 of this embodiment has a structure in which a portion of the dielectric layer 106 is sandwiched between a conductor layer 113 and a conductor layer 109 (GND).

[0058] (Specific materials and structural dimensions) A specific example of the antenna array 11 will be described. The antenna array 11 is a semiconductor device capable of single-mode oscillation in the frequency band of 0.45 to 0.50 THz. The substrate 110 is a semi-insulating InP substrate. The semiconductor layer 100 is composed of a multiple quantum well structure made of InGaAs / AlAs lattice-matched to the substrate 110, and in this embodiment, an RTD with a double-barrier structure is used. This is also called an RTD semiconductor heterostructure.

[0059] The current-voltage characteristics of the RTD used in this embodiment are measured with a peak current density of 9 mA / μm 2 and the negative differential conductance per unit area is 10 mS / μm 2 The semiconductor layer 100 is formed in a mesa structure and is composed of a semiconductor structure including an RTD and an ohmic electrode for electrical connection to the semiconductor structure. The mesa structure is circular with a diameter of 2 μm, and the magnitude of the negative differential resistance of the RTD in this case is approximately -30 Ω per diode. In this case, the negative differential conductance of the semiconductor layer 100 including the RTD is estimated to be approximately 30 mS, and the diode capacitance is approximately 10 fF.

[0060] The active antenna AA is a patch antenna having a structure in which dielectric layers 104 to 106 are sandwiched between a conductor layer 101, which is a patch conductor, and a conductor layer 109, which is a ground conductor. The conductor layer 101 is a square patch antenna with one side measuring 150 μm, and the resonator length (L) of the antenna is 150 μm. A semiconductor layer 100 including an RTD is integrated inside the antenna.

[0061] Conductor layer 101, which is a patch conductor, is composed of a metal layer (Ti / Au) mainly composed of a low-resistivity Au thin film. Conductor layer 109, which is a ground conductor, is composed of a Ti / Au layer and a semiconductor layer made of an n+-InGaAs layer, and the metal and semiconductor layers are connected by low-resistance ohmic contact. Dielectric layer 104 is composed of BCB (benzocyclobutene, manufactured by Dow Chemical Company). Dielectric layers 105 and 106 are each composed of SiO2 with a thickness of 1 μm.

[0062] As shown in FIG. 3(a), around the semiconductor layer 100, the conductors are arranged in the order from the substrate 110 side. The RTD, which is the semiconductor layer 100, is located at a position 40° from the center of gravity of the conductor layer 101 in the resonance direction (i.e., the A-A' direction) along one side of the conductor layer 101. The RTD is positioned at a position shifted by 60 μm. The input impedance when feeding high frequency power from the RTD to the patch antenna is determined by the position of the RTD within the antenna.

[0063] 3(b), the conductor layer 101 is connected to a wiring layer 108, which is located at the same level as a bias wiring layer 102 arranged on the dielectric layer 105, through a via 107 formed of Cu. The wiring layer 102 and the wiring layer 108 are formed of a metal layer containing Ti / Au stacked on the dielectric layer 105.

[0064] The wiring layer 108 is connected to the bias control unit 12 via a bias wiring layer 102, which is a common wiring formed within the chip. The active antenna AA is designed to obtain oscillation with a power of 0.2 mW at a frequency of fTHz=0.5 THz by setting a bias in the negative resistance region of the RTD included in the semiconductor layer 100.

[0065] The vias such as the vias 103 and 107 have a cylindrical structure with a diameter of 10 μm. The wiring layer 108 is a Ti / The active antenna AA1 is configured with a pattern formed of a metal layer containing Au. The via 107 is located at the center in the resonance direction (i.e., the A-A' direction) and is connected to the conductor layer 101 at the end of the conductor layer 101 in the B-B' direction. This connection position corresponds to a node of the electric field of the terahertz wave with a frequency of fTHz standing in the active antenna AA1.

[0066] [Embodiment 2] In this embodiment, an antenna device 20 in which active antennas are coupled by coupling lines will be described. Fig. 4 shows the configuration of the antenna device 20. Fig. 4(a) is a block diagram illustrating the system configuration of the antenna device 20, and Fig. 4(b) is a schematic top view of the antenna device 20 as viewed from above.

[0067] 4(a), the antenna device 20 of this embodiment has a configuration in which coupled lines CL1 to CLn-1 are added between the active antennas in addition to the antenna device 10 of embodiment 1. The coupled lines CL are transmission lines for mutual injection locking at the frequency fosc, and the active antennas are electrically connected by these coupled lines CL.

[0068] In one example, to synchronize the active antennas AA1-AA4 in the horizontal direction, a coupling line CL14 is connected between these active antennas. The same applies to the other active antennas. Here, the coupling line is implemented as, for example, a microstrip line. However, this is not limiting, and the coupling line may also be realized as a slot line. Connecting each active antenna with a coupling line can improve the accuracy of frequency and phase.

[0069] Next, the structure and configuration of the above-described antenna device 20 will be described with reference to Fig. 5 and Fig. 6. Fig. 5 is a schematic top view of the antenna array 21, and Fig. 6 is its cross-sectional view. Note that, in the following, detailed description of the same configuration as that of the antenna device 10 of the first embodiment will be omitted.

[0070] In the configurations shown in Figures 5 and 6, adjacent antennas are mutually coupled by a coupling line CL, and are synchronized with each other by the mutual injection locking phenomenon at the terahertz wave oscillation frequency fTHz. The mutual injection locking phenomenon occurs when multiple self-excited oscillators are pulled in by interaction. This is a phenomenon in which the signals oscillate in synchronization with each other.

[0071] For example, active antennas AA1 and AA4 are coupled to each other by a coupling line CL14, and are further coupled to each other via a conductor layer 111, as shown in Fig. 6(a). The conductor layer 111 is made of, for example, Ti / Au. The same applies to other adjacent active antennas.

[0072] Note that "mutually coupled" refers to a relationship in which a current induced in one active antenna acts on another adjacent active antenna due to the coupling, thereby changing the transmission and reception characteristics of the other.

[0073] When mutually coupled active antennas are synchronized in phase or in opposite phase, mutual injection locking occurs, causing the electromagnetic fields between the active antennas to strengthen or weaken each other, which allows the antenna gain to be adjusted.

[0074] The length of the path of the coupling line that couples the active antennas together is preferably set based on the wavelength of the electromagnetic wave, and is particularly preferably set to be approximately equal to n wavelengths (n is an integer) of the electromagnetic wave.

[0075] In this embodiment, the entire coupling line coupling the active antennas is referred to as coupling line CL. The coupling lines coupling each antenna that constitutes the coupling line CL are represented by numbers and letters corresponding to each active antenna. For example, the coupling line coupling active antennas AA1 and AA4 is represented as coupling line CL14.

[0076] The oscillation conditions of the antenna array 11 are determined by the conditions of mutual injection locking in a configuration in which two or more individual RTD oscillators are coupled, as described in Non-Patent Document 2. Specifically, consider the oscillation conditions of an antenna array in which active antennas AA1 and AA2 are coupled by a coupling line CL12. In this case, two oscillation modes occur: positive-phase mutual injection locking and anti-phase mutual injection locking. The oscillation conditions for the positive-phase mutual injection locking oscillation mode (even mode) are expressed by equations (3) and (4), and the oscillation conditions for the anti-phase mutual injection locking oscillation mode (odd mode) are expressed by equations (5) and (6).

[0077] Positive phase (even mode): Frequency f=feven Yeven=Y11+Y12+YRTD Re(Yeven)≦0 (3) Im(Yeven)=0 (4) Out of phase (odd mode): frequency f=fodd Yodd=Y11+Y12-YRTD Re(Yodd)≦0 (5) Im(Yodd)=0 (6)

[0078] Here, Y12 is the mutual admittance between active antenna AA1 and active antenna AA2. Y12 is proportional to the coupling constant that represents the strength of coupling between the antennas, and ideally, the real part of -Y12 is large and the imaginary part is zero. The antenna array 11 of this embodiment is coupled under the condition of mutual injection locking in positive phase, and the oscillation frequency fTHz≈feven. Similarly, the other antennas are coupled to each other along the coupling line CL so as to satisfy the above-mentioned condition of mutual injection locking in positive phase.

[0079] The bonded line CL is a microstrip line in which the dielectric layers 104-106 are sandwiched between the conductor layer 111 and the conductor layer 109 or the wiring layer 102. For example, as shown in FIG. 6(a), the bonded line CL45 has a structure in which the dielectric layers 104-106 are sandwiched between the conductor layer 111 (CL45) and the conductor layer 109 or the wiring layer 102. Similarly, the bonded line CL56 has a structure in which the dielectric layers 104-106 are sandwiched between the conductor layer 111 (CL56) and the conductor layer 109 or the wiring layer 102.

[0080] The antenna array 21 is an antenna array configured such that the antennas are coupled to each other by AC coupling (alternating current coupling, capacitive coupling). For example, in plan view, the conductor layer 111, which is the upper conductor layer of the coupling line CL45, overlaps with the conductor layers 101, which are the patch conductors of the active antennas AA4 and AA5, with the dielectric layer 112 sandwiched between them, and is connected by capacitive coupling. More specifically, in plan view, the conductor layer 111 of the coupling line CL45 overlaps with the conductor layer 101 by 5 μm, with the dielectric layer 112 sandwiched between them, near the radiation ends of the active antennas AA4 and AA5, forming capacitive structures C1 and C2.

[0081] The capacitance structures C1 and C2 in this configuration function as high-pass filters, shorting the terahertz band and opening the low-frequency band, thereby contributing to the suppression of multimode oscillation. However, this configuration is not essential, and a DC-coupling configuration may be used in which the conductor layer 111 of the coupling line CL45 is directly coupled (connected) to the conductor layers 101 of the active antennas AA4 and AA5. An antenna array synchronized by DC coupling can synchronize adjacent antennas with strong coupling, making it easier to synchronize by pulling and resistant to variations in frequency and phase between the antennas. Note that while the coupling between active antennas AA4 and AA5 has been described as an example here, the same applies to the coupling between the other active antennas AA1 to AA9.

[0082] In the antenna array 21, the conductor layer 101 of the active antenna AA, the conductor layer 111 of the coupled wire CL, and the bias wiring layer 102 are arranged on different layers. In this way, the conductor layer 101 of the active antenna AA and the conductor layer 111 of the coupled wire CL, which transmit high frequencies (fTHz), are arranged on different layers from the bias wiring layer, which transmits low frequencies (DC to several tens of GHz).

[0083] This allows for flexible configuration of the layout, such as the width, length, and routing of the transmission lines within each layer. Also, as shown in Figure 5, when viewed from above (in a plan view), the bond lines CL and the bias wiring layer 102 intersect with each other, resulting in a more compact layout. This allows for an increased number of antennas to be placed. Furthermore, this configuration allows for independent control of the impedance of the bond lines CL and bias control of the semiconductor layer 100.

[0084] In the terahertz band, resistance increases due to the skin effect, so conductor loss associated with high-frequency transmission between antennas cannot be ignored. As the current density between conductor layers increases, conductor loss per unit length (dB / mm) increases. In the case of microstrip lines, conductor loss per unit length (dB / mm) is inversely proportional to the square of the dielectric thickness. Therefore, to increase the radiation efficiency of an antenna array, conductor loss can be reduced by thickening not only the antenna but also the dielectric that makes up the coupled line CL.

[0085] In contrast, the antenna array 21 of this embodiment has a configuration in which a bias wiring layer 102 is disposed on a dielectric layer 105, and a conductor layer 101 of the antenna through which a high frequency wave of fTHz is transmitted and a conductor layer 111 of the coupling line CL are disposed on the upper layer of the dielectric layer 104. This configuration makes it possible to suppress a decrease in the radiation efficiency of the antenna array due to conductor loss in the terahertz band.

[0086] From the viewpoint of conductor loss, the thickness of the dielectric constituting the bonded line CL is preferably 1 μm or more, and in one example, by setting the dielectric thickness to 2 μm or more, the loss due to conductor loss in the terahertz band can be suppressed to about 20%. Similarly, from the viewpoint of conductor loss, a wide distance can be ensured in the thickness direction between the conductor layer 111 constituting the bonded line CL and the wiring layer 102 and the conductor layer 109.

[0087] The bias wiring layer 102 can function as a low-impedance line up to the gigahertz band by setting the dielectric to 2 μm or less, for example, 1 μm or less. Even if the dielectric is set to a thickness of 2 μm or more, connecting a shunt component consisting of a resistive layer 116 and an MIM capacitor 115 to the bias wiring layer 102 as shown in FIG. 6(b) can make it function as a low-impedance line and suppress low-frequency oscillation.

[0088] It is also possible that radiation from the coupled lines CL may affect radiation from the antenna array 21. For this reason, it is desirable to have a structure that suppresses radiation from the coupled lines CL, such as by arranging the coupled lines CL symmetrically in the antenna array or by making the bent portions curved with a large radius of curvature.

[0089] [Embodiment 3] 7 is a schematic top view of the antenna device 30, showing the configuration of the antenna device 30 arranged in a diamond (rhombus) shape. Active antennas AA1, AA2 to AA3, AA4 to AA6, AA7 to AA8, and AA9 are arranged in rows of one, two, three, two, and one in a first direction, respectively, and five rows are arranged in a second direction substantially perpendicular to the first direction. Each row is arranged with a substantially uniform offset length in the first direction relative to adjacent rows.

[0090] As in the second embodiment described above, the coupling line CL is a transmission line for mutual injection locking at the frequency f osc, and the active antennas are electrically connected by this coupling line CL. In one example, a coupling line CL24 is connected between the active antennas AA2-AA4 to synchronize these antennas in the horizontal direction. The same applies to the other active antennas.

[0091] Here, the coupling lines are implemented as, for example, microstrip lines. However, the present invention is not limited to this, and the coupling lines may be realized as slot lines. By connecting the active antennas with coupling lines, it is possible to improve the accuracy of frequency and phase. Note that a description of the same configuration as the antenna array 21 of the second embodiment will be omitted here.

[0092] According to this configuration, it is possible to change the arrangement while maintaining the same gain in the front direction as in the first or second embodiment, while keeping the antenna area the same, and this increases the degree of freedom in designing the routing and arrangement of circuits such as the coupling line CL and phase shifter.

[0093] In this embodiment, the number of active antennas arranged in the center row is greater than the other rows, and the number of active antennas arranged in the rows between the center row and the end rows is a value between the number of active antennas arranged in the center row and the number of active antennas arranged in the end rows.

[0094] [Embodiment 4] In this embodiment, an example of an antenna array arrangement configuration having nine active antennas will be described. Note that the following will be a detailed description of a configuration similar to that of the antenna device 10 of the first embodiment. The details will be omitted.

[0095] Fig. 8 shows a top view of antenna array 41, which is an example of an antenna array according to this embodiment. Fig. 9 shows a top view of antenna array 51, which is another example of an antenna array according to this embodiment. In antenna array 41 of this embodiment, active antenna AA4 of antenna array 21 of embodiment 2 has been removed, and active antennas AA4-1 and AA4-2 have been newly added.

[0096] In the antenna array 21 of the second embodiment, the active antennas AA are arranged in an array such that each row has a substantially uniform offset length in the first direction relative to adjacent rows. When arranged in this manner, a portion of the active antenna AA4 protrudes into the active antennas in the adjacent row. By halving the physical dimensions of this protruding active antenna AA4 and locating one half below the active antenna AA6, a higher-density antenna array can be realized. Furthermore, the arrangement of the active antennas and the coupling lines is more symmetrical, further reducing side lobes.

[0097] The other configurations of the antenna array 41 according to this embodiment are the same as those of the antenna array 21, and therefore detailed description thereof will be omitted here. Furthermore, the physical dimensions of the active antennas AA4-1 and AA4-2 are half the physical dimensions of the active antenna AAn. However, since two active antennas AA4-1 and AA4-2 are arranged in this embodiment, the effective aperture area is equivalent to the aperture area of ​​the antenna array 21 according to the second embodiment.

[0098] In addition, in the antenna array 51 shown in FIG. 9, in the array arrangement of active antennas AA, each of multiple rows is arranged with a substantially uniform offset length relative to adjacent rows in the second direction. When the active antennas AA are arranged with such substantially uniform offset lengths, some of the active antennas AA protrude. Therefore, in the antenna array 51, similar to the antenna array 41, the active antenna AA2 of the antenna array 21 of the second embodiment is removed, and active antennas AA2-1 and AA2-2 are newly added. In the antenna array 51, the active antenna AA2 is divided into active antennas AA2-1 and AA2-2. One of the active antennas, AA2-2, is arranged to the right of the active antenna AA8. As a result, according to this embodiment, a higher density antenna array than the antenna array 21 is realized.

[0099] In this embodiment, the active antennas AA4-1, AA4-2, AA2-1, and AA2-2 have a shape that is half the shape of the active antenna AAn. That is, in the antenna arrays 41 and 51, the dimensions of at least one of the multiple active antennas are different from the dimensions of the remaining active antennas. This reduces the fluctuations in the resonant frequency and radiation pattern of the active antennas AA4-1, AA4-2, AA2-1, and AA2-2, as well as their physical dimensions. This results in changes in antenna characteristics, such as reduced gain and radiation efficiency. Therefore, these antenna characteristics must be adjusted for the antenna array by changing the feed point position and conductor layer. Therefore, in the active antennas AA4-1, AA4-2, AA2-1, and AA2-2 of this embodiment, only the surface conductor layer 101 of the active antenna AAn is halved. As a result, the radiation pattern is improved when the active antennas of this embodiment are used compared to when all components of the active antenna AAn are halved. Therefore, compared to the antenna array 21, the antenna arrays 41 and 51 of this embodiment have further reduced side lobes and improved antenna array characteristics.

[0100] In this embodiment, an antenna array with higher density than the antenna array 21 is realized, and the size To reduce lobe, active antennas AA4-1, AA4-2, AA2-1, and AA2-2 are used, each of which has half the conductor layer 101 of the active antenna AAn. For example, as described above, with the antenna arrays 41 and 51 of this embodiment, further improvement in antenna array characteristics can be expected by changing the position of the feed point and the conductor layer. Note that the shapes of the antenna arrays 41 and 51 of this embodiment are not limited to those shown in Figures 8 and 9. Any shape may be adopted for the antenna arrays 41 and 51 as long as it satisfies the respective design concepts and constraints, such as whether to prioritize the desired radiation directivity, physical constraints such as board size, or structural constraints of the active antenna.

[0101] [Embodiment 5] In this embodiment, an example of the arrangement of the antenna array that is adopted when the above-mentioned active antenna is rotated 45 degrees in a plan view will be described. Note that, in the following, detailed description of the same configuration as the antenna device 10 of the first embodiment will be omitted.

[0102] 11 and 12 show antenna arrays 61 and 71 according to this embodiment, respectively. In the antenna arrays 61 and 71 according to this embodiment, each active antenna AA is rotated by approximately 45 degrees in a plan view compared to the active antenna AA of the antenna array 21 according to embodiment 2. That is, in the antenna arrays 61 and 71, the active antenna AA is arranged so that the first direction is rotated by approximately 45 degrees with respect to the electric field direction or magnetic field direction of the active antenna.

[0103] In the antenna arrays 61 and 71, various beams can be formed by adjusting the phase input to each active antenna AA. In the antenna array 21 of the second embodiment, the active antennas AA are arranged in an array such that each row has a substantially uniform offset length in a first direction relative to adjacent rows. When arranged in this manner, a portion of the active antenna AA4 protrudes into the active antennas in the adjacent rows. On the other hand, in the antenna arrays 61 and 71 of the present embodiment, the active antennas AA are arranged symmetrically with respect to an axis passing through the center of the antenna array in a planar view. Furthermore, in the antenna arrays 61 and 71, the active antennas AA are arranged so as to spread in multiple directions in a planar view. Note that the other configurations of the antenna arrays 61 and 71 are similar to those of the antenna array 21, and therefore detailed description thereof will be omitted here.

[0104] The antenna arrays 61 and 71 of the present embodiment, which employ such an arrangement, offer advantages in terms of beamforming optimization. Specifically, in the antenna arrays 61 and 71, the active antennas AA are arranged to spread in multiple directions, enabling more precise directional resolution and improved beamforming flexibility. Furthermore, the antenna arrays 61 and 71 make it easier to adjust the width and shape of the beam for a specific direction, enabling the formation of a beam that covers a wider area or a beam that is focused on a narrower area as needed.

[0105] The antenna array 61 shown in Fig. 11 is an example of an antenna array using 13 active antennas. The antenna array 71 shown in Fig. 12 is an example of an antenna array using 37 active antennas. In both antenna arrays, the active antennas AA are arranged in an array with a substantially uniform offset length in the second direction relative to adjacent rows. Therefore, by adopting a staggered active antenna arrangement in the antenna arrays 61 and 71, deterioration of side lobes that occurs with an increase in the number of active antennas is reduced, and not only can beam flexibility be improved but also main lobe gain can be improved.

[0106] In this embodiment, it is assumed that the shape of the substrate 110 in plan view is square. For example, by making the shape of the substrate 110 octagonal, similar to the external shape of the antenna array, it is possible to further reduce the size of the antenna array and improve its characteristics. Furthermore, any shape may be adopted for the antenna arrays 61 and 71 as long as it satisfies the respective design concepts and constraints, such as whether to prioritize the desired radiation directivity, physical constraints such as substrate size, or structural constraints of the active antenna.

[0107] In other embodiments, the bias wiring from the bias control unit 12 is connected to each active antenna AA individually. On the other hand, in this embodiment, multiple active antennas AA arranged along directions shifted approximately 45 degrees from the first direction are connected by a common bias wiring. This configuration can improve the degree of freedom in wiring layout.

[0108] [Other embodiments] Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and changes are possible within the scope of the gist of the present invention.

[0109] For example, in the above-described embodiment, the carriers are assumed to be electrons, but the present invention is not limited to this and may be implemented using holes. Furthermore, the materials for the substrate and dielectric may be selected according to the intended use, and semiconductor layers such as silicon, gallium arsenide, indium arsenide, and gallium phosphide, and resins such as glass, ceramic, polytetrafluoroethylene, and polyethylene terephthalate may be used.

[0110] Although the above-described embodiment uses a square patch antenna as a terahertz wave resonator, the shape of the resonator is not limited to this. For example, a resonator having a structure using a patch conductor of a polygonal shape such as a rectangle or a triangle, a circle, an ellipse, or the like may be used.

[0111] Furthermore, the number of negative differential resistance elements integrated in the element is not limited to one, and a resonator including multiple negative differential resistance elements may be used. The number of lines is also not limited to one, and a configuration having multiple lines may be used. By using the antenna device described in the above-mentioned embodiments, it is possible to oscillate and detect terahertz waves.

[0112] In addition, in each of the above-described embodiments, a double-barrier RTD made of InGaAs / AlAs grown on an InP substrate has been described as the RTD. However, the present invention is not limited to these structures and material systems, and other structures and material combinations can also be used to provide the device of the present invention. For example, an RTD with a triple-barrier quantum well structure or an RTD with four or more multi-barrier quantum wells may also be used.

[0113] In addition, for example, in some of the above-described embodiments, examples have been shown in which the antennas AN included in two active antennas arranged adjacent to each other in an array configuration among multiple active antennas are coupled, but this is not limited thereto. If wiring is possible, the two antennas AN included in two active antennas that are not adjacent to each other may also be coupled.

[0114] In the above-described embodiment, in the array arrangement of the active antennas AA, each of the multiple rows is arranged with a substantially uniform offset length in a first direction relative to the adjacent rows. The offset length can be substantially equal to, but is not limited to, half the wavelength of the electromagnetic wave (e.g., terahertz wave) to be detected or generated. For example, the beam direction can be changed by appropriately setting the offset length, i.e., the antenna element spacing, to obtain the desired directivity. Furthermore, the spacing between the multiple rows can be substantially equal to, but is not limited to, half the wavelength of the electromagnetic wave.

[0115] In the above-described embodiment, the horizontal direction, which is the electric field direction of the patch antenna, is defined as the second direction in the array arrangement of the active antennas AA, but this is not limited thereto. The vertical direction, which is the magnetic field direction of the patch antenna, may also be defined as the second direction. In this case, in the array arrangement of the active antennas AA, multiple rows in which the active antennas are arranged in the second direction may be arranged in the first direction, and each of the multiple rows may be arranged with a substantially uniform offset length in the second direction relative to adjacent rows. The definitions of the first direction and the second direction may be changed depending on the antenna elements used.

[0116] In the above embodiment, the antenna array is rotated approximately 45 degrees relative to the first direction, but the rotation angle is not limited to this and can be selected appropriately. Also, the number of active antennas AA arranged in each row can be changed.

[0117] Furthermore, the connection between the bias wiring from the bias control unit 12 and the active antenna is not limited to that shown in each embodiment, and can be changed as appropriate.

[0118] The embodiments described above can be modified as appropriate within the scope of the technical concept. The disclosure of this specification includes not only what is described in this specification, but also all matters that can be understood from this specification and the drawings attached hereto.

[0119] The disclosure of this embodiment includes the following configuration. (Configuration 1) An antenna device comprising an antenna array in which a plurality of active antennas, each of which includes an antenna and a semiconductor structure and which generates or detects electromagnetic waves, are arranged, wherein the antenna array is configured such that a plurality of rows, each of which has one or more of the active antennas arranged in a first direction, are arranged in a second direction intersecting the first direction, and each of the plurality of rows is arranged with an offset length in the first direction relative to adjacent rows. (Configuration 2) 2. The antenna device according to configuration 1, further comprising a coupling wire that couples at least two of the plurality of active antennas to each other. (Configuration 3) 3. The antenna device according to configuration 2, wherein the path length of the coupling line is based on the wavelength of the electromagnetic wave. (Configuration 4) 4. The antenna device according to configuration 3, wherein the path length of the coupled line is approximately equal to n wavelengths (n is an integer) of the electromagnetic wave. (Configuration 5) 5. The antenna device according to any one of configurations 1 to 4, wherein the electromagnetic waves are electromagnetic waves in the terahertz band. (Configuration 6) 6. The antenna device according to any one of configurations 1 to 5, wherein the offset length is approximately equal to half the wavelength of the electromagnetic wave. (Configuration 7) 7. The antenna device according to any one of configurations 1 to 6, wherein the intervals between the plurality of rows are approximately equal to half the wavelength of the electromagnetic wave. (Configuration 8) 8. The antenna device according to any one of configurations 1 to 7, wherein the first direction of the active antenna is substantially the same as the electric field direction of the antenna. (Configuration 9) The first direction of the active antenna is substantially the same as the magnetic field direction of the antenna; 8. The antenna device according to any one of configurations 1 to 7, wherein: (Configuration 10) 10. The antenna device according to any one of configurations 1 to 9, wherein the active antenna excites a circularly polarized wave. (Configuration 11) 11. The antenna device according to any one of configurations 1 to 10, wherein the plurality of active antennas are arranged in a staggered pattern. (Configuration 12) At least one of the plurality of active antennas has a different size from the other active antennas. 12. The antenna device according to any one of configurations 1 to 11, wherein: (Configuration 13) At least one active antenna among the plurality of active antennas has a physical dimension that is half the physical dimension of the other active antennas. 12. The antenna device according to any one of configurations 1 to 11, wherein: (Configuration 14) The active antenna is arranged so that the first direction is rotated by approximately 45 degrees with respect to the electric field direction of the antenna. 9. The antenna device according to configuration 8, (Configuration 15) The active antenna is arranged so that the first direction is rotated by approximately 45 degrees with respect to the magnetic field direction of the antenna. 10. The antenna device according to configuration 9, [Explanation of symbols]

[0120] AA Active Antenna AN Antenna RTD, 100: Semiconductor 10, 20, 30: Antenna device, 11, 21: Antenna array

Claims

1. an antenna array in which a plurality of active antennas are arranged, each of which includes an antenna and a semiconductor structure and generates or detects electromagnetic waves; the antenna array is configured such that a plurality of rows, each row having one or more active antennas arranged in a first direction, are arranged in a second direction intersecting the first direction; Each of the plurality of rows is arranged with an offset length in the first direction relative to an adjacent row. An antenna device characterized by:

2. The antenna further includes a coupling wire that couples at least two of the active antennas to each other.

2. The antenna device according to claim 1.

3. The path length of the bond line is based on the wavelength of the electromagnetic wave.

3. The antenna device according to claim 2.

4. The path length of the coupled wire is approximately equal to n wavelengths (n is an integer) of the electromagnetic wave.

4. The antenna device according to claim 3.

5. The electromagnetic waves are electromagnetic waves in the terahertz band.

2. The antenna device according to claim 1.

6. the offset length is approximately equal to half the wavelength of the electromagnetic wave; 2. The antenna device according to claim 1.

7. The spacing between the rows is approximately equal to half the wavelength of the electromagnetic wave.

2. The antenna device according to claim 1.

8. the first direction of the active antenna is substantially equal to the electric field direction of the antenna; 2. The antenna device according to claim 1.

9. the first direction of the active antenna is substantially equal to a magnetic field direction of the antenna; 2. The antenna device according to claim 1.

10. The active antenna excites a circularly polarized wave.

2. The antenna device according to claim 1.

11. the plurality of active antennas are arranged in a staggered pattern; 2. The antenna device according to claim 1.

12. At least one of the plurality of active antennas has a different size from the other active antennas.

2. The antenna device according to claim 1.

13. At least one active antenna among the plurality of active antennas has a physical size that is half the physical size of the other active antennas.

2. The antenna device according to claim 1.

14. The active antenna has a first direction that is approximately It is arranged so that it is rotated 45 degrees.

9. The antenna device according to claim 8.

15. the active antenna is arranged so that the first direction is a direction rotated by approximately 45 degrees with respect to the magnetic field direction of the antenna; 10. The antenna device according to claim 9.

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