Antenna substrate and antenna device

Abstract

Provided are an antenna substrate and an antenna device which can be applied to a dual polarization antenna corresponding to a plurality of frequency bands, and which can reduce the area required for disposing radiation electrodes. This antenna substrate is provided with: a dielectric substrate having a main surface; and first and second power supply lines and planar first to third radiation electrodes, which are on the main surface of the dielectric substrate. The size difference between the first and second radiation electrodes and the size difference between the first and third radiation electrodes are larger than the size difference between the second and third radiation electrodes. The first and second power supply lines are respectively connected to the first radiation electrode at first and second connection points which differ from each other. The first radiation electrode neighbors the second radiation electrode in a first direction which intersects, in the main surface, with the direction of a first line linking the first connection point and the center of the first radiation electrode, and neighbors the third radiation electrode in a second direction differing from the first direction and intersecting, in the main surface, with the direction of a second line linking the second connection point and the center of the first radiation electrode.

Description

Antenna board, antenna device

[0001] The present disclosure relates to an antenna substrate and an antenna device.

[0002] Non-Patent Document 1 discloses an example of the configuration of an antenna compatible with multiple frequency bands, which is configured by forming, on a substrate, a first square patch compatible with a first frequency, a first feed line connected to the first square patch, and a second square patch connected to the first square patch via a second feed line.

[0003] Antenna Theory and Design, WL Stutzman & GA Thiele, John Wiley and Sons, 1981, pp 295-303

[0004] According to the technology described in Non-Patent Document 1, a dual-polarized antenna that supports multiple frequencies can be configured by arranging two sets of a first square patch, a first feed line, and a first square patch so that their arrangement directions are orthogonal to each other. However, this requires multiple square patches (radiation electrodes) for each polarization, which increases the area required for arranging the radiation electrodes.

[0005] The present disclosure provides an antenna substrate and an antenna device that can be applied to a dual-polarized antenna that supports multiple frequency bands and that can reduce the area required for arranging a radiation electrode.

[0006] An antenna substrate according to one aspect of the present disclosure includes a dielectric substrate having a main surface, and planar first to third radiation electrodes and first and second feed lines located on the main surface of the dielectric substrate. A size difference between the first and second radiation electrodes and a size difference between the first and third radiation electrodes are larger than a size difference between the second and third radiation electrodes. The first and second feed lines are connected to the first radiation electrode at first and second connection points that are different from each other. The first radiation electrode is adjacent to the second radiation electrode in a first direction that intersects, within the main surface, with a first line connecting the first connection point and the center of the first radiation electrode, and is adjacent to the third radiation electrode in a second direction that intersects, within the main surface, with a second line connecting the second connection point and the center of the first radiation electrode and is different from the first direction.

[0007] An antenna substrate according to one aspect of the present disclosure includes a dielectric substrate having a main surface, and planar first to third radiation electrodes and first and second feed lines located on the main surface of the dielectric substrate. A size difference between the first and second radiation electrodes and a size difference between the first and third radiation electrodes are larger than a size difference between the second and third radiation electrodes. The first feed line is connected to the second radiation electrode at a first connection point. The second feed line is connected to the third radiation electrode at a second connection point. The first radiation electrode is adjacent to the second radiation electrode in a first direction that intersects, within the main surface, one of a first line connecting the first connection point and the center of the second radiation electrode and a second line connecting the second connection point and the center of the third radiation electrode, and is adjacent to the third radiation electrode in a second direction that intersects, within the main surface, the other of the first line and the second line and is different from the first direction.

[0008] An antenna device according to one aspect of the present disclosure includes any one of the antenna substrates described above and a ground electrode on the dielectric substrate opposite to the main surface.

[0009] Aspects of the present disclosure can be applied to a dual-polarized antenna that supports multiple frequency bands, and can reduce the area required for arranging the radiation electrodes.

[0010] 11. A perspective view of an antenna substrate according to a first embodiment. 12. A plan view of an antenna substrate according to a first embodiment. 13. A plan view of an antenna substrate according to a second embodiment. 14. A plan view of an antenna substrate according to a third embodiment. 15. A plan view of an antenna substrate according to a fourth embodiment. 16. A plan view of an antenna substrate according to a fifth embodiment. 17. A plan view of an antenna substrate according to a sixth embodiment. 18. A plan view of an antenna substrate according to a seventh embodiment. 19. A plan view of an antenna substrate according to an eighth embodiment. 20. A plan view of an antenna substrate according to a ninth embodiment.

[0011] [1. Embodiments] Hereinafter, embodiments of the present disclosure will be described, with reference to the drawings where appropriate. However, the following embodiments are merely examples for explaining the present disclosure, and are not intended to limit the present disclosure to the following content (e.g., the shape, dimensions, and arrangement of each component). Positional relationships, such as up, down, left, and right, are based on the positional relationships shown in the drawings unless otherwise specified. Each figure described in the following embodiments is a schematic diagram, and the ratios of the size and thickness of each component in each figure do not necessarily reflect the actual dimensional ratios. Furthermore, the dimensional ratios of each element are not limited to the ratios shown in the drawings.

[0012] In the following description, when it is necessary to distinguish between multiple components, prefixes such as "first" and "second" are added to the names of the components. However, when the components can be distinguished from each other by the symbols attached to them, the prefixes such as "first" and "second" may be omitted in consideration of readability of the text.

[0013] In the following description, for the sake of simplicity, the XYZ Cartesian coordinate system shown in the drawings will be used.

[0014] [1.1 First Embodiment] [1.1.1 Configuration] Fig. 1 is a perspective view of an antenna substrate 1 according to the first embodiment. Fig. 2 is a plan view of the antenna substrate 1. The antenna substrate 1 includes a dielectric substrate 2, a first radiation electrode 31, a second radiation electrode 32, a third radiation electrode 33, a first feed line 41, a second feed line 42, a third feed line 43, a fourth feed line 44, a ground electrode 5, and a processing circuit 6.

[0015] The dielectric substrate 2 has a thickness. In this embodiment, the thickness direction of the dielectric substrate 2 corresponds to the Z direction. The dielectric substrate 2 has a length direction and a width direction that are perpendicular to the thickness direction. In this embodiment, the length direction of the dielectric substrate 2 corresponds to the X direction, and the width direction of the dielectric substrate 2 corresponds to the Y direction.

[0016] The dielectric substrate 2 includes a dielectric layer 20. The dielectric layer 20 has a main surface 2a and a back surface 2b opposite to the main surface 2a. The main surface 2a and the back surface 2b are opposite surfaces in the thickness direction of the dielectric substrate 2. The normal direction of the main surface 2a coincides with the thickness direction of the dielectric substrate 2. Therefore, the thickness direction of the dielectric substrate 2 is sometimes referred to as the normal direction of the dielectric substrate 2.

[0017] The dielectric substrate 2 has a rectangular plate shape and includes first and second ends 2c and 2d opposite to each other in the X direction and third and fourth ends 2e and 2f opposite to each other in the Y direction.

[0018] Examples of the dielectric substrate 2 include a low-temperature co-fired ceramic (LTCC) multilayer substrate, a multilayer resin substrate formed by stacking multiple resin layers made of resins such as epoxy and polyimide, a multilayer resin substrate formed by stacking multiple resin layers made of liquid crystal polymer (LCP) having a lower dielectric constant, a multilayer resin substrate formed by stacking multiple resin layers made of fluorine-based resin, and a ceramic multilayer substrate other than LTCC.

[0019] The first radiation electrode 31, the second radiation electrode 32, the third radiation electrode 33, the first feed line 41, the second feed line 42, the third feed line 43, the fourth feed line 44, and the processing circuit 6 are located on the main surface 2 a of the dielectric substrate 2. In this embodiment, the first radiation electrode 31, the second radiation electrode 32, the third radiation electrode 33, the first feed line 41, the second feed line 42, the third feed line 43, and the fourth feed line 44 are located on the first end 2 c side of the dielectric substrate 2, and the processing circuit 6 is located on the second end 2 d side of the dielectric substrate 2.

[0020] More specifically, the second and third radiation electrodes 32 and 33 are located on the opposite side of the first radiation electrode 31 from the processing circuit 6. The first and second feed lines 41 and 42 are connected to the first radiation electrode 31.

[0021] The first radiation electrode 31 is planar. The first radiation electrode 31 has first and second sides 31a, 31b facing each other and third and fourth sides 31c, 31d facing each other. When viewed in the thickness direction of the dielectric substrate 2, the first radiation electrode 31 is a quadrilateral formed by the first to fourth sides 31a to 31d. In this embodiment, the first to fourth sides 31a to 31d have the same length, and the first radiation electrode 31 is a square when viewed in the thickness direction of the dielectric substrate 2.

[0022] The first side 31 a and the third side 31 c face toward the second end 2 d, and the second side 31 b and the fourth side 31 d face toward the first end 2 c. The first side 31 a and the fourth side 31 d face toward the third end 2 e, and the second side 31 b and the third side 31 c face toward the fourth end 2 f. In this embodiment, a diagonal line between the vertex between the first side 31 a and the third side 31 c and the vertex between the second side 31 b and the fourth side 31 d runs along the X direction, and a diagonal line between the vertex between the first side 31 a and the fourth side 31 d and the vertex between the second side 31 b and the third side 31 c runs along the Y direction.

[0023] In the first radiation electrode 31, first and second connection points P1 and P2 with the first and second feed lines 41 and 42 are set on the first and third sides 31 a and 31 c, respectively. The first and second connection points P1 and P2 are imaginary points. The first and second connection points P1 and P2 are, for example, midpoints of the first and third sides 31 a and 31 c.

[0024] The first and second feeder lines 41 and 42 are connected to the first radiation electrode 31 at first and second connection points P1 and P2, respectively, which are different from each other.

[0025] The first feed line 41 connects the processing circuit 6 and the first radiation electrode 31. The first feed line 41 includes a first portion 41a and a second portion 41b. The first portion 41a extends in the X direction from the processing circuit 6 toward the first radiation electrode 31. The first portion 41a is not aligned with the first connection point P1 of the first radiation electrode 31 in the Y direction, and is located on the opposite side of the first connection point P1 from the second connection point P2. The second portion 41b extends from the end of the first portion 41a facing the first radiation electrode 31 to the first side 31a of the first radiation electrode 31 and is connected to the first connection point P1. The extension direction of the second portion 41b coincides with the direction of a first straight line L1 connecting the first connection point P1 and the center C1 of the first radiation electrode 31. The first straight line L1 is an imaginary line.

[0026] The second feed line 42 connects the processing circuit 6 and the first radiation electrode 31. The second feed line 42 includes a first portion 42a and a second portion 42b. The first portion 42a extends in the X direction from the processing circuit 6 toward the first radiation electrode 31. The first portion 42a is not aligned with the second connection point P2 of the first radiation electrode 31 in the Y direction, but is located on the opposite side of the second connection point P2 from the first connection point P1. The second portion 42b extends from the end of the first portion 42a facing the first radiation electrode 31 to the third side 31c of the first radiation electrode 31 and is connected to the second connection point P2. The extension direction of the second portion 42b coincides with the direction of a second straight line L2 connecting the second connection point P2 and the center C1 of the first radiation electrode 31. The second straight line L2 is an imaginary line. In this embodiment, the second straight line L2 is perpendicular to the first straight line L1 within the main surface 2a.

[0027] The second radiation electrode 32 is planar. The second radiation electrode 32 has first and second sides 32a, 32b facing each other and third and fourth sides 32c, 32d facing each other. When viewed in the thickness direction of the dielectric substrate 2, the second radiation electrode 32 is a quadrilateral formed by the first to fourth sides 32a to 32d. In this embodiment, the first to fourth sides 32a to 32d have the same length, and the second radiation electrode 32 is a square when viewed in the thickness direction of the dielectric substrate 2.

[0028] The first side 32a and the third side 32c face toward the second end 2d, and the second side 32b and the fourth side 32d face toward the first end 2c. The first side 32a and the fourth side 32d face toward the third end 2e, and the second side 32b and the third side 32c face toward the fourth end 2f. In this embodiment, a diagonal line between the vertex between the first side 32a and the third side 32c and the vertex between the second side 32b and the fourth side 32d runs along the X direction, and a diagonal line between the vertex between the first side 32a and the fourth side 32d and the vertex between the second side 32b and the third side 32c runs along the Y direction.

[0029] The second radiation electrode 32 is adjacent to the first radiation electrode 31 in a first direction D1 that intersects with the direction of the first straight line L1 within the main surface 2a. In this embodiment, the first direction D1 is orthogonal to the direction of the first straight line L1 within the main surface 2a. Therefore, the first direction D1 and the direction of the second straight line L2 coincide with each other. The center C2 of the second radiation electrode 32 is on an extension of the second straight line L2. The third side 32c of the second radiation electrode 32 faces the fourth side 31d of the first radiation electrode 31 at a predetermined distance. The fourth side 31d of the first radiation electrode 31 and the third side 32c of the second radiation electrode 32 are parallel to each other. The second radiation electrode 32 is coupled to the first radiation electrode 31 at the third side 32c.

[0030] The third feed line 43 connects the first radiation electrode 31 and the second radiation electrode 32. This directly connects the first radiation electrode 31 and the second radiation electrode 32, and signals propagate from the first radiation electrode 31 to the second radiation electrode 32. In this embodiment, the third feed line 43 extends along the first direction D1.

[0031] The third radiation electrode 33 is planar. The third radiation electrode 33 has first and second sides 33a, 33b facing each other and third and fourth sides 33c, 33d facing each other. When viewed from the thickness direction of the dielectric substrate 2, the third radiation electrode 33 is a quadrilateral formed by the first to fourth sides 33a to 33d. In this embodiment, the first to fourth sides 33a to 33d have the same length, and the third radiation electrode 33 is a square when viewed from the thickness direction of the dielectric substrate 2.

[0032] The first side 33a and the third side 33c face toward the second end 2d, and the second side 33b and the fourth side 33d face toward the first end 2c. The first side 33a and the fourth side 33d face toward the third end 2e, and the second side 33b and the third side 33c face toward the fourth end 2f. In this embodiment, a diagonal line between the vertex between the first side 33a and the third side 33c and the vertex between the second side 33b and the fourth side 33d runs along the X direction, and a diagonal line between the vertex between the first side 33a and the fourth side 33d and the vertex between the second side 33b and the third side 33c runs along the Y direction.

[0033] The third radiation electrode 33 is adjacent to the first radiation electrode 31 in a second direction D2 that intersects with the direction of the second straight line L2 within the main surface 2a. In this embodiment, the second direction D2 is perpendicular to the direction of the second straight line L2 within the main surface 2a. Therefore, the second direction D2 and the direction of the first straight line L1 coincide with each other. The center C3 of the third radiation electrode 33 is on an extension of the first straight line L1. The third side 33a of the third radiation electrode 33 faces the second side 31b of the first radiation electrode 31 at a predetermined distance. The second side 31b of the first radiation electrode 31 and the first side 33a of the third radiation electrode 33 are parallel to each other. The third radiation electrode 33 is coupled to the first radiation electrode 31 at the first side 33a.

[0034] The fourth feed line 44 connects the first radiation electrode 31 and the third radiation electrode 33. This directly connects the first radiation electrode 31 and the third radiation electrode 33, and signals propagate from the first radiation electrode 31 to the third radiation electrode 33. In this embodiment, the fourth feed line 44 extends along the second direction D2.

[0035] As described above, the first to third radiation electrodes 31 to 33 are arranged so that the first radiation electrode 31 is adjacent to the second radiation electrode 32 in the first direction D1 that intersects with the direction of the first straight line L1 within the main surface 2a, and is adjacent to the third radiation electrode 33 in the second direction D2 that intersects with the direction of the second straight line L2 within the main surface 2a and is different from the first direction D1.

[0036] In the antenna substrate 1, the first radiation electrode 31, the second radiation electrode 32, and the third radiation electrode 33 constitute a dual-polarized antenna compatible with multiple frequency bands. In this embodiment, the first radiation electrode 31 has a shape symmetrical with respect to the center line of the first radiation electrode 31 along the X direction, and the second radiation electrode 32 and the third radiation electrode 33 are arranged symmetrical with respect to the center line of the first radiation electrode 31 along the X direction. Therefore, in the antenna substrate 1, it is possible to improve the symmetry of the arrangement of the planar first to third radiation electrodes 31 to 33.

[0037] The sizes of the first to third radiation electrodes 31 to 33 are determined according to the frequency band used for wireless communication. The antenna substrate 1 uses a first frequency band and a second frequency band as the frequency bands used for wireless communication. In this embodiment, the first frequency band is lower than the second frequency band. The first radiation electrode 31 corresponds to the first frequency band, and the second and third radiation electrodes 32 and 33 correspond to a second frequency band different from the first frequency band. As an example, the first frequency band is the 28 GHz band (24.25 to 29.5 GHz), and the second frequency band is the 39 GHz band (37.0 to 43.5 GHz).

[0038] In order to accommodate multiple frequency bands, the size difference between the first and second radiation electrodes 31 and 32 and the size difference between the first and third radiation electrodes 31 and 33 on the antenna substrate 1 are larger than the size difference between the second and third radiation electrodes 32 and 33.

[0039] In this embodiment, because the first frequency band is lower than the second frequency band, the size of the first radiation electrode 31 is larger than the sizes of the second radiation electrode 32 and the third radiation electrode 33. That is, the first radiation electrode 31 is configured to be suitable for radiating radio waves having a lower frequency band than the second and third radiation electrodes 32 and 33. The size difference between the first and second radiation electrodes 31 and 32 and the size difference between the first and third radiation electrodes 31 and 33 are determined so that the first radiation electrode 31 corresponds to the first frequency band but not to the second frequency band. The allowable size difference depends on the difference between the first frequency band and the second frequency band.

[0040] The size difference between the second and third radiation electrodes 32, 33 is set so that the second and third radiation electrodes 32, 33 correspond to the same second frequency band. In other words, the size difference between the second and third radiation electrodes 32, 33 is sufficient as long as the frequency corresponding to the size of the second radiation electrode 32 and the frequency corresponding to the size of the third radiation electrode 33 are included in the second frequency band. For example, even if the frequency corresponding to the size of the second radiation electrode 32 is set to 37.0 GHz and the frequency corresponding to the size of the third radiation electrode 33 is set to 43.5 GHz, both of these frequencies are included in the second frequency band (37.0 to 43.5 GHz). Therefore, it can be said that the size difference between the second and third radiation electrodes 32, 33 is set so that the second and third radiation electrodes 32, 33 correspond to the same second frequency band. Of course, the size difference between the second and third radiation electrodes 32, 33 may be zero, that is, the size of the second radiation electrode 32 and the size of the third radiation electrode 33 may be equal.

[0041] 2, the size of the first radiation electrode 31 is larger than the size of the second radiation electrode 32 and the size of the third radiation electrode 33, and the size of the second radiation electrode 32 is equal to the size of the third radiation electrode 33. This configuration enables improvement of the antenna characteristics.

[0042] In this embodiment, the first radiation electrode 31 includes first and second sides 31 a, 31 b facing each other in the direction of the first straight line L1 and third and fourth sides 31 c, 31 d facing each other in the direction of the second straight line L2. The second radiation electrode 32 includes first and second sides 32 a, 32 b facing each other in the direction of the first straight line L1 and third and fourth sides 32 c, 32 d facing each other in the direction of the second straight line L2. The third radiation electrode 33 includes first and second sides 33 a, 33 b facing each other in the direction of the first straight line L1 and third and fourth sides 33 c, 33 d facing each other in the direction of the second straight line L2.

[0043] The size of the first radiation electrode 31 may be defined by one or more arbitrary values ​​based on the distance between two intersections between a line passing through the center of the first radiation electrode 31 and the periphery of the first radiation electrode 31. For example, if the first radiation electrode 31 is square, the size of the first radiation electrode 31 may be defined by the distance between two opposing sides. For example, if the first radiation electrode 31 is rectangular, the size of the first radiation electrode 31 may be defined by the length of the diagonal, or by the distance between the short sides and the distance between the long sides. For example, if the first radiation electrode 31 is circular, the size of the first radiation electrode 31 may be defined by the diameter. For example, if the first radiation electrode 31 is elliptical, the size of the first radiation electrode 31 may be defined by the major axis and the minor axis. This also applies to the second radiation electrode 32 and the third radiation electrode 33. Note that the one or more arbitrary values ​​based on the distance between the two intersections may be a representative value, such as the average value, mode, maximum value, minimum value, median, or mode, of the distance between the two intersections.

[0044] In this embodiment, the size of the first radiation electrode 31 is defined by the distance between the first and second sides 31 a and 31 b or the distance between the third and fourth sides 31 c and 31 d. The size of the second radiation electrode 32 is defined by the distance between the first and second sides 32 a and 32 b or the distance between the third and fourth sides 32 c and 32 d. The size of the third radiation electrode 33 is defined by the distance between the first and second sides 33 a and 33 b or the distance between the third and fourth sides 33 c and 33 d.

[0045] In this embodiment, the first to third radiation electrodes 31 to 33 are square and similar when viewed in the thickness direction of the dielectric substrate 2. When the first to third radiation electrodes 31 to 33 are similar in shape, the size difference between the first to third radiation electrodes 31 to 33 can also be determined by the similarity ratio.

[0046] The ground electrode 5 is located on the opposite side to the main surface 2a of the dielectric substrate 2. The ground electrode 5 is located on the back surface 2b of the dielectric substrate 2. The ground electrode 5, together with the first to third radiation electrodes 31 to 33, respectively constitute patch antennas.

[0047] The processing circuit 6 is mounted on the main surface 2a of the dielectric substrate 2 and is connected to the first feed line 41 and the second feed line 42. The processing circuit 6 includes, for example, an IC. An example of the processing circuit 6 is a SiP (System in Package). The processing circuit 6 executes processing for wireless communication via the first to third radiation electrodes 31 to 33.

[0048] In this embodiment, the processing circuit 6 uses the first to third radiation electrodes 31 to 33 as a dual-polarized antenna compatible with multiple frequency bands. The processing circuit 6 outputs a first signal S1 to the first feed line 41 and outputs a second signal S2 to the second feed line 42. The first signal S1 and the second signal S2 are signals of the same frequency band. However, the first signal S1 and the second signal S2 have different polarizations. For example, the first signal S1 is a horizontally polarized (H-polarized) signal, and the second signal S2 is a vertically polarized (V-polarized) signal. The frequency bands of the first signal S1 and the second signal S2 are selected from a first frequency band corresponding to the first radiation electrode 31 and a second frequency band corresponding to the second and third radiation electrodes 32 and 33.

[0049] Next, a brief description will be given of the operation of the antenna substrate 1. The processing circuit 6 outputs a horizontally polarized (H-polarized) first signal S1 to the first feed line 41, and outputs a vertically polarized (V-polarized) second signal S2 to the second feed line 42.

[0050] Assume that the first signal S1 and the second signal S2 are signals in a first frequency band. In this case, the first signal S1 passes through the first feed line 41 to reach the first radiation electrode 31 and is radiated by the first radiation electrode 31 as a horizontally polarized radio wave. The second signal S2 passes through the second feed line 42 to reach the first radiation electrode 31 and is radiated by the first radiation electrode 31 as a vertically polarized radio wave. In this way, the first radiation electrode 31 functions alone as a dual-polarized antenna.

[0051] Assume that the first signal S1 and the second signal S2 are signals in the second frequency band. In this case, the first signal S1 passes through the first feed line 41 to reach the first radiation electrode 31, further passes through the first radiation electrode 31, and passes through the fourth feed line 44 to reach the third radiation electrode 33, where it is radiated as a horizontally polarized radio wave by the third radiation electrode 33. The second signal S2 passes through the second feed line 42 to reach the first radiation electrode 31, further passes through the first radiation electrode 31, and passes through the third feed line 43 to reach the second radiation electrode 32, where it is radiated as a vertically polarized radio wave by the second radiation electrode 32. In this way, the pair of the second and third radiation electrodes 32 and 33 functions as a dual-polarized antenna.

[0052] In the antenna substrate 1, the first radiation electrode 31 can function alone as a dual polarized antenna corresponding to the first frequency band. Therefore, as a dual polarized antenna corresponding to the first frequency band, it is sufficient to arrange only a single radiation electrode instead of multiple radiation electrodes, thereby reducing the area required for arranging the radiation electrodes.

[0053] [1.1.2 Effects, etc.] The antenna substrate 1 described above includes a dielectric substrate 2 having a main surface 2a, and planar first to third radiation electrodes 31 to 33 and first and second feed lines 41, 42 on the main surface 2a of the dielectric substrate 2. The size difference between the first and second radiation electrodes 31, 32 and the size difference between the first and third radiation electrodes 31, 33 are larger than the size difference between the second and third radiation electrodes 32, 33. The first and second feed lines 41, 42 are connected to the first radiation electrode 31 at first and second connection points P1, P2, which are different from each other, respectively. The first radiation electrode 31 is adjacent to the second radiation electrode 32 in a first direction that intersects, within the main surface 2a, with the direction of a first straight line L1 that connects the first connection point P1 and the center C1 of the first radiation electrode 31, and is adjacent to the third radiation electrode 33 in a second direction that intersects, within the main surface 2a, with the direction of a second straight line L2 that connects the second connection point P2 and the center C1 of the first radiation electrode 31. This configuration is applicable to dual-polarized antennas that support multiple frequency bands and can reduce the area required for arranging the radiation electrodes. Furthermore, this configuration enables improved symmetry in the arrangement of the planar first to third radiation electrodes 31 to 33.

[0054] In the antenna substrate 1, the first feed line 41 and the second feed line 42 transmit signals S1 and S2 in the same frequency band. This configuration is applicable to a dual polarized antenna that supports multiple frequency bands, and can reduce the area required for arranging the radiation electrodes.

[0055] The antenna substrate 1 further includes a third feed line 43 connecting the first radiation electrode 31 and the second radiation electrode 32, and a fourth feed line 44 connecting the first radiation electrode 31 and the third radiation electrode 33. This configuration can widen the frequency bands of the second radiation electrode 32 and the third radiation electrode 33 compared to when there is electromagnetic field coupling between the first radiation electrode 31 and the second radiation electrode 32 and between the first radiation electrode 31 and the third radiation electrode 33. This configuration improves the amount of power supplied to the second radiation electrode 32 and the third radiation electrode 33 compared to when there is electromagnetic field coupling between the first radiation electrode 31 and the second radiation electrode 32 and between the first radiation electrode 31 and the third radiation electrode 33, thereby enabling an improvement in antenna gain.

[0056] In the antenna substrate 1, the size of the first radiation electrode 31 is larger than the size of the second radiation electrode 32 and the size of the third radiation electrode 33. This configuration makes the first radiation electrode 31 suitable for radiating radio waves in a lower frequency band than the second and third radiation electrodes 32 and 33.

[0057] In the antenna substrate 1, each of the first to third radiation electrodes 31 to 33 includes first and second sides 31a to 33a and 31b to 33b that face each other in the direction of a first straight line L1, and third and fourth sides 31c to 33c and 31d to 33d that face each other in the direction of a second straight line L2. The size of each of the first to third radiation electrodes 31 to 33 is defined by the distance between the first and second sides 31a to 33a and 31b to 33b and the distance between the third and fourth sides 31c to 33c and 31d to 33d. This configuration is applicable to dual-polarized antennas that support multiple frequency bands, and can reduce the area required for arranging the radiation electrodes.

[0058] In the antenna substrate 1, the first to third radiation electrodes 31 to 33 are similar when viewed in the thickness direction of the dielectric substrate 2. The size difference between the first to third radiation electrodes 31 to 33 is determined by the similarity ratio. This configuration can be applied to a dual-polarized antenna that supports multiple frequency bands, and can reduce the area required for arranging the radiation electrodes.

[0059] In the antenna substrate 1, the size of the second radiation electrode 32 is equal to the size of the third radiation electrode 33. This configuration makes it possible to improve the antenna characteristics.

[0060] The first straight line L1 and the second straight line L2 are perpendicular to each other on the antenna substrate 1. This configuration makes it possible to improve the antenna characteristics.

[0061] The antenna substrate 1 further includes a ground electrode 5 located on the opposite side of the main surface 2a of the dielectric substrate 2. This configuration is applicable to a dual-polarized antenna compatible with multiple frequency bands, and can reduce the area required for arranging the radiation electrodes.

[0062] 3 is a plan view of an antenna substrate 1A according to embodiment 2. The antenna substrate 1A includes a dielectric substrate 2, a first radiation electrode 31A, a second radiation electrode 32A, a third radiation electrode 33A, a first feed line 41, a second feed line 42, a third feed line 43, a fourth feed line 44, a ground electrode 5, and a processing circuit 6.

[0063] The first to third radiation electrodes 31A to 33A are arranged, similarly to the first to third radiation electrodes 31 to 33, such that the first radiation electrode 31A is adjacent to the second radiation electrode 32A in a first direction D1 that intersects with the direction of the first straight line L1 within the main surface 2a, and is adjacent to the third radiation electrode 33A in a second direction D2 that intersects with the direction of the second straight line L2 within the main surface 2a and is different from the first direction D1.

[0064] The first to third radiation electrodes 31A to 33A have the same shape as the first to third radiation electrodes 31 to 33, and the size difference between the first and second radiation electrodes 31A, 32A and the size difference between the first and third radiation electrodes 31A, 33A are larger than the size difference between the second and third radiation electrodes 32A, 33A.

[0065] The first radiation electrode 31A corresponds to a first frequency band, and the second and third radiation electrodes 32A and 33A correspond to a second frequency band different from the first frequency band. In this embodiment, the first frequency band is higher than the second frequency band. As an example, the first frequency band is the 39 GHz band (37.0 to 43.5 GHz), and the second frequency band is the 28 GHz band (24.25 to 29.5 GHz).

[0066] Therefore, the size of the first radiation electrode 31A is smaller than the sizes of the second radiation electrode 32A and the third radiation electrode 33A. In other words, the first radiation electrode 31A is configured to be more suitable for radiating radio waves in a higher frequency band than the second and third radiation electrodes 32A and 33A. In Fig. 3, the size of the first radiation electrode 31A is smaller than the sizes of the second radiation electrode 32A and the third radiation electrode 33A, and the sizes of the second radiation electrode 32A and the third radiation electrode 33A are equal. This configuration enables improvement of the antenna characteristics.

[0067] [1.2.2 Effects, etc.] The antenna substrate 1A described above includes a dielectric substrate 2 having a main surface 2a, and planar first to third radiation electrodes 31A to 33A and first and second feed lines 41, 42 on the main surface 2a of the dielectric substrate 2. The size difference between the first and second radiation electrodes 31A, 32A and the size difference between the first and third radiation electrodes 31A, 33A are larger than the size difference between the second and third radiation electrodes 32A, 33A. The first and second feed lines 41, 42 are connected to the first radiation electrode 31A at first and second connection points P1, P2, which are different from each other. The first radiation electrode 31A is adjacent to the second radiation electrode 32A in a first direction that intersects, within the main surface 2a, with the direction of a first straight line L1 that connects the first connection point P1 and the center C1 of the first radiation electrode 31, and is adjacent to the third radiation electrode 33A in a second direction that intersects, within the main surface 2a, with the direction of a second straight line L2 that connects the second connection point P2 and the center C1 of the first radiation electrode 31A. This configuration is applicable to a dual-polarized antenna that supports multiple frequency bands, and can reduce the area required for arranging the radiation electrodes.

[0068] In the antenna substrate 1A, the size of the first radiation electrode 31A is smaller than the size of the second radiation electrode 32A and the size of the third radiation electrode 33A. This configuration makes the first radiation electrode 31A suitable for emitting radio waves in a higher frequency band than the second and third radiation electrodes 32A and 33A.

[0069] 4 is a plan view of an antenna substrate 1B according to embodiment 3. The antenna substrate 1B includes a dielectric substrate 2, a first radiation electrode 31B, a second radiation electrode 32B, a third radiation electrode 33B, a first feed line 41B, a second feed line 42B, a third feed line 43B, a fourth feed line 44B, a ground electrode 5, and a processing circuit 6.

[0070] In this embodiment, the first radiation electrode 31B is located on the opposite side of the second and third radiation electrodes 32B and 33B from the processing circuit 6. The first and second feed lines 41B and 42B are connected to the second and third radiation electrodes 32B and 33B, respectively, rather than to the first radiation electrode 31B.

[0071] The second radiation electrode 32B has a first side 32a and a third side 32c facing the processing circuit 6, and a first connection point P3 with the first feed line 41B is set on the third side 32c. The first connection point P3 is an imaginary point. The first connection point P3 is, for example, the midpoint of the third side 32c.

[0072] In the third radiation electrode 33B, the first side 33a and the third side 33c face the processing circuit 6, and a second connection point P4 with the second feed line 42B is set on the first side 33a. The second connection point P4 is a virtual point. The second connection point P4 is, for example, the midpoint of the first side 33a.

[0073] The first feed line 41B is connected to the second radiation electrode 32B at a first connection point P3. The first feed line 41B connects the processing circuit 6 and the second radiation electrode 32B. The first feed line 41B includes a first portion 41a and a second portion 41b. The first portion 41a extends in the X direction from the processing circuit 6 toward the second radiation electrode 32B. The first portion 41a is not aligned with the first connection point P3 of the second radiation electrode 32B in the Y direction, but is located on the second connection point P4 side of the first connection point P3. The second portion 41b extends from the end of the first portion 41a on the second radiation electrode 32B side to the third side 32c of the second radiation electrode 32B and is connected to the first connection point P3. The direction in which the second portion 41b extends coincides with the direction of a first straight line L3 that connects the first connection point P3 and the center C2 of the second radiation electrode 32B. The first straight line L3 is an imaginary line.

[0074] The second feed line 42B is connected to the third radiation electrode 33B at a second connection point P4. The second feed line 42B connects the processing circuit 6 and the third radiation electrode 33B. The second feed line 42B includes a first portion 42a and a second portion 42b. The first portion 42a extends in the X direction from the processing circuit 6 toward the third radiation electrode 33B. The first portion 42a is not aligned with the second connection point P4 of the third radiation electrode 33B in the Y direction, but is located on the first connection point P3 side of the second connection point P4. The second portion 42b extends from the end of the first portion 42a on the third radiation electrode 33B side to the first side 33a of the third radiation electrode 33B and is connected to the second connection point P4. The direction in which the second portion 42b extends coincides with the direction of a second line L4 that connects the second connection point P4 and the center C3 of the third radiation electrode 33B. The second line L4 is a virtual line. In this embodiment, the second line L4 is perpendicular to the first line L3 within the main surface 2a.

[0075] The first radiation electrode 31B is adjacent to the second radiation electrode 32B in a first direction D1 that intersects with the direction of the first straight line L3 within the main surface 2a. In this embodiment, the first direction D1 is orthogonal to the direction of the first straight line L3 within the main surface 2a. Therefore, the first direction D1 and the direction of the second straight line L2 coincide with each other. The first radiation electrode 31B is adjacent to the third radiation electrode 33B in a second direction D2 that intersects with the direction of the second straight line L4 within the main surface 2a. In this embodiment, the second direction D2 is orthogonal to the direction of the second straight line L4 within the main surface 2a. Therefore, the second direction D2 and the direction of the first straight line L3 coincide with each other.

[0076] The first side 31 a of the first radiation electrode 31B faces the second side 32 b of the second radiation electrode 32B at a predetermined distance. The first side 31 a of the first radiation electrode 31B and the second side 32 b of the second radiation electrode 32B are parallel to each other. The third side 31 c of the first radiation electrode 31B faces the fourth side 33 d of the third radiation electrode 33B at a predetermined distance. The third side 31 c of the first radiation electrode 31B and the fourth side 33 d of the third radiation electrode 33B are parallel to each other.

[0077] The third feed line 43B connects the first radiation electrode 31B and the second radiation electrode 32B. This directly connects the first radiation electrode 31B and the second radiation electrode 32B, and signals propagate from the first radiation electrode 31B to the second radiation electrode 32B. In this embodiment, the third feed line 43B extends along the first direction D1.

[0078] The fourth feed line 44B connects the first radiation electrode 31B and the third radiation electrode 33B. This directly connects the first radiation electrode 31B and the third radiation electrode 33B, and signals propagate from the first radiation electrode 31B to the third radiation electrode 33B. In this embodiment, the fourth feed line 44B extends along the second direction D2.

[0079] As described above, the first to third radiation electrodes 31B to 33B are arranged so that the first radiation electrode 31B is adjacent to the second radiation electrode 32B in the first direction D1 that intersects with the direction of the first straight line L3 within the main surface 2a, and is adjacent to the third radiation electrode 33B in the second direction D2 that intersects with the direction of the second straight line L4 within the main surface 2a and is different from the first direction D1.

[0080] In the antenna substrate 1B, the first radiation electrode 31B, the second radiation electrode 32B, and the third radiation electrode 33B constitute a dual polarized antenna that supports multiple frequency bands. In this embodiment, as in the second embodiment, the first frequency band is higher than the second frequency band, the size of the first radiation electrode 31B is smaller than the sizes of the second radiation electrode 32B and the third radiation electrode 33B, and the size of the second radiation electrode 32B is equal to the size B of the third radiation electrode 33B.

[0081] Next, a brief description will be given of the operation of the antenna substrate 1B. The processing circuit 6 outputs a horizontally polarized (H-polarized) first signal S1 to the first feed line 41B, and outputs a vertically polarized (V-polarized) second signal S2 to the second feed line 42B.

[0082] Assume that the first signal S1 and the second signal S2 are signals in a first frequency band. In this case, the first signal S1 passes through the first feed line 41B to reach the second radiation electrode 32B, further passes through the second radiation electrode 32B, and passes through the third feed line 43B to reach the first radiation electrode 31B, where it is radiated as a horizontally polarized radio wave by the first radiation electrode 31B. The second signal S2 passes through the second feed line 42B to reach the third radiation electrode 33B, further passes through the third radiation electrode 33B, and passes through the fourth feed line 44B to reach the first radiation electrode 31B, where it is radiated as a vertically polarized radio wave by the first radiation electrode 31B. In this way, the first radiation electrode 31B functions alone as a dual-polarized antenna.

[0083] Assume that the first signal S1 and the second signal S2 are signals in the second frequency band. In this case, the first signal S1 passes through the first feed line 41B to reach the second radiation electrode 32B and is radiated by the second radiation electrode 32B as a horizontally polarized radio wave. The second signal S2 passes through the second feed line 42B to reach the third radiation electrode 33B and is radiated by the third radiation electrode 33B as a vertically polarized radio wave. In this way, the pair of the second and third radiation electrodes 32B, 33B functions as a dual-polarized antenna.

[0084] In the antenna substrate 1B, the first radiation electrode 31B can function alone as a dual polarized antenna corresponding to the first frequency band, so that a single radiation electrode can be disposed instead of multiple radiation electrodes as a dual polarized antenna corresponding to the first frequency band, thereby reducing the area required for arranging the radiation electrodes.

[0085] [1.3.2 Effects, etc.] The antenna substrate 1B described above includes a dielectric substrate 2 having a main surface 2a, and planar first to third radiation electrodes 31B to 33B and first and second feed lines 41B, 42B on the main surface 2a of the dielectric substrate 2. The size difference between the first and second radiation electrodes 31B, 32B and the size difference between the first and third radiation electrodes 31B, 33B are greater than the size difference between the second and third radiation electrodes 32B, 33B. The first feed line 41B is connected to the second radiation electrode 32B at a first connection point P3. The second feed line 42B is connected to the third radiation electrode 33B at a second connection point P4. The first radiation electrode 31B is adjacent to the second radiation electrode 32B in a first direction D1 that intersects, within the main surface 2a, a first line L3 that connects the first connection point P3 and the center C2 of the second radiation electrode 32B, and is adjacent to the third radiation electrode 33B in a second direction D2 that is different from the first direction D1 and intersects, within the main surface 2a, a second line L4 that connects the second connection point P4 and the center C3 of the third radiation electrode 33B. This configuration is applicable to dual-polarized antennas that support multiple frequency bands and can reduce the area required for arranging the radiation electrodes. Furthermore, this configuration enables improved symmetry in the arrangement of the planar first to third radiation electrodes 31 to 33.

[0086] In the antenna substrate 1B, the size of the first radiation electrode 31B is smaller than the size of the second radiation electrode 32B and the size of the third radiation electrode 33B. This configuration makes the first radiation electrode 31B suitable for emitting radio waves in a higher frequency band than the second and third radiation electrodes 32B and 33B.

[0087] 5 is a plan view of an antenna substrate 1C according to embodiment 4. The antenna substrate 1C includes a dielectric substrate 2, a first radiation electrode 31C, a second radiation electrode 32C, a third radiation electrode 33C, a first feed line 41B, a second feed line 42B, a third feed line 43, a fourth feed line 44, a ground electrode 5, and a processing circuit 6.

[0088] The first to third radiation electrodes 31C to 33C are arranged, similarly to the first to third radiation electrodes 31B to 33B, such that the first radiation electrode 31C is adjacent to the second radiation electrode 32C in a first direction D1 that intersects with the direction of the first straight line L3 within the main surface 2a, and is adjacent to the third radiation electrode 33C in a second direction D2 that intersects with the direction of the second straight line L4 within the main surface 2a and is different from the first direction D1.

[0089] The first to third radiation electrodes 31C to 33C have the same shape as the first to third radiation electrodes 31B to 33B, and the size difference between the first and second radiation electrodes 31C, 32C and the size difference between the first and third radiation electrodes 31C, 33C is larger than the size difference between the second and third radiation electrodes 32C, 33C.

[0090] The first radiation electrode 31C corresponds to a first frequency band, and the second and third radiation electrodes 32C and 33C correspond to a second frequency band different from the first frequency band. In this embodiment, the first frequency band is lower than the second frequency band. As an example, the first frequency band is the 28 GHz band (24.25 to 29.5 GHz), and the second frequency band is the 39 GHz band (37.0 to 43.5 GHz).

[0091] Therefore, the size of the first radiation electrode 31C is larger than the sizes of the second radiation electrode 32C and the third radiation electrode 33C. In other words, the first radiation electrode 31C is configured to be suitable for radiating radio waves in a lower frequency band than the second and third radiation electrodes 32C and 33C. In Fig. 5, the size of the first radiation electrode 31C is larger than the sizes of the second radiation electrode 32C and the third radiation electrode 33C, and the sizes of the second radiation electrode 32C and the third radiation electrode 33C are equal. This configuration enables improvement of the antenna characteristics.

[0092] [1.4.2 Effects, etc.] The antenna substrate 1C described above comprises a dielectric substrate 2 having a main surface 2a, and planar first to third radiation electrodes 31C to 33C and first and second feed lines 41B, 42B on the main surface 2a of the dielectric substrate 2. The size difference between the first and second radiation electrodes 31C, 32C and the size difference between the first and third radiation electrodes 31C, 33C are greater than the size difference between the second and third radiation electrodes 32C, 33C. The first feed line 41B is connected to the second radiation electrode 32C at a first connection point P3. The second feed line 42B is connected to the third radiation electrode 33C at a second connection point P4. The first radiation electrode 31C is adjacent to the second radiation electrode 32C in a first direction D1 that intersects, within the main surface 2a, a first line L3 that connects the first connection point P3 and the center C2 of the second radiation electrode 32C, and intersects, within the main surface 2a, a second line L4 that connects the second connection point P4 and the center C3 of the third radiation electrode 33C, and is adjacent to the third radiation electrode 33C in a second direction D2 that is different from the first direction D1. This configuration is applicable to a dual-polarized antenna that supports multiple frequency bands, and can reduce the area required for arranging the radiation electrodes.

[0093] In the antenna substrate 1C, the size of the first radiation electrode 31C is larger than the size of the second radiation electrode 32C and the size of the third radiation electrode 33C. This configuration makes the first radiation electrode 31C suitable for emitting radio waves in a lower frequency band than the second and third radiation electrodes 32C and 33C.

[0094] 6 is a plan view of an antenna substrate 1D according to embodiment 5. Like the antenna substrate 1, the antenna substrate 1D includes a dielectric substrate 2, a first radiation electrode 31, a second radiation electrode 32, a third radiation electrode 33, a first feed line 41, a second feed line 42, a ground electrode 5, and a processing circuit 6.

[0095] Unlike the antenna substrate 1, the antenna substrate 1D does not include the third feed line 43 and the fourth feed line 44. Therefore, in the antenna substrate 1D, the first radiation electrode 31 is not directly connected to either the second radiation electrode 32 or the third radiation electrode 33.

[0096] The distance between the first radiation electrode 31 and the second radiation electrode 32 is smaller than both the sizes of the first and second radiation electrodes 31 and 32 in the first direction D1. The distance between the first radiation electrode 31 and the second radiation electrode 32 is the distance between the fourth side 31d of the first radiation electrode 31 and the third side 32c of the second radiation electrode 32. The size of the first radiation electrode 31 in the first direction D1 is the distance between the third and fourth sides 31c and 31d, and the size of the second radiation electrode 32 in the first direction D1 is the distance between the third and fourth sides 31c and 31d. This configuration enables electromagnetic field coupling, i.e., capacitive coupling, between the first radiation electrode 31 and the second radiation electrode 32. Therefore, when a current flows along the fourth side 31d of the first radiation electrode 31, a current can flow in the same direction along the third side 32c of the second radiation electrode 32.

[0097] The distance between the first radiation electrode 31 and the third radiation electrode 33 is smaller than both the sizes of the first and third radiation electrodes 31 and 33 in the second direction D2. The distance between the first radiation electrode 31 and the third radiation electrode 33 is the distance between the second side 31b of the first radiation electrode 31 and the first side 33a of the third radiation electrode 33. The size of the first radiation electrode 31 in the second direction D2 is the distance between the first and second sides 31a and 31b, and the size of the third radiation electrode 33 in the second direction D2 is the distance between the first and second sides 33a and 33b. This configuration enables electromagnetic field coupling, i.e., capacitive coupling, between the first radiation electrode 31 and the third radiation electrode 33. Therefore, when a current flows along the second side 31b of the first radiation electrode 31, a current can flow in the same direction along the first side 33a of the third radiation electrode 33.

[0098] The size of the first radiation electrode 31 is larger than the sizes of the second radiation electrode 32 and the third radiation electrode 33. In other words, the first radiation electrode 31 is configured to be suitable for radiating radio waves in a higher frequency band than the second and third radiation electrodes 32 and 33. In Fig. 6, the size of the first radiation electrode 31 is larger than the sizes of the second radiation electrode 32 and the third radiation electrode 33, and the sizes of the second radiation electrode 32 and the third radiation electrode 33 are equal. This configuration enables improvement of the antenna characteristics.

[0099] Since the size of the first radiation electrode 31 is larger than the size of the second radiation electrode 32, the fourth side 31d of the first radiation electrode 31 facing the second radiation electrode 32 is longer than the third side 32c of the second radiation electrode 32 facing the first radiation electrode 31. This makes it possible to increase the amount of power fed from the first radiation electrode 31 to the second radiation electrode 32, and the antenna efficiency of the second radiation electrode 32 can be improved.

[0100] Since the size of the first radiation electrode 31 is larger than the size of the third radiation electrode 33, the second side 31b of the first radiation electrode 31 facing the third radiation electrode 33 is longer than the first side 33a of the third radiation electrode 33 facing the first radiation electrode 31. This makes it possible to increase the amount of power fed from the first radiation electrode 31 to the third radiation electrode 33, and the antenna efficiency of the third radiation electrode 33 can be improved.

[0101] Next, a brief description will be given of the operation of the antenna board 1D. The processing circuit 6 outputs a horizontally polarized (H-polarized) first signal S1 to the first feed line 41, and outputs a vertically polarized (V-polarized) second signal S2 to the second feed line 42.

[0102] Assume that the first signal S1 and the second signal S2 are signals in a first frequency band. In this case, the first signal S1 passes through the first feed line 41 to reach the first radiation electrode 31 and is radiated by the first radiation electrode 31 as a horizontally polarized radio wave. The second signal S2 passes through the second feed line 42 to reach the first radiation electrode 31 and is radiated by the first radiation electrode 31 as a vertically polarized radio wave. In this way, the first radiation electrode 31 functions alone as a dual-polarized antenna.

[0103] Assume that the first signal S1 and the second signal S2 are signals in the second frequency band. In this case, the first signal S1 reaches the first radiation electrode 31 through the first feed line 41. The first signal S1 propagating along the fourth side 31 d of the first radiation electrode 31 reaches the second radiation electrode 32 due to electromagnetic field coupling between the first radiation electrode 31 and the second radiation electrode 32, and is radiated by the second radiation electrode 32 as a horizontally polarized radio wave. The second signal S2 reaches the first radiation electrode 31 through the second feed line 42. The second signal S2 propagating along the second side 31 b of the first radiation electrode 31 reaches the third radiation electrode 33 due to electromagnetic field coupling between the first radiation electrode 31 and the third radiation electrode 33, and is radiated by the third radiation electrode 33 as a vertically polarized radio wave. In this way, the pair of the second and third radiation electrodes 32 and 33 functions as a dual-polarized antenna.

[0104] In the antenna substrate 1D, the first radiation electrode 31 can function alone as a dual polarized antenna corresponding to the first frequency band. Therefore, as a dual polarized antenna corresponding to the first frequency band, it is sufficient to arrange only a single radiation electrode instead of multiple radiation electrodes, thereby reducing the area required for arranging the radiation electrodes.

[0105] [1.5.2 Effects, etc.] The antenna substrate 1D described above includes a dielectric substrate 2 having a main surface 2a, and planar first to third radiation electrodes 31 to 33 and first and second feed lines 41, 42 on the main surface 2a of the dielectric substrate 2. The size difference between the first and second radiation electrodes 31, 32 and the size difference between the first and third radiation electrodes 31, 33 are larger than the size difference between the second and third radiation electrodes 32, 33. The first and second feed lines 41, 42 are connected to the first radiation electrode 31 at first and second connection points P1, P2, which are different from each other, respectively. The first radiation electrode 31 is adjacent to the second radiation electrode 32 in a first direction that intersects, within the main surface 2 a, the direction of a first straight line L1 that connects the first connection point P1 and the center C1 of the first radiation electrode 31, and is adjacent to the third radiation electrode 33 in a second direction that intersects, within the main surface 2 a, the direction of a second straight line L2 that connects the second connection point P2 and the center C1 of the first radiation electrode 31. This configuration is applicable to a dual-polarized antenna that supports multiple frequency bands, and can reduce the area required for arranging the radiation electrodes.

[0106] In the antenna substrate 1D, the first radiation electrode 31 is not directly connected to either the second radiation electrode 32 or the third radiation electrode 33. The distance between the first radiation electrode 31 and the second radiation electrode 32 is smaller than both the sizes of the first and second radiation electrodes 31 and 32 in the first direction D1. The distance between the first radiation electrode 31 and the third radiation electrode 33 is smaller than both the sizes of the first and third radiation electrodes 31 and 33 in the second direction D2. This configuration enables electromagnetic field coupling between the first radiation electrode 31 and the second radiation electrode 32, and also enables electromagnetic field coupling between the first radiation electrode 31 and the third radiation electrode 33.

[0107] In the antenna substrate 1D, the size of the first radiation electrode 31 is larger than the size of the second radiation electrode 32 and the size of the third radiation electrode 33. This configuration makes the first radiation electrode 31 suitable for radiating radio waves in a lower frequency band than the second and third radiation electrodes 32, 33. Furthermore, it is possible to increase the amount of power fed from the first radiation electrode 31 to the second and third radiation electrodes 32, 33, and the antenna efficiency of the second and third radiation electrodes 32, 33 can be improved.

[0108] 7 is a plan view of an antenna substrate 1E according to embodiment 6. The antenna substrate 1E includes a dielectric substrate 2, a first radiation electrode 31A, a second radiation electrode 32A, a third radiation electrode 33A, a first feed line 41, a second feed line 42, a ground electrode 5, and a processing circuit 6, similar to the antenna substrate 1A.

[0109] Unlike the antenna substrate 1A, the antenna substrate 1E does not include the third feed line 43 and the fourth feed line 44. Therefore, in the antenna substrate 1E, the first radiation electrode 31A is not directly connected to either the second radiation electrode 32A or the third radiation electrode 33A.

[0110] In the antenna substrate 1E, the distance between the first radiation electrode 31A and the second radiation electrode 32A is smaller than both the sizes of the first and second radiation electrodes 31A, 32A in the first direction D1. The distance between the first radiation electrode 31A and the third radiation electrode 33A is smaller than both the sizes of the first and third radiation electrodes 31A, 33A in the second direction D2. This enables electromagnetic field coupling between the first radiation electrode 31A and the second radiation electrode 32A and between the first radiation electrode 31A and the third radiation electrode 33A.

[0111] The size of the first radiation electrode 31A is smaller than the sizes of the second radiation electrode 32A and the third radiation electrode 33A. That is, the first radiation electrode 31A is configured to be more suitable for radiating radio waves in a higher frequency band than the second and third radiation electrodes 32A and 33A. In Fig. 7, the size of the first radiation electrode 31A is smaller than the sizes of the second radiation electrode 32A and the third radiation electrode 33A, and the sizes of the second radiation electrode 32A and the third radiation electrode 33A are equal. This configuration enables improvement of the antenna characteristics.

[0112] [1.6.2 Effects, etc.] The antenna substrate 1E described above includes a dielectric substrate 2 having a main surface 2a, and planar first to third radiation electrodes 31A to 33A and first and second feed lines 41, 42 on the main surface 2a of the dielectric substrate 2. The size difference between the first and second radiation electrodes 31A, 32A and the size difference between the first and third radiation electrodes 31A, 33A are larger than the size difference between the second and third radiation electrodes 32A, 33A. The first and second feed lines 41, 42 are connected to the first radiation electrode 31A at first and second connection points P1, P2, which are different from each other. The first radiation electrode 31A is adjacent to the second radiation electrode 32A in a first direction that intersects, within the main surface 2a, with the direction of a first straight line L1 that connects the first connection point P1 and the center C1 of the first radiation electrode 31A, and is adjacent to the third radiation electrode 33A in a second direction that intersects, within the main surface 2a, with the direction of a second straight line L2 that connects the second connection point P2 and the center C1 of the first radiation electrode 31A. This configuration is applicable to a dual-polarized antenna that supports multiple frequency bands, and can reduce the area required for arranging the radiation electrodes.

[0113] In the antenna substrate 1E, the first radiation electrode 31A is not directly connected to either the second radiation electrode 32A or the third radiation electrode 33A. The distance between the first radiation electrode 31A and the second radiation electrode 32A is smaller than the sizes of the first and second radiation electrodes 31A and 32A in the first direction D1. The distance between the first radiation electrode 31A and the third radiation electrode 33A is smaller than the sizes of the first and third radiation electrodes 31A and 33A in the second direction D2. This configuration enables electromagnetic field coupling between the first radiation electrode 31A and the second radiation electrode 32A, and also enables electromagnetic field coupling between the first radiation electrode 31A and the third radiation electrode 33A.

[0114] In the antenna substrate 1E, the size of the first radiation electrode 31A is smaller than the size of the second radiation electrode 32A and the size of the third radiation electrode 33A. This configuration makes the first radiation electrode 31A suitable for emitting radio waves in a higher frequency band than the second and third radiation electrodes 32A and 33A.

[0115] 8 is a plan view of an antenna substrate 1F according to embodiment 7. The antenna substrate 1F includes a dielectric substrate 2, a first radiation electrode 31B, a second radiation electrode 32B, a third radiation electrode 33B, a first feed line 41B, a second feed line 42B, a ground electrode 5, and a processing circuit 6, similar to the antenna substrate 1B.

[0116] Unlike the antenna substrate 1B, the antenna substrate 1F does not include the third feed line 43B and the fourth feed line 44B. Therefore, in the antenna substrate 1F, the first radiation electrode 31B is not directly connected to either the second radiation electrode 32B or the third radiation electrode 33B.

[0117] The distance between the first radiation electrode 31B and the second radiation electrode 32B is smaller than both the sizes of the first and second radiation electrodes 31B and 32B in the first direction D1. The distance between the first radiation electrode 31B and the second radiation electrode 32B is the distance between the first side 31a of the first radiation electrode 31B and the second side 32b of the second radiation electrode 32B. The size of the first radiation electrode 31B in the first direction D1 is the distance between the first and second sides 31a and 31b, and the size of the second radiation electrode 32B in the first direction D1 is the distance between the first and second sides 32a and 32b. This configuration enables electromagnetic field coupling, i.e., capacitive coupling, between the first radiation electrode 31B and the second radiation electrode 32B. Therefore, when a current flows along the second side 32b of the second radiation electrode 32B, a current can flow in the same direction along the first side 31a of the first radiation electrode 31B.

[0118] The distance between the first radiation electrode 31B and the third radiation electrode 33B is smaller than both the sizes of the first and third radiation electrodes 31B, 33B in the second direction D2. The distance between the first radiation electrode 31B and the third radiation electrode 33B is the distance between the third side 31c of the first radiation electrode 31B and the fourth side 33d of the third radiation electrode 33B. The size of the first radiation electrode 31B in the second direction D2 is the distance between the third and fourth sides 31c, 31d, and the size of the third radiation electrode 33B in the second direction D2 is the distance between the third and fourth sides 33c, 33d. This configuration enables electromagnetic field coupling, i.e., capacitive coupling, between the first radiation electrode 31B and the third radiation electrode 33B. Therefore, when a current flows along the fourth side 33d of the third radiation electrode 33B, a current can flow in the same direction along the third side 31c of the first radiation electrode 31B.

[0119] The size of the first radiation electrode 31B is smaller than the sizes of the second radiation electrode 32B and the third radiation electrode 33B. In other words, the first radiation electrode 31B is configured to be suitable for radiating radio waves in a lower frequency band than the second and third radiation electrodes 32B and 33B. In Fig. 8, the size of the first radiation electrode 31B is smaller than the sizes of the second radiation electrode 32B and the third radiation electrode 33B, and the sizes of the second radiation electrode 32B and the third radiation electrode 33B are equal. This configuration enables improvement of the antenna characteristics.

[0120] Because the size of the first radiation electrode 31B is smaller than the size of the second radiation electrode 32B, the second side 32b of the second radiation electrode 32B facing the first radiation electrode 31B is longer than the first side 31a of the first radiation electrode 31B facing the second radiation electrode 32B. This makes it possible to increase the amount of power fed from the second radiation electrode 32B to the first radiation electrode 31B, and can improve the antenna efficiency of the first radiation electrode 31B.

[0121] Since the size of the first radiation electrode 31B is larger than the size of the third radiation electrode 33B, the fourth side 33d of the third radiation electrode 33B facing the first radiation electrode 31B is longer than the third side 31c of the first radiation electrode 31B facing the third radiation electrode 33B. This makes it possible to increase the amount of power fed from the third radiation electrode 33B to the first radiation electrode 31B, and can improve the antenna efficiency of the first radiation electrode 31B.

[0122] Next, a brief description will be given of the operation of the antenna board 1F. The processing circuit 6 outputs a horizontally polarized (H-polarized) first signal S1 to the first feed line 41B, and outputs a vertically polarized (V-polarized) second signal S2 to the second feed line 42B.

[0123] Assume that the first signal S1 and the second signal S2 are signals in a first frequency band. In this case, the first signal S1 reaches the second radiation electrode 32B through the first feed line 41B. The first signal S1 propagating along the fourth side 31d of the second radiation electrode 32B reaches the first radiation electrode 31B due to electromagnetic field coupling between the second radiation electrode 32B and the first radiation electrode 31B, and is radiated by the first radiation electrode 31B as a horizontally polarized radio wave. The second signal S2 reaches the third radiation electrode 33B through the second feed line 42B. The second signal S2 propagating along the fourth side 33d of the third radiation electrode 33B reaches the first radiation electrode 31B due to electromagnetic field coupling between the third radiation electrode 33B and the first radiation electrode 31B, and is radiated by the first radiation electrode 31B as a vertically polarized radio wave. In this way, the first radiation electrode 31B functions independently as a dual-polarized antenna.

[0124] Assume that the first signal S1 and the second signal S2 are signals in the second frequency band. In this case, the first signal S1 passes through the first feed line 41B to reach the second radiation electrode 32B and is radiated by the second radiation electrode 32B as a horizontally polarized radio wave. The second signal S2 passes through the second feed line 42B to reach the third radiation electrode 33B and is radiated by the third radiation electrode 33B as a vertically polarized radio wave. In this way, the pair of the second and third radiation electrodes 32B, 33B functions as a dual-polarized antenna.

[0125] In the antenna substrate 1F, the first radiation electrode 31B can function alone as a dual polarized antenna corresponding to the first frequency band, so that a single radiation electrode can be disposed instead of multiple radiation electrodes as a dual polarized antenna corresponding to the first frequency band, thereby reducing the area required for arranging the radiation electrodes.

[0126] [1.7.2 Effects, etc.] The antenna substrate 1F described above includes a dielectric substrate 2 having a main surface 2a, and planar first to third radiation electrodes 31B to 33B and first and second feed lines 41B, 42B on the main surface 2a of the dielectric substrate 2. The size difference between the first and second radiation electrodes 31B, 32B and the size difference between the first and third radiation electrodes 31B, 33B are greater than the size difference between the second and third radiation electrodes 32B, 33B. The first feed line 41B is connected to the second radiation electrode 32B at a first connection point P3. The second feed line 42B is connected to the third radiation electrode 33B at a second connection point P4. The first radiation electrode 31B is adjacent to the second radiation electrode 32B in a first direction D1 that intersects, within the main surface 2a, a first line L3 that connects the first connection point P3 and the center C2 of the second radiation electrode 32B, and intersects, within the main surface 2a, a second line L4 that connects the second connection point P4 and the center C3 of the third radiation electrode 33B, and is adjacent to the third radiation electrode 33B in a second direction D2 that is different from the first direction D1. This configuration is applicable to a dual-polarized antenna that supports multiple frequency bands, and can reduce the area required for arranging the radiation electrodes.

[0127] In the antenna substrate 1F, the size of the first radiation electrode 31B is smaller than the sizes of the second radiation electrode 32B and the third radiation electrode 33B. This configuration makes the first radiation electrode 31B suitable for radiating radio waves in a higher frequency band than the second and third radiation electrodes 32B, 33B. Furthermore, it is possible to increase the amount of power fed from the second and third radiation electrodes 32B, 33B to the first radiation electrode 31B, thereby improving the antenna efficiency of the first radiation electrode 31B.

[0128] 9 is a plan view of an antenna substrate 1G according to embodiment 8. Like the antenna substrate 1C, the antenna substrate 1G includes a dielectric substrate 2, a first radiation electrode 31C, a second radiation electrode 32C, a third radiation electrode 33C, a first feed line 41B, a second feed line 42B, a ground electrode 5, and a processing circuit 6.

[0129] Unlike the antenna substrate 1C, the antenna substrate 1G does not include the third feed line 43B and the fourth feed line 44B. Therefore, in the antenna substrate 1G, the first radiation electrode 31C is not directly connected to either the second radiation electrode 32C or the third radiation electrode 33C.

[0130] In the antenna substrate 1C, the distance between the first radiation electrode 31C and the second radiation electrode 32C is smaller than both the sizes of the first and second radiation electrodes 31C, 32C in the first direction D1. The distance between the first radiation electrode 31C and the third radiation electrode 33C is smaller than both the sizes of the first and third radiation electrodes 31C, 33C in the second direction D2. This enables electromagnetic field coupling between the first radiation electrode 31C and the second radiation electrode 32C and between the first radiation electrode 31C and the third radiation electrode 33C.

[0131] The size of the first radiation electrode 31C is larger than the sizes of the second radiation electrode 32C and the third radiation electrode 33C. In other words, the first radiation electrode 31C is configured to be suitable for radiating radio waves in a lower frequency band than the second and third radiation electrodes 32C and 33C. In Fig. 9, the size of the second radiation electrode 32C and the size of the third radiation electrode 33C are equal. This configuration enables improvement of the antenna characteristics.

[0132] [1.8.2 Effects, etc.] The antenna substrate 1G described above includes a dielectric substrate 2 having a main surface 2a, and planar first to third radiation electrodes 31C to 33C and first and second feed lines 41B, 42B on the main surface 2a of the dielectric substrate 2. The size difference between the first and second radiation electrodes 31C, 32C and the size difference between the first and third radiation electrodes 31C, 33C are greater than the size difference between the second and third radiation electrodes 32C, 33C. The first feed line 41B is connected to the second radiation electrode 32C at a first connection point P3. The second feed line 42B is connected to the third radiation electrode 33C at a second connection point P4. The first radiation electrode 31C is adjacent to the second radiation electrode 32C in a first direction D1 that intersects, within the main surface 2a, a first line L3 that connects the first connection point P3 and the center C2 of the second radiation electrode 32C, and intersects, within the main surface 2a, a second line L4 that connects the second connection point P4 and the center C3 of the third radiation electrode 33C, and is adjacent to the third radiation electrode 33C in a second direction D2 that is different from the first direction D1. This configuration is applicable to a dual-polarized antenna that supports multiple frequency bands, and can reduce the area required for arranging the radiation electrodes.

[0133] In the antenna substrate 1G, the size of the first radiation electrode 31C is larger than the size of the second radiation electrode 32C and the size of the third radiation electrode 33C. This configuration makes the first radiation electrode 31C suitable for emitting radio waves in a lower frequency band than the second and third radiation electrodes 32C and 33C.

[0134] 10 is a plan view of an antenna substrate 1H according to the ninth embodiment. Similar to the antenna substrate 1A, the antenna substrate 1H includes a dielectric substrate 2, a first radiation electrode 31A, a second radiation electrode 32A, a third radiation electrode 33A, a first feed line 41, a second feed line 42, a ground electrode 5, and a processing circuit 6. Furthermore, the antenna substrate 1H includes a fourth radiation electrode 34.

[0135] The fourth radiation electrode 34 is planar. The fourth radiation electrode 34 has first and second sides 34a, 34b facing each other and third and fourth sides 34c, 34d facing each other. When viewed in the thickness direction of the dielectric substrate 2, the fourth radiation electrode 34 is a quadrilateral formed by the first to fourth sides 34a to 34d. In this embodiment, the first to fourth sides 34a to 34d have the same length, and the fourth radiation electrode 34 is a square when viewed in the thickness direction of the dielectric substrate 2.

[0136] The first side 34a and the third side 34c face toward the second end 2d, and the second side 34b and the fourth side 34d face toward the first end 2c. The first side 34a and the fourth side 34d face toward the third end 2e, and the second side 34b and the third side 34c face toward the fourth end 2f. In this embodiment, the diagonal line between the vertex between the first side 34a and the third side 34c and the vertex between the second side 34b and the fourth side 34d runs along the X direction, and the diagonal line between the vertex between the first side 34a and the fourth side 34d and the vertex between the second side 34b and the third side 34c runs along the Y direction.

[0137] The fourth radiation electrode 34 is located on the opposite side to the first radiation electrode 31A with respect to a third line L5 connecting the center C2 of the second radiation electrode 32A and the center C3 of the third radiation electrode 33A.

[0138] Furthermore, the fourth radiation electrode 34 is adjacent to the third radiation electrode 33A in a direction that intersects the direction of the first straight line L1 within the main surface 2a, and is adjacent to the second radiation electrode 32A in a direction that intersects the direction of the second straight line L2 within the main surface. In this embodiment, the direction in which the fourth radiation electrode 34 and the third radiation electrode 33A are adjacent to each other is orthogonal to the direction of the first straight line L1 within the main surface 2a and coincides with the first direction D1. The direction in which the fourth radiation electrode 34 and the second radiation electrode 32A are adjacent to each other is orthogonal to the direction of the second straight line L2 within the main surface 2a and coincides with the second direction D2.

[0139] The first side 34a of the fourth radiation electrode 34 faces the second side 32b of the second radiation electrode 32A at a predetermined distance. The first side 34a of the fourth radiation electrode 34 and the second side 32b of the second radiation electrode 32A are parallel to each other. The third side 34c of the fourth radiation electrode 34 faces the fourth side 33d of the third radiation electrode 33A at a predetermined distance. The third side 34c of the fourth radiation electrode 34 and the fourth side 33d of the third radiation electrode 33A are parallel to each other.

[0140] The distance between the fourth radiation electrode 34 and the second radiation electrode 32A is smaller than both the sizes of the second and fourth radiation electrodes 32A, 34 in the second direction D2. The distance between the fourth radiation electrode 34 and the second radiation electrode 32A is the distance between the first side 34a of the fourth radiation electrode 34 and the second side 32b of the second radiation electrode 32A. The size of the fourth radiation electrode 34 in the second direction D2 is the distance between the first and second sides 34a, 34b, and the size of the second radiation electrode 32A in the second direction D2 is the distance between the first and second sides 32a, 32b. This configuration enables electromagnetic field coupling, i.e., capacitive coupling, between the fourth radiation electrode 34 and the second radiation electrode 32A. Therefore, when a current flows along the second side 32b of the second radiation electrode 32A, a current can flow in the same direction along the first side 34a of the fourth radiation electrode 34.

[0141] The distance between the fourth radiation electrode 34 and the third radiation electrode 33A is smaller than both the sizes of the third and fourth radiation electrodes 33A and 34 in the first direction D1. The distance between the fourth radiation electrode 34 and the third radiation electrode 33A is the distance between the third side 34c of the fourth radiation electrode 34 and the fourth side 33d of the third radiation electrode 33A. The size of the fourth radiation electrode 34 in the first direction D1 is the distance between the third and fourth sides 34c and 34d, and the size of the third radiation electrode 33A in the first direction D1 is the distance between the third and fourth sides 33c and 33d. This configuration enables electromagnetic field coupling, i.e., capacitive coupling, between the fourth radiation electrode 34 and the third radiation electrode 33A. Therefore, when a current flows along the fourth side 33d of the third radiation electrode 33A, a current can flow in the same direction along the third side 34c of the fourth radiation electrode 34.

[0142] The size of the fourth radiation electrode 34 is determined depending on the frequency band used for wireless communication. In the present embodiment, the fourth radiation electrode 34 corresponds to the same first frequency band as the first radiation electrode 31A. Therefore, the size difference between the second and fourth radiation electrodes 32A and 34 and the size difference between the third and fourth radiation electrodes 33A and 34 are larger than the size difference between the first and fourth radiation electrodes 31A and 34.

[0143] In this embodiment, since the first frequency band is higher than the second frequency band, the size of the first radiation electrode 31A and the size of the fourth radiation electrode 34 are smaller than the size of the second radiation electrode 32A and the size of the third radiation electrode 33A.

[0144] Because the size of the fourth radiation electrode 34 is smaller than the size of the second radiation electrode 32A, the second side 32b of the second radiation electrode 32A facing the fourth radiation electrode 34 is longer than the first side 34a of the fourth radiation electrode 34 facing the second radiation electrode 32A. This makes it possible to increase the amount of power fed from the second radiation electrode 32A to the fourth radiation electrode 34, and the antenna efficiency of the fourth radiation electrode 34 can be improved.

[0145] Because the size of the fourth radiation electrode 34 is larger than the size of the third radiation electrode 33A, the fourth side 33d of the third radiation electrode 33A facing the fourth radiation electrode 34 is longer than the third side 34c of the fourth radiation electrode 34 facing the third radiation electrode 33A. This makes it possible to increase the amount of power fed from the third radiation electrode 33A to the fourth radiation electrode 34, and the antenna efficiency of the fourth radiation electrode 34 can be improved.

[0146] Next, a brief description will be given of the operation of the antenna board 1H. The processing circuit 6 outputs a horizontally polarized (H-polarized) first signal S1 to the first feed line 41 and outputs a vertically polarized (V-polarized) second signal S2 to the second feed line 42.

[0147] It is assumed that the first signal S1 and the second signal S2 are signals in a first frequency band.

[0148] The first signal S1 reaches the first radiation electrode 31A through the first feed line 41 and is radiated as a horizontally polarized radio wave by the first radiation electrode 31A. A portion of the first signal S1 passes through the first radiation electrode 31A and reaches the third radiation electrode 33A through the fourth feed line 44. The first signal S1 propagating along the fourth side 33d of the third radiation electrode 33A reaches the fourth radiation electrode 34 due to electromagnetic field coupling between the third radiation electrode 33A and the fourth radiation electrode 34 and is radiated as a horizontally polarized radio wave by the fourth radiation electrode 34.

[0149] The second signal S2 reaches the first radiation electrode 31A through the second feed line 42 and is radiated as a vertically polarized radio wave by the first radiation electrode 31A. A portion of the second signal S2 passes through the first radiation electrode 31A and reaches the second radiation electrode 32A through the third feed line 43. The second signal S2 propagating along the second side 32b of the second radiation electrode 32A reaches the fourth radiation electrode 34 due to electromagnetic field coupling between the second radiation electrode 32A and the fourth radiation electrode 34 and is radiated as a vertically polarized radio wave by the fourth radiation electrode 34.

[0150] In this way, when the first signal S1 and the second signal S2 are signals in the first frequency band, each of the first radiation electrode 31A and the fourth radiation electrode 34 functions independently as a dual polarized antenna.

[0151] Assume that the first signal S1 and the second signal S2 are signals in the second frequency band. In this case, the first signal S1 passes through the first feed line 41 to reach the first radiation electrode 31A, further passes through the first radiation electrode 31A, and passes through the fourth feed line 44 to reach the third radiation electrode 33A, where it is radiated as a horizontally polarized radio wave by the third radiation electrode 33A. The second signal S2 passes through the second feed line 42 to reach the first radiation electrode 31A, further passes through the first radiation electrode 31A, and passes through the third feed line 43 to reach the second radiation electrode 32A, where it is radiated as a vertically polarized radio wave by the second radiation electrode 32A. In this way, the pair of the second and third radiation electrodes 32A and 33A functions as a dual-polarized antenna.

[0152] In the antenna substrate 1H, the fourth radiation electrode 34 enables an improvement in antenna gain in a frequency band corresponding to the size of the fourth radiation electrode 34. The fourth radiation electrode 34 can function independently as a dual polarized antenna, and therefore the area required for arranging the dual polarized antenna can be reduced compared to when a dual polarized antenna is configured using multiple radiation electrodes.

[0153] [1.9.2 Effects, etc.] The antenna substrate 1H further includes a planar fourth radiation electrode 34. The fourth radiation electrode 34 is located on the opposite side to the first radiation electrode 31A with respect to a third line L5 connecting the center C2 of the second radiation electrode 32A and the center C3 of the third radiation electrode 33A. This configuration enables improvement of the antenna gain in a frequency band corresponding to the size of the fourth radiation electrode 34.

[0154] The fourth radiation electrode 34 is adjacent to the third radiation electrode 33A in a direction that intersects the direction of the first straight line L1 within the main surface 2 a, and is adjacent to the second radiation electrode 32A in a direction that intersects the direction of the second straight line L2 within the main surface 2 a. This configuration allows the fourth radiation electrode 34 to function alone as a dual polarized antenna, and can reduce the area required for arranging the dual polarized antenna compared to when a dual polarized antenna is formed using multiple radiation electrodes.

[0155] 11 is an enlarged view of an antenna substrate 1I according to embodiment 10. Like the antenna substrate 1D, the antenna substrate 1I includes a dielectric substrate 2, a first radiation electrode 31, a second radiation electrode 32, a third radiation electrode 33, a first feed line 41, a second feed line 42, a ground electrode 5, and a processing circuit 6.

[0156] 11 is an enlarged view of the first radiation electrode 31 and the first and second feed lines 41, 42 of the antenna substrate 1I. The antenna substrate 1I differs from the antenna substrate 1D in that the first to third radiation electrodes 31 to 33, the first and second feed lines 41, 42, and the ground electrode 5 all have the same mesh structure 7.

[0157] The mesh structure 7 includes a plurality of first linear conductors 7a and a plurality of second linear conductors 7b that intersect with the plurality of first linear conductors 7a. The plurality of first linear conductors 7a are parallel to one another. The plurality of first linear conductors 7a extend in a third direction. The plurality of second linear conductors 7b are parallel to one another. The plurality of second linear conductors 7b extend in a fourth direction different from the third direction.

[0158] In the mesh structure 7, adjacent first linear conductors 7a and adjacent second linear conductors 7b define one opening 7c. The multiple openings 7c are regularly arranged in the third and fourth directions. The presence of the multiple openings 7c reduces the visibility of the mesh structure 7 itself. In other words, the mesh structure 7 becomes difficult to see with the naked eye. As an example, the width of the first linear conductors 7a and the width of the second linear conductors 7b are 1 μm, and the spacing between the first linear conductors 7a and the spacing between the second linear conductors 7b are 100 μm. The ratio of the total area of ​​the multiple openings 7c to the area of ​​the region where the mesh structure 7 is arranged is preferably 80% or more. The mesh structure 7 preferably has a visible light transmittance of 80% or more.

[0159] In this way, since the first to third radiation electrodes 31 to 33, the first and second feed lines 41, 42, and the ground electrode 5 have the mesh structure 7, the visibility of the first to third radiation electrodes 31 to 33, the first and second feed lines 41, 42, and the ground electrode 5 can be reduced.

[0160] The third direction of the mesh structure 7 is parallel to the direction D3 in which the first feed line 41 is connected to the first connection point P1. The direction D3 in which the first feed line 41 is connected to the first connection point P1 corresponds to the length direction of the second portion 41b of the first feed line 41 connected to the first connection point P1. The length direction of the second portion 41b of the first feed line 41 coincides with the direction of the first straight line L1 connecting the first connection point P1 and the center C1 of the first radiation electrode 31. The fourth direction of the mesh structure 7 is parallel to the direction D4 in which the second feed line 42 is connected to the second connection point P2. The direction D4 in which the second feed line 42 is connected to the second connection point P2 corresponds to the length direction of the second portion 42b of the second feed line 42. The length direction of the second portion 42b of the second feed line 42 coincides with the direction of the first straight line L1 connecting the first connection point P1 and the center C1 of the first radiation electrode 31.

[0161] In the first radiation electrode 31, the direction in which a current flows from the first feed line 41 to the first radiation electrode 31 coincides with the direction in which the first linear conductor 7a extends. The direction in which a current flows from the second feed line 42 to the first radiation electrode 31 coincides with the direction in which the second linear conductor 7b extends. This suppresses current loss in the first radiation electrode 31 and enables an improvement in antenna gain.

[0162] Because the second radiation electrode 32 is electromagnetically coupled to the first radiation electrode 31, a current flows through the second radiation electrode 32 in the same direction as the direction in which a current flows from the first feed line 41 to the first radiation electrode 31, that is, the direction D3 in which the first feed line 41 is connected to the first connection point P1. Therefore, since the direction in which a current flows from the first feed line 41 to the first radiation electrode 31 coincides with the extending direction of the first linear conductor 7 a, current loss in the second radiation electrode 32 is suppressed, and the antenna gain can be improved.

[0163] Because the third radiation electrode 33 is electromagnetically coupled to the first radiation electrode 31, a current flows through the third radiation electrode 33 in the same direction as the direction in which a current flows from the second feed line 42 to the first radiation electrode 31, that is, the direction D4 in which the second feed line 42 is connected to the second connection point P2. Therefore, since the direction in which a current flows from the first feed line 41 to the first radiation electrode 31 coincides with the extending direction of the first linear conductor 7 a, current loss in the third radiation electrode 33 is suppressed, and the antenna gain can be improved.

[0164] The antenna substrate 1I differs from the antenna substrate 1D in that the dielectric layer 20 of the dielectric substrate 2 is transparent. The dielectric layer 20 may be formed of, for example, well-known glass or transparent resin. Examples of transparent resins that can be used include organic insulating materials such as polyester resins such as polyethylene terephthalate, acrylic resins such as polymethyl methacrylate, polycarbonate resins, polyimide resins, polyolefin resins such as cycloolefin polymers, and cellulose resin materials such as triacetyl cellulose.

[0165] The antenna substrate 1I can reduce the visibility of each of the dielectric substrate 2, the first to third radiation electrodes 31 to 33, the first and second feed lines 41 and 42, and the ground electrode 5. This makes it possible to arrange the antenna substrate 1I, for example, by overlapping it with a display or the like that is viewed by people, thereby improving the degree of freedom in arranging the antenna substrate 1I.

[0166] [1.10.2 Effects, etc.] In the antenna substrate 1I described above, the first radiation electrode 31 has a mesh structure 7. The mesh structure 7 includes a plurality of first linear conductors 7a extending parallel to one another in a third direction and a plurality of second linear conductors 7b extending parallel to one another in a fourth direction different from the third direction and intersecting the plurality of first linear conductors 7a. The third direction is parallel to the direction D3 in which the first feed line 41 is connected to the first connection point P1. The fourth direction is parallel to the direction D4 in which the second feed line 42 is connected to the second connection point P2. This configuration can reduce the visibility of the first radiation electrode 31. Furthermore, this configuration can suppress current loss in the first radiation electrode 31 and improve antenna gain.

[0167] In the antenna substrate 1I, the second and third radiation electrodes 32 and 33 have the same mesh structure 7 as the first radiation electrode 31. This configuration can reduce the visibility of the second and third radiation electrodes 32 and 33. Furthermore, this configuration can suppress current loss in the second and third radiation electrodes 32 and 33, enabling an improvement in the antenna gain.

[0168] 12 is an enlarged view of an antenna substrate 1J according to embodiment 11. Like the antenna substrate 1D, the antenna substrate 1J includes a dielectric substrate 2, a first radiation electrode 31, a second radiation electrode 32, a third radiation electrode 33, a first feed line 41, a second feed line 42, a ground electrode 5, and a processing circuit 6.

[0169] 12 is an enlarged view of the first radiation electrode 31 and the first and second feed lines 41, 42 of the antenna substrate 1J. The antenna substrate 1J differs from the antenna substrate 1D in that the first to third radiation electrodes 31 to 33, the first and second feed lines 41, 42, and the ground electrode 5 have a mesh structure 8.

[0170] The mesh structure 8 includes a plurality of first linear conductors 8a and a plurality of second linear conductors 8b intersecting the plurality of first linear conductors 8a. The plurality of first linear conductors 8a are parallel to one another. The plurality of first linear conductors 8a extend in a third direction. The plurality of second linear conductors 8b are parallel to one another. The plurality of second linear conductors 8b extend in a fourth direction different from the third direction. In this embodiment, the third direction and the fourth direction are different from both directions D3 and D4. For example, the third direction is inclined 30° with respect to the X direction, and the fourth direction is inclined 60° with respect to the third direction. This makes the mesh structure 8 less noticeable than the mesh structure 7, reducing the visibility of the mesh structure 8.

[0171] In the mesh structure 8, adjacent first linear conductors 8a and adjacent second linear conductors 8b define one opening 8c. The multiple openings 8c are regularly arranged in the third and fourth directions. The presence of the multiple openings 8c reduces the visibility of the mesh structure 8 itself. In other words, the mesh structure 8 becomes difficult to see with the naked eye. As an example, the width of the first linear conductors 8a and the width of the second linear conductors 8b are 1 μm, and the spacing between the first linear conductors 8a and the spacing between the second linear conductors 8b are 100 μm. The ratio of the total area of ​​the multiple openings 8c to the area of ​​the region where the mesh structure 8 is arranged is preferably 80% or more. The mesh structure 8 preferably has a visible light transmittance of 80% or more.

[0172] [1.11.2 Effects, etc.] In the antenna substrate 1J described above, the first to third radiation electrodes 31 to 33 have the mesh structure 8. This configuration can reduce the visibility of the first to third radiation electrodes 31 to 33.

[0173] [1.12 Twelfth Embodiment] [1.12.1 Configuration] Fig. 13 is a perspective view of an antenna device 100 according to a twelfth embodiment. The antenna device 100 includes an antenna substrate 1K and a ground electrode 5K.

[0174] Like the antenna substrate 1 in embodiment 1, the antenna substrate 1K includes a dielectric substrate 2, a first radiation electrode 31, a second radiation electrode 32, a third radiation electrode 33, a first power feed line 41, a second power feed line 42, and a processing circuit 6, but does not include a ground electrode 5.

[0175] The ground electrode 5K is located on the opposite side of the dielectric substrate 2 from the main surface 2a. The ground electrode 5K is disposed, for example, on the motherboard of an electronic device that mounts the antenna substrate 1K. An electrode within the display device can also be used as the ground electrode 5K. In this case, in the antenna substrate 1K, the first to third radiation electrodes 31 to 33 and the first and second feed lines 41, 42 preferably have the mesh structure 7 or the mesh structure 8, and the dielectric layer 20 of the dielectric substrate 2 may be transparent.

[0176] [1.12.2 Effects, etc.] The antenna device 100 described above includes an antenna substrate 1K and a ground electrode 5K located on the side of the dielectric substrate 2 opposite the main surface 2a. This configuration is applicable to a dual-polarized antenna that supports multiple frequency bands and reduces the area required for arranging the radiation electrode. Furthermore, since there is no need to provide a ground electrode on the antenna substrate 1K itself, the thickness of the antenna substrate 1K can be reduced. Furthermore, processing of the antenna substrate 1K can be simplified. Furthermore, since the ground electrode 5K can be located away from the antenna substrate 1K, a longer distance can be secured between the first to third radiation electrodes 31 to 33 and the ground electrode 5K compared to when the ground electrode 5K is located on the antenna substrate 1K. This allows the bandwidth of the patch antenna formed by the first to third radiation electrodes 31 to 33 and the ground electrode 5K to be broadened.

[0177] [2. Modifications] The embodiments of the present disclosure are not limited to the above-described embodiments. The above-described embodiments can be modified in various ways depending on the design, etc., as long as the object of the present disclosure can be achieved. Modifications of the above-described embodiments are listed below. The modifications described below can be applied in appropriate combinations.

[0178] In the following, except when referring to specific embodiments, reference will be made to the symbols used in embodiment 1 even though they are applicable to any of the above embodiments 1 to 12. However, this is merely to simplify the description and is not intended to exclude application to embodiments 2 to 12.

[0179] In one modified example, the shapes of the first to third radiation electrodes 31 to 33 are not particularly limited. In the first embodiment, the outer shapes of the first to third radiation electrodes 31 to 33 are square when viewed in the thickness direction of the dielectric substrate 2, but this is not limited thereto and may be rectangular or other polygonal shapes, or circular, and may be changed as appropriate in consideration of the desired antenna characteristics, etc. The first to third radiation electrodes 31 to 33 do not necessarily have to be similar to each other. As an example, the first radiation electrode 31 may be circular, and the second and third radiation electrodes 32 and 33 may be rectangular, or the first to third radiation electrodes 31 to 33 may have shapes that are not similar to each other.

[0180] In one modified example, there is no particular limitation on the shapes of the first and second feed lines 41, 42. The first and second feed lines 41, 42 may be appropriately changed depending on the arrangement of the first to third radiation electrodes 31 to 33 and the processing circuit 6 on the dielectric substrate 2, and may include not only the main surface 2 a of the dielectric substrate 2 but also a portion that passes through a surface other than the main surface 2 a of the dielectric substrate 2, for example, a portion that penetrates the dielectric substrate 2.

[0181] In the third and seventh embodiments, the first connection point P3 between the first feed line 41B and the second radiation electrode 32B may be located on the first side 32a rather than the third side 32c of the second radiation electrode 32B. The second connection point P4 between the second feed line 42B and the third radiation electrode 33B may be located on the third side 33c rather than the first side 33a of the third radiation electrode 33B. In this case, the first radiation electrode 31B is adjacent to the third radiation electrode 33B in a first direction that intersects, within the main surface 2a, a first line L3 that connects the first connection point P3 and the center C2 of the second radiation electrode 32B, and is adjacent to the second radiation electrode 32B in a second direction D2 that is different from the first direction D1 and that intersects, within the main surface 2a, a second line L4 that connects the second connection point P4 and the center C3 of the third radiation electrode 33B.

[0182] In one modification, the shape, size, number and position of the fourth radiation electrode 34 may be changed as appropriate.

[0183] For example, in the antenna substrate 1H, the position of the fourth radiation electrode 34 may be changed so that it is adjacent to the fourth side 32d of the second radiation electrode 32A. This fourth radiation electrode 34 is located on the opposite side of the third line L5 from the first radiation electrode 31A and is adjacent to the second radiation electrode 32A but not adjacent to the third radiation electrode 33A. In the antenna substrate 1H, the fourth radiation electrode 34 may be located so that it is adjacent to the second side 33b of the third radiation electrode 33A. This fourth radiation electrode 34 is located on the opposite side of the third line L5 from the first radiation electrode 31A and is adjacent to the third radiation electrode 33A but not adjacent to the second radiation electrode 32A. The antenna substrate 1H may include a plurality of fourth radiation electrodes 34 located at different positions.

[0184] For example, in the antenna substrate 1F, the fourth radiation electrode 34 may be arranged adjacent to the first side 32a of the second radiation electrode 32B. This fourth radiation electrode 34 is located on the opposite side of the first radiation electrode 31B with respect to a third line connecting the center C2 of the second radiation electrode 32B and the center C3 of the third radiation electrode 33B, and is adjacent to the second radiation electrode 32B but not adjacent to the third radiation electrode 33B. In the antenna substrate 1F, the fourth radiation electrode 34 may be arranged adjacent to the third side 33c of the third radiation electrode 33B. This fourth radiation electrode 34 is located on the opposite side of the first radiation electrode 31B with respect to the third line connecting the center C2 of the second radiation electrode 32B and the center C3 of the third radiation electrode 33B, and is adjacent to the third radiation electrode 33B but not adjacent to the second radiation electrode 32B. The antenna substrate 1F may include a plurality of fourth radiation electrodes 34 at different positions.

[0185] In one modified example, there is no particular limitation on the size of the fourth radiation electrode 34. For example, the fourth radiation electrode 34 may have a size corresponding to either the first frequency band or the second frequency band, or may have a size corresponding to a third frequency band that is different from the first frequency band and the second frequency band.

[0186] In one modification, the fourth radiation electrode 34 may be directly connected to the second radiation electrode 32 or the third radiation electrode 33 or may be electromagnetically coupled thereto.

[0187] In one modified example, the mesh structure 7 may also be applied to the first to third radiation electrodes 31 to 33 and the first to fourth feed lines 41 to 44 of the antenna substrate 1. In this case, the third and fourth directions of the mesh structure 7 may be parallel to the direction D3 in which the first feed line 41 is connected to the first connection point P1 and the direction D4 in which the second feed line 42 is connected to the second connection point P2, respectively. In the antenna substrate 1, the second and third radiation electrodes 32, 33 are linearly connected to the first radiation electrode 31, so that a current flows in the second radiation electrode 32 in the same direction as the direction D4, and a current flows in the third radiation electrode 33 in the same direction as the direction D3. Therefore, by having the third and fourth directions of the mesh structure 7 parallel to the directions D3 and D4, respectively, current loss in the second and third radiation electrodes 32, 33 is suppressed, enabling an improvement in antenna gain.

[0188] In one modified example, the mesh structure 7 may also be applied to the first to third radiation electrodes 31B to 33B and the first to fourth feed lines 41B to 44B of the antenna substrate 1B, 1F. In this case, too, the third direction of the mesh structure 7 is parallel to the direction in which the first feed line 41B is connected to the first connection point P3. The direction in which the first feed line 41B is connected to the first connection point P3 corresponds to the length direction of the second portion 41b of the first feed line 41B connected to the first connection point P3. The length direction of the second portion 41b of the first feed line 41B coincides with the direction of the first straight line L3 connecting the first connection point P3 and the center C2 of the second radiation electrode 32B. The fourth direction of the mesh structure 7 is parallel to the direction in which the second feed line 42B is connected to the second connection point P4. The direction in which the second feed line 42B is connected to the second connection point P4 corresponds to the length direction of the second portion 42b of the second feed line 42B. The length direction of the second portion 42b of the second feed line 42B coincides with the direction of a second straight line L4 that connects the second connection point P4 and the center C3 of the third radiation electrode 33B.

[0189] In one modified example, the third direction of the mesh structure 7 does not necessarily need to be parallel to the direction D3 in which the first feed line 41 is connected to the first connection point P1, but may be parallel to the direction (X direction) in which the first portion 41 a of the first feed line 41 or the first portion 42 a of the second feed line 42 extends. In this case, the fourth direction of the mesh structure 7 may be parallel to the width direction (Y direction) of the first portion 41 a of the first feed line 41 or the first portion 42 a of the second feed line 42. In other words, the third and fourth directions of the mesh structure 7 may be changed as appropriate.

[0190] In the antenna substrate 1B, the first radiation electrode 31B is directly connected to the second and third radiation electrodes 32B and 33B, so that the direction of current flow from the third feed line 43B to the first radiation electrode 31B coincides with the direction of extension of the first linear conductor 7a, and the direction of current flow from the fourth feed line 44B to the first radiation electrode 31B coincides with the direction of extension of the second linear conductor 7b. This suppresses current loss in the first radiation electrode 31B and enables improvement of the antenna gain.

[0191] In the antenna substrate 1F, the first radiation electrode 31B is directly connected to the second and third radiation electrodes 32B and 33B, so that the direction of current flow from the third feed line 43B to the first radiation electrode 31B coincides with the direction of extension of the first linear conductor 7a, and the direction of current flow from the fourth feed line 44B to the first radiation electrode 31B coincides with the direction of extension of the second linear conductor 7b. This suppresses current loss in the first radiation electrode 31B and enables improvement of the antenna gain.

[0192] In both antenna substrates 1B and 1F, when the second and third radiation electrodes 32B and 33B have the same mesh structure 7 as the first radiation electrode 31B, the direction of current flow from the first feed line 41B to the second radiation electrode 32B coincides with the direction of extension of the second linear conductor 7b. The direction of current flow from the second feed line 42B to the third radiation electrode 33B coincides with the direction of extension of the first linear conductor 7a. This suppresses current loss in the second and third radiation electrodes 32B and 33B, enabling an improvement in antenna gain.

[0193] In one modified example, all of the first to third radiation electrodes 31 to 33, the first to fourth feed lines 41 to 44, and the ground electrode 5 do not have to have the mesh structure 7 or the mesh structure 8. At least one of the first to third radiation electrodes 31 to 33, the first to fourth feed lines 41 to 44, and the ground electrode 5 may have the mesh structure 7 or the mesh structure 8. Furthermore, all or part of at least one of the first to third radiation electrodes 31 to 33, the first to fourth feed lines 41 to 44, and the ground electrode 5 may have the mesh structure 7 or the mesh structure 8.

[0194] In one modified example, there are no particular limitations on the structure and method of forming the mesh structures 7 and 8. The mesh structures 7 and 8 may be formed by patterning a conductor, by printing, by punching a metal plate, or by using a metal net.

[0195] In one modified example, the frequency band used for wireless communication on the antenna substrate 1 is not particularly limited. The frequency band may be selected from well-known frequency bands such as the frequency band for Wi-Fi wireless communication, the frequency band for UWB wireless communication, the frequency band for Bluetooth (registered trademark), the frequency band for Wi-Fi wireless communication, the mid-band of the 2G (second generation mobile communication) standard, the low-band of the 4G (fourth generation mobile communication) standard, and the low-band of the 5G (fifth generation mobile communication) standard. Examples of frequency bands for Wi-Fi wireless communication include a frequency band around 2.4 GHz (e.g., 2.4 GHz to 2.5 GHz) and a frequency band around 5 GHz (e.g., 5.15 GHz to 5.8 GHz). An example of the 2G standard is the GSM (registered trademark) standard (GSM: Global System for Mobile Communications). The 4G standard is, for example, the 3GPP (registered trademark) LTE standard (LTE: Long Term Evolution). The 5G standard is, for example, 5G NR (New Radio). The frequency band may be selected from frequency bands used for various communication standards such as wireless LAN, specified low-power radio, and short-range wireless communication.

[0196] [3. Aspects] As is clear from the above-described embodiment and modifications, the present disclosure includes the following aspects.

[0197] a first direction intersecting with a first straight line connecting the first connection point and a center of the first radiation electrode within the first direction, and a second direction intersecting with a second straight line connecting the second connection point and the center of the first radiation electrode within the first direction, and a second direction intersecting with a first straight line connecting the second connection point and the center of the first radiation electrode within the first direction, and the second direction intersecting with a second straight line connecting the second connection point and the center of the first radiation electrode within the first direction, and the second direction intersecting with a second straight line connecting the second connection point and the center of the first radiation electrode within the first direction, and the second direction intersecting with a second straight line connecting the second connection point and the center of the first radiation electrode within the first direction, and the second direction intersecting with a

[0198] a first line connecting the first and second radiation electrodes to a first line within the first plane and a second line connecting the second line to a center of the third radiation electrode; a second line connecting the second line to a center of the third radiation electrode; a second line connecting the second line to a center of the third radiation electrode; a third line connecting the second line to a center of the third radiation electrode; a second line connecting the second line to a center of the third radiation electrode; a second line connecting the second line to a center of the third radiation electrode;

[0199] [Aspect 3] The antenna substrate according to Aspect 1 or 2, wherein the first feed line and the second feed line transmit signals in the same frequency band.

[0200] [Aspect 4] The antenna substrate according to any one of Aspects 1 to 3, further comprising: a third feed line connecting the first radiation electrode and the second radiation electrode; and a fourth feed line connecting the first radiation electrode and the third radiation electrode.

[0201] [Aspect 5] The antenna substrate according to aspect 4, wherein the first radiation electrode is larger in size than the second radiation electrode and the third radiation electrode.

[0202] [Aspect 6] The antenna substrate according to Aspect 4, wherein the first radiation electrode is smaller in size than the second radiation electrode and the third radiation electrode.

[0203] [Aspect 7] The antenna substrate of any one of Aspects 1 to 3, wherein the first radiation electrode is not directly connected to either the second radiation electrode or the third radiation electrode, the distance between the first radiation electrode and the second radiation electrode is smaller than the size of either the first or second radiation electrode in the first direction, and the distance between the first radiation electrode and the third radiation electrode is smaller than the size of either the first or third radiation electrode in the second direction.

[0204] [Aspect 8] The antenna substrate according to Aspect 7, wherein the size of the first radiation electrode is larger than the size of the second radiation electrode and the size of the third radiation electrode when viewed in a thickness direction of the dielectric substrate.

[0205] [Aspect 9] The antenna substrate according to Aspect 7, wherein the size of the first radiation electrode is smaller than the size of the second radiation electrode and the size of the third radiation electrode when viewed in a thickness direction of the dielectric substrate.

[0206] [Aspect 10] The antenna substrate according to any one of Aspects 1 to 9, further comprising: a planar fourth radiation electrode located on the opposite side of the first radiation electrode with respect to a third line connecting the center of the second radiation electrode and the center of the third radiation electrode.

[0207] [Aspect 11] The antenna substrate according to any one of Aspects 1 to 10, further comprising: a planar fourth radiation electrode adjacent to the third radiation electrode in a direction intersecting the direction of the first straight line within the main surface, and adjacent to the second radiation electrode in a direction intersecting the direction of the second straight line within the main surface.

[0208] [Aspect 12] The antenna substrate according to any one of Aspects 1 to 11, wherein at least one of the first to third radiation electrodes has a mesh structure.

[0209] [Aspect 13] The antenna substrate of any one of Aspects 1 to 12, wherein the first radiation electrode has a mesh structure, and the mesh structure has: a plurality of first linear conductors extending in a third direction and parallel to one another; and a plurality of second linear conductors extending in a fourth direction different from the third direction and intersecting the plurality of first linear conductors, and parallel to one another; the third direction is parallel to a direction in which the first feed line is connected to the first connection point; and the fourth direction is parallel to a direction in which the second feed line is connected to the second connection point.

[0210] [Aspect 14] The antenna substrate of Aspect 13, wherein the second and third radiation electrodes have the same mesh structure as the first radiation electrode.

[0211] [Aspect 15] The antenna substrate of any one of Aspects 1 to 14, wherein each of the first to third radiation electrodes includes first and second sides facing each other in the direction of the first straight line and third and fourth sides facing each other in the direction of the second straight line, and the size of each of the first to third radiation electrodes is defined by the distance between the first and second sides and the distance between the third and fourth sides.

[0212] [Aspect 16] The antenna substrate according to any one of Aspects 1 to 15, wherein the first to third radiation electrodes are similar when viewed in a thickness direction of the dielectric substrate, and a size difference between the first to third radiation electrodes is determined by a similarity ratio.

[0213] [Aspect 17] The antenna substrate according to any one of Aspects 1 to 16, wherein the second radiation electrode and the third radiation electrode are equal in size.

[0214] [Aspect 18] The antenna substrate according to any one of Aspects 1 to 17, wherein the first straight line and the second straight line are perpendicular to each other.

[0215] [Aspect 19] The antenna substrate according to any one of Aspects 1 to 18, further comprising a ground electrode on the dielectric substrate opposite the main surface.

[0216] [Aspect 20] An antenna device comprising: the antenna substrate according to any one of Aspects 1 to 18; and a ground electrode on the dielectric substrate opposite the main surface.

[0217] The second to nineteenth aspects are optional elements and are not essential.

[0218] The present disclosure is applicable to an antenna substrate and an antenna device, particularly to an antenna substrate applicable to a dual-polarized antenna that supports multiple frequency bands, and an antenna device including the antenna substrate.

[0219] DESCRIPTION OF SYMBOLS 1, 1A to 1K Antenna substrate 2 Dielectric substrate 2a Main surface 5, 5K Ground electrode 7 Mesh structure 7a First linear conductor 7b Second linear conductor 8 Mesh structure 8a First linear conductor 8b Second linear conductor 31, 31A to 31C First radiation electrode 32, 32A to 32C Second radiation electrode 33, 33A to 33C Third radiation electrode 34 Fourth radiation electrode 41, 41B First power feed line 42, 42B Second power feed line 43, 43B Third power feed line 44, 44B Fourth power feed line 100 Antenna device

Claims

1. An antenna substrate comprising: a dielectric substrate having a main surface; and first to third planar radiation electrodes and first and second feed lines on the main surface of the dielectric substrate, wherein a size difference between the first and second radiation electrodes and a size difference between the first and third radiation electrodes are greater than a size difference between the second and third radiation electrodes, the first and second feed lines are connected to the first radiation electrode at first and second connection points which are different from each other, and the first radiation electrode is adjacent to the second radiation electrode in a first direction which intersects, within the main surface, with a direction of a first straight line connecting the first connection point and a center of the first radiation electrode, and is adjacent to the third radiation electrode in a second direction which intersects, within the main surface, with a direction of a second straight line connecting the second connection point and the center of the first radiation electrode and is different from the first direction.

2. An antenna substrate comprising: a dielectric substrate having a main surface; first to third planar radiation electrodes and first and second feed lines on the main surface of the dielectric substrate; a size difference between the first and second radiation electrodes and a size difference between the first and third radiation electrodes are greater than a size difference between the second and third radiation electrodes; the first feed line is connected to the second radiation electrode at a first connection point; and the second feed line is connected to the third radiation electrode at a second connection point; the first radiation electrode is adjacent to one of the second radiation electrode and the third radiation electrode in a first direction that intersects, within the main surface, a first straight line connecting the first connection point and a center of the second radiation electrode, and intersects, within the main surface, a second straight line connecting the second connection point and the center of the third radiation electrode, and is adjacent to the other of the second radiation electrode and the third radiation electrode in a second direction different from the first direction.

3. The antenna board according to claim 1 or 2, wherein the first feed line and the second feed line transmit signals in the same frequency band.

4. An antenna substrate according to any one of claims 1 to 3, further comprising: a third feed line connecting the first radiation electrode and the second radiation electrode; and a fourth feed line connecting the first radiation electrode and the third radiation electrode.

5. The antenna substrate according to claim 4, wherein the size of the first radiation electrode is larger than the size of the second radiation electrode and the size of the third radiation electrode.

6. The antenna substrate according to claim 4, wherein the size of the first radiation electrode is smaller than the size of the second radiation electrode and the size of the third radiation electrode.

7. An antenna substrate according to any one of claims 1 to 3, wherein the first radiation electrode is not directly connected to either the second radiation electrode or the third radiation electrode, the distance between the first radiation electrode and the second radiation electrode is smaller than both of the sizes of the first and second radiation electrodes in the first direction, and the distance between the first radiation electrode and the third radiation electrode is smaller than both of the sizes of the first and third radiation electrodes in the second direction.

8. The antenna substrate according to claim 7, wherein the size of the first radiation electrode is larger than the size of the second radiation electrode and the size of the third radiation electrode when viewed in a thickness direction of the dielectric substrate.

9. The antenna substrate according to claim 7, wherein the size of the first radiation electrode is smaller than the size of the second radiation electrode and the size of the third radiation electrode when viewed in a thickness direction of the dielectric substrate.

10. An antenna substrate according to any one of claims 1 to 9, further comprising a planar fourth radiation electrode located on the opposite side to the first radiation electrode with respect to a third line connecting the center of the second radiation electrode and the center of the third radiation electrode.

11. An antenna substrate according to any one of claims 1 to 10, further comprising a planar fourth radiation electrode adjacent to the third radiation electrode in a direction intersecting the direction of the first straight line within the main surface, and adjacent to the second radiation electrode in a direction intersecting the direction of the second straight line within the main surface.

12. The antenna substrate according to any one of claims 1 to 11, wherein at least one of the first to third radiation electrodes has a mesh structure.

13. An antenna substrate according to any one of claims 1 to 12, wherein the first radiation electrode has a mesh structure comprising: a plurality of first linear conductors extending in a third direction and parallel to each other; and a plurality of second linear conductors extending in a fourth direction different from the third direction and intersecting with the plurality of first linear conductors, wherein the third direction is parallel to the direction in which the first feed line is connected to the first connection point; and the fourth direction is parallel to the direction in which the second feed line is connected to the second connection point.

14. The antenna substrate according to claim 13, wherein the second and third radiation electrodes have the same mesh structure as the first radiation electrode.

15. An antenna substrate according to any one of claims 1 to 14, wherein each of the first to third radiation electrodes includes first and second sides facing each other in the direction of the first straight line, and third and fourth sides facing each other in the direction of the second straight line, and the size of each of the first to third radiation electrodes is defined by the distance between the first and second sides and the distance between the third and fourth sides.

16. The antenna substrate of any one of claims 1 to 15, wherein, when viewed in the thickness direction of the dielectric substrate, the first to third radiation electrodes are similar, and a size difference between the first to third radiation electrodes is determined by a similarity ratio.

17. The antenna substrate according to any one of claims 1 to 16, wherein the second radiation electrode and the third radiation electrode are equal in size.

18. The antenna substrate of any one of claims 1 to 17, wherein the first straight line and the second straight line are perpendicular to each other.

19. The antenna substrate according to any one of claims 1 to 18, further comprising a ground electrode on the side of the dielectric substrate opposite the main surface.

20. An antenna device comprising: an antenna substrate according to any one of claims 1 to 18; and a ground electrode on the opposite side of the dielectric substrate to the main surface.

Images