Antenna substrate, antenna module, and communication device

Abstract

Provided are an antenna substrate, an antenna module, and a communication device that make it possible to suppress deterioration in antenna efficiency while making it possible to improve radio wave radiation to the sides of a dielectric substrate. This antenna substrate comprises: a ground electrode on a dielectric substrate; and first and second antennas respectively including flat plate-shaped first and second radiation electrodes located at positions different from that of the ground electrode in the normal direction of the dielectric substrate, and first and second parasitic elements connected to the ground electrode. A first direction for determining the sizes of the first and second radiation electrodes is orthogonal to the normal direction, and the first and second radiation electrodes are located at different positions in the first direction. The first and second parasitic elements extend in the first direction, are respectively located at the same positions as those of the first and second radiation electrodes in the first direction, and are located at different positions in a second direction orthogonal to the normal direction and intersecting the first direction. The first and second radiation electrodes are located between the first and second parasitic elements in the second direction.

Description

Antenna board, antenna module, communication device

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

[0002] Patent Document 1 discloses an antenna array for ultra-wideband radar, which includes a plurality of radiating patch elements formed on an upper layer of a printed circuit board (PCB), a distribution feed network on an intermediate layer of the PCB having the patch array, and a continuous feed device from a 1 / 4λ coupling slot to each feed patch.

[0003] Special Publication No. 2014-514801

[0004] In devices and systems using antennas, radiation coverage over the entire space is often emphasized. In the antenna array disclosed in Patent Document 1, multiple radiating patch elements (radiating electrodes) are arranged on a printed circuit board (dielectric substrate). Since the direction of radio wave radiation from each radiating patch element is the normal direction of the printed circuit board, radio wave radiation to the sides of the printed circuit board is not practical. Therefore, 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.

[0006] An antenna substrate according to one aspect of the present disclosure comprises a dielectric substrate having a dielectric layer, a ground electrode on the dielectric substrate, and first and second antennas on the dielectric substrate corresponding to a first frequency band, wherein the first and second antennas respectively include first and second radiating electrodes having a flat plate shape and located at different positions from the ground electrode in a normal direction of the dielectric substrate, and first and second parasitic elements connected to the ground electrodes, wherein the first and second radiating electrodes have sizes determined in a first direction orthogonal to the normal direction and are located at different positions in the first direction, the first and second parasitic elements extend in the first direction and are located at different positions in a second direction orthogonal to the normal direction and intersecting the first direction, and the first and second radiating electrodes are located between the first and second parasitic elements in the second direction.

[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.

[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.

[0010] 1. Block diagram of a communication device including an antenna module according to a first embodiment. 2. Perspective view of an antenna substrate according to a first embodiment. 3. Plan view showing the structure of a main surface of the antenna substrate according to a first embodiment. 4. Plan view showing the structure of a back surface of the antenna substrate according to a first embodiment. 5. Plan view showing the structure of an intermediate layer of the antenna substrate according to a first embodiment. 6. Perspective view of an antenna substrate according to a second embodiment. 7. Plan view showing the structure of a main surface of the antenna substrate according to a second embodiment. 8. Plan view showing the structure of a back surface of the antenna substrate according to a second embodiment. 9. Plan view showing the structure of an intermediate layer of the antenna substrate according to a second embodiment. Graph showing the relationship between the angle and the antenna phase difference in the first frequency band. Graph showing the relationship between the angle and the antenna phase difference in the second frequency band. Graph showing the relationship between the antenna efficiency and the antenna phase difference in the first frequency band for each antenna substrate. Graph showing the relationship between the antenna efficiency and the antenna phase difference in the second frequency band for each antenna substrate.

[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, 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, for the sake of simplicity, the XYZ Cartesian coordinate system shown in the drawings will be used.

[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 is a block diagram of a communication device 100 according to one 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 through 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 IEEE 802.11, 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, for example, by 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, a ground electrode 3, first to fourth antennas 4-1 to 4-4, first and second feeder lines 51 and 52, and first to fourth feeder connection lines 6-1 to 6-4. Note that in Fig. 2, the thickness of the dielectric substrate 2 is emphasized 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 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.

[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 ground electrode 3, the first to fourth antennas 4-1 to 4-4, the first and second feeder lines 51, 52, and the first to fourth feeder connection lines 6-1 to 6-4 are provided on a dielectric substrate 2.

[0029] The antenna substrate 1 will be further described below with reference to Figures 3 to 5. Figure 3 is a plan view showing the structure of the main surface 2a of the antenna substrate 1, Figure 4 is a plan view showing the structure of the back surface 2b of the antenna substrate 1, and Figure 5 is a plan view showing the structure of the intermediate layer of the antenna substrate 1. However, in Figure 4, the back surface 2b of the antenna substrate 1 is viewed from the main surface 2a side simply to make the explanation easier to understand.

[0030] The ground electrode 3 is located on the back surface 2b of the dielectric substrate 2. As shown in FIG. 4 , the ground electrode 3 is a conductor pattern that covers substantially the entire back surface 2b. The ground electrode 3 includes a first portion 31 at a first end (left end in FIG. 4 ) in the length direction (X direction) of the dielectric substrate 2, a second portion 32 at a second end (right end in FIG. 4 ) in the length direction (X direction) of the dielectric substrate 2, and a third portion 33 between the first portion 31 and the second portion 32. In the width direction (Y direction) of the dielectric substrate 2, the dimension of the third portion 33 is smaller than the dimensions of the first portion 31 and the second portion 32. The first, second, and third portions 31, 32, and 33 have first ends 31a, 32a, and 33a and second ends 31b, 32b, and 33b, respectively, in the width direction (Y direction) of the dielectric substrate 2. The first ends 31 a, 32 a, and 33 a are on the same side (upper side in FIG. 4 ) of the ground electrode 3, and the second ends 31 b, 32 b, and 33 b are on the same side (lower side in FIG. 4 ) of the ground electrode 3. In the width direction (Y direction) of the dielectric substrate 2, the first end 33 a of the third portion 33 is closer to the center of the ground electrode 3 than the first ends 31 a and 32 a of the first and second portions 31 and 32, and the second end 33 b of the third portion 33 is closer to the center of the ground electrode 3 than the second ends 31 b and 32 b of the first and second portions 31 and 32.

[0031] The first and second antennas 4-1 and 4-2 correspond to a first frequency band. The third and fourth antennas 4-3 and 4-4 correspond to a second frequency band different from the first frequency band. For example, the first and second frequency bands may be frequency bands used in UWB (Ultra-Wide Band) wireless communications. As an example, in the case of the IEEE 802.15.4a short-range wireless standard established by the Institute of Electrical and Electronic Engineers (IEEE), the first frequency band may be channel number 5 (center frequency: 6489.6 MHz, frequency bandwidth: 499.2 MHz), and the second frequency band may be channel number 9 (center frequency: 7987.2 MHz, frequency bandwidth: 499.2 MHz).

[0032] Each of the first to fourth antennas 4-1 to 4-4 includes a combination of a radiation electrode (a feed element) and a parasitic element. More specifically, the first to fourth antennas 4-1 to 4-4 include first to fourth radiation electrodes 41-1 to 41-4 and first to fourth parasitic elements 42-1 to 42-4, respectively.

[0033] The first to fourth radiation electrodes 41-1 to 41-4 are located at different positions from the ground electrode 3 in the normal direction of the dielectric substrate 2. Therefore, the first to fourth radiation electrodes 41-1 to 41-4 face the ground electrode 3 with at least a part of the dielectric layer 20 of the dielectric substrate 2 sandwiched therebetween. In this embodiment, as shown in FIG. 3 , the first to fourth radiation electrodes 41-1 to 41-4 are located on the main surface 2a of the dielectric substrate 2. Each of the first to fourth radiation electrodes 41-1 to 41-4, together with the ground electrode 3, forms a patch antenna. In this embodiment, the first to fourth radiation electrodes 41-1 to 41-4 are contained within the ground electrode 3 when viewed from the normal direction of the dielectric substrate 2.

[0034] The first to fourth radiation electrodes 41-1 to 41-4 have a flat plate shape (planar shape). In particular, the first to fourth radiation electrodes 41-1 to 41-4 have a generally rectangular shape when viewed from the normal direction of the dielectric substrate 2.

[0035] In this embodiment, the first to fourth radiation electrodes 41-1 to 41-4 have the same shape. Below, the shapes of the first to fourth radiation electrodes 41-1 to 41-4 will be described based on the first radiation electrode 41-1. The first radiation electrode 41-1 has a first side 41a, a second side 41b, a third side 41c, and a fourth side 41d. The first side 41a and the second side 41b are long sides and are both ends in the width direction (Y direction) of the dielectric substrate 2. The first side 41a and the second side 41b are linear and extend along the length direction (X direction) of the dielectric substrate 2. The third side 41c and the fourth side 41d are short sides and are both ends in the length direction (X direction) of the dielectric substrate 2. The third side 41c and the fourth side 41d are linear and extend along the width direction (Y direction) of the dielectric substrate 2.

[0036] The size of the first radiation electrode 41-1 can be determined based on the corresponding frequency band. The first direction that determines the size of the first radiation electrode 41-1 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. Therefore, in this embodiment, the size of the first radiation electrode 41-1 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 41c and the fourth side 41d, which are the shorter sides. This is also true for the second to fourth radiation electrodes 41-2 to 41-4. In this embodiment, the first and second antennas 4-1 and 4-2 correspond to a first frequency band. The third and fourth antennas 4-3 and 4-4 correspond to a second frequency band that is different from the first frequency band. Therefore, the first and second radiation electrodes 41-1 and 41-2 have the same size, and the third and fourth antennas 4-3 and 4-4 have the same size. In this embodiment, since the first frequency band is lower than the second frequency band, the sizes of the first and second radiation electrodes 41-1 and 41-2 are larger than the third and fourth radiation electrodes 41-3 and 41-4.

[0037] The first to fourth parasitic elements 42-1 to 42-4 are provided to improve radio wave radiation to the sides of the dielectric substrate 2. As shown in Fig. 4, the first to fourth parasitic elements 42-1 to 42-4 are located on the back surface 2b of the dielectric substrate 2. Each of the first to fourth parasitic elements 42-1 to 42-4 is connected to the ground electrode 3.

[0038] The first to fourth parasitic elements 42-1 to 42-4 extend in a first direction. The first to fourth parasitic elements 42-1 to 42-4 are conductor patterns formed integrally with the ground electrode 3. More specifically, the first parasitic element 42-1 extends from the first end 31a of the first portion 31 of the ground electrode 3 toward the second portion 32. The second parasitic element 42-2 extends from the second end 32b of the second portion 32 of the ground electrode 3 toward the first portion 31. The third parasitic element 42-3 extends from the first end 32a of the second portion 32 of the ground electrode 3 toward the first portion 31. The fourth parasitic element 42-4 extends from the second end 31c of the first portion 31 of the ground electrode 3 toward the second portion 32.

[0039] In the width direction (Y direction) of the dielectric substrate 2, the first and third parasitic elements 42-1, 42-3 are located between the first ends 31a, 32a of the first and second portions 31, 32 of the ground electrode 3 and the first end 33a of the third portion 33. In the width direction (Y direction) of the dielectric substrate 2, the second and fourth parasitic elements 42-2, 42-4 are located between the second ends 31b, 32b of the first and second portions 31, 32 of the ground electrode 3 and the second end 33b of the third portion 33.

[0040] The electrical lengths of the first and second parasitic elements 42-1, 42-2 are determined according to the wavelength in the substrate corresponding to the first frequency band. The wavelength in the substrate corresponding to the first frequency band is determined by taking into account the wavelength in free space (free space wavelength) corresponding to the first frequency band and the dielectric constant of the dielectric substrate 2. The electrical lengths of the first and second parasitic elements 42-1, 42-2 are set so that the first and second parasitic elements 42-1, 42-2 resonate in the first frequency band. The electrical length refers to the electrical length of the medium as opposed to the physical length of the medium. It can also be said that the electrical length represents the length of the medium based on the signal delay time.

[0041] The wavelength in the substrate corresponding to the first frequency band is λ ｇ１ Then, the electrical length of the first and second parasitic elements 42-1 and 42-2 is λ ｇ１ The first and second parasitic elements 42-1 and 42-2 have a shape corresponding to a so-called grounded λ / 4 monopole antenna, which enables the first and second parasitic elements 42-1 and 42-2 to improve the radio wave radiation in the first frequency band.

[0042] The electrical lengths of the third and fourth parasitic elements 42-3 and 42-4 are determined according to the wavelength in the substrate corresponding to the second frequency band. The wavelength in the substrate corresponding to the second frequency band is determined by taking into account the wavelength in free space (free space wavelength) corresponding to the second frequency band and the dielectric constant of the dielectric substrate 2. The electrical lengths of the third and fourth parasitic elements 42-3 and 42-4 are set so that the third and fourth parasitic elements 42-3 and 42-4 resonate in the second frequency band. The electrical length refers to the electrical length of the medium as opposed to the physical length of the medium. It can also be said that the electrical length represents the length of the medium based on the signal delay time.

[0043] The wavelength in the substrate corresponding to the second frequency band is λ ｇ２ Then, the electrical length of the third and fourth parasitic elements 42-3 and 42-4 is λ ｇ２ The third and fourth parasitic elements 42-3 and 42-4 have a shape corresponding to a so-called grounded λ / 4 monopole antenna, which enables the third and fourth parasitic elements 42-3 and 42-4 to improve the radio wave radiation in the second frequency band.

[0044] Next, the arrangement of the first to fourth antennas 4-1 to 4-4 as viewed from the normal direction of the dielectric substrate 2, that is, the positional relationship of the first to fourth radiation electrodes 41-1 to 41-4 and the first to fourth parasitic elements 42-1 to 42-4 as viewed from the normal direction of the dielectric substrate 2, will be described mainly with reference to FIG.

[0045] The first and second radiation electrodes 41-1 and 41-2 are located at different positions in the first direction (X direction). This makes it possible to determine the angle at which the radio waves arrive in a plane that includes the first direction (X direction) and the normal direction of the dielectric substrate 2, from the phase difference between the radio waves in the first frequency band that reach the first and second radiation electrodes 41-1 and 41-2.

[0046] The first and second parasitic elements 42-1 and 42-2 are located at the same positions as the first and second radiation electrodes 41-1 and 41-2, respectively, in the first direction (X direction). The first and second parasitic elements 42-1 and 42-2 are located at different positions in a second direction that is orthogonal to the normal direction (Z direction) of the dielectric substrate 2 and intersects with 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 the second direction (Y direction), the first and second radiation electrodes 41-1 and 41-2 are located between the first and second parasitic elements 42-1 and 42-2. In this way, the presence of the first and second parasitic elements 42-1 and 42-2 enables improved radio wave radiation (in the first frequency band) laterally (particularly in the second direction) of the dielectric substrate 2. In addition, in the second direction (Y direction), the first and second parasitic elements 42-1 and 42-2 are located on opposite sides of the first and second radiation electrodes 41-1 and 41-2, which reduces interference between the first and second parasitic elements 42-1 and 42-2 and makes it possible to reduce deterioration of the antenna efficiency.

[0047] The third and fourth radiation electrodes 41-3 and 41-4 are located at different positions in the first direction (X direction). This makes it possible to determine the angle at which the radio waves arrive in a plane including the first direction (X direction) and the normal direction of the dielectric substrate 2, from the phase difference between the radio waves in the second frequency band that reach the third and fourth radiation electrodes 41-3 and 41-4.

[0048] The third and fourth parasitic elements 42-3 and 42-4 are located at the same positions as the third and fourth radiation electrodes 41-3 and 41-4, respectively, in the first direction (X direction). The third and fourth parasitic elements 42-3 and 42-4 are located at different positions in the second direction (Y direction). In the second direction (Y direction), the third and fourth radiation electrodes 41-3 and 41-4 are located between the third and fourth parasitic elements 42-3 and 42-4. In this way, the presence of the third and fourth parasitic elements 42-3 and 42-4 enables improved radio wave radiation (in the second frequency band) to the sides of the dielectric substrate 2 (particularly in the second direction). Furthermore, in the second direction (Y direction), the third and fourth parasitic elements 42-2 and 42-4 are located on the opposite side of the third and fourth radiation electrodes 41-3 and 41-4. This can reduce interference between the third and fourth parasitic elements 42-3 and 42-4, making it possible to reduce deterioration in antenna efficiency.

[0049] The first radiation electrode 41-1 and the third radiation electrode 41-3 are located at different positions in the first direction (X direction). The second radiation electrode 41-2 and the fourth radiation electrode 41-4 are located at different positions in the first direction (X direction). The first and third radiation electrodes 41-1, 41-3 and the second and fourth radiation electrodes 41-2, 41-4 are located at different positions in the second direction (Y direction). This allows the first to fourth radiation electrodes 41-1 to 41-4 to be efficiently arranged on the dielectric substrate 2, reduces the area required for arranging the first to fourth radiation electrodes 41-1 to 41-4, and enables the dielectric substrate 2 to be made smaller.

[0050] At least a portion of the first and fourth radiation electrodes 41-1 and 41-4 is located at the same position in the first direction (X direction), and at least a portion of the second and third radiation electrodes 41-2 and 41-3 is located at the same position in the first direction (X direction). This allows the first to fourth radiation electrodes 41-1 to 41-4 to be efficiently arranged on the dielectric substrate 2 in the first direction, reduces the area required for arranging the first to fourth radiation electrodes 41-1 to 41-4 in the first direction, and enables miniaturization of the dielectric substrate 2. In particular, in this embodiment, the centers C1 and C4 of the first and fourth radiation electrodes 41-1 and 41-4 coincide with each other in the first direction (X direction), and the centers C2 and C3 of the second and third radiation electrodes 41-2 and 41-3 coincide with each other in the first direction (X direction).

[0051] At least a portion of the first and third radiation electrodes 41-1 and 41-3 is located at the same position in the second direction (Y direction), and at least a portion of the second and fourth radiation electrodes 41-2 and 41-4 is located at the same position in the second direction (Y direction). This allows the first to fourth radiation electrodes 41-1 to 41-4 to be efficiently arranged on the dielectric substrate 2 in the second direction, and reduces the area required for arranging the first to fourth radiation electrodes 41-1 to 41-4 in the second direction, thereby enabling miniaturization of the dielectric substrate 2. In particular, in this embodiment, the centers C1 and C3 of the first and third radiation electrodes 41-1 and 41-3 coincide with each other in the second direction (Y direction), and the centers C2 and C4 of the second and fourth radiation electrodes 41-2 and 41-4 coincide with each other in the second direction (Y direction).

[0052] The first radiation electrode 41-1 is closer to the first parasitic element 42-1 than the second parasitic element 42-2 in the second direction (Y direction). The second radiation electrode 41-2 is closer to the second parasitic element 42-1 than the first parasitic element 42-1 in the second direction (Y direction). The third radiation electrode 41-3 is closer to the third parasitic element 42-3 than the fourth parasitic element 42-4 in the second direction (Y direction). The fourth radiation electrode 41-4 is closer to the fourth parasitic element 42-4 than the third parasitic element 42-3 in the second direction (Y direction). This enables further improvement in radio wave radiation to the sides of the dielectric substrate 2.

[0053] A line segment L1 connecting the centers C1, C2 of the first and second radiation electrodes 41-1, 41-2 and a line segment L2 connecting the centers C3, C4 of the third and fourth radiation electrodes 41-3, 41-4 intersect with each other. This configuration improves the symmetry of the antenna characteristics and improves the accuracy of detecting the phase difference. In particular, in this embodiment, the lengths of the line segments L1 and L2 are equal. This configuration further improves the symmetry of the antenna characteristics. In particular, in this embodiment, an intersection C5 between the line segments L1 and L2 is the midpoint of each of the line segments L1 and L2. This configuration further improves the symmetry of the antenna characteristics.

[0054] In this way, the radiation electrodes 41 of the four antennas 4 are arranged in a 2×2 array on the dielectric substrate 2. Here, the free space wavelength corresponding to the first frequency band is λ ｏ１ Then, the size of the dielectric substrate 2 in the first direction (X direction) is λ ｏ１ This allows the dielectric substrate 2 to be made smaller.

[0055] The first and second feed lines 51, 52 are used to feed power to the first to fourth antennas 4-1 to 4-4. More specifically, the first feed line 51 is used to feed power to the first and fourth antennas 4-1 and 4-4. The second feed line 52 is used to feed power to the second and third antennas 4-1 to 4-4. As shown in Fig. 5, the first and second feed lines 51, 52 are provided as intermediate layers between the main surface 2a and the back surface 2b of the dielectric substrate 2.

[0056] The first feed line 51 includes a branch connection point 511 and connection lines 512 and 513. The branch connection point 511 is a portion between the connection lines 512 and 513 and 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 connection point 511 via a transmission line or through-hole wiring as an intermediate layer. The connection line 512 is used for connection between the branch connection point 511 and the first radiation electrode 41-1. The connection line 512 extends from the branch connection point 511 so as to overlap with the first radiation electrode 41-1 when viewed from the normal direction of the dielectric substrate 2. The length of the connection line 512 is set so that the first radiation electrode 41-1 appears open for the second frequency band. Therefore, the connection line 512 is set to pass signals in the first frequency band but not signals in the second frequency band. The connection line 513 is used for connection between the branch connection point 511 and the fourth radiation electrode 41-4. The connection line 513 extends from the connection point 511 so as to overlap with the fourth radiation electrode 41-4 when viewed from the normal direction of the dielectric substrate 2. The length of the connection line 513 is set so that the fourth radiation electrode 41-4 appears open for the first frequency band. Therefore, the connection line 513 is set so as to pass signals in the second frequency band but not signals in the first frequency band.

[0057] The second feed line 52 includes a branch connection point 521 and connection lines 522 and 523. The branch connection point 521 is a portion between the connection lines 522 and 523 and 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 connection point 521 via a wiring pattern, a through-hole wiring, or the like. The connection line 522 is used for connection between the branch connection point 521 and the second radiation electrode 41-2. The connection line 522 extends from the branch connection point 521 so as to overlap with the second radiation electrode 42-1 when viewed from the normal direction of the dielectric substrate 2. The length of the connection line 522 is set so that the second radiation electrode 41-2 appears open for the second frequency band. Therefore, the connection line 522 is set to pass signals in the first frequency band but not signals in the second frequency band. The connection line 523 is used for connection between the branch connection point 521 and the third radiation electrode 41-3. The connection line 523 extends from the connection point 521 so as to overlap with the third radiation electrode 41-3 when viewed from the normal direction of the dielectric substrate 2. The length of the connection line 523 is set so that the third radiation electrode 41-3 appears open for the first frequency band. Therefore, the connection line 523 is set to pass signals in the second frequency band but not signals in the first frequency band.

[0058] The first to fourth feed connection lines 6-1 to 6-4 are interlayer connection lines used to connect the first and second feed lines 51, 52 to the first to fourth antennas 4-1 to 4-4. The first feed connection line 6-1 connects the connection line 512 of the first feed line 51 to the first radiation electrode 41-1. The position of the first feed connection line 6-1 as viewed from the normal direction of the dielectric substrate 2 corresponds to the position of the feed point of the first radiation electrode 41-1. The second feed connection line 6-2 connects the connection line 522 of the second feed line 52 to the second radiation electrode 41-2. The position of the second feed connection line 6-2 as viewed from the normal direction of the dielectric substrate 2 corresponds to the position of the feed point of the second radiation electrode 41-2. The third feed connection line 6-3 connects the connection line 522 of the second feed line 52 to the third radiation electrode 41-3. The position of the third feed connection line 6-3 when viewed from the normal direction of the dielectric substrate 2 corresponds to the position of the feed point of the third radiation electrode 41-3. The fourth feed connection line 6-4 connects the connection line 512 of the first feed line 51 and the fourth radiation electrode 41-4. The position of the fourth feed connection line 6-3 when viewed from the normal direction of the dielectric substrate 2 corresponds to the position of the feed point of the fourth radiation electrode 41-4.

[0059] [1.1.2 Effects, etc.] The antenna substrate 1 described above includes a dielectric substrate 2 having a dielectric layer 20, a ground electrode 3 on the dielectric substrate 2, and first and second antennas 4-1 and 4-2 on the dielectric substrate 2 corresponding to a first frequency band. The first and second antennas 4-1 and 4-2 each include first and second flat radiation electrodes 41-1 and 41-2 located at different positions from the ground electrode 3 in the normal direction (Z direction) of the dielectric substrate 2, and first and second parasitic elements 42-1 and 42-2 connected to the ground electrode 3. A first direction (X direction) that determines the size of the first and second radiation electrodes 41-1 and 41-2 is orthogonal to the normal direction. The first and second radiation electrodes 41-1 and 41-2 are located at different positions in the first direction. The first and second parasitic elements 42-1 and 42-2 extend in a first direction and are respectively located at the same positions as the first and second radiation electrodes 41-1 and 41-2 in the first direction. The first and second parasitic elements 42-1 and 42-2 are located at different positions in a second direction (Y direction) that is orthogonal to the normal direction and intersects the first direction. The first and second radiation electrodes 41-1 and 41-2 are located between the first and second parasitic elements 42-1 and 42-2 in the second direction. This configuration enables improved radio wave radiation to the sides of the dielectric substrate 2 while reducing deterioration in antenna efficiency.

[0060] The antenna substrate 1 described above includes third and fourth antennas 4-3 and 4-4 on the dielectric substrate 2, which correspond to a second frequency band different from the first frequency band. The third and fourth antennas 4-3 and 4-4 each include third and fourth radiation electrodes 41-3 and 41-4 that are located at different positions from the ground electrode 3 in the normal direction, and third and fourth parasitic elements 42-3 and 42-4 that are connected to the ground electrode 3. The third and fourth radiation electrodes 41-3 and 41-4 have sizes determined in a first direction and are located at different positions in the first direction. The third and fourth parasitic elements 42-3 and 42-4 extend in the first direction and are located at the same positions as the third and fourth radiation electrodes 41-3 and 41-4, respectively, in the first direction. The third and fourth parasitic elements 42-3 and 42-4 are located at different positions in the second direction. The third and fourth radiation electrodes 41-3 and 41-4 are located between the third and fourth parasitic elements 42-3 and 42-4 in the second direction. This configuration enables dual-band compatibility, improves radio wave radiation to the sides of the dielectric substrate 2, and reduces deterioration of antenna efficiency.

[0061] In the antenna substrate 1 described above, the first radiation electrode 41-1 and the third radiation electrode 41-3 are located at different positions in the first direction. The second radiation electrode 41-2 and the fourth radiation electrode 41-4 are located at different positions in the first direction. The first and third radiation electrodes 41-1, 41-3 and the second and fourth radiation electrodes 41-2, 41-4 are located at different positions in the second direction. This configuration can reduce the area required for arranging the first to fourth radiation electrodes 41-1 to 41-4, and enables the dielectric substrate 2 to be made smaller.

[0062] In the antenna substrate 1 described above, at least a portion of the first and fourth radiation electrodes 41-1 and 41-4 are located at the same position in the first direction. At least a portion of the second and third radiation electrodes 41-2 and 41-3 are located at the same position in the first direction. This configuration can reduce the area required for arranging the first to fourth radiation electrodes 41-1 to 41-4 in the first direction, and enables the dielectric substrate 2 to be made smaller.

[0063] In the antenna substrate 1 described above, at least a portion of the first and third radiation electrodes 41-1 and 41-3 are located at the same position in the second direction. At least a portion of the second and fourth radiation electrodes 41-2 and 41-4 are located at the same position in the second direction. This configuration can reduce the area required for arranging the first to fourth radiation electrodes 41-1 to 41-4 in the second direction, and enables the dielectric substrate 2 to be made smaller.

[0064] In the antenna substrate 1 described above, the first radiation electrode 41-1 is closer to the first parasitic element 42-1 than the second parasitic element 42-2 in the second direction (Y direction). The second radiation electrode 41-2 is closer to the second parasitic element 42-1 than the first parasitic element 42-1 in the second direction (Y direction). The third radiation electrode 41-3 is closer to the third parasitic element 42-3 than the fourth parasitic element 42-4 in the second direction (Y direction). The fourth radiation electrode 41-4 is closer to the fourth parasitic element 42-4 than the third parasitic element 42-3 in the second direction (Y direction). This configuration enables further improvement in radio wave radiation to the sides of the dielectric substrate 2.

[0065] In the above-described antenna substrate 1, the first to fourth radiation electrodes 41-1 to 41-4 have the same size. This configuration makes it possible to improve the symmetry of the antenna characteristics and improve the accuracy of detecting the phase difference.

[0066] In the above-described antenna substrate 1, the first to fourth radiation electrodes 41-1 to 41-4 have the same shape. This configuration makes it possible to improve the symmetry of the antenna characteristics and improve the accuracy of detecting the phase difference.

[0067] In the antenna substrate 1 described above, the line segment L1 connecting the centers C1 and C2 of the first and second radiation electrodes 41-1 and 41-2 and the line segment L2 connecting the centers C3 and C4 of the third and fourth radiation electrodes 41-3 and 41-4 intersect with each other. This configuration improves the symmetry of the antenna characteristics and improves the accuracy of phase difference detection.

[0068] In the antenna substrate 1 described above, the first and second parasitic elements 42-1, 42-2 are located in the same position in the normal direction as the ground electrode 3. This configuration makes it possible to improve radio wave radiation to the sides of the dielectric substrate 2 while reducing degradation in antenna efficiency.

[0069] In the antenna substrate 1 described above, the free space wavelength corresponding to the first frequency band is λ ｏ１ Then, the size of the dielectric substrate 2 in the first direction is λ ｏ１ This configuration allows the dielectric substrate 2 to be made smaller.

[0070] In the antenna substrate 1 described above, the dielectric substrate 2 has a main surface 2a and a back surface 2b opposite to the main surface 2a in the normal direction. The ground electrode 3 is located on the back surface 2b. The first and second radiation electrodes 41-1 and 41-2 are located on the main surface 2a. This configuration can maximize the distance between the first and second radiation electrodes 41-1 and 41-2 and the ground electrode 3, and can increase the bandwidth of the first frequency band.

[0071] In the antenna substrate 1 described above, the wavelength in the substrate corresponding to the first frequency band is λ ｇ１ Then, the electrical length of the first and second parasitic elements 42-1 and 42-2 is λ ｇ１ / 4±25%. This configuration enables the first and second parasitic elements 42-1 and 42-2 to improve the radiation of radio waves in the first frequency band.

[0072] 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.

[0073] 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.

[0074] [1.2 Second Embodiment] [1.2.1 Configuration] Fig. 6 is a perspective view of an antenna substrate 1A according to the second embodiment. The antenna substrate 1A includes a dielectric substrate 2, a ground electrode 3, first to fourth antennas 4A-1 to 4A-4, first and second feed lines 51, 52, first to fourth feed connection lines 6-1 to 6-4, and first to fourth ground connection lines 7-1 to 7-4. Note that in Fig. 6, the thickness of the dielectric substrate 2 is exaggerated for ease of understanding.

[0075] The antenna substrate 1A will be further described below with reference to Figures 7 to 9. Figure 7 is a plan view showing the structure of the main surface 2a of the antenna substrate 1A, Figure 8 is a plan view showing the structure of the back surface 2b of the antenna substrate 1A, and Figure 9 is a plan view showing the structure of the intermediate layer of the antenna substrate 1A. However, in Figure 8, the back surface 2b of the antenna substrate 1A is viewed from the main surface 2a side simply to make the description easier to understand.

[0076] Each of the first to fourth antennas 4A-1 to 4A-4 is configured by combining a radiation electrode (a feed element) and a parasitic element. More specifically, the first to fourth antennas 4A-1 to 4A-4 include first to fourth radiation electrodes 41-1 to 41-4 and first to fourth parasitic elements 42A-1 to 42A-4, respectively.

[0077] 7 to 9, the first to fourth parasitic elements 42A-1 to 42A-4 are provided as intermediate layers between the main surface 2a and the back surface 2b of the dielectric substrate 2. Therefore, the first and second parasitic elements 42A-1 and 42A-2 are located between the ground electrode 3 and the first and second radiation electrodes 41-1 and 41-2 in the normal direction of the dielectric substrate 2. The third and fourth parasitic elements 42A-3 and 42A-4 are located between the ground electrode 3 and the third and fourth radiation electrodes 41-3 and 41-4 in the normal direction of the dielectric substrate 2.

[0078] Each of the first to fourth parasitic elements 42A-1 to 42A-4 is connected to the ground electrode 3. In this embodiment, the first to fourth parasitic elements 42A-1 to 42A-4 are connected to the ground electrode 3 via the first to fourth ground connection lines 7-1 to 7-4, respectively.

[0079] The first to fourth ground connection wires 7-1 to 7-4 are interlayer connection wires used to connect the ground electrode 3 to the first to fourth parasitic elements 42A-1 to 42A-4. The first ground connection wire 7-1 connects the first end 31a of the first portion 31 of the ground electrode 3 to the first parasitic element 42A-1. The second ground connection wire 7-2 connects the second end 32b of the second portion 32 of the ground electrode 3 to the second parasitic element 42A-2. The third ground connection wire 7-3 connects the first end 32a of the second portion 32 of the ground electrode 3 to the third parasitic element 42A-3. The fourth ground connection wire 7-4 connects the second end 31c of the first portion 31 of the ground electrode 3 to the fourth parasitic element 42A-4.

[0080] In the present embodiment, the arrangement of the first to fourth antennas 4A-1 to 4A-4 as viewed from the normal direction of the dielectric substrate 2 is the same as in embodiment 1. The description of the arrangement of the first to fourth antennas 4-1 to 4-4 as viewed from the normal direction of the dielectric substrate 2 in embodiment 1 can be applied to the description of embodiment 2 by replacing the parasitic element 42 with the parasitic element 42A.

[0081] [1.2.2 Effects, etc.] In the antenna substrate 1A described above, the first and second parasitic elements 42A-1, 42A-2 are located between the ground electrode 3 and the first and second radiation electrodes 41-1, 41-2 in the normal direction. This configuration can reduce degradation of antenna characteristics due to the influence of noise from a wiring substrate or the like when a wiring substrate or the like is present around the antenna substrate 1A.

[0082] In the antenna substrate 1A described above, the third and fourth parasitic elements 42A-3 and 42A-4 are located between the ground electrode 3 and the third and fourth radiation electrodes 41-3 and 41-4 in the normal direction. This configuration can reduce the degradation of antenna characteristics caused by the influence of noise from a wiring substrate or the like when a wiring substrate or the like is present around the antenna substrate 1A.

[0083] [1.3 Third Embodiment] [1.3.1 Configuration] Fig. 10 is a perspective view of an antenna substrate 1B according to the third embodiment. The antenna substrate 1B includes a dielectric substrate 2, a ground electrode 3B, first to fourth antennas 4A-1 to 4A-4, first and second feed lines 51 and 52, first to fourth feed connection lines 6-1 to 6-4, and first to fourth ground connection lines 7-1 to 7-4. Note that in Fig. 10, the thickness of the dielectric substrate 2 is exaggerated for ease of understanding.

[0084] The antenna substrate 1B will be further described below with reference to Figures 11 to 13. Figure 11 is a plan view showing the structure of the main surface 2a of the antenna substrate 1B, Figure 12 is a plan view showing the structure of the back surface 2b of the antenna substrate 1B, and Figure 13 is a plan view showing the structure of the intermediate layer of the antenna substrate 1B. However, in Figure 12, the back surface 2b of the antenna substrate 1B is viewed from the main surface 2a side simply to make the description easier to understand.

[0085] As is clear from Figure 12, the ground electrode 3B comprises a first portion 31 at a first end (left end in Figures 11 to 13) in the longitudinal direction (X direction) of the dielectric substrate 2, a second portion 32 at a second end (right end in Figures 11 to 13) in the longitudinal direction (X direction) of the dielectric substrate 2, and a third portion 33B between the first portion 31 and the second portion 32.

[0086] In the width direction (Y direction) of the dielectric substrate 2, the dimension of the third portion 33B is equal to the dimensions of the first portion 31 and the second portion 32. As a result, as shown in FIGS. 11 to 13 , the ground electrode 3B overlaps with the first to fourth parasitic elements 42A-1 to 42A-4 when viewed from the normal direction of the dielectric substrate 2. That is, in this embodiment, the first and second parasitic elements 42A-1 and 42A-2 overlap with the ground electrode 3B when viewed from the normal direction. The third and fourth parasitic elements 42A-3 and 42A-4 overlap with the ground electrode 3B when viewed from the normal direction. As a result, the ground electrode 3B can function as a shield for the first to fourth parasitic elements 42A-1 to 42A-4.

[0087] In the present embodiment, the arrangement of the first to fourth antennas 4A-1 to 4A-4 as viewed from the normal direction of the dielectric substrate 2 is the same as in embodiment 1. The description of the arrangement of the first to fourth antennas 4-1 to 4-4 as viewed from the normal direction of the dielectric substrate 2 in embodiment 1 can be applied to the description of embodiment 3 by replacing the parasitic element 42 with the parasitic element 42A.

[0088] [1.3.2 Effects, etc.] In the antenna substrate 1B described above, the first and second parasitic elements 42A-1, 42A-2 overlap with the ground electrode 3B when viewed from the normal direction. This configuration can reduce degradation of antenna characteristics due to the influence of noise from a wiring substrate or the like when a wiring substrate or the like is present around the antenna substrate 1B.

[0089] In the antenna substrate 1B described above, the third and fourth parasitic elements 42A-3 and 42A-4 overlap the ground electrode 3B when viewed from the normal direction. This configuration can reduce the degradation of antenna characteristics caused by the influence of noise from a wiring substrate or the like when a wiring substrate or the like is present around the antenna substrate 1B.

[0090] [1.4 Fourth Embodiment] [1.4.1 Configuration] Fig. 14 is a perspective view of an antenna substrate 1C. The antenna substrate 1C includes a dielectric substrate 2, a ground electrode 3, first to fourth antennas 4C-1 to 4C-4, first and second feed lines 51, 52, first to fourth feed connection lines 6-1 to 6-4, first connection lines 8-1, 8-2, second connection lines 8-3, 8-4, third connection lines 8-5, 8-6, and fourth connection lines 8-7, 8-8. Note that in Fig. 14, the thickness of the dielectric substrate 2 is exaggerated for ease of understanding.

[0091] The antenna substrate 1C will be further described below with reference to Figures 15 to 17. Figure 15 is a plan view showing the structure of the main surface 2a of the antenna substrate 1C, Figure 16 is a plan view showing the structure of the back surface 2b of the antenna substrate 1C, and Figure 17 is a plan view showing the structure of the intermediate layer of the antenna substrate 1C. However, in Figure 16, the back surface 2b of the antenna substrate 1C is viewed from the main surface 2a side simply to make the description easier to understand.

[0092] Like the first to fourth antennas 4-1 to 4-4, the first to fourth antennas 4C-1 to 4C-4 include first to fourth radiation electrodes 41-1 to 41-4 and first to fourth parasitic elements 42-1 to 42-4, respectively.

[0093] The first antenna 4C-1 further includes first auxiliary electrodes 43-1 and 43-2. ​​The second antenna 4C-2 further includes second auxiliary electrodes 43-3 and 43-4. The third antenna 4C-3 further includes third auxiliary electrodes 43-5 and 43-6. The fourth antenna 4C-4 further includes fourth auxiliary electrodes 43-7 and 43-8.

[0094] 15 to 17, the first auxiliary electrodes 43-1 and 43-2 and the second auxiliary electrodes 43-3 and 43 are provided as intermediate layers between the main surface 2a and the back surface 2b of the electric circuit board 2.

[0095] The first auxiliary electrodes 43-1 and 43-2 are located in the normal direction between the end of the first radiation electrode 41-1 in the first direction and the ground electrode 3. In particular, the first auxiliary electrode 43-1 is located in the normal direction between the end of the first radiation electrode 41-1 opposite to the second radiation electrode 41-2 in the first direction (the end on the third side 41c side) and the ground electrode 3. The first auxiliary electrode 43-2 is located in the normal direction between the end of the first radiation electrode 41-1 on the second radiation electrode 41-2 side in the first direction (the end on the fourth side 41d side) and the ground electrode 3. The first auxiliary electrodes 43-1 and 43-2 are connected to the ground electrode 3 or the first radiation electrode 41-1.

[0096] The second auxiliary electrodes 43-3 and 43-4 are located in the normal direction between the end of the second radiation electrode 41-2 in the first direction and the ground electrode 3. In particular, the second auxiliary electrode 43-3 is located in the normal direction between the end of the second radiation electrode 41-2 on the first radiation electrode 41-1 side in the first direction (the end on the third side 41c side) and the ground electrode 3. The second auxiliary electrode 43-4 is located in the normal direction between the end of the second radiation electrode 41-2 on the opposite side to the first radiation electrode 41-1 in the first direction (the end on the fourth side 41d side) and the ground electrode 3. The second auxiliary electrodes 43-3 and 43-4 are connected to the ground electrode 3 or the second radiation electrode 41-2.

[0097] The third auxiliary electrodes 43-5 and 43-6 are located in the normal direction between the end of the third radiation electrode 41-3 in the first direction and the ground electrode 3. In particular, the third auxiliary electrode 43-5 is located in the normal direction between the end of the third radiation electrode 41-3 on the fourth radiation electrode 41-4 side in the first direction (the end on the third side 41c side) and the ground electrode 3. The third auxiliary electrode 43-6 is located in the normal direction between the end of the third radiation electrode 41-3 on the opposite side to the fourth radiation electrode 41-4 in the first direction (the end on the fourth side 41d side) and the ground electrode 3. The third auxiliary electrodes 43-5 and 43-6 are connected to the ground electrode 3 or the third radiation electrode 41-3.

[0098] The fourth auxiliary electrodes 43-7 and 43-8 are located in the normal direction between the end of the fourth radiation electrode 41-4 in the first direction and the ground electrode 3. In particular, the fourth auxiliary electrode 43-7 is located in the normal direction between the end of the fourth radiation electrode 41-4 opposite to the third radiation electrode 41-3 in the first direction (the end on the third side 41c side) and the ground electrode 3. The fourth auxiliary electrode 43-8 is located in the normal direction between the end of the fourth radiation electrode 41-4 on the third radiation electrode 41-3 side in the first direction (the end on the fourth side 41d side) and the ground electrode 3. The fourth auxiliary electrodes 43-7 and 43-8 are connected to the ground electrode 3 or the fourth radiation electrode 41-4.

[0099] Since the first auxiliary electrodes 43-1 and 43-2 are located between the first radiation electrode 41-1 and the ground electrode 3, connecting them to the ground electrode 3 or the first radiation electrode 41-1 increases the capacitance between the first radiation electrode 41-1 and the ground electrode 3 at the end of the first radiation electrode 41-1 in the first direction. This provides a wavelength shortening effect, allowing the size of the first radiation electrode 41-1 to be reduced. Similarly, the second auxiliary electrodes 43-3 and 43-4 provide a wavelength shortening effect, allowing the size of the second radiation electrode 41-2 to be reduced. The third auxiliary electrodes 43-5 and 43-6 provide a wavelength shortening effect, allowing the size of the third radiation electrode 41-3 to be reduced. The fourth auxiliary electrodes 43-7 and 43-8 provide a wavelength shortening effect, allowing the size of the fourth radiation electrode 41-4 to be reduced.

[0100] The shape and size of the auxiliary electrode 43 are appropriately set so as to obtain a desired wavelength shortening effect.

[0101] The first connection lines 8-1 and 8-2 are interlayer connection lines used to connect the ground electrode 3 or the first radiation electrode 41-1 to the first auxiliary electrodes 43-1 and 43-2. ​​The second connection lines 8-3 and 8-4 are interlayer connection lines used to connect the ground electrode 3 or the second radiation electrode 41-2 to the second auxiliary electrodes 43-3 and 43-4. The third connection lines 8-5 and 8-6 are interlayer connection lines used to connect the ground electrode 3 or the third radiation electrode 41-3 to the third auxiliary electrodes 43-5 and 43-6. The fourth connection lines 8-7 and 8-8 are interlayer connection lines used to connect the ground electrode 3 or the fourth radiation electrode 41-4 to the fourth auxiliary electrodes 43-7 and 43-8.

[0102] For radiation electrodes 41 corresponding to the same frequency band, it is preferable that the connection mode of the auxiliary electrode 43 (i.e., whether the auxiliary electrode 43 is connected to the radiation electrode 41 or the ground electrode 3) be the same. In this embodiment, the first connection lines 8-1 and 8-2 connect the first radiation electrode 41-1 to the first auxiliary electrodes 43-1 and 43-2, respectively, and the second connection lines 8-3 and 8-4 connect the second radiation electrode 41-2 to the second auxiliary electrodes 43-3 and 43-4, respectively. In this embodiment, the pair of first connection lines 8-1 and the pair of first connection lines 8-2 are aligned in the width direction of the dielectric substrate 2, and the pair of second connection lines 8-3 and the pair of second connection lines 8-4 are aligned in the width direction of the dielectric substrate 2. The third connection lines 8-5 and 8-6 connect the ground electrode 3 to the third auxiliary electrodes 43-5 and 43-6, respectively, and the fourth connection lines 8-7 and 8-8 connect the ground electrode 3 to the fourth auxiliary electrodes 43-7 and 43-8, respectively. In this embodiment, the pair of third connection lines 8-5 and the pair of third connection lines 8-6 are aligned in the width direction of the dielectric substrate 2, and the pair of fourth connection lines 8-7 and the pair of fourth connection lines 8-8 are aligned in the width direction of the dielectric substrate 2.

[0103] [1.4.2 Effects, etc.] In the antenna substrate 1C described above, the first antenna 4C-1 includes first auxiliary electrodes 43-1 and 43-2 that are located in the normal direction between the end of the first radiation electrode 41-1 in the first direction and the ground electrode 3, and are connected to the first radiation electrode 41-1 or the ground electrode 3. The second antenna 4C-2 includes second auxiliary electrodes 43-3 and 43-4 that are located in the normal direction between the end of the second radiation electrode 41-2 in the first direction and the ground electrode 3, and are connected to the second radiation electrode 41-2 or the ground electrode 3. This configuration enables the sizes of the first and second radiation electrodes 41-1 and 41-2 to be reduced.

[0104] In the antenna substrate 1C described above, the third antenna 4C-3 includes third auxiliary electrodes 43-5 and 43-6 that are located in the normal direction between the end of the third radiation electrode 41-3 in the first direction and the ground electrode 3, and are connected to the third radiation electrode 41-3 or the ground electrode 3. The fourth antenna 4C-4 includes fourth auxiliary electrodes 43-7 and 43-8 that are located in the normal direction between the end of the fourth radiation electrode 41-4 in the first direction and the ground electrode 3, and are connected to the fourth radiation electrode 41-4 or the ground electrode 3. This configuration enables the sizes of the third and fourth radiation electrodes 41-3 and 41-4 to be reduced.

[0105] 18 is a plan view of an antenna substrate 1D according to the fifth embodiment. The antenna substrate 1D includes a dielectric substrate 2, a ground electrode 3D, and first and second antennas 4-1 and 4-2. That is, the antenna substrate 1D constitutes a single-band antenna corresponding to the first frequency band.

[0106] The ground electrode 3D comprises a first portion 31D at a first end (left end in Figure 18) in the longitudinal direction (X direction) of the dielectric substrate 2, a second portion 32D at a second end (right end in Figure 18) in the longitudinal direction (X direction) of the dielectric substrate 2, and a third portion 33 between the first portion 31D and the second portion 32D.

[0107] In the width direction (Y direction) of the dielectric substrate 2, the first end 31 a of the first portion 31D is located outside the ground electrode 3D more than the first ends 32 a, 33 a of the second and third portions 32D, 33. The first ends 32 a, 33 a of the second and third portions 32D, 33 are aligned in the length direction (X direction) of the dielectric substrate 2.

[0108] In the width direction (Y direction) of the dielectric substrate 2, the second end 32b of the second portion 32D is located outside the ground electrode 3D more than the second ends 31b, 33b of the first and third portions 31D, 33. The second ends 31b, 33b of the first and third portions 31D, 33 are aligned in the length direction (X direction) of the dielectric substrate 2.

[0109] The first and second antennas 4-1 and 4-2 include first and second radiation electrodes 41-1 and 41-2 and first and second parasitic elements 42-1 and 42-2, respectively.

[0110] The first and second radiation electrodes 41-1 and 41-2 are arranged on the main surface 2a of the dielectric substrate 2. The first and second parasitic elements 42-1 and 42-2 are connected to the ground electrode 3D. The first parasitic element 42-1 extends from the first end 31a side of the first portion 31 of the ground electrode 3 toward the second portion 32. The second parasitic element 42-2 extends from the second end 32b side of the second portion 32 of the ground electrode 3 toward the first portion 31.

[0111] Next, the arrangement of the first and second antennas 4-1, 4-2 when viewed from the normal direction of the dielectric substrate 2, that is, the positional relationship between the first and second radiation electrodes 41-1, 41-2 and the first and second parasitic elements 42-1, 42-2 when viewed from the normal direction of the dielectric substrate 2, will be described.

[0112] The first and second radiation electrodes 41-1 and 41-2 are located at different positions in the first direction (X direction). This makes it possible to determine the angle at which the radio waves arrive in a plane that includes the first direction (X direction) and the normal direction of the dielectric substrate 2, from the phase difference between the radio waves in the first frequency band that reach the first and second radiation electrodes 41-1 and 41-2.

[0113] The first and second parasitic elements 42-1 and 42-2 are located at the same positions as the first and second radiation electrodes 41-1 and 41-2, respectively, in the first direction (X direction). The first and second parasitic elements 42-1 and 42-2 are located at different positions in a second direction that is orthogonal to the normal direction (Z direction) of the dielectric substrate 2 and intersects with 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 the second direction (Y direction), the first and second radiation electrodes 41-1 and 41-2 are located between the first and second parasitic elements 42-1 and 42-2. In this way, the presence of the first and second parasitic elements 42-1 and 42-2 enables improved radio wave radiation (in the first frequency band) laterally (particularly in the second direction) of the dielectric substrate 2. In addition, in the second direction (Y direction), the first and second parasitic elements 42-1 and 42-2 are located on opposite sides of the first and second radiation electrodes 41-1 and 41-2, which reduces interference between the first and second parasitic elements 42-1 and 42-2 and makes it possible to reduce deterioration of the antenna efficiency.

[0114] At least a portion of the first and second radiation electrodes 41-1 and 41-2 is located at the same position in the second direction (Y direction). This allows the first and second radiation electrodes 41-1 and 41-2 to be efficiently arranged on the dielectric substrate 2 in the second direction, and reduces the area required for arranging the first and second radiation electrodes 41-1 and 41-2 in the second direction, thereby enabling the miniaturization of the dielectric substrate 2. In particular, in this embodiment, the centers C1 and C2 of the first and second radiation electrodes 41-1 and 41-2 coincide with each other in the second direction (Y direction).

[0115] The first and second radiation electrodes 41-1 and 41-2 are located on opposite sides of a line L3 that passes through a midpoint C6 of a line segment L1 connecting the centers C1 and C2 of the first and second radiation electrodes 41-1 and 41-2 and is perpendicular to the first direction. That is, the first radiation electrode 41-1 is located within a region on the center C1 side of the line L3 and does not protrude toward the center C2 side of the line L3. The second radiation electrode 41-2 is located within a region on the center C2 side of the line L3 and does not protrude toward the center C1 side of the line L3. This configuration improves the symmetry of the antenna characteristics and improves the accuracy of phase difference detection. In particular, in this embodiment, the center C6 is the center in the first direction of the region between the first and second radiation electrodes 41-1 and 41-2. This configuration further improves the symmetry of the antenna characteristics.

[0116] The first and second parasitic elements 42-1 and 42-2 are located on opposite sides of a line L3 that passes through a midpoint C6 of a line segment L1 that connects the centers C1 and C2 of the first and second radiation electrodes 41-1 and 41-2 and is perpendicular to the first direction. This configuration improves the symmetry of the antenna characteristics and improves the accuracy of detecting the phase difference.

[0117] [1.5.2 Effects, etc.] In the antenna substrate 1D described above, at least a portion of the first and second radiation electrodes 41-1 and 41-2 are located at the same position in the second direction. This configuration can reduce the area required for arranging the first and second radiation electrodes 41-1 and 41-2 in the second direction, and enables the size of the dielectric substrate 2 to be reduced.

[0118] In the antenna substrate 1D described above, the first and second radiation electrodes 41-1 and 41-2 are located on opposite sides of a line L3 that passes through a midpoint C6 of a line segment L1 that connects the centers C1 and C2 of the first and second radiation electrodes 41-1 and 41-2 and is perpendicular to the first direction. This configuration improves the symmetry of the antenna characteristics and improves the accuracy of detecting the phase difference.

[0119] [1.6 Evaluation, etc.] In order to confirm the effects of the antenna substrates 1, 1A, and 1B according to the first, second, and third embodiments, the relationship between the antenna phase difference (PDOA) and the antenna efficiency was evaluated.

[0120] 19 and 20 are graphs showing the relationship between the angle [deg.] and the antenna phase difference (PDOA) [deg.] in the antenna substrate 1 of the first embodiment. In particular, FIG. 19 is a graph showing the relationship between the angle and the antenna phase difference (PDOA) in the first frequency band. FIG. 20 is a graph showing the relationship between the angle and the antenna phase difference (PDOA) in the second frequency band. Here, the angle is the angle from the normal direction in a plane (i.e., the XZ plane) that includes the normal direction (Z direction) and the length direction (X direction) of the dielectric substrate 2 of the antenna substrate 1. A positive angle is the direction from the normal direction toward the side where the second and third antennas 4-2 and 4-3 are located. A negative angle is the direction from the normal direction toward the side where the first and second antennas 4-1 and 4-4 are located. The antenna phase difference in FIG. 19 represents the angle corresponding to the phase difference between the radio waves arriving at the first antenna 4-1 and the second antenna 4-2. The antenna phase difference in FIG. 20 represents an angle corresponding to the phase difference between the radio waves arriving at the third antenna 4-3 and the fourth antenna 4-4.

[0121] 19 and 20, it was confirmed that there is a correlation between the angle and the PDOA for the antenna substrate 1, and that the angle at which the radio waves arrive can be determined with high accuracy. Here, the larger the PDOA value, the more clearly the information indicating the direction, such as the angle at which the radio waves arrive, is expressed, thereby improving accuracy. The minimum PDOA value was used to evaluate the PDOA of the antenna substrates 1, 1A, and 1B. It can be seen from FIGS. 19 and 20 that the minimum PDOA value is generally the value when the angle is near 0 (e.g., the average value in the angle range from 0 to a predetermined value).

[0122] Fig. 21 is a graph showing the relationship between antenna efficiency and antenna phase difference in the first frequency band for each antenna substrate. Fig. 22 is a graph showing the relationship between antenna efficiency and antenna phase difference in the second frequency band for each antenna substrate. In Fig. 21, the antenna efficiency is the average value of the antenna efficiency at any three points in the first frequency band. In Fig. 22, the antenna efficiency is the average value of the antenna efficiency at any three points in the second frequency band.

[0123] 21 and 22, Con. 1 is an antenna substrate of a comparative example. The antenna substrate of the comparative example differs from antenna substrate 1 in that it does not include first to fourth parasitic elements 42-1 to 42-4. Con. 2 is antenna substrate 1 according to the first embodiment, Con. 3 is antenna substrate 1A according to the second embodiment, and Con. 4 is antenna substrate 1B according to the third embodiment.

[0124] 21 and 22, it was confirmed that the antenna substrates 1, 1A, and 1B of Embodiments 1 to 3 had higher antenna efficiency than the antenna substrate of the comparative example in both the first frequency band and the second frequency band. In particular, the antenna efficiency was highest in the antenna substrate 1 of Embodiment 1, followed by the antenna substrate 1A of Embodiment 2, and then the antenna substrate 1B of Embodiment 3. On the other hand, the antenna substrates 1, 1A, and 1B of Embodiments 1 to 3 tended to have lower PDOA than the antenna substrate of the comparative example. This is thought to be because improved radio wave radiation to the sides of the dielectric substrate 2 reduced radio wave radiation in the normal direction of the dielectric substrate 2. However, the reduction in PDOA shown in FIGS. 21 and 22 is well within the acceptable range.

[0125] [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.

[0126] In the following, reference will be made to the symbols used in embodiment 1, even though they are applicable to any of the above embodiments 1 to 5. However, this is merely to simplify the description and is not intended to exclude application to embodiments 2 to 5.

[0127] In one modification, the shape of the dielectric substrate 2 is not particularly limited.

[0128] In one modified example, there is no particular limitation on the shape of the ground electrode 3. The ground electrode 3 may be provided separately for each of the antennas 4.

[0129] In one modified example, the first to fourth radiation electrodes 41-1 to 41-4 do not necessarily have to have the same size and / or shape, but the first and second radiation electrodes 41-1 and 41-2 may have the same size and / or shape, and the third and fourth radiation electrodes 41-3 and 41-4 may have the same size and / or shape.

[0130] In one modified example, the radiation electrode 41 may be connected to the ground electrode 3 at the end in the X direction. That is, the radiation electrode 41 may form a planar inverted-F antenna (PIFA).

[0131] In one modified example, the shape of the radiating electrode 41 is not limited to a rectangle as in the embodiment. The shape of the radiating electrode 41 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 41 is circular, the size of the radiating electrode 41 is defined by its diameter. For example, if the radiating electrode 41 is elliptical, the size of the radiating electrode 41 may be defined by its major axis. If the radiating electrode 41 is polygonal, the size of the radiating electrode 41 may be defined by the distance between corresponding sides in the first direction.

[0132] In one modified example, the radiating electrode 41 does not necessarily have to be arranged on the main surface 2 a of the dielectric substrate 2. The radiating electrode 41 may be arranged on an inner layer (intermediate layer) of the dielectric substrate 2. The ground electrode 3 does not necessarily have to be arranged on the rear surface 2 b of the dielectric substrate 2. The ground electrode 3 may be arranged on an inner layer (intermediate layer) of the dielectric substrate 2. The radiating electrode 41 and the ground electrode 3 only need to be arranged so as to face each other with at least a portion of the dielectric layer 20 of the dielectric substrate 2 sandwiched therebetween.

[0133] In one modified example, the parasitic element 42 does not necessarily have to be linear along the first direction. The parasitic element 42 is not limited to a linear shape, and may have a curved shape, such as a meandering shape, as long as it has a shape extending in the first direction that determines the size of the radiation electrode 41. In other words, the parasitic element 42 may have any shape that can resonate in the frequency band of the corresponding radiation electrode 41.

[0134] In one modification, the first and second parasitic elements 42A-1 and 42A-2 may be located at the same positions as the first and second radiation electrodes 41-1 and 41-2 in the normal direction. The third and fourth parasitic elements 42A-3 and 42A-4 may be located at the same positions as the third and fourth radiation electrodes 41-3 and 41-4 in the normal direction.

[0135] In one variation, the parasitic element 42 may include an adjustment element. The adjustment element is an inductive reactance (inductor) or a capacitive reactance (capacitor). The adjustment element is used to adjust the electrical length of the parasitic element. The adjustment element may be a separate circuit element or an IPD (Integrated Passive Device).

[0136] In one variation, the first antenna 4C-1 may include only one of the first auxiliary electrodes 43-1 and 43-2. ​​The second antenna 4C-2 may include only one of the second auxiliary electrodes 43-3 and 43-4. The third antenna 4C-3 may include only one of the third auxiliary electrodes 43-5 and 43-6. The fourth antenna 4C-4 may include only one of the fourth auxiliary electrodes 43-7 and 43-8.

[0137] In one modified example, the connection lines 512 and 513 may be electrically independent and connected to the first and fourth radiation electrodes 41-1 and 41-4, respectively, without being connected at the branch connection point 511. The connection lines 522 and 523 may be electrically independent and connected to the second and third radiation electrodes 41-2 and 41-3, respectively, without being connected at the branch connection point 521.

[0138] 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.

[0139] [3. Aspects] As is clear from the above-described embodiment and modifications, the present disclosure includes the following aspects.

[0140] a first direction that determines the size of the first and second radiating electrodes is orthogonal to the normal direction, the first and second radiating electrodes are at different positions in the first direction, the first and second parasitic elements extend in the first direction and are at the same positions as the first and second radiating electrodes in the first direction, the first and second parasitic elements are at different positions in a second direction that is orthogonal to the normal direction and intersects the first direction, and the first and second parasitic elements are at different positions in a second direction that is orthogonal to the normal direction and intersects the first direction, and the first and second radiating electrodes are between the first and second parasitic elements in the second direction.

[0141] [Aspect 2] The antenna substrate of Aspect 1, further comprising: third and fourth antennas on the dielectric substrate corresponding to a second frequency band different from the first frequency band, the third and fourth antennas including: third and fourth radiation electrodes at positions different from the ground electrode in the normal direction; and third and fourth parasitic elements connected to the ground electrodes, respectively; the third and fourth radiation electrodes have a determined size in the first direction and are at different positions in the first direction; the third and fourth parasitic elements extend in the first direction and are at the same positions as the third and fourth radiation electrodes in the first direction; the third and fourth parasitic elements are at different positions in the second direction; and the third and fourth radiation electrodes are between the third and fourth parasitic elements in the second direction.

[0142] [Aspect 3] The antenna substrate of Aspect 2, wherein the first radiation electrode and the third radiation electrode are located at different positions in the first direction, the second radiation electrode and the fourth radiation electrode are located at different positions in the first direction, and the first and third radiation electrodes and the second and fourth radiation electrodes are located at different positions in the second direction.

[0143] [Aspect 4] The antenna substrate of Aspect 2 or 3, wherein at least a portion of the first and fourth radiation electrodes are located at the same position in the first direction, and at least a portion of the second and third radiation electrodes are located at the same position in the first direction.

[0144] [Aspect 5] The antenna substrate according to any one of Aspects 2 to 4, wherein at least a portion of the first and third radiation electrodes are located at the same position in the second direction, and at least a portion of the second and fourth radiation electrodes are located at the same position in the second direction.

[0145] [Aspect 6] The antenna substrate of any one of Aspects 2 to 5, wherein the first radiation electrode is closer to the first parasitic element than the second parasitic element in the second direction; the second radiation electrode is closer to the second parasitic element than the first parasitic element in the second direction; the third radiation electrode is closer to the third parasitic element than the fourth parasitic element in the second direction; and the fourth radiation electrode is closer to the fourth parasitic element than the third parasitic element in the second direction.

[0146] [Aspect 7] The antenna substrate according to any one of Aspects 2 to 6, wherein the first to fourth radiation electrodes are the same size.

[0147] [Aspect 8] The antenna substrate according to any one of Aspects 2 to 7, wherein the first to fourth radiation electrodes have the same shape.

[0148] [Aspect 9] The antenna substrate according to any one of Aspects 2 to 8, wherein a line segment connecting the centers of the first and second radiation electrodes and a line segment connecting the centers of the third and fourth radiation electrodes intersect with each other.

[0149] [Aspect 10] The antenna substrate of Aspect 1, wherein at least a portion of the first and second radiation electrodes are at the same position in the second direction.

[0150] [Aspect 11] The antenna substrate of aspect 10, wherein the first and second radiation electrodes are located on opposite sides of a line that passes through a midpoint of a line segment connecting centers of the first and second radiation electrodes and is perpendicular to the first direction.

[0151] [Aspect 12] The antenna substrate according to any one of Aspects 1 to 11, wherein the first and second parasitic elements are located at the same position as the ground electrode in the normal direction.

[0152] [Aspect 13] The antenna substrate according to any one of Aspects 1 to 12, wherein, in the normal direction, the first and second parasitic elements are located at the same positions as the first and second radiation electrodes, or between the ground electrode and the first and second radiation electrodes.

[0153] [Aspect 14] The antenna substrate according to any one of Aspects 1 to 13, wherein the first and second parasitic elements overlap the ground electrode when viewed from the normal direction.

[0154] [Aspect 15] The antenna substrate of any one of Aspects 1 to 14, wherein the first antenna includes a first auxiliary electrode that is located between an end of the first radiation electrode in the first direction and the ground electrode in the normal direction, and that is connected to the first radiation electrode or the ground electrode, and the second antenna includes a second auxiliary electrode that is located between an end of the second radiation electrode in the first direction and the ground electrode in the normal direction, and that is connected to the second radiation electrode or the ground electrode.

[0155] [Aspect 16] The free space wavelength corresponding to the first frequency band is λ ｏ１ Then, the size of the dielectric substrate in the first direction is λ ｏ１ 16. The antenna substrate of any one of aspects 1 to 15, wherein

[0156] [Aspect 17] The antenna substrate according to any one of Aspects 1 to 16, wherein the dielectric substrate has a main surface and a back surface opposite to the main surface in the normal direction, the ground electrode is on the back surface, and the first and second radiation electrodes are on the main surface.

[0157] [Aspect 18] The wavelength in the substrate corresponding to the first frequency band is λ ｇ１ Then, the electrical length of the first and second parasitic elements is λ ｇ１ 18. The antenna substrate of any one of Aspects 1 to 17, wherein the σ is within the range of 4±25%.

[0158] [Aspect 19] An antenna module comprising the antenna substrate according to any one of aspects 1 to 18.

[0159] Aspect 20: A communication device comprising the antenna module of aspect 19.

[0160] Aspects 2 to 18 are optional elements and are not essential.

[0161] 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.

[0162] REFERENCE SIGNS LIST 100 Communication device 10 Antenna module 1, 1A, 1B, 1C, 1D Antenna substrate 2 Dielectric substrate 2a Main surface 2b Back surface 3, 3B, 3C Ground electrode 4-1, 4A-1, 4C-1 First antenna 4-2, 4A-2, 4C-2 Second antenna 4-3, 4A-3, 4C-3 Third antenna 4-4, 4A-4, 4C-4 Fourth antenna 41-1 First radiation electrode 41-2 Second radiation electrode 41-3 Third radiation electrode 41-4 Fourth radiation electrode 42-1, 42A-1 First parasitic element 42-2, 42A-2 Second parasitic element 42-3, 42A-3 Third parasitic element 42-4, 42A-4 Fourth parasitic element 43-1, 43-2 First auxiliary electrode 43-3, 43-4 2nd auxiliary electrode 43-5, 43-6 3rd auxiliary electrode 43-7, 43-8 4th auxiliary electrode

Claims

1. An antenna substrate comprising: a dielectric substrate having a dielectric layer; a ground electrode on the dielectric substrate; and first and second antennas on the dielectric substrate corresponding to a first frequency band, wherein the first and second antennas respectively include first and second radiating electrodes having a flat plate shape and located at a different position from the ground electrode in a normal direction of the dielectric substrate, and first and second parasitic elements connected to the ground electrodes, wherein a first direction determining a size of the first and second radiating electrodes is perpendicular to the normal direction, the first and second radiating electrodes are located at different positions in the first direction, the first and second parasitic elements extend in the first direction and are respectively located at the same positions as the first and second radiating electrodes in the first direction, the first and second parasitic elements are located at different positions in a second direction which is perpendicular to the normal direction and intersects the first direction, and the first and second radiating electrodes are located between the first and second parasitic elements in the second direction.

2. The antenna substrate of claim 1, further comprising third and fourth antennas on the dielectric substrate corresponding to a second frequency band different from the first frequency band, the third and fourth antennas respectively including third and fourth radiating electrodes at positions different from the ground electrode in the normal direction, and third and fourth parasitic elements connected to the ground electrodes, the third and fourth radiating electrodes having a determined size in the first direction and at different positions in the first direction, the third and fourth parasitic elements extending in the first direction and at the same positions as the third and fourth radiating electrodes in the first direction, the third and fourth parasitic elements at different positions in the second direction, and the third and fourth radiating electrodes between the third and fourth parasitic elements in the second direction.

3. The antenna substrate of claim 2, wherein the first radiation electrode and the third radiation electrode are located at different positions in the first direction, the second radiation electrode and the fourth radiation electrode are located at different positions in the first direction, and the first and third radiation electrodes and the second and fourth radiation electrodes are located at different positions in the second direction.

4. The antenna substrate according to claim 2 or 3, wherein at least a portion of the first and fourth radiation electrodes are in the same position in the first direction, and at least a portion of the second and third radiation electrodes are in the same position in the first direction.

5. An antenna substrate according to any one of claims 2 to 4, wherein at least a portion of the first and third radiation electrodes are located at the same position in the second direction, and at least a portion of the second and fourth radiation electrodes are located at the same position in the second direction.

6. An antenna substrate according to any one of claims 2 to 5, wherein the first radiating electrode is closer to the first parasitic element than the second parasitic element in the second direction, the second radiating electrode is closer to the second parasitic element than the first parasitic element in the second direction, the third radiating electrode is closer to the third parasitic element than the fourth parasitic element in the second direction, and the fourth radiating electrode is closer to the fourth parasitic element than the third parasitic element in the second direction.

7. The antenna substrate according to any one of claims 2 to 6, wherein the first to fourth radiation electrodes are the same size.

8. The antenna substrate according to any one of claims 2 to 7, wherein the first to fourth radiation electrodes have the same shape.

9. The antenna substrate of any one of claims 2 to 8, wherein a line segment connecting the centers of the first and second radiation electrodes and a line segment connecting the centers of the third and fourth radiation electrodes intersect with each other.

10. The antenna substrate according to claim 1, wherein at least a portion of the first and second radiation electrodes are located at the same position in the second direction.

11. The antenna substrate according to claim 10, wherein the first and second radiation electrodes are located on opposite sides of a line that passes through a midpoint of a line segment connecting the centers of the first and second radiation electrodes and is perpendicular to the first direction.

12. The antenna substrate according to any one of claims 1 to 11, wherein in the normal direction, the first and second parasitic elements are in the same position as the ground electrode.

13. An antenna substrate according to any one of claims 1 to 12, wherein, in the normal direction, the first and second parasitic elements are located at the same positions as the first and second radiation electrodes, or between the ground electrode and the first and second radiation electrodes.

14. The antenna substrate of any one of claims 1 to 13, wherein the first and second parasitic elements overlap the ground electrode when viewed from the normal direction.

15. The antenna substrate of any one of claims 1 to 14, wherein the first antenna includes a first auxiliary electrode located in the normal direction between an end of the first radiation electrode in the first direction and the ground electrode, and connected to the first radiation electrode or the ground electrode, and the second antenna includes a second auxiliary electrode located in the normal direction between an end of the second radiation electrode in the first direction and the ground electrode, and connected to the second radiation electrode or the ground electrode.

16. Let λ be the free space wavelength corresponding to the first frequency band. ｏ１ Then, the size of the dielectric substrate in the first direction is λ ｏ１ The antenna substrate according to any one of claims 1 to 15, wherein the thickness of the antenna substrate is less than 100 nm.

17. The antenna substrate of any one of claims 1 to 16, wherein the dielectric substrate has a main surface and a back surface opposite the main surface in the normal direction, the ground electrode is on the back surface, and the first and second radiation electrodes are on the main surface.

18. The wavelength in the substrate corresponding to the first frequency band is λ ｇ１ Then, the electrical length of the first and second parasitic elements is λ ｇ１ 18. The antenna substrate according to claim 1, wherein the .lambda. / 4±25% is within the range.

19. An antenna module comprising an antenna substrate according to any one of claims 1 to 18.

20. A communication device comprising the antenna module of claim 19.

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