Antenna device

Abstract

An antenna device (120) includes a main substrate (10) formed with a ground electrode (GND) extending in a Y-axis direction, and a sub substrate (23) mounted to the main substrate (10). The sub substrate (23) has an upper surface (23a) on which a first antenna element (21) and a second antenna element (22) are arranged in the Y-axis direction, and a lower surface (23b) on which a mounting terminal portion (24) is arranged. A recessed portion (25) recessed toward the upper surface (23a) is formed in a central region (a region between the first antenna element (21) and the second antenna element (22)) of the lower surface (23b) of the sub substrate (23).

Description

Technical Field

[0001] This disclosure relates to an antenna device consisting of a second substrate on which a plurality of antenna elements are mounted and configured on a first substrate having a grounding element. Background Technology

[0002] Japanese Patent Application Publication No. 2008-98919 (Patent Document 1) discloses an antenna device having a first substrate and a second substrate mounted on the first substrate. The second substrate has: an upper surface on which two antenna elements are arranged adjacently; and a lower surface on which a grounding element is disposed. Furthermore, in order to suppress surface current transmitted between the two antenna elements, a slit is provided in the region between the antenna elements of the second substrate. The second substrate is divided by this slit into a substrate for arranging one antenna element and a substrate for arranging the other antenna element.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2008-98919 Summary of the Invention

[0006] The problem the invention aims to solve

[0007] In the antenna device described in Japanese Patent Application Publication No. 2008-98919, a grounding element and two antenna elements are disposed on a second substrate.

[0008] However, some antenna devices exist where a grounding element is disposed on a first substrate, while a second substrate has no grounding element but only multiple antenna elements. In this structure, mounting terminals for mounting the second substrate to the first substrate are provided between the antenna elements on the second substrate and the grounding element on the first substrate. Therefore, it is possible that the antenna elements are coupled to the mounting terminals instead of the grounding element, leading to a deterioration in antenna characteristics.

[0009] Furthermore, when two antenna elements are arranged in an array on the second substrate, the electric field lines formed between the outer ends of each antenna element in the arrangement direction and the grounding element pass through the exterior of the second substrate (a layer with a lower dielectric constant than the dielectric constant of the second substrate, such as an air layer). On the other hand, the electric field lines formed between the inner ends of each antenna element in the arrangement direction and the grounding element pass through the interior of the second substrate. Therefore, the symmetry of the dielectric constant in the arrangement direction of each antenna element (the balance of the proportion occupied by the outer layer of the second substrate) may be significantly disrupted, leading to a deterioration in the antenna characteristics.

[0010] This disclosure was made to solve such a problem, and its purpose is to improve the characteristics of an antenna device consisting of a second substrate on which a plurality of antenna elements are mounted on a first substrate having a grounding element.

[0011] Solution for solving the problem

[0012] The antenna device disclosed herein includes: a first substrate having a grounding member extending in a first direction; and a second substrate mounted on the first substrate. The second substrate has: a first antenna element; a second antenna element; a first surface; and a second surface opposite to the first surface. The first antenna element and the second antenna element are arranged in a first direction on the first surface or in a layer between the first surface and the second surface. A recess is formed in the region between the first antenna element and the second antenna element on the second surface of the second substrate, recessed towards the first surface.

[0013] The effects of the invention

[0014] According to this disclosure, a recess is formed in the region between the first antenna element and the second antenna element on the second surface of the second substrate, recessed towards the first surface. Therefore, electric field lines formed between the inner ends of each antenna element in the arrangement direction and the grounding member pass through the recess (a layer with a lower dielectric constant than the second substrate, such as an air layer). As a result, compared to the case where no recess is provided, the symmetry of the dielectric constant in the arrangement direction of each antenna element (the balance of the proportion occupied by the outer layers of the second substrate) becomes better. Furthermore, the isolation between the antenna elements and the terminal portions disposed opposite to the antenna elements across the recess can be improved. Consequently, the characteristics of the antenna device constructed by mounting a second substrate with multiple antenna elements on a first substrate having a grounding member can be improved. Attached Figure Description

[0015] Figure 1 This is an example of a block diagram of a communication device that uses an antenna device.

[0016] Figure 2 This is a three-dimensional view of the antenna device (Figure 1).

[0017] Figure 3 This is a cross-sectional view of the antenna device (1).

[0018] Figure 4 This is a diagram obtained by observing the array antenna from the plane along the positive Z-axis.

[0019] Figure 5 This is a cross-sectional view of the antenna device (section 2).

[0020] Figure 6 This is a cross-sectional view of the antenna device (3).

[0021] Figure 7 This is a cross-sectional view of the antenna device (4).

[0022] Figure 8 This is a cross-sectional view of the antenna device (5). Detailed Implementation

[0023] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Furthermore, identical or equivalent parts in the drawings will be labeled with the same reference numerals and will not be described again.

[0024] (Basic structure of a communication device)

[0025] Figure 1 This is an example of a block diagram of a communication device 1 using the antenna device 120 of this embodiment. The communication device 1 is, for example, a mobile phone, a smartphone, a tablet computer, or a personal computer with communication capabilities.

[0026] Reference Figure 1 The communication device 1 includes an antenna module 100 and a BBIC 200 constituting a baseband signal processing circuit. The antenna module 100 includes an RFIC 110, which serves as an example of a power supply circuit, and an antenna device 120. The communication device 1 up-converts the signal transmitted from the BBIC 200 to the antenna module 100 into a high-frequency signal and radiates it from the antenna device 120, and down-converts the high-frequency signal received by the antenna device 120 and processes the signal using the BBIC 200.

[0027] exist Figure 1 For ease of explanation, only the structures corresponding to four antenna elements 121 of the plurality of antenna elements 121 constituting the antenna device 120 are shown, and the structures corresponding to other antenna elements 121 having the same structure are omitted. Furthermore, in Figure 1 The image shows an example of an antenna device 120 formed by a plurality of antenna elements 121 arranged in a two-dimensional array. In this embodiment, the antenna elements 121 are patch antennas with a generally square planar shape.

[0028] RFIC 110 includes switches 111A-111D, 113A-113D, 117, power amplifiers 112AT-112DT, low-noise amplifiers 112AR-112DR, attenuators 114A-114D, phase shifters 115A-115D, signal synthesizer / demultiplexer 116, mixer 118, and amplifier circuit 119.

[0029] When transmitting high-frequency signals, switches 111A-111D and 113A-113D switch to the power amplifiers 112AT-112DT, and switch 117 is connected to the transmitting amplifier of amplifier circuit 119. When receiving high-frequency signals, switches 111A-111D and 113A-113D switch to the low-noise amplifiers 112AR-112DR, and switch 117 is connected to the receiving amplifier of amplifier circuit 119.

[0030] The signal from BBIC 200 is amplified by amplifier circuit 119 and up-converted by mixer 118. The high-frequency signal obtained by up-conversion is divided into four signals by signal synthesizer / demultiplexer 116, and supplied to different antenna elements 121 through four signal paths. At this time, the directivity of antenna device 120 can be adjusted by adjusting the phase shift of phase shifters 115A to 115D arranged in each signal path.

[0031] The received high-frequency signals received by each antenna element 121 are combined by a signal synthesizer / demultiplexer 116 via four different signal paths. The combined received signals are down-converted by a mixer 118, amplified by an amplifier circuit 119, and then transmitted to the BBIC 200.

[0032] RFIC 110 may be configured as a single-chip integrated circuit component, for example, containing the circuit structure described above. Alternatively, for the devices (switches, power amplifiers, low-noise amplifiers, attenuators, phase shifters) corresponding to each antenna element 121 of RFIC 110, they may also be configured as single-chip integrated circuit components for each corresponding antenna element 121.

[0033] (Structure of the antenna device)

[0034] Figure 2 This is a perspective view of the antenna device 120. The antenna device 120 includes a main substrate 10 and array antennas 20 and 30. Furthermore, hereinafter, the normal direction of the main surface of the main substrate 10 will be referred to as the "Z-axis direction," and the directions perpendicular to and mutually perpendicular to the Z-axis direction will be referred to as the "X-axis direction" and "Y-axis direction," respectively. Additionally, in the following descriptions, the positive direction of the Z-axis in each figure may be used as the upper surface side, and the negative direction as the lower surface side.

[0035] exist Figure 2 In the example shown, four array antennas 20 are arranged in the X-axis direction at predetermined intervals on the upper surface of the main substrate 10, and four array antennas 30 are arranged in the X-axis direction at predetermined intervals. The four array antennas 30 are arranged in a manner that is separated from the four array antennas 20 by predetermined intervals and is adjacent to the four array antennas 20 in the Y-axis direction.

[0036] Each array antenna 20 includes a first antenna element 21, a second antenna element 22, and a sub-substrate 23. The sub-substrate 23, when viewed from the Z-axis plane, is generally rectangular with its longer side along the Y-axis. The first antenna element 21 and the second antenna element 22, when viewed from the Z-axis plane, are generally square. The first antenna element 21 and the second antenna element 22 are arranged at predetermined intervals along the Y-axis on the upper surface of the sub-substrate 23. Alternatively, the first antenna element 21 and the second antenna element 22 may also be arranged at predetermined intervals along the Y-axis in a layer near the upper surface of the sub-substrate 23 (the layer between the upper and lower surfaces of the sub-substrate 23).

[0037] Each array antenna 30 includes a first antenna element 31, a second antenna element 32, and a sub-substrate 33. The sub-substrate 33, when viewed from the Z-axis plane, is generally rectangular with its long side along the Y-axis. The first antenna element 31 and the second antenna element 32, when viewed from the Z-axis plane, are generally square. The first antenna element 31 and the second antenna element 32 are arranged at predetermined intervals along the Y-axis on the upper surface of the sub-substrate 33. Alternatively, the first antenna element 31 and the second antenna element 32 may also be arranged at predetermined intervals along the Y-axis in a layer near the upper surface of the sub-substrate 33 (the layer between the upper and lower surfaces of the sub-substrate 33).

[0038] The first antenna elements 21 and 31 and the second antenna elements 22 and 32 are all configured to radiate radio waves polarized along the Y-axis. Furthermore, the first antenna elements 21 and 31 and the second antenna elements 22 and 32 are... Figure 1 Any of the antenna elements 121 shown.

[0039] Thus, by mounting four array antennas 20 and four array antennas 30 on the main substrate 10, a two-dimensional antenna device 120 with a total of 16 antenna elements arranged in a 4×4 configuration is formed.

[0040] Furthermore, the distance between the center points (intersections of the diagonals) of the antenna elements is set to a value greater than or equal to half (λ / 2) of the wavelength λ of the radio wave in free space.

[0041] Figure 3 yes Figure 2 Sectional view III-III of antenna assembly 120. Figure 3 The cross-sectional shape of the array antenna 30 is omitted here. Furthermore, the cross-sectional shape of the array antenna 30 is approximately the same as that of the array antenna 20.

[0042] The main substrate 10 includes a dielectric 11 and a ground electrode GND disposed inside the dielectric 11. The ground electrode GND has a flat plate shape extending in the Y-axis direction and the X-axis direction.

[0043] The sub-substrate 23 of the array antenna 20 has an upper surface 23a and a lower surface 23b opposite to the upper surface 23a. A first antenna element 21 and a second antenna element 22 are arranged in the Y-axis direction at predetermined intervals on the upper surface 23a of the sub-substrate 23. Furthermore, as described above, the first antenna element 21 and the second antenna element 22 may also be arranged in the Y-axis direction at predetermined intervals in a layer of the sub-substrate 23 near the upper surface 23a (the layer between the upper surface 23a and the lower surface 23b of the sub-substrate 23).

[0044] A mounting terminal portion 24 for mounting the sub-substrate 23 to the upper surface 10a of the main substrate 10 is disposed on the lower surface 23b of the sub-substrate 23. The mounting terminal portion 24 is formed of a plurality of conductive materials such as solder bumps.

[0045] A recess 25 is formed in the region (planar region) between the first antenna element 21 and the second antenna element 22 on the lower surface 23b of the sub-substrate 23, which is recessed toward the upper surface 23a.

[0046] The mounting terminal portion 24 includes: a first terminal portion 24a, which has a first region on the side of the lower surface 23b where the recessed portion 25 is close to the first antenna element 21 (negative Y-axis direction side); and a second terminal portion 24b, which has a second region on the side of the lower surface 23b where the recessed portion 25 is close to the second antenna element 22 (positive Y-axis direction side).

[0047] The recess 25 is formed between the first antenna element 21 and the second terminal portion 24b of the sub-substrate 23 and is the area (three-dimensional area) between the second antenna element 22 and the first terminal portion 24a.

[0048] Furthermore, the recess 25 is formed in a manner that extends in the X-axis direction (i.e., the direction orthogonal to the polarization direction of the radio waves radiated by each antenna element). Additionally, a recess 35 identical to the recess 25 is also formed in the array antenna 30 (see reference). Figure 2 ).

[0049] exist Figure 3 The illustration shows an example where the mounting terminal portion 24 includes a first terminal portion 24a located in the first region and a second terminal portion 24b located in the second region, but the configuration of the mounting terminal portion 24 is not limited to this configuration. For example, the mounting terminal portion 24 may also include only one of the first terminal portion 24a and the second terminal portion 24b.

[0050] In addition, Figure 3The example shown illustrates a case where the first terminal portion 24a is disposed over a substantially entire surface of the first region and the second terminal portion 24b is disposed over a substantially entire surface of the second region. However, the configuration of the first terminal portion 24a and the second terminal portion 24b is not limited to this configuration. For example, the first terminal portion 24a may also be disposed over a portion of the first region, and the second terminal portion 24b may also be disposed over a portion of the second region. In either case, the recess 25 may be formed at least in at least one of the regions between the first antenna element 21 and the second terminal portion 24b on the sub-substrate 23 and the region between the second antenna element 22 and the first terminal portion 24a.

[0051] Figure 4 This is a diagram obtained by viewing the array antenna 20 from the plane along the positive Z-axis. Furthermore, the shape of the array antenna 30 obtained by viewing the array antenna 20 from the plane along the positive Z-axis is approximately the same as the shape obtained by viewing the array antenna 20 from the plane along the positive Z-axis.

[0052] The sub-substrate 23 has a first end face 23c near the first antenna element 21 and a second end face 23d near the second antenna element 22 in the Y-axis direction. The recess 25 has a first side face 25c near the first antenna element 21 and a second side face 25d near the second antenna element 22 in the Y-axis direction.

[0053] The distances in the Y-axis direction between the first antenna element 21 and the first end face 23c, the distances in the Y-axis direction between the first antenna element 21 and the first side face 25c, the distances in the Y-axis direction between the second antenna element 22 and the second end face 23d, and the distances in the Y-axis direction between the second antenna element 22 and the second side face 25d are all predetermined values ​​d.

[0054] As described above, the antenna device 120 of this embodiment is configured by mounting a sub-substrate 23 on a main substrate 10 on which a ground electrode GND is formed. A recess 25 is formed in the central region of the lower surface 23b of the sub-substrate 23 (the region between the first antenna element 21 and the second antenna element 22) that is recessed toward the upper surface 23a. Therefore, the electric field lines formed between the outer ends of each antenna element 21, 22 (each of the first antenna element 21 and the second antenna element 22) in the arrangement direction and the ground electrode GND pass through the outside of the sub-substrate 23 (air layer), while the electric field lines formed between the inner ends of each antenna element 21, 22 in the arrangement direction and the ground electrode GND also pass through the recess 25 (air layer). Therefore, compared with the case where the recess 25 is not provided, the symmetry of the dielectric constant (the balance of the proportion occupied by the air layer) in the arrangement direction of each antenna element 21, 22 becomes better.

[0055] Furthermore, the recess 25 is formed between the first antenna element 21 and the second terminal portion 24b on the sub-substrate 23, and is located in the region between the second antenna element 22 and the first terminal portion 24a. This reduces the coupling strength between the first antenna element 21 and the second terminal portion 24b (the terminal portion disposed opposite to the first antenna element 21 via the recess 25), thereby improving the isolation between them. Additionally, it also reduces the coupling strength between the second antenna element 22 and the first terminal portion 24a (the terminal portion disposed opposite to the second antenna element 22 via the recess 25), further improving the isolation between them.

[0056] As a result, the characteristics of the antenna device 120, which is constructed by mounting a sub-board 23 with multiple antenna elements 21 and 22 on a main board 10 having a ground electrode GND, can be improved.

[0057] In particular, the recess 25 is formed in a manner that extends in the X-axis direction (i.e., the direction orthogonal to the polarization direction of the radio waves radiated by each antenna element 21, 22). As a result, the isolation between the first antenna element 21 and the second antenna element 22 can also be improved.

[0058] In addition, by forming a recess 25 on the lower surface 23b of the sub-substrate 23, the surface area of ​​the upper surface 10a of the main substrate 10 in contact with air can be increased, thereby improving the heat dissipation of the main substrate 10.

[0059] Furthermore, by forming a recess 25 in the sub-substrate 23, the strength of the portion where the recess 25 is formed is reduced, thus allowing stress generated within the sub-substrate 23 to be absorbed by concentrating the stress in the portion where the recess 25 is formed. As a result, the stress acting around the mounting terminal portion 24 can be reduced, ensuring mounting strength.

[0060] Furthermore, the “main substrate 10”, “ground electrode GND”, “first antenna element 21”, “second antenna element 22” and “sub-substrate 23” in this embodiment can correspond to the “first substrate”, “grounding element”, “first antenna element”, “second antenna element” and “second substrate” of this disclosure, respectively.

[0061] Furthermore, the "upper surface 23a", "lower surface 23b", "mounting terminal portion 24", and "recess 25" in this embodiment can correspond to the "first surface", "second surface", "terminal portion", and "recess" of this disclosure, respectively.

[0062] Furthermore, the "first terminal portion 24a" and "second terminal portion 24b" of this embodiment can correspond to the "first terminal portion" and "second terminal portion" of this disclosure, respectively.

[0063] In addition, the "first end face 23c", "second end face 23d", "first side face 25c" and "second side face 25d" in this embodiment can correspond to the "first end face", "second end face", "first side face" and "second side face" of this disclosure, respectively.

[0064] [Variation Example 1]

[0065] The space formed by the recess 25 and the main substrate 10 can also be used as a space for configuring components mounted on the main substrate 10.

[0066] Figure 5 This is a cross-sectional view of the antenna device 120A of this modified example 1. The antenna device 120A is a structure formed by adding a metal wall 50 connected to the ground electrode GND via a conductor 51 to the space formed by the recess 25 and the main substrate 10, relative to the antenna device 120 of the above embodiment.

[0067] By this modification, the space formed by the recess 25 and the main substrate 10 can be utilized as a space for the metal wall 50 mounted on the main substrate 10. Furthermore, the isolation between the first antenna element 21 and the second terminal portion 24b, and the isolation between the second antenna element 22 and the first terminal portion 24a can be further improved.

[0068] The “metal wall 50” in this variation 1 can correspond to the “component” in this disclosure.

[0069] [Variation Example 2]

[0070] Alternatively, the surface of the recess 25 can be made into a concave-convex shape to increase the surface area of ​​the recess 25.

[0071] Figure 6 This is a cross-sectional view of the antenna device 120B of this modified example 2. The antenna device 120B is a structure formed by changing the recess 25 of the antenna device 120 of the above embodiment to a recess 25B. The recess 25B is a structure formed by changing the surface of the recess 25 to a concave-convex shape.

[0072] This deformation increases the surface area of ​​the recess 25, thereby further improving the heat dissipation of the main substrate 10.

[0073] [Variation Example 3]

[0074] The antenna device 120 in the above-described embodiment can also be changed to a stacked patch antenna.

[0075] Figure 7 This is a cross-sectional view of the antenna device 120C of this modified example 3. The antenna device 120C is a structure formed by adding a third antenna element 21C and a fourth antenna element 22C to the antenna device 120 of the above-described embodiment.

[0076] The third antenna element 21C is formed in a layer between the first antenna element 21 and the lower surface 23b. The third antenna element 21C, together with the first antenna element 21, forms a single-band or dual-band stacked antenna. Furthermore, a single-band antenna means that the first antenna element 21 and the third antenna element 21C radiate radio waves in the same frequency band or frequency range. A dual-band antenna means that the first antenna element 21 and the third antenna element 21C radiate radio waves in different frequency bands or frequency ranges.

[0077] The fourth antenna element 22C is formed in a layer between the second antenna element 22 and the lower surface 23b. The fourth antenna element 22C, together with the second antenna element 22, forms a single-band or dual-band stacked antenna. Furthermore, a single-band antenna means that the second antenna element 22 and the fourth antenna element 22C radiate radio waves in the same frequency band or frequency range. A dual-band antenna means that the second antenna element 22 and the fourth antenna element 22C radiate radio waves in different frequency bands or frequency ranges.

[0078] In this antenna device 120C, a recess 25 is disposed in the region between the third antenna element 21C and the fourth antenna element 22C. More specifically, the depth H of the recess 25 is formed in a manner greater than the distance h1 between the lower surface 23b and the third antenna element 21C and the distance h2 between the lower surface 23b and the fourth antenna element 22C. This also improves the isolation between the third antenna element 21C and the fourth antenna element 22C.

[0079] The "third antenna element 21C" and "fourth antenna element 22C" in this variation 3 can correspond to the "third antenna element" and "fourth antenna element" of this disclosure, respectively.

[0080] [Variation Example 4]

[0081] In the antenna device 120 of the above-described embodiment, the width of the recess 25 and the recess 35 in the Y-axis direction may be larger than the distance in the Y-axis direction between the sub-substrate 23 and the sub-substrate 33.

[0082] Figure 8 This is a cross-sectional view of the antenna device 120D of this modified example 4. The antenna device 120D is a structure formed in the antenna device 120 of the above-described embodiment, in which the width W of the recess 25 and the recess 35 in the Y-axis direction is larger than the distance D in the Y-axis direction between the sub-substrate 23 and the sub-substrate 33.

[0083] By configuring it in this way, the volume of the air layer formed by the recess 25 can be made approximately equal to the volume of the air layer formed between adjacent sub-sub-substrate 23 and sub-substrate 33. Therefore, the symmetry of the dielectric constant in the Y-axis direction of the second antenna element 22 can be improved. Similarly, the symmetry of the dielectric constant in the Y-axis direction of the first antenna element 31 can be improved.

[0084] The "sub-substrate 33" in this variation 4 can correspond to the "third substrate" of this disclosure.

[0085] [Variation Example 5]

[0086] The above embodiments illustrate an example in which an air layer is formed in the region between the recess 25 and the main substrate 10, but it is also possible to fill at least a portion of the region between the recess 25 and the main substrate 10 with a resin whose dielectric constant is smaller than that of the sub-substrate 23.

[0087] The embodiments disclosed herein should be considered illustrative in all respects and not limiting. The scope of the invention is defined by the claims rather than by the foregoing description of the embodiments, and is intended to include all modifications within the equivalent meaning and scope of the claims.

[0088] Explanation of reference numerals in the attached figures

[0089] 1. Communication device; 10. Main substrate; 10a, 23a. Upper surface; 11. Dielectric; 20, 30. Array antenna; 21. First antenna element; 21C. Third antenna element; 22. Second antenna element; 22C. Fourth antenna element; 23, 33. Sub-substrate; 23b. Lower surface; 23c. First end face; 23d. Second end face; 24. Mounting terminal portion; 24a. First terminal portion; 24b. Second terminal portion; 25, 25B, 35. Recess; 25c. First side surface; 2 5d, second side; 50, metal wall; 51, conductor; 100, antenna module; 111A, 111D, 113A, 113D, 117, switch; 112AR, 112DR, low noise amplifier; 112AT, 112DT, power amplifier; 114A, 114D, attenuator; 115A, 115D, phase shifter; 116, demultiplexer; 118, mixer; 119, amplifier circuit; 120, 120A~120D, antenna assembly; 121, antenna element.

Claims

1. An antenna device, wherein, The antenna device includes: A first substrate having a grounding member extending in a first direction; and The second substrate is mounted on the first substrate. The second substrate has: First antenna element; Second antenna element; Page 1; and The second surface is opposite to the first surface. The first antenna element and the second antenna element are arranged in a manner along the first direction on the first surface or in a layer between the first surface and the second surface. A recess is formed in the region between the first antenna element and the second antenna element on the second surface of the second substrate, recessed towards the first surface. The second surface is provided with a terminal portion for mounting the second substrate to the first substrate. The recess is formed in the region between at least one of the first antenna element and the second antenna element of the second substrate and the terminal portion.

2. The antenna device according to claim 1, wherein, The terminal portion includes: The first terminal portion, which is located on the second surface in the region closer to the first antenna element than the recess; and The second terminal portion is located on the second surface in the region closer to the second antenna element than the recess. The recess is formed between the first antenna element and the second terminal portion of the second substrate, and is the region between the second antenna element and the first terminal portion.

3. The antenna device according to claim 1 or 2, wherein, The second substrate has a first end face near the first antenna element and a second end face near the second antenna element in the first direction. The recess has a first side surface near the first antenna element and a second side surface near the second antenna element in the first direction. The distance in the first direction between the first antenna element and the first end face of the second substrate is equal to the distance in the first direction between the first antenna element and the first side face of the recess. The distance in the first direction between the second antenna element and the second end face of the second substrate is equal to the distance in the first direction between the second antenna element and the second side face of the recess.

4. The antenna device according to claim 1 or 2, wherein, The antenna device also includes a component disposed in the space formed by the recess of the second substrate and the first substrate.

5. The antenna device according to claim 1 or 2, wherein, The surface of the recess has an uneven shape.

6. The antenna device according to claim 1 or 2, wherein, The second substrate further comprises: A third antenna element is formed in the region between the first antenna element and the second surface; as well as The fourth antenna element is formed in the region between the second antenna element and the second surface. The recess is disposed in the region between the third antenna element and the fourth antenna element.

7. The antenna device according to claim 6, wherein, The depth of the recess is greater than the distance between the second surface and the third antenna element and the distance between the second surface and the fourth antenna element.

8. The antenna device according to claim 1 or 2, wherein, The antenna device further includes a third substrate arranged on the first substrate in the first direction, which is aligned with the second substrate. The width of the recess in the first direction is greater than the distance in the first direction between the second substrate and the third substrate.

9. The antenna device according to claim 7, wherein, The antenna device further includes a third substrate arranged on the first substrate in the first direction, which is aligned with the second substrate. The width of the recess in the first direction is greater than the distance in the first direction between the second substrate and the third substrate.

10. The antenna device according to claim 1 or 2, wherein, The first antenna element and the second antenna element radiate radio waves with polarization direction. The recess extends in a direction intersecting the polarization direction.

11. The antenna device according to claim 7, wherein, The first antenna element and the second antenna element radiate radio waves with polarization direction. The recess extends in a direction intersecting the polarization direction.

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