Antenna substrate, antenna module, and communication device

Abstract

To provide an antenna substrate, an antenna module, and a communication device that can reduce deterioration in antenna efficiency while enabling improvement in radio wave radiation to the lateral directions of a dielectric substrate.SOLUTION: An antenna substrate 1 includes a flat first radiation electrode 3-1 on a dielectric substrate 2 and a flat ground electrode 4 located at a position different from the first radiation electrode 3-1 in a normal direction of the dielectric substrate 2. A first direction determining the size of the first radiation electrode 3-1 is perpendicular to the normal direction. The first radiation electrode 3-1 has first and second sides 31 and 32 that extend in the first direction and are on opposite sides in a second direction perpendicular to the first direction. The ground electrode 4 has first and second sides 41 and 42 that are on opposite sides in the second direction. When viewed from the normal direction, the first side 41 includes an edge between the first and second sides 31 and 32 of the first radiation electrode 3-1, and the second side 42 is not between the first and second sides 31 and 32 of the first radiation electrode 3-2.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to an antenna substrate, an antenna module, and a communication device. [Background technology]

[0002] Patent Document 1 discloses a patch antenna. The patch antenna disclosed in Patent Document 1 has a three-layer substrate (dielectric substrate) in which a ground plane is stacked on a lower layer, a power supply plane is stacked on a middle layer, and an antenna plane is stacked on an upper layer. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-83046 Summary of the Invention [Problem to be solved by the invention]

[0004] With patch antennas, radiation coverage over the entire space is often emphasized. However, because the direction of radio wave radiation from a patch antenna is normal to the dielectric substrate, radio wave radiation to the sides of the dielectric substrate is not practical. As a result, sufficient radiation coverage over the entire space cannot be obtained.

[0005] The present disclosure provides an antenna substrate, an antenna module, and a communication device that enable improved lateral radio wave radiation from a dielectric substrate while reducing degradation of antenna efficiency. [Means for solving the problem]

[0006] An antenna substrate according to one embodiment of the present disclosure comprises a dielectric substrate having a dielectric layer, a flat radiating electrode on the dielectric substrate, and a flat ground electrode located at a position different from the radiating electrode in the normal direction of the dielectric substrate, wherein a first direction determining the size of the radiating electrode is perpendicular to the normal direction, the radiating electrode has first and second ends that are on opposite sides in a second direction perpendicular to the first direction and extend in the first direction, the ground electrode has third and fourth ends that are on opposite sides in the second direction, and when viewed from the normal direction, one of the third and fourth ends includes an edge that is between the first and second ends of the radiating electrode, and the other of the third and fourth ends is not between the first and second ends of the radiating electrode.

[0007] An antenna module according to one aspect of the present disclosure includes the above antenna substrate.

[0008] A communication device according to one aspect of the present disclosure includes the antenna module described above. [Effects of the Invention]

[0009] Aspects of the present disclosure allow for improved radio wave radiation to the sides of a dielectric substrate while reducing degradation of antenna efficiency. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a block diagram of a communication device including an antenna module according to a first embodiment; [Figure 2] FIG. 1 is a perspective view of an antenna substrate according to a first embodiment; [Figure 3] FIG. 1 is a plan view of an antenna substrate according to a first embodiment; [Figure 4] FIG. 1 is a partial cross-sectional view of an antenna substrate according to a first embodiment; [Figure 5] FIG. 1 shows the directivity of an antenna substrate according to the first embodiment and a comparative example. [Figure 6] FIG. 10 is a plan view of an antenna substrate according to a second embodiment; [Figure 7] 10 is a partially enlarged view of an antenna substrate according to a second embodiment. [Figure 8]FIG. 10 is a partial cross-sectional view of a first example of an antenna substrate according to a second embodiment; [Figure 9] FIG. 10 is a partial cross-sectional view of a second example of the antenna substrate according to the second embodiment; DETAILED DESCRIPTION OF THE INVENTION

[0011] [1. Embodiment] Hereinafter, embodiments of the present disclosure will be described, occasionally with reference to the drawings. 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, when it is necessary to distinguish between multiple components, suffixes such as "-1" and "-2" are added to the symbols of the components. However, when it is not necessary to distinguish between multiple components, the suffixes "-1" and "-2" may be omitted to improve readability.

[0014] In the following description, the XYZ Cartesian coordinate system shown in the drawings will be used simply for the sake of simplicity.

[0015] In the following description, "B and C are at different positions in the A direction" means that B and C do not overlap even partially in the A direction.

[0016] In the following description, "B and C are at the same position in the A direction" means that B and C are entirely or partially overlapping in the A direction.

[0017] 1.1 First Embodiment [1.1.1 Configuration] 1 is a block diagram of a communication device 100 according to an embodiment. The communication device 100 is, for example, a personal computer (desktop computer, laptop computer), a mobile terminal (smartphone, tablet terminal, etc.), a server, etc.

[0018] The communication device 100 includes an antenna module 10 , an input / output device 11 , a storage device 12 , and an arithmetic circuit 13 .

[0019] The antenna module 10 is used for communication over a communication network. The communication network may include the Internet. The communication network may be configured not only of a network conforming to a single communication protocol, but also of multiple networks conforming to different communication protocols. The communication network may include data communication devices such as repeater hubs, switching hubs, bridges, gateways, and routers.

[0020] The antenna module 10 includes an antenna substrate 1 and a communication circuit 9. The communication circuit 9 constitutes a communication interface that performs wireless communication using the antenna substrate 1. The wireless communication protocol used by the communication circuit 9 can be selected from various well-known wireless communication standards. Examples of wireless communication standards include IEEE802.11, 4G, and 5G.

[0021] The input / output device 11 includes one or more human-machine interfaces for inputting and outputting information. Examples of the human-machine interfaces include input interfaces such as a keyboard, a pointing device (such as a mouse or a trackball), a touchpad, and a position input device for a touch panel display, and output interfaces such as a display, a speaker, and a display device for a touch panel display. The one or more human-machine interfaces may be built into the communication device 100 or may be externally attached.

[0022] The storage device 12 is used to store information used by the communication device 100. The storage device 12 includes one or more storages (non-transitory storage media). The storage may be, for example, a hard disk drive, an optical drive, or a solid-state drive (SSD). The storage may also be an internal type, an external type, or a network-attached storage (NAS) type.

[0023] The arithmetic circuit 13 can be connected to the antenna module 10, the input / output device 11, and the storage device 12. The arithmetic circuit 13 can be realized by, for example, a computer system. The computer system includes one or more processors (microprocessors) and one or more memories. The one or more processors execute programs (stored in one or more memories or the storage device 12) to realize various functions of the communication device 100. The programs may be pre-recorded in the storage device 12, or may be provided via a telecommunications line such as the Internet, or recorded on a non-transitory storage medium such as a memory card.

[0024] Fig. 2 is a perspective view of the antenna substrate 1. The antenna substrate 1 includes a dielectric substrate 2, first to third radiation electrodes 3-1 to 3-3, a ground electrode 4, and first to third feed lines 5-1 to 5-3. Note that in Fig. 2, the thickness of the dielectric substrate 2 is exaggerated for ease of understanding.

[0025] 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 (long side direction) and a width direction (short side 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.

[0026] 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 both 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.

[0027] 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.

[0028] The first to third radiation electrodes 3-1 to 3-3, the ground electrode 4, and the first and second feed lines 5-1 to 5-3 are provided on a dielectric substrate 2.

[0029] The antenna substrate 1 will be further described below with reference to Fig. 3 and Fig. 4. Fig. 3 is a plan view of the antenna substrate 1, and Fig. 4 is a partial cross-sectional view of the antenna substrate 1. In particular, Fig. 4 is a partial cross-sectional view of the periphery of the first radiation electrode 3-1 of the antenna substrate 1. In Fig. 4, hatching of the dielectric substrate 2 has been omitted to make the drawing easier to see.

[0030] The first to third radiation electrodes 3-1 to 3-3 correspond to a predetermined frequency band. For example, the predetermined frequency band may be a frequency band used in UWB (Ultra-Wide Band) wireless communication. As an example, in the case of IEEE802.15.4a, a short-range wireless standard established by the IEEE (Institute of Electrical and Electronic Engineers), the predetermined frequency band may be channel number 5 (center frequency: 6489.6 MHz, frequency bandwidth: 499.2 MHz) or channel number 9 (center frequency: 7987.2 MHz, frequency bandwidth: 499.2 MHz).

[0031] The first to third radiation electrodes 3-1 to 3-3 are located on the main surface 2a of the dielectric substrate 2. Each of the first to third radiation electrodes 3-1 to 3-3, together with the ground electrode 4, constitutes a patch antenna.

[0032] The first to third radiation electrodes 3-1 to 3-3 have a flat plate shape (planar shape). In particular, the first to third radiation electrodes 3-1 to 3-3 have a generally rectangular shape when viewed from the normal direction of the dielectric substrate 2.

[0033] In this embodiment, the first to third radiation electrodes 3-1 to 3-3 have the same shape. The shapes of the first to third radiation electrodes 3-1 to 3-3 will be explained below based on the first radiation electrode 3-1.

[0034] The first radiation electrode 3-1 has a first side 31, a second side 32, a third side 33, and a fourth side 34. The first side 31 and the second side 32 are long sides and are a first end and a second end that are opposite each other in the width direction (Y direction) of the dielectric substrate 2. The first side 31 and the second side 32 extend along the length direction (X direction) of the dielectric substrate 2. The first side 31 and the second side 32 are linear. The third side 33 and the fourth side 34 are short sides and are both ends in the length direction (X direction) of the dielectric substrate 2. The third side 33 and the fourth side 34 extend along the width direction (Y direction) of the dielectric substrate 2. The third side 33 and the fourth side 34 are linear. The first radiation electrode 3-1 has slits 35 on the first side 31 and the second side 32, respectively.

[0035] The size of the first radiation electrode 3-1 may be determined based on a predetermined frequency band. More specifically, the size of the first radiation electrode 3-1 is determined according to the wavelength in the substrate corresponding to the predetermined frequency band. As an example, the size of the first radiation electrode 3-1 may be set to 1 / 2 of the wavelength in the substrate corresponding to the predetermined frequency band. The wavelength in the substrate corresponding to the predetermined frequency band is determined by taking into account the wavelength in free space (free space wavelength) corresponding to the predetermined frequency band and the dielectric constant of the dielectric substrate 2.

[0036] The first direction that determines the size of the first radiation electrode 3-1 corresponds to the polarization direction. The first direction is orthogonal to the normal direction of the dielectric substrate 2. In this embodiment, the first direction corresponds to the longitudinal direction (X direction) of the dielectric substrate 2. In this embodiment, the size of the first radiation electrode 3-1 is determined by the distance between both ends in the first direction. The distance between both ends in the first direction is the distance between the third side 33 and the fourth side 34, which are the shorter sides. In this embodiment, the presence of the slit 35 provides a wavelength shortening effect, so the size of the first radiation electrode 3-1 can be reduced. This is also true for the second and third radiation electrodes 3-2 and 3-3.

[0037] In this embodiment, the first to third radiation electrodes 3-1 to 3-3 correspond to the same frequency band, and therefore have the same size.

[0038] Next, the arrangement of the first to third radiation electrodes 3-1 to 3-3 as viewed from the normal direction of the dielectric substrate 2 will be described mainly with reference to FIG.

[0039] The first and second radiation electrodes 3-1 and 3-2 are aligned in the second direction when viewed from the normal direction (Z direction) of the dielectric substrate 2 so that the second sides 32 (second ends) of the first and second radiation electrodes 3-1 and 3-2 face each other. The second direction is perpendicular to the normal direction (Z direction) of the dielectric substrate 2 and perpendicular to the first direction (X direction). In this embodiment, the second direction corresponds to the width direction of the dielectric substrate 2 and therefore coincides with the Y direction. In this embodiment, the centers C1 of the first and second radiation electrodes 3-1 and 3-2 are aligned in the second direction. When viewed from the normal direction, the distance D3 between the centers C1 of the first and second radiation electrodes 3-1 and 3-2 is between ¼ and ½ of the free space wavelength corresponding to the frequency band corresponding to the first and second radiation electrodes 3-1 and 3-2.

[0040] The first and second radiation electrodes 3-1 and 3-2 are located at the same position in the first direction (X direction) and at different positions in the second direction (Y direction). This makes it possible to determine the angle at which the radio waves arrive in the plane including the second direction (Y direction) and the normal direction of the dielectric substrate 2, from the phase difference between the radio waves of the corresponding frequency bands that reach the first and second radiation electrodes 3-1 and 3-2.

[0041] The first and third radiation electrodes 3-1 and 3-3 are aligned in a first direction (X direction) when viewed from the normal direction (Z direction) of the dielectric substrate 2 so that the fourth side 34 of the first radiation electrode 3-1 faces the third side 33 of the third radiation electrode 3-2. In this embodiment, the centers C1 of the first and third radiation electrodes 3-1 and 3-3 are aligned in the first direction. When viewed from the normal direction, the distance between the centers C1 of the first and third radiation electrodes 3-1 and 3-3 is between ¼ and ½ of the free space wavelength corresponding to the frequency band corresponding to the first and third radiation electrodes 3-1 and 3-3.

[0042] The first and third radiation electrodes 3-1 and 3-3 are located at the same position in the second direction (Y direction) and at different positions in the first direction (X direction). This makes it possible to determine the angle at which the radio waves arrive in the plane including the first direction (X direction) and the normal direction of the dielectric substrate 2, from the phase difference between the radio waves of the corresponding frequency bands that reach the first and third radiation electrodes 3-1 and 3-3.

[0043] The ground electrode 4 is located at a different position from the first to third radiation electrodes 3-1 to 3-3 in the normal direction of the dielectric substrate 2. Therefore, the ground electrode 4 faces the first to third radiation electrodes 3-1 to 3-3 with at least a part of the dielectric layer 20 of the dielectric substrate 2 sandwiched therebetween.

[0044] As shown in FIG. 2, the ground electrode 4 is provided on the dielectric substrate 2 as an intermediate layer between the main surface 2a and the back surface 2b.

[0045] 3, the ground electrode 4 includes a first portion 401 and a second portion 402. The first portion 401 mainly configures a patch antenna together with the first to third radiation electrodes 3-1 to 3-3. Connectors to be connected to the first to third feed lines 5-1 to 5-3 may be disposed below the second portion 402.

[0046] The first portion 401 has a first side 41, a second side 42, a third side 43, and a fourth side 44. The first and second sides 42 are third and fourth ends that are on opposite sides in the width direction (second direction) of the dielectric substrate 2. The third side 43 and fourth side 44 are both ends of the dielectric substrate 2 in the length direction (X direction).

[0047] The third side 43 and the fourth side 44 extend along the width direction (Y direction) of the dielectric substrate 2. The third side 43 and the fourth side 44 are linear. The third side 43 is longer than the fourth side 44. Therefore, the first portion 401 has a shape in which the width on the third side 43 side is greater than the width on the fourth side 44 side.

[0048] The first side 41 extends along the length direction (X direction) of the dielectric substrate 2. The first side 41 is linear. The second side 42 extends overall along the length direction (X direction) of the dielectric substrate 2. The second side 42 is polygonal rather than linear. More specifically, the second side 42 has a first edge 421, a second edge 422, and a third edge 423. The first edge 421 extends from the end of the third side 43 opposite to the first side 41 along the length direction (X direction) of the dielectric substrate 2 toward the fourth side 44. The second edge 422 extends from the end of the fourth side 44 opposite to the first side 41 toward the third side 43 along the length direction (X direction) of the dielectric substrate 2. The third edge portion 423 extends along the length direction (X direction) of the dielectric substrate 2 and connects the end of the first edge portion 421 opposite to the third side 43 and the end of the second edge portion 422 opposite to the fourth side 44.

[0049] The second portion 402 extends from the second side portion 422 of the second side 42 of the first portion 401 to the opposite side to the first side 41. The second portion 402 is generally rectangular when viewed in the normal direction of the dielectric substrate 2.

[0050] Next, the positional relationship between the first to third radiation electrodes 3-1 to 3-3 and the ground electrode 4 when viewed from the normal direction of the dielectric substrate 2 will be described mainly with reference to FIG.

[0051] When viewed from the normal direction of the dielectric substrate 2, the first to third radiation electrodes 3-1 to 3-3 are not entirely inside the ground electrode 4, but are partially outside the ground electrode 4.

[0052] The positional relationship between the first radiation electrode 3-1 and the ground electrode 4 will be described.

[0053] When viewed from the normal direction of the dielectric substrate 2, the first side 41 (third end) of the ground electrode 4 includes an edge (third end) located between the first and second sides 31, 32 (first and second ends) of the first radiation electrode 3-1. The second side 42 (fourth end) of the ground electrode 4 is not located between the first and second sides 31, 32 (first and second ends) of the first radiation electrode 3-1.

[0054] As described above, the first side 41 (third end) of the ground electrode 4 includes an edge portion between the first and second sides 31, 32 (first and second ends) of the first radiation electrode 3-1. A current flowing through the first side 31 of the first radiation electrode 3-1 generates a current distribution similar to that of a dipole antenna on the first side 41. This excites the first side 41 of the ground electrode 4. This improves radio wave radiation (in a predetermined frequency band) toward the side of the dielectric substrate 2 (particularly, in the second direction, from the first side 41 of the ground electrode 4 toward the first side 31 of the first radiation electrode 3-1). Furthermore, because the second side 42 (fourth end) of the ground electrode 4 is not between the first and second sides 31, 32 (first and second ends) of the first radiation electrode 3-1, an overlapping area between the ground electrode 4 and the first radiation electrode 3-1 can be secured when viewed from the normal direction of the dielectric substrate 2. This makes it possible to reduce deterioration in antenna efficiency (especially antenna efficiency in the normal direction of the dielectric substrate 2). Therefore, this configuration makes it possible to reduce deterioration in antenna efficiency while improving radio wave radiation to the sides of the dielectric substrate 2.

[0055] When viewed from the normal direction of the dielectric substrate 2, it is sufficient that at least one of the third and fourth sides 43, 44 (both ends in the first direction) of the ground electrode 4 is not located between the third and fourth sides 33, 34 (both ends in the first direction) of the first radiation electrode 3-1. In this embodiment, when viewed from the normal direction of the dielectric substrate 2, neither of the third and fourth sides 43, 44 (both ends in the first direction) of the ground electrode 4 is located between the third and fourth sides 33, 34 (both ends in the first direction) of the first radiation electrode 3-1. This makes it easier to excite the first side 41 of the ground electrode 4, and enables improved radio wave radiation (in a predetermined frequency band) toward the side of the dielectric substrate 2 (particularly, in the second direction, from the first side 41 of the ground electrode 4 toward the first side 31 of the first radiation electrode 3-1).

[0056] The positional relationship between the second radiation electrode 3-2 and the ground electrode 4 will be described.

[0057] When viewed from the normal direction of the dielectric substrate 2, the second side 42 (fourth end) of the ground electrode 4 includes an edge (first edge 421) located between the first and second sides 31, 32 (first and second ends) of the second radiation electrode 3-2. The first side 41 (third end) of the ground electrode 4 is not located between the first and second sides 31, 32 (first and second ends) of the second radiation electrode 3-2.

[0058] As described above, the second side 42 (fourth end) of the ground electrode 4 includes an edge (first edge 421) located between the first and second sides 31, 32 (first and second ends) of the second radiation electrode 3-2. A current distribution similar to that of a dipole antenna occurs in the first edge 421 of the second side 42 due to the current flowing through the first side 31 of the second radiation electrode 3-2. This excites the first edge 421 of the second side 42 of the ground electrode 4. This enables improved radio wave radiation (in a predetermined frequency band) laterally from the dielectric substrate 2 (particularly, in the second direction, from the first edge 421 of the second side 42 of the ground electrode 4 toward the first side 31 of the second radiation electrode 3-2). Furthermore, since the first side 41 (third end) of the ground electrode 4 is not between the first and second sides 31, 32 (first and second ends) of the second radiation electrode 3-2, an area where the ground electrode 4 and the second radiation electrode 3-2 overlap can be secured when viewed from the normal direction of the dielectric substrate 2. This makes it possible to reduce deterioration in antenna efficiency (especially antenna efficiency in the normal direction of the dielectric substrate 2). Therefore, this configuration makes it possible to reduce deterioration in antenna efficiency while improving radio wave radiation to the sides of the dielectric substrate 2.

[0059] When viewed from the normal direction of the dielectric substrate 2, at least one of the third and fourth sides 43, 44 (both ends in the first direction) of the ground electrode 4 need not be between the third and fourth sides 33, 34 (both ends in the first direction) of the second radiation electrode 3-2. In this embodiment, when viewed from the normal direction of the dielectric substrate 2, neither of the third and fourth sides 43, 44 (both ends in the first direction) of the ground electrode 4 is between the third and fourth sides 33, 34 (both ends in the first direction) of the second radiation electrode 3-2. This facilitates excitation of the first edge portion 421 of the second side 42 of the ground electrode 4, enabling improved radio wave radiation (in a predetermined frequency band) toward the side of the dielectric substrate 2 (particularly, in the second direction, from the first side 41 of the ground electrode 4 toward the first side 31 of the first radiation electrode 3-1).

[0060] The positional relationship between the third radiation electrode 3-3 and the ground electrode 4 will be described.

[0061] When viewed from the normal direction of the dielectric substrate 2, the first side 41 (third end) of the ground electrode 4 includes an edge (third end) located between the first and second sides 31, 32 (first and second ends) of the first radiation electrode 3-1. The second side 42 (fourth end) of the ground electrode 4 is not located between the first and second sides 31, 32 (first and second ends) of the first radiation electrode 3-1. Therefore, similar to the case of the first radiation electrode 3-1, it is possible to improve radio wave radiation (in a predetermined frequency band) toward the side of the dielectric substrate 2 (particularly, in the second direction, from the first side 41 of the ground electrode 4 toward the first side 31 of the first radiation electrode 3-1) while reducing deterioration of antenna efficiency (particularly, antenna efficiency in the normal direction of the dielectric substrate 2).

[0062] When viewed from the normal direction of the dielectric substrate 2, it is sufficient that at least one of the third and fourth sides 43, 44 (both ends in the first direction) of the ground electrode 4 is not located between the third and fourth sides 33, 34 (both ends in the first direction) of the third radiation electrode 3-3. In this embodiment, when viewed from the normal direction of the dielectric substrate 2, neither of the third and fourth sides 43, 44 (both ends in the first direction) of the ground electrode 4 is located between the third and fourth sides 33, 34 (both ends in the first direction) of the third radiation electrode 3-3. As with the first radiation electrode 3-1, this enables improvement of radio wave radiation (in a predetermined frequency band) toward the side of the dielectric substrate 2 (particularly, in the second direction, from the first side 41 of the ground electrode 4 toward the first side 31 of the first radiation electrode 3-1).

[0063] Next, the dimensional relationship between the first to third radiation electrodes 3-1 to 3-3 and the ground electrode 4 when viewed from the normal direction of the dielectric substrate 2 will be described mainly with reference to FIG.

[0064] When viewed from the normal direction of the dielectric substrate 2, the distance between the first and second sides 31, 32 (first and second ends) of the first radiation electrode 3-1 is D1, and the distance between the first side 41 (third end) of the ground electrode 4 and the first side 31 (first end) of the first radiation electrode 3-1 is D2. It is preferable that D2≦D1×1 / 2. More preferably, D2≦D1×3 / 4. Even more preferably, D2≦D1×7 / 8. In this embodiment, D2=D1×1 / 2. This also applies to the second and third radiation electrodes 3-2, 3-3. This ensures an overlapping region between the ground electrode 4 and the radiation electrode 3 when viewed from the normal direction of the dielectric substrate 2. This reduces degradation of the antenna efficiency (particularly, the antenna efficiency in the normal direction of the dielectric substrate 2).

[0065] The length L2 of the first side 31 of the ground electrode 4 (the length of the edge in the first direction relative to the first radiation electrode 3-1 or the third radiation electrode 3-3) is preferably 0.8 times or more the size L1 of the first radiation electrode 3-1 or the third radiation electrode 3-3. More preferably, L2≧L1. In this embodiment, L2>L1. The length L3 of the first edge 421 of the second side 42 of the ground electrode 4 (the length of the edge in the first direction relative to the second radiation electrode 3-2) is preferably 0.8 times or more the size L1 of the second radiation electrode 3-2. More preferably, L3≧L1. In this embodiment, L3>L1.

[0066] The first to third power feed lines 5-1 to 5-3 are used to feed power to the first to third radiation electrodes 3-1 to 3-3, respectively. As shown in FIG. 2 , each of the first to third power feed lines 5-1 to 5-3 includes a first wire portion 51 and a second wire portion 52. The first wire portion 51 is provided on the rear surface 2b of the dielectric substrate 2. When viewed from the normal direction of the dielectric substrate 2, a first end of the first wire portion 51 is located within the second part 402 of the ground electrode 4, and a second end of the first wire portion 51 is located within the corresponding radiation electrode 3. The first end of the first wire portion 51 is used for connection to the communication circuit 9. A coaxial cable or the like for connection to the communication circuit 9 can be connected to the first end of the first wire portion 51. The second end of the first wire portion 51 is used for connection to the corresponding radiation electrode 3. The second wire portion 52 is an interlayer connection line. The second line portion 52 connects the second end of the first line portion 51 to the corresponding radiation electrode 3. The connection portion between the power supply line 5 and the radiation electrode 3 is the power supply point P1 of the radiation electrode 3.

[0067] 3, when viewed from the normal direction of the dielectric substrate 2, the feed point P1 of the radiating electrode 3 is located at a position different from the center C1 of the radiating electrode 3 in a third direction that intersects the length direction (first direction) of the dielectric substrate 2 without being orthogonal to the length direction of the dielectric substrate 2. That is, when viewed from the normal direction of the dielectric substrate 2, the feed point P1 is located at a position different from the center C1 in both the length direction (first direction) and the width direction (second direction) of the dielectric substrate 2. This makes it easier for current to flow in the length direction (first direction) of the dielectric substrate 2 in the radiating electrode 3. This configuration enables to improve the antenna efficiency (especially the antenna efficiency in the normal direction of the dielectric substrate 2).

[0068] In this embodiment, the feed point P1 is closer to the second side 32 than to the first side 31 of the radiation electrode 3, and closer to the third side 33 than to the fourth side .

[0069] As shown in FIG. 4 , the feed point P1 of the first radiation electrode 3-1 is located between the first side 41 (third end) of the ground electrode 4 and the second side 32 (second end) of the first radiation electrode 3-1 when viewed from the normal direction of the dielectric substrate 2. Therefore, when viewed from the normal direction of the dielectric substrate 2, the feed point P1 of the first radiation electrode 3-1 is located inside the ground electrode 4. The ground electrode 4 has an opening 45 through which the second line portion 52 of the first feed line 5-1 passes. The second line portion 52 of the first feed line 5-1 passes through the opening 45 and connects the second end of the first line portion 51 of the first feed line 5-1 to the first radiation electrode 3-1. In this manner, the first feed line 5-1 penetrates the ground electrode 4 without coming into contact with the ground electrode 4. In this configuration, the first feed line 5-1 is located inside the first side 41 of the ground electrode 4 when viewed from the normal direction of the dielectric substrate 2. Therefore, compared to when the first feed line 5-1 is located outside the first side 41 of the ground electrode 4, it is possible to reduce the possibility of reducing radio wave radiation from the first side 41. This makes it possible to improve radio wave radiation (in a predetermined frequency band) to the side of the dielectric substrate 2 (particularly, in the second direction, from the first side 41 of the ground electrode 4 toward the first side 31 of the first radiation electrode 3-1).

[0070] The feed point P1 of the second radiation electrode 3-2 is located between the second side 42 (fourth end) of the ground electrode 4 and the second side 32 (second end) of the second radiation electrode 3-2, when viewed from the normal direction of the dielectric substrate 2. Therefore, when viewed from the normal direction of the dielectric substrate 2, the feed point P1 of the second radiation electrode 3-2 is located inside the ground electrode 4. Similar to the first feed line 5-1, the second feed line 5-2 penetrates the ground electrode 4 so as not to come into contact with the ground electrode 4. In this configuration, the second feed line 5-2 is located inside the second side 42 of the ground electrode 4, when viewed from the normal direction of the dielectric substrate 2. Therefore, compared to when the second feed line 5-2 is located outside the second side 42 of the ground electrode 4, the possibility of reducing radio wave radiation from the second side 42 can be reduced. This enables improved radio wave radiation (in a specified frequency band) to the side of the dielectric substrate 2 (particularly in the second direction, from the second side 42 of the ground electrode 4 toward the first side 31 of the second radiation electrode 3-2).

[0071] The feed point P1 of the third radiation electrode 3-3 is located between the first side 41 (third end) of the ground electrode 4 and the second side 32 (second end) of the third radiation electrode 3-3, when viewed from the normal direction of the dielectric substrate 2. Therefore, when viewed from the normal direction of the dielectric substrate 2, the feed point P1 of the third radiation electrode 3-3 is located inside the ground electrode 4. Similar to the first feed line 5-1, the third feed line 5-3 penetrates the ground electrode 4 so as not to come into contact with the ground electrode 4. In this configuration, the third feed line 5-3 is located inside the first side 41 of the ground electrode 4, when viewed from the normal direction of the dielectric substrate 2. Therefore, the possibility of reducing radio wave radiation from the first side 41 can be reduced compared to when the third feed line 5-3 is located outside the first side 41 of the ground electrode 4. This enables improved radio wave radiation (in a specified frequency band) to the side of the dielectric substrate 2 (particularly in the second direction, from the first side 41 of the ground electrode 4 toward the first side 31 of the third radiation electrode 3-3).

[0072] [1.1.2 Evaluation, etc.] As described above, the antenna substrate 1 enables improvement of radio wave radiation to the sides of the dielectric substrate 2 while reducing deterioration of antenna efficiency. To confirm the effect of this antenna substrate 1, the directivity was evaluated by simulation.

[0073] FIG. 5 is a diagram illustrating the directivity of the antenna substrate 1 of the first embodiment and the comparative example. FIG. 5 shows the directivity of the first radiation electrode 3-1 in the YZ plane. In FIG. 5, the 0° direction corresponds to the Z direction (the normal direction of the dielectric substrate 2), and the 90° direction corresponds to the X direction (the length direction of the dielectric substrate 2), i.e., the lateral direction of the dielectric substrate 2. The comparative example differs from the antenna substrate 1 of the first embodiment in that the first side 41 of the ground electrode 4 is located on the opposite side of the first side 31 of the first radiation electrode 3-1 from the second side 32. That is, in the comparative example, the entire first radiation electrode 3-1 is contained within the ground electrode 4 when viewed from the normal direction of the dielectric substrate 2. From FIG. 5, it can be confirmed that the radio wave radiation toward the side (90° direction) of the dielectric substrate 2, indicated by R, is increased in the antenna substrate 1 compared to the comparative example. On the other hand, there is almost no decrease in the radio wave radiation in the normal direction of the dielectric substrate 2 (0° direction). This indicates that there is little deterioration in the antenna efficiency. Thus, the simulation results also confirmed that the antenna substrate 1 enables improvement of radio wave radiation to the sides of the dielectric substrate 2 while reducing deterioration of antenna efficiency.

[0074] [1.1.3 Effects, etc.] The antenna substrate 1 described above includes a dielectric substrate 2 having a dielectric layer 20, a flat radiating electrode 3 on the dielectric substrate 2, and a flat ground electrode 4 located at a different position from the radiating electrode 3 in the normal direction (Z direction) of the dielectric substrate 2. A first direction (the length direction of the dielectric substrate 2, the X direction) that determines the size of the radiating electrode 3 is perpendicular to the normal direction. The radiating electrode 3 has first and second ends (first and second sides 31 and 32) that are opposite each other in a second direction (the width direction of the dielectric substrate 2, the Y direction) that is perpendicular to the first direction and extend in the first direction. The ground electrode 4 has third and fourth ends (first and second sides 41 and 42) that are opposite each other in the second direction. When viewed from the normal direction, one of the third and fourth ends includes an edge portion between the first and second ends of the radiation electrode 3 (the first side 41 for the first and third radiation electrodes 3-1 and 3-3, and the first edge portion 421 of the second side 42 for the second radiation electrode 3-2), and the other of the third and fourth ends is not between the first and second ends of the radiation electrode 3. This configuration enables improvement of radio wave radiation to the sides of the dielectric substrate 2 while reducing deterioration in antenna efficiency.

[0075] In the antenna substrate 1, when viewed from the normal direction, if the distance between the first and second ends (first and second sides 31, 32 of the radiation electrode 3) is D1 and the distance between the edge (first side 41 for the first and third radiation electrodes 3-1, 3-3, and first edge 421 of the second side 42 for the second radiation electrode 3-2) and the first end (first side 31 of the radiation electrode 3) is D2, then D2≦D1×½. This configuration enables further reduction in degradation of antenna efficiency.

[0076] In the antenna substrate 1, D2≦D1×3 / 4. This configuration enables further reduction in the deterioration of the antenna efficiency.

[0077] In the antenna substrate 1, D2≦D1×7 / 8. This configuration enables further reduction in the degradation of the antenna efficiency.

[0078] In the antenna substrate 1, the length of the edge (the first side 41 for the first and third radiation electrodes 3-1 and 3-3, and the first edge 421 of the second side 42 for the second radiation electrode 3-2) in the first direction (the length direction of the dielectric substrate 2, the X direction) is 0.8 times or more the size of the radiation electrode 3. This configuration enables further improvement in the lateral radio wave radiation of the dielectric substrate 2.

[0079] In the antenna substrate 1, when viewed from the normal direction, the feeding point P1 of the radiation electrode 3 is located in a third direction that is not orthogonal to the first direction but intersects with the first direction, at a position different from the center of the radiation electrode 3. This configuration enables improvement of the antenna efficiency (particularly, the antenna efficiency in the normal direction of the dielectric substrate 2).

[0080] In the antenna substrate 1, when viewed from the normal direction, the feed point P1 is located between the edge (the first side 41 for the first and third radiation electrodes 3-1 and 3-3, and the first edge 421 of the second side 42 for the second radiation electrode 3-2) and the second end (the second side 32). In this configuration, when viewed from the normal direction of the dielectric substrate 2, the feed line 5 connected to the feed point P1 can be located inside the edge of the ground electrode 4. Therefore, compared to when the feed line 5 is located outside the edge of the ground electrode 4, the possibility of reducing radio wave radiation from the edge can be reduced.

[0081] The antenna substrate 1 is provided with a feed line 5 on the dielectric substrate 2 and connected to a feed point P1. The feed line 5 passes through the ground electrode 4 so as not to come into contact with the ground electrode 4. In this configuration, the feed line 5 connected to the feed point P1 can be arranged inside the edge of the ground electrode 4 when viewed from the normal direction of the dielectric substrate 2. Therefore, compared to when the feed line 5 is located outside the edge of the ground electrode 4, the possibility of reducing radio wave radiation from the edge can be reduced.

[0082] In the antenna substrate 1, when viewed from the normal direction, at least one of the ends in the first direction (third and fourth sides 43, 44) of the ground electrode 4 is not between the ends in the first direction (third and fourth sides 33, 34) of the radiation electrode 3. This configuration makes it easier to excite the edge of the ground electrode 4, enabling further improvement in radio wave radiation to the sides of the dielectric substrate 2.

[0083] The antenna substrate 1 includes a plurality of radiation electrodes 3. The plurality of radiation electrodes 3 includes a first radiation electrode 3-1 and a second radiation electrode 3-2. When viewed from the normal direction, the third end (first side 41) includes an edge (first side 41) between the first and second ends (first and second sides 31 and 32) of the first radiation electrode 3-1, and the fourth end (second side 42) is not between the first and second ends (first and second sides 31 and 32) of the first radiation electrode 3-1. When viewed from the normal direction, the fourth end (second side 42) includes an edge (first edge 421) between the first and second ends (first and second sides 31 and 32) of the second radiation electrode 3-2, and the third end (first side 41) is not between the first and second ends (first and second sides 31 and 32) of the second radiation electrode 3-2. This configuration makes it possible to improve radio wave radiation to both sides of the dielectric substrate 2 while reducing the deterioration of antenna efficiency.

[0084] In the antenna substrate 1, the first and second radiation electrodes 3-1 and 3-2 are aligned in the second direction as viewed from the normal direction so that the second ends (second sides 32) of the first and second radiation electrodes 3-1 and 3-2 face each other. This configuration enables improved radio wave radiation to both sides of the dielectric substrate 2.

[0085] In the antenna substrate 1, the distance D3 between the centers C1 of the first and second radiation electrodes 3-1 and 3-2, as viewed from the normal direction, is between ¼ and ½ of the free space wavelength corresponding to the frequency band corresponding to the first and second radiation electrodes 3-1 and 3-2. This configuration enables improved isolation between the first and second radiation electrodes 3-1 and 3-2.

[0086] The above-described antenna module 10 includes the above-described antenna substrate 1. This configuration makes it possible to improve radio wave radiation to the sides of the dielectric substrate 2 while reducing deterioration in antenna efficiency.

[0087] The communication device 100 described above includes the antenna module 10. This configuration makes it possible to improve radio wave radiation to the sides of the dielectric substrate 2 while reducing deterioration in antenna efficiency.

[0088] 1.2 Second Embodiment [1.2.1 Configuration] 6 is a plan view of an antenna substrate 1A according to embodiment 2. The antenna substrate 1A includes a dielectric substrate 2, first to third radiation electrodes 3-1 to 3-3, a ground electrode 4A, first to third power feed lines 5-1 to 5-3, and first to third auxiliary electrodes 6-1a to 6-3b.

[0089] The ground electrode 4A includes a first portion 401A and a second portion 402. Unlike the first portion 401, the first portion 401A includes first to third recesses 46-1 to 46-3.

[0090] The positions of the first to third recesses 46-1 to 46-3 will be described in more detail below.

[0091] The first and third recesses 46-1, 46-3 are located on the first side 41A of the first portion 401A and recessed toward the second side 42A. The first recess 46-1 is located on the third side 43 of the first side 41A and overlaps with the first radiation electrode 3-1 when viewed from the normal direction of the dielectric substrate 2. The third recess 46-3 is located on the fourth side 44 of the first side 41A and overlaps with the third radiation electrode 3-3 when viewed from the normal direction of the dielectric substrate 2. The second recess 46-2 is located on the second side 42A of the first portion 401A and recessed toward the first side 41A. The second recess 46-2 is located on the first edge portion 421A of the second side 42A and overlaps with the second radiation electrode 3-2 when viewed from the normal direction of the dielectric substrate 2. It is located in a position where

[0092] In this way, the first to third recesses 46-1 to 46-3 are located at positions corresponding to the first to third radiation electrodes 3-1 to 3-3, respectively.

[0093] Next, the positional relationship between the first to third recesses 46-1 to 46-3 and the first to third radiation electrodes 3-1 to 3-3 will be described in more detail.

[0094] Fig. 7 is a partially enlarged view of the antenna substrate 1A, particularly a portion of the antenna substrate 1 including the first radiation electrode 3-1.

[0095] The first recess 46-1 has a bottom 46a and two side edges 46b, 46c. In the present embodiment, the bottom 46a is linear and extends along the length direction (X direction) of the dielectric substrate 2. The two side edges 46b, 46c are linear and extend along the width direction (Y direction) of the dielectric substrate 2. The bottom 46a forms an edge of the first side 31A of the ground electrode 3A between the first and second sides 31, 32 of the first radiation electrode 3-1, and the two side edges 46b, 46c are located between the third and fourth sides 33, 34 (both ends in the first direction) of the first radiation electrode 3-1 when viewed from the normal direction of the dielectric substrate 2.

[0096] As shown in FIG. 6, the second recess 46-2 and the third recess 46-3 have a bottom side 46a and opposite side sides 46b, 46c, similar to the first recess 46-1.

[0097] In the second recess 46-2, the bottom edge 46a is an edge portion of the second edge 32A of the ground electrode 3A between the first and second edges 31, 32 of the second radiation electrode 3-2, and both side edges 46b, 46c are located between the third and fourth edges 33, 34 (both ends in the first direction) of the second radiation electrode 3-2 when viewed from the normal direction of the dielectric substrate 2.

[0098] In the third recess 46-3, the bottom edge 46a is an edge portion of the first edge 31A of the ground electrode 3A between the first and second edges 31, 32 of the third radiation electrode 3-3, and the two side edges 46b, 46c are located between the third and fourth edges 33, 34 (both ends in the first direction) of the third radiation electrode 3-3 when viewed from the normal direction of the dielectric substrate 2.

[0099] The first auxiliary electrodes 6-1a and 6-1b are provided on the dielectric substrate 2 as intermediate layers between the first radiation electrode 3-1 and the ground electrode 4A. The first auxiliary electrodes 6-1a and 6-1b are located between the first radiation electrode 3-1 and both side edges 46b and 46c of the first recess 46-1 of the ground electrode 4A, respectively, in the normal direction of the dielectric substrate 2. The first auxiliary electrodes 6-1a and 6-1b are connected to either the first radiation electrode 3-1 or the ground electrode 4A.

[0100] The second auxiliary electrodes 6-2a and 6-2b are provided on the dielectric substrate 2 as intermediate layers between the second radiation electrode 3-2 and the ground electrode 4A. The second auxiliary electrodes 6-2a and 6-2b are located between the second radiation electrode 3-2 and both side edges 46b and 46c of the second recess 46-2 of the ground electrode 4A, respectively, in the normal direction of the dielectric substrate 2. The second auxiliary electrodes 6-2a and 6-2b are connected to either the second radiation electrode 3-2 or the ground electrode 4A.

[0101] The third auxiliary electrodes 6-3a and 6-3b are provided on the dielectric substrate 2 as intermediate layers between the third radiation electrode 3-3 and the ground electrode 4A. The third auxiliary electrodes 6-3a and 6-3b are located between the third radiation electrode 3-3 and both side edges 46b and 46c of the third recess 46-3 of the ground electrode 4A in the normal direction of the dielectric substrate 2. The third auxiliary electrodes 6-3a and 6-3b are connected to either the third radiation electrode 3-3 or the ground electrode 4A.

[0102] Since the first auxiliary electrodes 6-1a and 6-1b are located between the first radiation electrode 3-1 and the ground electrode 4A, connecting them to the ground electrode 4A or the first radiation electrode 3-1 increases the capacitance between the first radiation electrode 3-1 and the ground electrode 4A at both ends of the first radiation electrode 3-1 in the first direction. This provides a wavelength shortening effect, allowing the size of the first radiation electrode 3-1 to be reduced. Similarly, the second auxiliary electrodes 6-2a and 6-2b provide a wavelength shortening effect, allowing the size of the second radiation electrode 3-2 to be reduced. The third auxiliary electrodes 6-3a and 6-3b provide a wavelength shortening effect, allowing the size of the third radiation electrode 3-3 to be reduced.

[0103] The shape and size of the auxiliary electrode 6 are appropriately set so as to obtain a desired wavelength shortening effect.

[0104] 7, interlayer connection lines 7 are used to connect the first auxiliary electrodes 6-1a, 6-1b to the ground electrode 4A or the first radiation electrode 3-1. In FIG. 7, three interlayer connection lines 7 are used for one auxiliary electrode 6. The three interlayer connection lines 7 are aligned in the width direction of the dielectric substrate 2.

[0105] Fig. 8 is a partial cross-sectional view of a first example of the antenna substrate 1A, and Fig. 9 is a partial cross-sectional view of a second example of the antenna substrate 1A. In particular, Figs. 8 and 9 are partial cross-sectional views of the periphery of the first radiation electrode 3-1 of the antenna substrate 1A. In Figs. 8 and 9, hatching of the dielectric substrate 2 has been omitted for ease of viewing.

[0106] In a first example shown in Fig. 8, the interlayer connection line 7 connects the first auxiliary electrode 6-1a to the first radiation electrode 3-1 instead of the ground electrode 4A. In a second example shown in Fig. 9, the interlayer connection line 7 connects the first auxiliary electrode 6-1a to the ground electrode 4A instead of the first radiation electrode 3-1.

[0107] Similar to the first auxiliary electrodes 6-1a and 6-1b, the second auxiliary electrodes 6-2a and 6-2b are also connected to the ground electrode 4A or the second radiation electrode 3-2 by interlayer connection lines 7, and the third auxiliary electrodes 6-3a and 6-3b are also connected to the ground electrode 4A or the third radiation electrode 3-3 by interlayer connection lines 7.

[0108] The auxiliary electrode 6 may be connected to either the radiation electrode 3 or the ground electrode 4A. However, it is preferable that the connection mode of the auxiliary electrode 6 (i.e., whether the auxiliary electrode 6 is connected to the radiation electrode 3 or the ground electrode 4A) be the same for radiation electrodes 3 corresponding to the same frequency band.

[0109] [1.2.2 Effects, etc.] In the antenna substrate 1A described above, the ground electrode 4A has a recess 46 at one of the third and fourth ends (first and second sides 41A, 42A) that is recessed toward the other side of the third and fourth ends (first and second sides 41A, 42A). The edge is the bottom side 46a of the recess 46. When viewed from the normal direction, both sides 46b, 46c of the recess 46 are located between both ends (third and fourth sides 33, 34) of the radiation electrode 3 in the first direction. This configuration allows the size of the ground electrode 4A to be increased, ensuring space for arranging components and transmission lines.

[0110] The antenna substrate 1A described above includes auxiliary electrodes 6 located between both side edges 46b, 46c of the recess 46 and the radiation electrode 3 in the normal direction. The auxiliary electrodes 6 are connected to either the radiation electrode 3 or the ground electrode 4. This configuration allows the size of the radiation electrode 3 to be reduced.

[0111] [2. Modifications] The embodiments of the present disclosure are not limited to Embodiments 1 and 2. Various modifications of Embodiments 1 and 2 can be made depending on the design, etc., as long as the object of the present disclosure can be achieved. Modifications of Embodiments 1 and 2 are listed below. The modifications described below can be applied in appropriate combinations.

[0112] In the following, although the symbols used in embodiment 1 are applicable to both embodiment 1 and embodiment 2, this is merely to simplify the description and is not intended to exclude application to embodiment 2.

[0113] In one modification, the shape of the dielectric substrate 2 is not particularly limited.

[0114] In one modification, the first to third radiation electrodes 3-1 to 3-3 do not necessarily have to have the same size and / or shape.

[0115] In one modified example, the radiation electrode 3 may be connected to the ground electrode 4 at the end in the X direction. That is, the radiation electrode 3 may form a planar inverted-F antenna (PIFA).

[0116] In one modified example, the shape of the radiating electrode 3 is not limited to a rectangle as in the first embodiment. The shape of the radiating electrode 3 does not necessarily have to be a rectangle, and may be a quadrangle such as a trapezoid or a parallelogram, or may be a circle. For example, if the radiating electrode 3 is circular, the size of the radiating electrode 3 is defined by its diameter. For example, if the radiating electrode 3 is elliptical, the size of the radiating electrode 3 may be defined by its major axis. If the radiating electrode 3 is polygonal, the size of the radiating electrode 3 may be defined by the distance between corresponding sides in the first direction.

[0117] In one modified example, the radiating electrode 3 does not necessarily have to be arranged on the main surface 2a of the dielectric substrate 2. The radiating electrode 3 may be arranged on an inner layer (intermediate layer) of the dielectric substrate 2. The ground electrode 4 does not necessarily have to be arranged on an inner layer (intermediate layer) of the dielectric substrate 2. The ground electrode 4 may be arranged on the rear surface 2b of the dielectric substrate 2. The radiating electrode 3 and the ground electrode 4 may be arranged so as to face each other with at least a part of the dielectric layer 20 of the dielectric substrate 2 sandwiched therebetween.

[0118] In one modified example, there is no particular limitation on the number of radiation electrodes 3. The antenna substrate 1 may include a single radiation electrode 3, or may include a plurality of radiation electrodes 3 arranged in an array.

[0119] In one modified example, there is no particular limitation on the shape of the ground electrode 4. The ground electrode 4 may be provided separately for each of the plurality of radiation electrodes 3.

[0120] In one modified example, the ground electrode 4A does not have to include the recess 46 for each radiation electrode 3.

[0121] In one modified example, the power supply line 5 does not necessarily have to be provided so as to pass through the ground electrode 4 .

[0122] 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 a frequency band for Wi-Fi wireless communication, a frequency band for UWB wireless communication, a frequency band for Bluetooth (registered trademark), a frequency band for Wi-Fi wireless communication, a mid-band of the 2G (second generation mobile communication) standard, a low-band of the 4G (fourth generation mobile communication) standard, and a low-band of the 5G (fifth generation mobile communication) standard. Examples of the frequency band 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 (Global System for Mobile Communications). An example of the 4G standard is the 3GPP (registered trademark) LTE (Long Term Evolution) standard. An example of the 5G standard is 5G NR (New Radio). The frequency band may be selected from frequency bands used in various communication standards such as wireless LAN, specified low-power radio, and short-distance wireless communication.

[0123] [3. Aspects] As is apparent from the above-described embodiment and modifications, the present disclosure includes the following aspects.

[0124] [Aspect 1] a dielectric substrate having a dielectric layer; a flat radiation electrode on the dielectric substrate; a flat-plate-shaped ground electrode located at a position different from that of the radiation electrode in a normal direction of the dielectric substrate; Equipped with a first direction that determines the size of the radiation electrode is perpendicular to the normal direction; the radiation electrode has first and second ends that are opposite to each other in a second direction perpendicular to the first direction and extend in the first direction; the ground electrode has third and fourth ends that are opposite to each other in the second direction; When viewed from the normal direction, one of the third and fourth ends includes an edge portion between the first and second ends of the radiation electrode, and the other of the third and fourth ends is not between the first and second ends of the radiation electrode. Antenna board.

[0125] [Aspect 2] When viewed from the normal direction, the distance between the first and second ends is D1, and the distance between the edge and the first end is D2. D2≦D1×1 / 2, 1 shows the antenna substrate of embodiment 1.

[0126] [Aspect 3] D2≦D1×3 / 4, 10 is an antenna substrate according to embodiment 2.

[0127] [Aspect 4] D2≦D1×7 / 8; The antenna substrate according to aspect 2 or 3.

[0128] [Aspect 5] The length of the edge portion in the first direction is 0.8 times or more the size of the radiation electrode. The antenna substrate according to any one of the first to fourth embodiments.

[0129] [Aspect 6] When viewed from the normal direction, the feeding point of the radiation electrode is at a position different from the center of the radiation electrode in a third direction that intersects with the first direction without being orthogonal to the first direction. The antenna substrate according to any one of embodiments 1 to 5.

[0130] [Aspect 7] When viewed from the normal direction, the feed point is between the edge portion and the second end. The antenna substrate of embodiment 6.

[0131] [Aspect 8] a feed line connected to the feed point on the dielectric substrate; the power supply line passes through the ground electrode so as not to come into contact with the ground electrode; The antenna substrate of embodiment 6 or 7.

[0132] [Aspect 9] When viewed from the normal direction, at least one of both ends of the ground electrode in the first direction is not between both ends of the radiation electrode in the first direction. The antenna substrate according to any one of the first to eighth embodiments.

[0133] [Aspect 10] the ground electrode has a recess at one of the third and fourth ends that is recessed toward the other of the third and fourth ends, the edge is a bottom of the recess, When viewed from the normal direction, both sides of the recess are located between both ends of the radiation electrode in the first direction. The antenna substrate according to any one of embodiments 1 to 9.

[0134] [Aspect 11] an auxiliary electrode provided between each of both sides of the recess and the radiation electrode in the normal direction; the auxiliary electrode is connected to either the radiation electrode or the ground electrode; The antenna substrate of embodiment 10.

[0135] [Aspect 12] a plurality of the radiation electrodes; the plurality of radiation electrodes include a first radiation electrode and a second radiation electrode, When viewed from the normal direction, the third end includes an edge portion between the first and second ends of the first radiation electrode, and the fourth end is not between the first and second ends of the first radiation electrode, When viewed from the normal direction, the fourth end includes an edge portion between the first and second ends of the second radiation electrode, and the third end is not between the first and second ends of the second radiation electrode. The antenna substrate according to any one of embodiments 1 to 11.

[0136] [Aspect 13] the first and second radiation electrodes are aligned in the second direction when viewed from the normal direction so that the second ends of the first and second radiation electrodes face each other. The antenna substrate according to any one of embodiments 1 to 12.

[0137] [Aspect 14] a center-to-center distance between the first and second radiation electrodes, as viewed from the normal direction, is equal to or greater than ¼ and equal to or less than ½ of a free space wavelength corresponding to a frequency band corresponding to the first and second radiation electrodes; The antenna substrate of embodiment 13.

[0138] [Aspect 15] The antenna substrate according to any one of aspects 1 to 14 is provided. Antenna module.

[0139] [Aspect 16] 16. The antenna module of claim 15, Communication equipment.

[0140] Aspects 2 to 13 are optional elements and are not essential. [Industrial Applicability]

[0141] The present disclosure is applicable to an antenna substrate, an antenna module, and a communication device. Specifically, the present disclosure is applicable to an antenna substrate, an antenna module, and a communication device that configure a plurality of antennas, each of which includes a radiation electrode and a parasitic element. [Explanation of symbols]

[0142] 100 Communication equipment 10 Antenna Module 1,1A Antenna Board 2. Dielectric substrate 2a Main surface 2b Back side 3-1 First radiation electrode (radiation electrode) 3-2 Second radiation electrode (radiation electrode) 3-3 Third radiation electrode (radiation electrode) 31 First side (first end) 32 Second side (second edge) 33 Third Side 34 Side 4 4,4A ground electrode 41 First side (third edge) 42 Side 2 (4th edge) 46-1 First recess (recess) 46-2 Second recess (recess) 46-3 Third recess (recess) 46a Bottom 46b,46c side 5-1 1st feed line (power feed line) 5-2 2nd power feed line (power feed line) 5-3 3rd feeder line (power feeder line) 6-1a,6-1b 1st auxiliary electrode (auxiliary electrode) 6-2a,6-2b 2nd auxiliary electrode (auxiliary electrode) 6-3a,6-3b 3rd auxiliary electrode (auxiliary electrode)

Claims

1. a dielectric substrate having a dielectric layer; a flat radiation electrode on the dielectric substrate; a flat-plate-shaped ground electrode located at a position different from that of the radiation electrode in a normal direction of the dielectric substrate; Equipped with a first direction that determines the size of the radiation electrode is perpendicular to the normal direction; the radiation electrode has first and second ends that are opposite to each other in a second direction perpendicular to the first direction and extend in the first direction; the ground electrode has third and fourth ends that are opposite to each other in the second direction; When viewed from the normal direction, one of the third and fourth ends includes an edge portion between the first and second ends of the radiation electrode, and the other of the third and fourth ends is not between the first and second ends of the radiation electrode. Antenna board.

2. When viewed from the normal direction, the distance between the first and second ends is D1, and the distance between the edge portion and the first end is D2. D2≦D1×1 / 2, The antenna substrate of claim 1 .

3. D2≦D1×3 / 4; The antenna substrate of claim 2.

4. D2≦D1×7 / 8; The antenna substrate of claim 2.

5. the length of the edge portion in the first direction is 0.8 times or more the size of the radiation electrode; The antenna substrate of claim 1 .

6. When viewed from the normal direction, the feeding point of the radiation electrode is at a position different from the center of the radiation electrode in a third direction that intersects with the first direction without being orthogonal to the first direction. The antenna substrate of claim 1 .

7. When viewed from the normal direction, the feed point is located between the edge portion and the second end. The antenna substrate of claim 6.

8. a feed line connected to the feed point on the dielectric substrate; the power supply line passes through the ground electrode so as not to come into contact with the ground electrode; The antenna substrate of claim 6.

9. When viewed from the normal direction, at least one of both ends of the ground electrode in the first direction is not between both ends of the radiation electrode in the first direction. The antenna substrate of claim 1 .

10. the ground electrode has a recess at one of the third and fourth ends that is recessed toward the other of the third and fourth ends, the edge is a bottom of the recess, When viewed from the normal direction, both side edges of the recess are located between both ends of the radiation electrode in the first direction. The antenna substrate of claim 1 .

11. an auxiliary electrode provided between each of both sides of the recess and the radiation electrode in the normal direction; the auxiliary electrode is connected to either the radiation electrode or the ground electrode; The antenna substrate of claim 10.

12. a plurality of the radiation electrodes; the plurality of radiation electrodes include a first radiation electrode and a second radiation electrode, When viewed from the normal direction, the third end includes an edge portion between the first and second ends of the first radiation electrode, and the fourth end is not between the first and second ends of the first radiation electrode, When viewed from the normal direction, the fourth end includes an edge portion between the first and second ends of the second radiation electrode, and the third end is not between the first and second ends of the second radiation electrode. The antenna substrate of claim 1 .

13. the first and second radiation electrodes are aligned in the second direction when viewed from the normal direction so that the second ends of the first and second radiation electrodes face each other. The antenna substrate of claim 1 .

14. a center-to-center distance between the first and second radiation electrodes, as viewed from the normal direction, is equal to or greater than ¼ and equal to or less than ½ of a free space wavelength corresponding to a frequency band corresponding to the first and second radiation electrodes; The antenna substrate of claim 13.

15. The antenna substrate according to any one of claims 1 to 14 is provided. Antenna module.

16. comprising the antenna module of claim 15; Communication equipment.

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