Antenna device

Abstract

To provide an antenna device that can achieve the radiation directivity at a wide angle in all the orientations without enlarging a device or complicating a structure due to array formation, by using a pair of upper and lower patch antennas.SOLUTION: An antenna device 1 including a dielectric substrate includes ground conductors 21, 22a, 22b, 23a, and 23b, a first patch antenna 20a, a second patch antenna 20b, a first cavity 12a that is formed in a first dielectric layer 11a and has a shape surrounding the first patch antenna 20a in a plan view, and a second cavity 12b that is formed in a second dielectric layer 11b and has a shape surrounding the second patch antenna 20b in the plan view. The first and second patch antennas 20a and 20b face each other in a Z direction and the first and second cavities 12a and 12b face each other in the Z direction with the ground conductors 21, 22a, 22b, 23a, and 23b held therebetween.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an antenna device configured using a dielectric substrate. [Background technology]

[0002] In mobile communications such as 5G and 6G, high-frequency radio waves are transmitted and received in various environments, such as inside buildings and outdoors, and therefore antenna devices are required to have a wide-angle radiation directivity that enables radio waves to be transmitted and received in various directions. To meet this requirement, a method is known in which an array antenna is configured by arranging multiple antenna elements in an array to achieve a wide-angle radiation directivity overall. For example, Patent Document 1 discloses a technology that can obtain a wide-angle radiation directivity by applying a phase difference to each antenna in an array antenna in which multiple antennas are arranged in an array, thereby performing beamforming. [Prior art documents] [Patent documents]

[0003] Patent No. 6818757 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, antenna devices have widely adopted structures that use dielectric substrates in order to reduce size and weight. For example, forming a single patch antenna on a dielectric substrate makes it easy to miniaturize the antenna device, but it is difficult to achieve a wide-angle radiation directivity. As mentioned above, to achieve a wide-angle radiation directivity of an antenna device, it is necessary to form an array antenna by arranging multiple antennas, such as patch antennas, in an array on a dielectric substrate. However, array antennas using dielectric substrates require space for arranging multiple antennas, which increases the size and makes it difficult to miniaturize the antenna device. Furthermore, complex electronic circuits must be formed to provide phase differences for beamforming to multiple antennas, which increases both component and implementation costs and requires strict dimensional tolerances during the fabrication of the dielectric substrate. Furthermore, while the radiation directivity of an antenna device is generally oriented toward the zenith, some applications may require omnidirectional radiation directivity, including the zenith and the opposite direction. However, achieving such omnidirectional radiation directivity is not easy. As described above, when constructing an antenna device using a dielectric substrate using the above-mentioned conventional method, it has been difficult to achieve a small size, low cost, and wide-angle radiation directivity including all directions.

[0005] The present invention has been made to solve the above-mentioned problems, and when constructing an antenna device using a dielectric substrate, a pair of patch antennas arranged symmetrically above and below are used to ensure omnidirectional radiation directivity while sufficiently maintaining the radiation directivity of each patch antenna, thereby realizing an antenna device that can be made smaller and less expensive. [Means for solving the problem]

[0006] In order to solve the above problems, the antenna device (1) of the present invention is an antenna device configured using a dielectric substrate having a first surface (S1) and a second surface (S2) that face each other in a first direction (Z) that is a thickness direction, and includes: a ground conductor (21, 22a, 22b, 23a, 23b) arranged in a region between the first surface and the second surface; a first patch antenna (20a) formed on a first conductor layer between the ground conductor and the first surface; a second patch antenna (20b) formed on a second conductor layer between the ground conductor and the second surface; and a first dielectric layer (11a) between the first conductor layer and the first surface. and a second cavity (12b) formed in a second dielectric layer (11b) between the second conductor layer and the second surface and having a shape surrounding the second patch antenna in a plan view seen from the second surface along the first direction, wherein the first patch antenna and the second patch antenna face each other in the first direction with the ground conductor sandwiched therebetween, and the first cavity and the second cavity face each other in the first direction.

[0007] The antenna device of the present invention uses a dielectric substrate and includes a pair of upper and lower patch antennas and a pair of upper and lower cavities formed on either side of a central ground conductor, with each cavity having a shape that surrounds the corresponding patch antenna in a plan view from a first direction. With this structure, radio waves radiated from the upper and lower patch antennas via a feed structure have a wide-angle radiation directivity due to the influence of the electromagnetic field distribution on the dielectric surfaces on the side faces of the upper and lower cavities, and can be radiated in all directions, including both sides of the first direction. This eliminates the need for additional space for arranging multiple antennas in an array or for complex electronic circuits for phase control during beamforming, making it possible to construct a compact, low-cost antenna device with omnidirectional radiation directivity that can be used for a variety of applications.

[0008] In the present invention, the pair of patch antennas and the pair of cavities may each have a rectangular shape in a plan view seen from a first direction. In this case, the height of each cavity along the first direction is preferably set within a range of 0.7λ to 0.8λ, where λ is the wavelength of the frequency used in the dielectric substrate. Furthermore, the outer edge of each cavity is preferably set to be larger than the outer edge of the corresponding patch antenna by a distance within a range of 0.03λ to 0.07λ in a plan view seen from the first direction.

[0009] In the present invention, the patch antenna and the cavity can be arranged symmetrically with respect to the center of the dielectric substrate in a plan view seen from the first direction. This allows the antenna device to obtain symmetric radiation directivity in each direction from approximately the center in the substrate plane. Furthermore, the first patch antenna and the second patch antenna can be shaped symmetrically with respect to each other with respect to the first direction, and the first cavity and the second cavity can be shaped symmetrically with respect to each other with respect to the first direction. This allows for approximately equal radiation directivity to be ensured on both sides of the first direction.

[0010] In the present invention, the ground conductor can be formed on multiple conductor layers that are connected to each other through multiple via conductors extending in the first direction, thereby increasing the area of ​​the ground conductor and strengthening the ground, thereby improving the antenna characteristics.

[0011] In the present invention, the patch antenna can be provided with a feeding structure for feeding either or both of horizontally polarized waves and vertically polarized waves, thereby enabling a single patch antenna to transmit and receive at least either or both of horizontally polarized radio waves and vertically polarized radio waves, and allowing each to be used appropriately depending on the usage situation. [Effects of the Invention]

[0012] According to the present invention, a pair of patch antennas, one above the other and one below the other, is arranged on a dielectric substrate, and cavities are arranged above and below them. This makes it possible to avoid the increase in size and cost that would accompany an array of antenna devices, while achieving a wide angle of radiation directivity in all directions, and to realize an antenna device that is applicable to a variety of applications and is easy to use. [Brief explanation of the drawings]

[0013] [Figure 1] 1A and 1B are perspective views of the antenna device 1 of the present embodiment as viewed obliquely from above and below. [Figure 2] 2 is a cross-sectional structural diagram of the antenna device 1 of FIG. 1 taken along the line AA. [Figure 3] FIG. 1 is a plan view of the antenna device 1 of the present embodiment as viewed from above. [Figure 4] 3A and 3B are diagrams illustrating a conductor structure in the center of the antenna device 1 of the present embodiment. [Figure 5] 1A and 1B are diagrams illustrating the concept of a power supply method for the antenna device 1 of the present embodiment. [Figure 6] 3 is a diagram showing radiation directivity in the XZ plane of the antenna device 1 of the present embodiment. FIG. [Figure 7] 3 is a diagram showing radiation directivity in the YZ plane of the antenna device 1 of the present embodiment. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0014] Preferred embodiments of the present invention will be described below with reference to Figures 1 to 7. In these embodiments, an antenna device embodying the present invention will be described. However, the embodiments described below are merely examples of applications of the present invention, and the present invention is not limited to the content of these embodiments.

[0015] The structure of an antenna device 1 according to one embodiment of this invention will be described with reference to Figs. 1 to 4. Fig. 1 is a perspective view of the antenna device 1, with Fig. 1(A) showing a perspective view from diagonally above and Fig. 1(B) showing a perspective view from diagonally below. Fig. 2 is a cross-sectional structural diagram of the antenna device 1 taken along the line AA in Fig. 1. Fig. 3 is a plan view of the antenna device 1 as seen from above. Fig. 4 is a diagram illustrating the conductor structure of the central portion of the antenna device 1. For ease of explanation, the X, Y, and Z directions (first directions according to the present invention), which are orthogonal to each other, are indicated by arrows in Figs. 1 to 4.

[0016] The antenna device 1 of this embodiment is configured using a dielectric substrate made of a dielectric material and has a structure in which three dielectric layers 10, 11a, and 11b are stacked between an uppermost surface S1 (a first surface of the present invention) and a lowermost surface S2 (a second surface of the present invention) that face each other along the Z direction. That is, the antenna device 1 has a dielectric layer 10 disposed at the center in the Z direction, a dielectric layer 11a (a first dielectric layer of the present invention) disposed between the dielectric layer 10 and the surface S1, and a dielectric layer 11b (a second dielectric layer of the present invention) disposed between the dielectric layer 10 and the surface S2. Furthermore, five-layer ground conductors 21, 22a, 22b, 23a, and 23b are disposed on the central dielectric layer 10. The antenna device 1 of this embodiment has a structure that is symmetrical above and below the dielectric layer 10 in the Z direction.

[0017] A patch antenna 20a (first patch antenna of the present invention) is formed at the center of the conductor layer (first conductor layer of the present invention) on the upper surface of the dielectric layer 10, and a cavity 12a (first cavity of the present invention) is formed at the center of the dielectric layer 11a directly above it. A patch antenna 20b (second patch antenna of the present invention) is formed at the center of the conductor layer (second conductor layer of the present invention) on the lower surface of the dielectric layer 10, and a cavity 12b (second cavity of the present invention) is formed at the center of the dielectric layer 11b directly below it. That is, rectangular hollow portions formed by removing the central dielectric material in each of the pair of upper and lower dielectric layers 11a and 11b form the pair of upper and lower cavities 12a and 12b. The pair of upper and lower patch antennas 20a and 20b face each other in the Z direction, with the dielectric layer 10 sandwiched between them. These patch antennas 20a, 20b and cavities 12a, 12b all have a rectangular shape in plan view seen from the Z direction.

[0018] As shown in Figures 2 and 3, in a plan view from the Z direction, the three dielectric layers 10, 11a, and 11b all have rectangular planar shapes of the same size. Also, as shown in Figure 3, the patch antenna 20a has a rectangular planar shape that is significantly smaller than the dielectric layer 11a, and the cavity 12a has a rectangular planar shape that is slightly larger than the patch antenna 20a. Note that while Figure 3 shows a plan view from above in the Z direction, the relationship between the patch antenna 20b and the dielectric layer 11b in a plan view from below in the Z direction is the same as in Figure 2, and the pair of patch antennas 20a, 20b are arranged in a position where they overlap when viewed from the Z direction. Furthermore, in a plan view from the Z direction, the cavity 12a surrounds the patch antenna 20a at the top, and the cavity 12b surrounds the patch antenna 20b at the bottom. Therefore, the upper and lower patch antennas 20a and 20b face the air inside the upper and lower cavities 12a and 12b, respectively, and are structured so that the upper and lower patch antennas 20a and 20b are exposed to the outside.

[0019] FIG. 2 shows the Z-direction height Z1 of the central dielectric layer 10 and the Z-direction height Z2 of the upper and lower dielectric layers 11a and 11b (the height Z2 of the cavities 12a and 12b). It can be seen that Z2 is set larger than Z1. FIG. 3 shows the X-direction length X1 and the Y-direction length Y1 of the central dielectric layer 10 and the X-direction length X2 and the Y-direction length Y2 of the upper and lower cavities 12a and 12b, respectively. As already mentioned, X1 and Y1 are set larger than X2 and Y2. The sizes of the upper and lower patch antennas 20a and 20b are set slightly smaller than X2 and Y2. FIGS. 1 to 4 illustrate a case where the three dielectric layers 10, 11a, and 11b and the pair of cavities 12a and 12b all have a square planar shape, and X1 = Y1 and X2 = Y2.

[0020] In this embodiment, the specific dimensional conditions, such as X1, X2, Y1, Y2, Z1, and Z2, must be appropriately determined depending on the frequency band used, antenna characteristics, and the like. For example, assuming a frequency of 28 GHz, one example of dimensional conditions is X1=Y1=7.5 mm, Z1=1.2 mm, and Z2=3.3 mm for the dielectric layers 10, 11a, and 11b, and X2=Y2=2.35 mm for the cavities 12a and 12b. The height of the cavities 12a and 12b is equal to Z2, and the size of the patch antennas 20a and 20b is approximately 2 mm, slightly smaller than X2 and Y2. Generally, the lower the frequency band used, the larger the dimensional parameters should be set, and the higher the frequency band used, the smaller the dimensional parameters should be set.

[0021] Next, the conductor structure of the antenna device 1 will be described with reference to Fig. 4. Fig. 4 shows only the central region of the dielectric layer 10 with the upper and lower dielectric layers 11a and 11b removed, and shows the upper and lower patch antennas 20a and 20b, the ground conductors 21, 22a, 22b, 23a, and 23b, and multiple via conductors 30, 31a, 31b, 32a, and 32b extending in the stacking direction of the dielectric layer 10. First, the five-layer ground conductors 21, 22a, 22b, 23a, and 23b are arranged such that the central ground conductor 21 is sandwiched between the two layers of ground conductors 21a and 22a arranged on the upper layer and the two layers of ground conductors 22b and 23b arranged on the lower layer. Each of these ground conductors 21, 22a, 22b, 23a, and 23b is formed to extend over substantially the entire rectangular region of the dielectric layer 10 and is electrically connected to each other via multiple via conductors 30. Since the large-area ground conductors 21, 22a, 22b, 23a, and 23b and the upper and lower patch antennas 20a and 21b are arranged to face each other, the ground of the antenna device 1 is strengthened, which is effective in improving the antenna characteristics.

[0022] FIG. 4 also shows four via conductors 31a, 31b, 32a, and 32b that function as feeder lines. Two via conductors 31a and 32a are connected to the upper patch antenna 20a and configured to be externally powered via a pair of feeder lines coplanar with the ground conductor 22a. Two via conductors 31b and 32b are connected to the lower patch antenna 20b and configured to be externally powered via a pair of feeder lines coplanar with the ground conductor 22b. Of these, a horizontally polarized high-frequency signal is fed to the via conductors 31a and 31b, and a vertically polarized high-frequency signal is fed to the via conductors 32a and 32b. As shown in FIG. 3, the upper patch antenna 20a shows an upper end Ea of the horizontally polarized via conductor 31a and an upper end Eb of the vertically polarized via conductor 32a, which are connected at positions offset in the X and Y directions from the center of the patch antenna 20a, respectively. Although not shown, the lower patch antenna 20b is arranged symmetrically in the Z direction with respect to that in Fig. 3. With this structure, the antenna device 1 can radiate either or both horizontally polarized waves and vertically polarized waves via the feeding structure.

[0023] Here, the concept of a power supply method for the antenna device 1 of this embodiment will be described with reference to FIG. 5. Since the antenna device 1 of this embodiment includes two patch antennas 20a and 20b, an external mechanism for switching the power supply to the antenna device 1 is required. Therefore, the example of FIG. 5 shows a switch 40 and a signal source 41 provided in an external circuit to selectively transmit radio waves from the two patch antennas 20a and 20b of the antenna device 1. The switch 40 is connected to the feed lines of the upper patch antenna 20a and the lower patch antenna 20b, and to the signal source 41 that outputs a high-frequency signal of a predetermined frequency. When the upper patch antenna 20a is used, the switch 40 is switched and controlled so that the signal source 41 is connected to the feed line of the patch antenna 20a. However, when the lower patch antenna 20b is used, the switch 40 is switched and controlled so that the signal source 41 is connected to the feed line of the patch antenna 20b. When receiving radio waves selectively from the two patch antennas 20 and 20b, the signal source 41 can be replaced with a receiving circuit.

[0024] When a high-frequency signal is externally supplied to either of the two patch antennas 20a, 20b of the antenna device 1 of this embodiment, radio waves are generally emitted upward or downward in the Z direction. In this case, in a conventional general structure, the upper and lower cavities 12a, 12b are not provided, and both surfaces of the dielectric layer 10 including the upper and lower patch antennas 20a, 20b are entirely exposed to air, making it difficult to achieve a wide-angle radiation directivity. In contrast, in this embodiment, the cavity 12a above the upper patch antenna 20a and the cavity 12b below the lower patch antenna 20b are provided, thereby achieving a wide-angle radiation directivity of the antenna device 1. Furthermore, by further switching between the upper and lower patch antennas 20a, 20b using the method shown in FIG. 5, the radiation directivity of the antenna device 1 can be expanded substantially in all directions. The verification results of this point will be described later.

[0025] Hereinafter, the results of verification of the antenna characteristics of the antenna device 1 of this embodiment will be described with reference to Figs. 6 and 7. Here, as the antenna characteristics of the antenna device 1, both the radiation directivity when power is fed to the upper patch antenna 20a and the radiation directivity when power is fed to the lower patch antenna 20b are verified. Fig. 6 shows the directivity in the XZ plane, and Fig. 7 shows the directivity in the YZ plane. Both are the results of verification by simulation of the directivity of radio waves radiated from the patch antennas 20a and 20b when a signal with a frequency of 28 GHz is input. In Figs. 6 and 7, the radiation directivity of the upper patch antenna 20a (solid line) and the radiation directivity of the lower patch antenna 20b (dashed line) are shown superimposed.

[0026] As shown in FIGS. 6 and 7 , the gain of the patch antenna 20a reaches its peak when the radiation direction faces upward in the Z direction. The gain decreases as the radiation direction deviates from the Z direction in the XZ and YZ planes. On the other hand, the gain of the patch antenna 20b reaches its peak when the radiation direction faces downward in the Z direction. The gain decreases as the radiation direction deviates from the Z direction in the XZ and YZ planes. In FIGS. 6 and 7 , the half-width, or the angular range over which the gain is half its peak, is calculated. Both the half-width of the patch antenna 20a (solid line) and the half-width of the patch antenna 20b (dashed line) exceed 180°. Considering the pair of patch antennas 20a and 20b together, it can be seen that sufficient gain is ensured in all directions (360°). Therefore, the results in FIGS. 6 and 7 demonstrate that the antenna device 1 of this embodiment can achieve a wide-angle radiation directivity and cover all directions.

[0027] 6 and 7, when the VSWR (Voltage Standing Wave Ratio) of the reflection characteristics of the antenna device 1 of this embodiment was verified by simulation according to frequency, the VSWR of both patch antennas 20a and 20b reached a minimum value near a frequency of 28 GHz, and the frequency range over which the VSWR was favorable was relatively wide. In other words, the antenna device 1 of this embodiment can obtain favorable reflection characteristics over a wide frequency range.

[0028] As described above, by adopting the structure of the antenna device 1 of this embodiment, it is possible to achieve good antenna characteristics, including wide-angle radiation directivity. That is, while a conventional structure in which patch antennas 20a and 20b are arranged on the surface of dielectric layer 10 results in a relatively narrow-angle radiation directivity, in this embodiment, a wide-angle radiation directivity is possible due to the effect of providing cavities 12a and 12b in dielectric layers 11a and 11b stacked above and below dielectric layer 10. It is assumed that radio waves radiated upward and downward in the Z direction from patch antennas 20a and 20b generate electromagnetic field distributions on the dielectric surfaces constituting the four side surfaces of each of cavities 12a and 12b, and when these fields propagate along the Z direction to the openings at the tops of cavities 12a and 12b, they spread in various directions, thereby widening the radiation directivity.

[0029] In conventional configurations, achieving a wide-angle radiation directivity required an array antenna in which multiple antennas were arranged in an array and a method of controlling the phase of each antenna using beamforming. In contrast, the antenna device 1 of this embodiment achieves a wide-angle radiation directivity using only a pair of patch antennas 20a, 20b without configuring an array antenna. This eliminates the need for space for multiple antennas and the need for complex electronic circuits to impart phase differences to each antenna. Therefore, in addition to the superior antenna performance described above, the antenna device 1 of this embodiment is suitable for miniaturizing the antenna device 1 by reducing the size of the dielectric substrate compared to arrays using conventional configurations. This also allows for relaxed dimensional tolerances during the manufacture of the dielectric substrate, reducing component and implementation costs and enabling cost reductions.

[0030] In this embodiment, as described above, appropriate setting of dimensional parameters is important for achieving good antenna characteristics, including wide-angle radiation directivity. That is, the dimensional parameters of the antenna device 1 are not limited to those shown in FIGS. 1 to 4 , but are preferably set to match the wavelength λ corresponding to the operating frequency of the dielectric substrate. This wavelength λ takes into consideration the wavelength shortening effect of the dielectric substrate. Specifically, the height Z2 of the cavities 12a and 12b along the Z direction is preferably set within a range of 0.7λ to 0.8λ relative to the wavelength λ of the operating frequency of the dielectric substrate. Furthermore, the lengths X2 and Y2 of the cavity 12 in the X and Y directions are preferably set to be greater than the lengths of the rectangular patch antennas 20a and 20b in the X and Y directions by a distance within a range of 0.03λ to 0.07λ. These dimensional parameter conditions are desirable for ensuring the desired antenna characteristics, such as wide-angle radiation directivity and good reflection characteristics, of the antenna device 1.

[0031] In addition, in this embodiment, as shown in FIG. 3, the patch antennas 20a, 20b and the cavities 12a, 12b have a rectangular planar shape when viewed from the Z direction. However, the planar shape is not limited to a rectangle, and other planar shapes may be used. For example, the present invention can be applied even when the patch antennas 20a, 20b and the cavities 12a, 12b have a circular planar shape or a polygonal planar shape other than a rectangle. Even in this case, the effects of the antenna device 1 to which the present invention is applied can be obtained. Furthermore, in this embodiment, the patch antennas 20a, 20b and the cavities 12a, 12b are arranged symmetrically with respect to the center of the dielectric substrate when viewed from the Z direction. However, the present invention can be applied even when the patch antennas 20a, 20b and the cavities 12a, 12b are arranged asymmetrically with respect to the center.

[0032] Although the present invention has been specifically described based on the present embodiment, the present invention is not limited to the above embodiment and can be modified without departing from the spirit of the present invention. In other words, the basic structure of the antenna device 1 described using Figures 1 to 4 can be widely applied to various antenna devices 1 with other structures and shapes, as long as the effects of the present invention can be obtained. For example, the shape, power feeding method, size, etc. of the patch antennas 20a and 20b can be modified in various ways as long as the effects of the present invention can be obtained. [Explanation of symbols]

[0033] 1...Antenna device 10, 11a, 11a...Dielectric layers 12a, 12a…cavity 20a, 20b...Patch antenna 21, 22a, 22b, 23a, 23b...Ground conductors 30, 31a, 31b, 32a, 32b...Via conductors 40...Switch 41…Signal source

Claims

1. An antenna device configured using a dielectric substrate having a first surface and a second surface that face each other in a first direction that is a thickness direction, a ground conductor disposed in a region between the first surface and the second surface; a first patch antenna formed on a first conductor layer between the ground conductor and the first surface; a second patch antenna formed on a second conductor layer between the ground conductor and the second surface; a first cavity formed in a first dielectric layer between the first conductor layer and the first surface, the first cavity having a shape surrounding the first patch antenna in a plan view seen from the first surface along the first direction; a second cavity formed in a second dielectric layer between the second conductor layer and the second surface, the second cavity having a shape surrounding the second patch antenna in a plan view seen from the second surface along the first direction; wherein the first patch antenna and the second patch antenna face each other in the first direction with the ground conductor interposed therebetween, and the first cavity and the second cavity face each other in the first direction.

2. 2. The antenna device according to claim 1, wherein the first patch antenna, the second patch antenna, the first cavity, and the second cavity each have a rectangular shape in a plan view seen from the first direction.

3. The antenna device according to claim 1, characterized in that the heights of the first cavity and the second cavity along the first direction are set within a range of 0.7λ to 0.8λ, where λ is the wavelength of the frequency used in the dielectric substrate.

4. The antenna device according to claim 1, characterized in that, in a planar view from the first direction, the outer edges of the first cavity and the second cavity are set to be larger by a distance in the range of 0.03λ to 0.07λ from the outer edges of the first patch antenna and the second patch antenna, respectively.

5. 2. The antenna device according to claim 1, wherein the first patch antenna and the second patch antenna are shaped symmetrically to each other with respect to the first direction, and the first cavity and the second cavity are shaped symmetrically to each other with respect to the first direction.

6. 6. The antenna device according to claim 5, wherein, in a planar view from the first direction, the first patch antenna, the second patch antenna, the first cavity, and the second cavity are arranged symmetrically with respect to the center of the dielectric substrate.

7. The antenna device according to claim 1 , wherein the ground conductor is formed on a plurality of conductor layers that are connected to each other through a plurality of via conductors that extend in the first direction.

8. 2. The antenna device according to claim 1, wherein each of the first patch antenna and the second patch antenna is provided with a feeding structure for feeding one or both of horizontally polarized waves and vertically polarized waves.

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