Antenna substrate, antenna module, communication device

Abstract

To provide an antenna substrate, an antenna module, and a communication device that can reduce degradation of transmission characteristics even while reducing the distance between a radiation electrode and a transmission line.SOLUTION: An antenna substrate 1 includes: a dielectric substrate 2 having a dielectric layer 20; a radiation electrode 3 and a ground electrode 5 that face each other with at least a part of the dielectric layer 20 sandwiched therebetween; and a transmission line 4 on the dielectric substrate 2. The transmission line 4 extends in a first direction perpendicular to the normal direction of the dielectric substrate 2 and includes a line portion 41 spaced apart from the radiation electrode 3 in a second direction intersecting the first direction. The distance between the radiation electrode 3 and the line portion 41 is smallest at a first end 31a and a second end 31b of the radiation electrode 3 in the first direction, and is largest at an intermediate portion 31c between the first end 31a and the second end 31b of the radiation electrode 3 in the first direction. The minimum value of the distance between the radiation electrode 3 and the line portion 41 is smaller than a width w of the line portion 41.SELECTED DRAWING: Figure 5

Description

[Technical field]

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

[0002] Patent Document 1 discloses an antenna. The antenna disclosed in Patent Document 1 is provided on a first main surface of a substrate, and includes a feed element having a patch electrode and a parasitic element, and a transmission line provided on the first main surface is connected to the parasitic element. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2008-164354 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the antenna disclosed in Patent Document 1, it is believed that the transmission line of the parasitic element is sufficiently separated from the feed element (radiation electrode) to ensure isolation between the radiation electrode and the transmission line, thereby reducing the deterioration of the transmission characteristic of the transmission line. In recent years, there has been a demand for miniaturization of antennas, and it is sometimes difficult to sufficiently separate the transmission line from the radiation electrode.

[0005] The present disclosure provides an antenna substrate, an antenna module, and a communication device that can reduce degradation of transmission characteristics while reducing the distance between a radiation electrode and a transmission line. [Means for solving the problem]

[0006] An antenna substrate according to an embodiment of the present disclosure includes a dielectric substrate having a dielectric layer, a radiation electrode and a ground electrode that face each other with at least a portion of the dielectric layer interposed therebetween, and a transmission line on the dielectric substrate. The transmission line includes a line portion that extends in a first direction perpendicular to a normal direction of the dielectric substrate and is spaced apart from the radiation electrode in a second direction intersecting the first direction. The distance between the radiation electrode and the line portion is smallest at a first end and a second end of the radiation electrode in the first direction, and is largest at an intermediate portion between the first end and the second end of the radiation electrode in the first direction. The minimum value of the distance between the radiation electrode and the line portion is smaller than the width of the line portion.

[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 above antenna module. Effect of the Invention

[0009] The aspects of the present disclosure can reduce degradation of transmission characteristics while reducing the distance between the radiation electrode and the transmission line. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a block diagram of a communication device including an antenna module according to an embodiment; [Diagram 2] FIG. 1 is a partial perspective view of an antenna substrate according to an embodiment; [Diagram 3] FIG. 2 is a plan view of an antenna substrate according to an embodiment; [Figure 4] 1 is a cross-sectional view of an antenna substrate according to an embodiment; [Diagram 5] FIG. 2 is an enlarged view of a main part of an antenna substrate according to an embodiment; [Figure 6] A diagram showing the current distribution on the antenna board when the length of the loop-shaped current path is changed. [Figure 7] A graph showing the isolation characteristics of an antenna board when the length of the loop-shaped current path is changed. [Figure 8]Graph showing isolation characteristics of an antenna substrate according to an embodiment [Figure 9] Graph showing isolation characteristics of an antenna substrate according to Comparative Example 1 [Figure 10] Graph showing isolation characteristics of an antenna substrate according to Comparative Example 2 [Figure 11] FIG. 1 is an enlarged view of a main part of an antenna substrate according to a first modified example; [Figure 12] FIG. 13 is an enlarged view of a main part of an antenna substrate according to a second modified example. [Figure 13] FIG. 13 is an enlarged view of a main part of an antenna substrate according to a third modified example. [Figure 14] FIG. 13 is an enlarged view of a main part of an antenna substrate according to a fourth modified example. [Figure 15] FIG. 13 is an enlarged view of a main part of an antenna substrate according to a fifth modified example. [Figure 16] 13 is an enlarged view of a main part of an antenna substrate according to a sixth modified example. [Figure 17] 13 is an enlarged view of a main part of an antenna substrate according to Modification 7. [Figure 18] 13 is a plan view of an antenna substrate according to Modification 8. [Figure 19] 23 is a cross-sectional view of an antenna substrate according to Modification 8. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] [1. Embodiment] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings in some cases. However, the following embodiments are examples for explaining the present disclosure, and are not intended to limit the present disclosure to the following contents (e.g., the shape, dimensions, arrangement, etc. 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 size and thickness ratios 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 one another by the symbols added to them, the prefixes such as "first" and "second" may be omitted in consideration of readability of the text.

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

[0014] In the following description, unless otherwise specified, "wavelength" refers to the wavelength in free space (free space wavelength).

[0015] In the following description, "linear" means a shape composed of a single straight line, and "non-linear" includes shapes other than straight lines, such as curves, as well as shapes composed of a combination of multiple straight lines.

[0016] [1.1 Configuration] 1 is a block diagram of a communication device 100 according to an embodiment. The communication device 100 is, for example, a personal computer (desktop computer, laptop computer, etc.), a mobile terminal (smartphone, tablet terminal, etc.), a server, etc.

[0017] The communication device 100 includes an antenna module 10 , an input / output device 11 , a storage device 12 , and an arithmetic circuit 13 .

[0018] 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.

[0019] 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. A wireless communication protocol used in the communication circuit 9 can be selected from various well-known wireless communication standards. Examples of wireless communication standards include IEEE802.11, 4G, and 5G standards.

[0020] 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 (mouse, trackball, etc.), a touchpad, a position input device for a touch panel display, and output interfaces such as a display, a speaker, 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.

[0021] 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, any of a hard disk drive, an optical drive, and a solid-state drive (SSD). The storage may be any of an internal type, an external type, and a NAS (network-attached storage) type.

[0022] 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 telecommunication line such as the Internet, or recorded on a non-transitory recording medium such as a memory card.

[0023] Fig. 2 is a partial perspective view of the antenna substrate 1. Fig. 3 is a plan view of the antenna substrate 1. Fig. 4 is a cross-sectional view of the antenna substrate 1. The antenna substrate 1 includes a dielectric substrate 2, a first radiation electrode 3, a second radiation electrode 6, a first transmission line 7, a second transmission line 4, a ground electrode 5, and a connector 8. Note that in Fig. 2, for ease of understanding, the thicknesses of the dielectric substrate 2, the radiation electrodes 3 and 6, the transmission lines 4 and 7, and the ground electrode 5 are emphasized.

[0024] 2, 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) 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.

[0025] The dielectric substrate 2 includes a dielectric layer 20. The dielectric layer 20 has a main surface 2a and a back surface 2b opposite to the main surface 2a. The main surface 2a and the back surface 2b are both sides 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 may be referred to as the normal direction of the dielectric substrate 2.

[0026] 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.

[0027] As shown in Fig. 4, the radiating electrode 3 and the ground electrode 5 face each other with at least a part of the dielectric layer 20 of the dielectric substrate 2 sandwiched therebetween. In this embodiment, the radiating electrode 3 is on the main surface 2a of the dielectric substrate 2, and the ground electrode 5 is on the rear surface 2b of the dielectric substrate 2. Therefore, the radiating electrode 3 and the ground electrode 5 face each other with the entire dielectric layer 20 of the dielectric substrate 2 sandwiched therebetween. The radiating electrode 6, like the radiating electrode 3, is also on the main surface 2a, and the radiating electrode 6 and the ground electrode 5 face each other with the entire dielectric layer 20 of the dielectric substrate 2 sandwiched therebetween.

[0028] The radiating electrodes 3 and 6 are arranged on the main surface 2a of the dielectric substrate 2 in the longitudinal direction of the dielectric substrate 2. In this embodiment, the radiating electrode 3 is located at a first end side in the longitudinal direction (upper end side in FIG. 3) on the main surface 2a of the dielectric substrate 2, and the radiating electrode 6 is located at a second end side in the longitudinal direction (lower end side in FIG. 3) on the main surface 2a of the dielectric substrate 2. In this embodiment, the polarization direction of the radiating electrodes 3 and 6 is set in the longitudinal direction of the dielectric substrate 2. The radiating electrodes 3 and 6 have a planar shape. In particular, the radiating electrodes 3 and 6 are roughly rectangular when viewed from the thickness direction of the dielectric substrate 2.

[0029] The ground electrode 5 is used as a common ground electrode for the radiation electrodes 3 and 6. The radiation electrode 3 and the ground electrode 5 form a patch antenna, and the radiation electrode 6 and the ground electrode 5 form a patch antenna.

[0030] The transmission lines 4 , 7 and the connector 8 are on a main surface 2 a of the dielectric substrate 2 .

[0031] The connector 8 is used for connection to a communication circuit 9. The connector 8 is located closer to the first end of the main surface 2a of the dielectric substrate 2 in the longitudinal direction X than the radiation electrode 3.

[0032] The transmission line 7 connects the connector 8 and the radiation electrode 3. The transmission line 7 extends from the connector 8 along the length direction of the dielectric substrate 2 and is connected to the radiation electrode 3.

[0033] The transmission line 4 connects the connector 8 and the radiating electrode 6. As shown in Fig. 3, the transmission line 4 includes line portions 41, 42, and 43. The line portions 41, 42, and 43 are on the main surface 2a. In other words, the line portions 41, 42, and 43 are at the same position as the radiating electrode 3 in the normal direction of the dielectric substrate 2.

[0034] The line portion 41 extends from the connector 8. In particular, the line portion 41 extends in a first direction perpendicular to the normal direction (Z direction) of the dielectric substrate 2, and is spaced apart from the radiation electrode 3 in a second direction intersecting the first direction. In this embodiment, the first direction corresponds to the polarization direction of the radiation electrode 3. Therefore, the first direction corresponds to the length direction (X direction) of the dielectric substrate 2. The second direction corresponds to the width direction (Y direction) of the dielectric substrate 2. That is, the line portion 41 passes beside the radiation electrode 3 and extends to the second end side of the length direction X of the dielectric substrate 2. The line portion 42 extends from the tip of the line portion 41 along the width direction of the dielectric substrate 2. The line portion 43 extends from the tip of the line portion 42 along the length direction of the dielectric substrate 2 and is connected to the radiation electrode 6.

[0035] Fig. 5 is an enlarged view of a main part of the antenna substrate 1. Note that the transmission line 7 is omitted in Fig. 5, and as a result, the radiation electrode 3 is cut at the connection point with the transmission line 7.

[0036] The radiation electrode 3 has a first side 31, a second side 32, a third side 33, and a fourth side 34. The first side 31 and the second side 32 are both ends in the width direction (Y direction) of the dielectric substrate 2. In particular, the first side 31 is a side on the line portion 41 side, and the second side 32 is a side opposite to the line portion 41. The first side 31 and the second side 32 are linear and extend along the length direction (X direction) of the dielectric substrate 2. The third side 33 and the fourth side 34 are both ends in the length direction (X direction) of the dielectric substrate 2. In particular, the third side 33 is a side on the connector 8 side, and the fourth side 34 is a side on the radiation electrode 6 side. The third side 33 and the fourth side 34 are linear and extend along the width direction (Y direction) of the dielectric substrate 2. The radiation electrode 3 is connected to the transmission line 7 at the third side 33, so that a feeding point P is present on the third side 33.

[0037] The line portion 41 of the transmission line 4 has a first side 411 and a second side 412. The first side 411 and the second side 412 are both sides in the width direction (Y direction) of the dielectric substrate 2. In particular, the first side 411 is the side on the radiating electrode 3 side, and the second side 412 is the side opposite to the radiating electrode 3.

[0038] In the line portion 41, the first side 411 and the second side 412 are not straight.

[0039] The first side 411 includes first side portions 411a-1 and 411a-2, a second side portion 411b, and third side portions 411c-1 and 411c-2.

[0040] The first side portions 411a-1, 411a-2 and the second side portion 411b are linear and extend along the first direction (X direction). The first side portions 411a-1, 411a-2 are closer to the radiating electrode 3 than the second side portion 411b. A distance g1 between the first side portions 411a-1, 411a-2 and the radiating electrode 3 is smaller than a distance g2 between the second side portion 411b and the radiating electrode 3. The distance g1 is the minimum value of the distance between the radiating electrode 3 and the line portion 41, and the distance g2 is the maximum value of the distance between the radiating electrode 3 and the line portion 41.

[0041] The first side portions 411a-1 and 411a-2 are located on both sides of the second side portion 411b in the first direction. The first side portion 411a-1 is on the third side 33 side of the radiating electrode 3. The first side portion 411a-1 faces the first end portion 31a of the radiating electrode 3 in the first direction. The first end portion 31a is a portion on the third side 33 side of the first side 31 of the radiating electrode 3. The first side portion 411a-2 is on the fourth side 34 side of the radiating electrode 3. The first side portion 411a-2 faces the second end portion 31b of the radiating electrode 3 in the first direction. The second end portion 31b is a portion on the fourth side 34 side of the first side 31 of the radiating electrode 3. The second side portion 411b faces the intermediate portion 31c between the first end portion 31a and the second end portion 31b of the radiating electrode 3 in the first direction. The intermediate portion 31c is a portion of the first side 31 of the radiation electrode 3 between the first end portion 31a and the second end portion 31b.

[0042] The third side portion 411c-1 connects the first side portion 411a-1 and the second side portion 411b. The third side portion 411c-2 connects the first side portion 411a-2 and the second side portion 411b. The third sides 411c-1 and 411c-2 are linear and extend along the width direction (Y direction) of the dielectric substrate 2.

[0043] The second side 412 includes fourth side portions 412a-1 and 412a-2, a fifth side portion 412b, and sixth side portions 412c-1 and 412c-2.

[0044] The fourth side portions 412a-1, 412a-2 and the fifth side portion 412b are linear and extend along the first direction (X direction). The fourth side portions 412a-1, 412a-2 are closer to the radiation electrode 3 than the fifth side portion 412b.

[0045] The fourth side portions 412a-1 and 412a-2 are located on both sides of the fifth side portion 412b in the first direction. The fourth side portion 412a-1 is on the third side 33 side of the radiating electrode 3. The fourth side portion 412a-1 does not face the first end portion 31a of the radiating electrode 3 in the first direction. The fourth side portion 412a-2 is on the fourth side 34 side of the radiating electrode 3. The fourth side portion 412a-2 does not face the second end portion 31b of the radiating electrode 3 in the first direction. The fifth side portion 412b extends from the third side 33 to the fourth side 34 of the radiating electrode 3 in the first direction.

[0046] The sixth side portion 412c-1 connects the fourth side portion 412a-1 and the fifth side portion 412b. The sixth side portion 412c-2 connects the fourth side portion 412a-2 and the fifth side portion 412b. The sixth sides 412c-1 and 412c-2 are linear and extend along the width direction (Y direction) of the dielectric substrate 2.

[0047] In the line portion 41, the distance between the first side portion 411a-1 and the fourth side portion 412a-1, the distance between the first side portion 411a-2 and the fourth side portion 412a-2, and the distance between the second side portion 411b and the fifth side portion 412b are equal to each other and define the width w of the line portion 41.

[0048] In this embodiment, the radiation electrode 3 has a shape that is line-symmetrical with respect to a straight line L1 that passes through the center C1 of the radiation electrode 3 in the first direction and is perpendicular to the first direction. In the line portion 41, a straight line L2 that passes through the center of the second side portion 411b and is perpendicular to the first direction coincides with the straight line L1. Therefore, in the line portion 41, the length of the range in which the first side portion 411a-1 overlaps with the radiation electrode 3 in the second direction (the length of the first end portion 31a) is equal to the length of the range in which the first side portion 411a-2 overlaps with the radiation electrode 3 in the second direction (the length of the second end portion 31b). Therefore, at least in the range between both ends (the third side 33 and the fourth side 34) of the radiation electrode 3 in the first direction as viewed from the thickness direction (Z direction) of the dielectric substrate 2, the line portion 41 and the radiation electrode 3 have a shape that is line-symmetrical with respect to a straight line L1 that passes through the center C1 of the radiation electrode 3 in the first direction and is perpendicular to the first direction. This makes the current distribution in the radiation electrode 3 symmetrical with respect to the line L1 passing through the center C1 of the radiation electrode 3. Therefore, the deviation of the directivity of the radiation electrode 3 from the thickness direction of the dielectric substrate 2 can be reduced.

[0049] As described above, the side (first side 411) of the line portion 41 on the radiation electrode 3 side is recessed at the portion (second side 411b) corresponding to the intermediate portion 31c compared to the portions (first side portions 411a-1, 411a-2) corresponding to the first end portion 31a and the second end portion 31b. In other words, the first side 411 of the line portion 41 is nonlinear in that the distance g2 between the line portion 41 and the radiation electrode 3 at the intermediate portion 31c is greater than the distance g1 between the line portion 41 and the radiation electrode 3 at the first end portion 31a and the second end portion 31b. Therefore, the distance between the radiation electrode 3 and the line portion 41 is smallest at the first end portion 31a and the second end portion 31b of the radiation electrode 3 in the first direction and is largest at the intermediate portion 31c between the first end portion 31a and the second end portion 31b of the radiation electrode 3 in the first direction.

[0050] As a result, the line section 41 and the radiation electrode 3 can be capacitively coupled at two points, namely, the first end portion 31a and the second end portion 31b of the radiation electrode 3. This can create a loop-shaped current path surrounding the gap between the second side portion 411b of the line section 41 and the intermediate portion 31c of the radiation electrode 3. Thus, even when current flows through the transmission line 4, the current flows in a loop between the line section 41 and the radiation electrode 3, so that the amount of current leaking from the transmission line 4 through the radiation electrode 3 to the transmission line 7 can be reduced. As a result, it becomes possible to ensure the isolation between the transmission line 4 and the radiation electrode 3. Therefore, it is possible to reduce the degradation of transmission characteristics while reducing the distance between the radiation electrode 3 and the transmission line 4.

[0051] Further, referring to FIG. 5, the dimensions of the radiation electrode 3 and the transmission line 4 on the antenna substrate 1 will be described.

[0052] As described above, in the line section 41, the distance g1 between the first side portions 411a-1 and 411a-2 and the radiation electrode 3 is the minimum value of the distance between the radiation electrode 3 and the line section 41. Considering the capacitive coupling between the line section 41 of the transmission line 4 and the radiation electrode 3, the distance g1 is preferably smaller than the width w of the line section 41. That is, in the line section 41, it is preferable that g1 < w. This makes it easier to form a loop-shaped current path between the radiation electrode 3 and the transmission line 4, and further reduces the degradation of transmission characteristics.

[0053] As described above, in the line section 41, the distance g2 between the second side portion 411b and the radiation electrode 3 is the maximum value of the distance between the radiation electrode 3 and the line section 41. The distance g2 is preferably smaller than the width w of the line section 41. That is, in the line section 41, it is preferable that g2 < w. This can reduce the distance between the radiation electrode 3 and the transmission line 4.

[0054] The length of the loop-shaped current path may be set based on the wavelength corresponding to the frequency band to which the radiation electrode 3 corresponds.

[0055] The wavelength corresponding to the frequency band supported by the radiating electrode 3 is determined taking into consideration the wavelength shortening effect caused by the arrangement environment of the radiating electrode 3. The arrangement environment of the radiating electrode 3 includes, for example, the dielectric constant of the dielectric substrate 2 on which the radiating electrode 3 is arranged, the impedance (reactance, inductance) caused by the circuit configuration around the radiating electrode 3, and the like.

[0056] The length of the loop-shaped current path is mainly determined by the distance between a first point at which the distance between the line portion 41 and the radiation electrode 3 is the smallest at the first end 31a of the radiation electrode 3, and a second point at which the distance between the line portion 41 and the radiation electrode 3 is the smallest at the second end 31b of the radiation electrode 3. The distance between the first point and the second point may be the shortest distance along the first direction, the distance along the first side 411 of the line portion 41 on the radiation electrode 3 side, or the distance along the first side 31 of the radiation electrode 3 on the line portion 41 side. In this embodiment, the distance between the first side portions 411a-1, 411a-2 and the radiation electrode 3 is constant, so the distance between the first point and the second point is the distance between the first side portions 411a-1, 411a-2, i.e., the distance between the first end 31a and the second end 31b.

[0057] The wavelength corresponding to the frequency band supported by the radiation electrode 3 is denoted by λ, and the distance between the first point and the second point is denoted by d. FIG. 6 shows the current distribution in the antenna substrate 1 when the length of the loop-shaped current path is changed. In particular, FIG. 6 shows the current distribution in the antenna substrate 1 in three cases: d=λ / 4, d>λ / 4, and d<λ / d. In FIG. 6, the darker the color of the arrow, the higher the current density. It was confirmed from FIG. 6 that a loop-shaped current path was formed in the antenna substrate 1.

[0058] Next, the isolation characteristics of the antenna substrate 1 when the length of the loop-shaped current path is changed are evaluated by simulation. FIG. 7 is a graph showing the isolation characteristics of the antenna substrate 1 when the length of the loop-shaped current path is changed. In FIG. 7, the S parameters indicating the transmission characteristics with the radiation electrode 3 as the input port and the connector 8 side of the transmission line 4 as the output port are obtained by simulation as the isolation characteristics. In the simulation, the frequency band supported by the radiation electrode 3 is set to about 6.5 GHz. In FIG. 7, F1 corresponds to d=λ / 4, F2 corresponds to d>λ / 4, and F3 corresponds to d<λ / d. As is clear from FIG. 7, the best isolation characteristics are obtained when d=λ / 4.

[0059] Furthermore, when the change in isolation characteristics was investigated by changing d with respect to λ, it was confirmed that good isolation characteristics were obtained and the degradation of transmission characteristics could be reduced when d was greater than 3λ / 20 and smaller than λ / 2. In particular, it was confirmed that the degradation of transmission characteristics could be further reduced when d was within λ / 4±40%.

[0060] The dimensions and shape of the radiating electrode 3 are set based on the wavelength λ corresponding to the frequency band supported by the radiating electrode 3. In this embodiment, the size of the radiating electrode 3 in the polarization direction (first direction) is set to λ / 2. The size of the radiating electrode 3 in the first direction is the distance between the third side 33 and the fourth side 34 of the radiating electrode 3. The size of the radiating electrode 3 in the first direction is defined as D. In this case, it is preferable that d is larger than 3D / 10 and smaller than D. Furthermore, it is preferable that d is within D / 2±40%. This can further reduce the deterioration of the transmission characteristics.

[0061] [1.2 Evaluation] In order to confirm that the deterioration of the transmission characteristics of the transmission line 4 is suppressed in the antenna substrate 1, the isolation characteristics between the radiation electrode 3 and the transmission line 4 were evaluated by simulation. Figs. 8 to 10 show the evaluation results. In Figs. 8 to 10, F4 is an S-parameter indicating the transmission characteristics when the radiation electrode 3 is the input port and the connector 8 side of the transmission line 4 is the output port, and F5 is an S-parameter indicating the transmission characteristics when the radiation electrode 3 is the input port and the radiation electrode 6 side of the transmission line 4 is the output port. In the simulation, the frequency band supported by the radiation electrode 3 was set to about 6.5 GHz.

[0062] FIG. 8 is a graph showing the isolation characteristics of the antenna substrate 1 according to the embodiment. FIG. 9 and FIG. 10 are graphs showing the isolation characteristics of the antenna substrates of Comparative Examples 1 and 2. In Comparative Examples 1 and 2, the distance between the radiation electrode 3 and the transmission line 4 is constant. In Comparative Examples 1 and 2, the distance between the radiation electrode 3 and the transmission line 4 is greater in Comparative Example 2 than in Comparative Example 1. In particular, the distance between the radiation electrode 3 and the transmission line 4 in Comparative Example 1 is set to g1, which is the minimum value of the distance between the radiation electrode 3 and the transmission line 4 in the antenna substrate 1. The distance between the radiation electrode 3 and the transmission line 4 in Comparative Example 2 is set to g2, which is the maximum value of the distance between the radiation electrode 3 and the transmission line 4 in the antenna substrate 1.

[0063] 8 to 10, it was confirmed that the isolation characteristics at about 6.5 GHz are better in Comparative Example 2 than in Comparative Example 1, and that the isolation characteristics at about 6.5 GHz are better in the antenna substrate 1 according to the present embodiment than in Comparative Example 2. In other words, it was confirmed that the isolation characteristics between the transmission line 4 and the radiation electrode 3 can be improved by forming a loop-shaped current path between the transmission line 4 and the radiation electrode 3 as in the antenna substrate 1 according to the present embodiment, rather than simply increasing the distance between the transmission line 4 and the radiation electrode 3.

[0064] [1.3 Effects, etc.] The antenna substrate 1 described above includes a dielectric substrate 2 having a dielectric layer 20, a radiation electrode 3 and a ground electrode 5 which face each other with at least a part of the dielectric layer 20 interposed therebetween, and a transmission line 4 on the dielectric substrate 2, the transmission line 4 extending in a first direction perpendicular to the normal direction of the dielectric substrate 2 and including a line portion 41 spaced apart from the radiation electrode 3 in a second direction intersecting the first direction, the distance between the radiation electrode 3 and the line portion 41 being minimum at the first end 31a and the second end 31b of the radiation electrode 3 in the first direction and maximum at an intermediate portion 31c between the first end 31a and the second end 31b of the radiation electrode 3 in the first direction, and the minimum value of the distance between the radiation electrode 3 and the line portion 41 (the distance g1 between the first side portions 411a-1, 411a-2 and the radiation electrode 3) is smaller than the width w of the line portion 41. This configuration can reduce the degradation of the transmission characteristics while reducing the distance between the radiation electrode 3 and the transmission line 4.

[0065] In the antenna substrate 1 described above, if λ is the wavelength corresponding to the frequency band supported by the radiation electrode 3 and d is the distance between a first point at which the distance between the line portion 41 and the radiation electrode 3 at the first end 31a of the radiation electrode 3 is minimum and a second point at which the distance between the line portion 41 and the radiation electrode 3 at the second end 31b of the radiation electrode 3 is minimum, then d is within λ / 4±40%. This configuration can further reduce degradation of the transmission characteristics.

[0066] In the above-described antenna substrate 1, if the size of the radiation electrode 3 in the first direction is D and the distance between the first point at which the distance between the line portion 41 and the radiation electrode 3 at the first end 31a of the radiation electrode 3 is the smallest and the second point at which the distance between the line portion 41 and the radiation electrode 3 at the second end 31b of the radiation electrode 3 is the smallest, then d is within D / 2±40%. This configuration can further reduce degradation of the transmission characteristics.

[0067] In the antenna substrate 1 described above, if λ is the wavelength corresponding to the frequency band supported by the radiation electrode 3, D is the size of the radiation electrode in the first direction, and d is the distance between a first point at which the distance between the line portion 41 and the radiation electrode 3 at the first end 31a of the radiation electrode 3 is minimum and a second point at which the distance between the line portion 41 and the radiation electrode 3 at the second end 31b of the radiation electrode 3 is minimum, then d is greater than 3λ / 20 and smaller than D. This configuration can further reduce degradation of the transmission characteristics.

[0068] In the antenna substrate 1 described above, if the size of the radiation electrode 3 in the first direction is D and the distance between the first point at which the distance between the line portion 41 and the radiation electrode 3 at the first end 31a of the radiation electrode 3 is minimum and the second point at which the distance between the line portion 41 and the radiation electrode 3 at the second end 31b of the radiation electrode 3 is minimum is d, then d is greater than 3D / 10 and smaller than D. This configuration can further reduce degradation of the transmission characteristics.

[0069] In the antenna substrate 1 described above, the maximum value of the distance between the radiation electrode 3 and the line portion 41 (the distance g2 between the second side portion 411b and the radiation electrode 3) is smaller than the width w of the line portion 41. This configuration can reduce the distance between the radiation electrode 3 and the transmission line 4.

[0070] In the antenna substrate 1 described above, at least in the range between both ends (third side 33 and fourth side 34) of the radiation electrode 3 in the first direction when viewed from the thickness direction of the dielectric substrate 2, the line portion 41 and the radiation electrode 3 have shapes that are line symmetrical with respect to a straight line L1 that passes through the center C1 of the radiation electrode 3 in the first direction and is perpendicular to the first direction. In this configuration, the current distribution is line symmetrical with respect to the straight line L1 that passes through the center of the radiation electrode 3, so that deviation of the directivity of the radiation electrode 3 from the thickness direction of the dielectric substrate 2 can be reduced.

[0071] In the antenna substrate 1 described above, the line portion 41 is located at the same position as the radiation electrode 3 in the normal direction of the dielectric substrate 2. This configuration simplifies the arrangement of the radiation electrode 3 and the transmission line 4, while reducing the distance between the radiation electrode 3 and the transmission line 4 and reducing degradation in transmission characteristics.

[0072] In the antenna substrate 1 described above, the side (first side 411) of the line portion 41 on the radiation electrode 3 side is non-linear in that the distance g2 between the line portion 41 and the radiation electrode 3 at the intermediate portion 31c is greater than the distance g1 between the line portion 41 and the radiation electrode 3 at the first end 31a and the second end 31b. This configuration can reduce degradation in transmission characteristics while reducing the distance between the radiation electrode 3 and the transmission line 4. In addition, since there is no need to change the shape of the radiation electrode 3, degradation in the antenna characteristics of the radiation electrode 3 can be reduced.

[0073] The above-described antenna module 10 includes the antenna substrate 1. This configuration can reduce degradation of the transmission characteristics while reducing the distance between the radiation electrode 3 and the transmission line 4.

[0074] The communication device 100 described above includes the antenna module 10. This configuration can reduce degradation of the transmission characteristics while reducing the distance between the radiation electrode 3 and the transmission line 4.

[0075] [2. Modifications] The embodiments of the present disclosure are not limited to the above-mentioned embodiments. The above-mentioned embodiments can be modified in various ways depending on the design, etc., as long as the object of the present disclosure can be achieved. Below, modified examples of the above-mentioned embodiments are listed. The modified examples described below can be applied in appropriate combination.

[0076] [2.1 Variation 1] 11 is an enlarged view of a main portion of an antenna substrate 1A according to Modification 1. Like the antenna substrate 1, the antenna substrate 1A includes a dielectric substrate 2, radiation electrodes 3 and 6, transmission lines 4 and 7, a ground electrode 5, and a connector 8.

[0077] In the first modification, the arrangement of the radiation electrode 3 and the line portion 41 of the transmission line 4 is different from that of the above embodiment. In the first modification, in the line portion 41, a straight line L2 that passes through the center of the second side portion 411b and is perpendicular to the first direction does not coincide with the straight line L1. Therefore, in the line portion 41, the length of the range in which the first side portion 411a-1 overlaps with the radiation electrode 3 in the second direction (the length of the first end portion 31a) is different from the length of the range in which the first side portion 411a-2 overlaps with the radiation electrode 3 in the second direction (the length of the second end portion 31b). Therefore, at least in the range between both ends (the third side 33 and the fourth side 34) of the radiation electrode 3 in the first direction as viewed from the thickness direction (Z direction) of the dielectric substrate 2, the line portion 41 and the radiation electrode 3 are not symmetrical with respect to the straight line L1 that passes through the center C1 of the radiation electrode 3 in the first direction and is perpendicular to the first direction. In this case, the degree of freedom in arranging the radiation electrode 3 on the dielectric substrate 2 can be improved, and it is possible to secure space for arranging other components as necessary.

[0078] In the first modification, the center C1 of the radiation electrode 3 is located closer to the connector 8 than the straight line L2 (upper side in FIG. 11). The radiation electrode 3 is connected to the transmission line 7 at the third side 33, and therefore the power feed point P is located on the third side 33. Therefore, the power feed point P is located on the opposite side of the straight line L2 with respect to the center C1 of the radiation electrode 3 in the first direction. The straight line L2 is also a straight line passing through the midpoint of a line segment connecting a first point at which the distance between the line portion 41 and the radiation electrode 3 at the first end 31a of the radiation electrode 3 is the smallest, and a second point at which the distance between the line portion 41 and the radiation electrode 3 at the second end 31b of the radiation electrode 3 is the smallest. This midpoint is a reference point for the position of the loop-shaped current path formed by the radiation electrode 3 and the transmission line 4. That is, the power feed point P is located farther away from the loop-shaped current path formed by the radiation electrode 3 and the transmission line 4 than when the center C1 of the radiation electrode 3 is on the straight line L2 as in the above embodiment. That is, in the first modification, the feeding point P of the radiation electrode 3 can be separated from the loop-shaped current path formed by the radiation electrode 3 and the transmission line 4. This can further reduce the amount of current that reaches the feeding point P from the transmission line 4. As a result, the deterioration of the transmission characteristics can be further reduced.

[0079] In the antenna substrate 1A described above, at least in the range between both ends (third side 33 and fourth side 34) of the radiation electrode 3 in the first direction when viewed from the thickness direction of the dielectric substrate 2, the line portion 41 and the radiation electrode 3 are not symmetrical with respect to a straight line L1 that passes through the center C1 of the radiation electrode 3 in the first direction and is perpendicular to the first direction. This configuration can improve the degree of freedom in arranging the radiation electrode 3 on the dielectric substrate 2, and can ensure space for arranging other components as necessary.

[0080] In the antenna substrate 1A, the feed point P of the radiation electrode 3 is located on the opposite side, with respect to the center C1 of the radiation electrode 3 in the first direction, to a straight line passing through the midpoint of a line segment connecting a first point, at which the distance between the line portion 41 and the radiation electrode 3 at the first end 31a of the radiation electrode 3 is minimum, and a second point, at which the distance between the line portion 41 and the radiation electrode 3 at the second end 31b of the radiation electrode 3 is minimum. This configuration can separate the feed point P of the radiation electrode 3 from the loop-shaped current path formed by the radiation electrode 3 and the transmission line 4, thereby further reducing degradation of the transmission characteristics.

[0081] In addition, in the antenna substrate 1A, the feeding point P of the radiation electrode 3 does not necessarily have to be on the opposite side of the straight line L2 passing through the midpoint of the line segment connecting the first point where the distance between the line portion 41 and the radiation electrode 3 at the first end 31a of the radiation electrode 3 is the smallest and the second point where the distance between the line portion 41 and the radiation electrode 3 at the second end 31b of the radiation electrode 3 is the smallest, relative to the center C1 of the radiation electrode 3 in the first direction.

[0082] [2.2 Variation 2] Fig. 12 is an enlarged view of a main portion of an antenna substrate 1B according to Modification 2. Like the antenna substrate 1, the antenna substrate 1A includes a dielectric substrate 2, radiation electrodes 3 and 6, transmission lines 4B and 7, a ground electrode 5, and a connector 8. The dielectric substrate 2, radiation electrodes 3 and 6, transmission line 7, ground electrode 5, and connector 8 are the same as those of the antenna substrate 1, so Figs. 1 to 4 will be referred to for these as necessary.

[0083] The line portion 41B of the transmission line 4B has a first side 411B and a second side 412B.

[0084] The first side 411B includes first side portions 411a-1 and 411a-2, a second side portion 411b, and third side portions 411d-1 and 411d-2.

[0085] The third side portion 411d-1 connects the first side portion 411a-1 and the second side portion 411b, similar to the third side portion 411c-1. The third side portion 411d-2 connects the first side portion 411a-2 and the second side portion 411b, similar to the third side portion 411c-2. The third sides 411d-1 and 411d-2 are arc-shaped rather than linear.

[0086] The third side 411d-1 is obtained by rounding the corners between the first side 411a-1 and the third side 411c-1 in the above embodiment to form a fillet shape. Similarly, the third side 411d-2 is obtained by rounding the corners between the first side 411a-2 and the third side 411c-2 in the above embodiment to form a fillet shape.

[0087] Such third side portions 411d-1 and 411d-2 can reduce the change in width w of the line portion 41 compared to the third side portions 411c-1 and 411c-2. This means that the change in impedance due to the change in width w of the line portion 41 can be reduced. Therefore, it is possible to reduce the reflection of signals in the transmission line 4, and reduce the deterioration of the transmission characteristics of the transmission line 4. In particular, the radius of the third side portions 411d-1 and 411d-2 is 1 / 10 or more of the width w of the line portion 41B. This can reduce the change in width w of the line portion 41.

[0088] The second side 412 includes fourth side portions 412a-1 and 412a-2, a fifth side portion 412b, and sixth side portions 412d-1 and 412d-2.

[0089] The sixth side portion 412d-1 connects the fourth side portion 412a-1 and the fifth side portion 412b, similar to the sixth side portion 412c-1. The sixth side portion 412d-2 connects the fourth side portion 412a-2 and the fifth side portion 412b, similar to the sixth side portion 412c-2. The sixth sides 412d-1 and 412d-2 are arc-shaped rather than linear.

[0090] The sixth side 412d-1 is obtained by rounding the corners between the fourth side 412a-1 and the sixth side 412c-1 in the above embodiment to form a fillet shape. Similarly, the sixth side 412d-2 is obtained by rounding the corners between the fourth side 412a-2 and the sixth side 412c-2 in the above embodiment to form a fillet shape.

[0091] Such sixth side portions 412d-1 and 412d-2 can reduce the change in width w of the line portion 41 compared to the sixth side portions 412c-1 and 412c-2. This means that the change in impedance due to the change in width w of the line portion 41 can be reduced. Therefore, it is possible to reduce the reflection of signals in the transmission line 4, and reduce the deterioration of the transmission characteristics of the transmission line 4. In particular, the radius of the sixth side portions 412d-1 and 412d-2 is 1 / 10 or more of the width w of the line portion 41B. This can reduce the change in width w of the line portion 41.

[0092] Here, if the corners of the first side portions 411a-1, 411a-2 and the third side portions 411c-1, 411c-2 of the antenna substrate 1 are simply rounded to form the third side portions 411d-1, 411d-2 as a fillet shape, the first side portions 411a-1, 411a-2 become shorter than the antenna substrate 1, and the capacitance between the line portion 41B and the radiation electrode 3 decreases. Therefore, in the second modification, in order to make the capacitance between the line portion 41B and the radiation electrode 3 equal to the capacitance between the line portion 41 and the radiation electrode 3, the lengths of the first side portions 411a-1, 411a-2 are maintained, but the second side portion 411b and the fifth side portion 412b facing the second side portion 411b are shortened. This narrows the range in which the line portion 41B protrudes on the opposite side to the radiation electrode 3, making it easier to secure space for arranging other components.

[0093] In the antenna substrate 1B described above, the side (first side) 411B of the line portion 41B on the radiation electrode 3 side includes first side portions 411a-1 and 411a-2 along the first direction in which the distance between the radiation electrode 3 and the line portion 41B is minimum, a second side portion 411b along the first direction in which the distance between the radiation electrode 3 and the line portion 41B is maximum, and third side portions 411d-1 and 411d-2 connecting the first side portions 411a-1 and 411a-2 and the second side portion 411b, and the third side portions 411d-1 and 411d-2 are arc-shaped with a radius of 1 / 10 or more of the width w of the line portion 41B. This configuration makes it possible to reduce signal reflection on the transmission line 4B and reduce deterioration of the transmission characteristics of the transmission line 4B. Furthermore, this configuration can narrow the range in which line portion 41B protrudes on the side opposite radiation electrode 3, making it easier to ensure space for arranging other components.

[0094] In the second modification, the line portion 41B may include at least one of the third side portions 411d-1 and 411d-2. That is, the line portion 41B may include the third side portions 411c-1 and 411d-2, or may include the third side portions 411d-1 and 411c-2. The line portion 41B does not necessarily have to include the sixth side portions 412d-1 and 412d-2, and may include the sixth side portions 412c-1 and 412c-2.

[0095] [2.3 Variation 3] Fig. 13 is an enlarged view of a main portion of an antenna substrate 1C according to Modification 3. Like the antenna substrate 1, the antenna substrate 1C includes a dielectric substrate 2, radiation electrodes 3 and 6, transmission lines 4C and 7, a ground electrode 5, and a connector 8. The dielectric substrate 2, radiation electrode 6, transmission line 7, ground electrode 5, and connector 8 are the same as those of the antenna substrate 1, so Figs. 1 to 4 will be referred to for these as necessary.

[0096] A line portion 41C of the transmission line 4C has a first side 411C and a second side 412C.

[0097] The first side 411C includes first side portions 411a-1 and 411a-2, a second side portion 411b, and third side portions 411e-1 and 411e-2.

[0098] The third side portion 411e-1 connects the first side portion 411a-1 and the second side portion 411b, similar to the third side portion 411c-1. The third side portion 411e-2 connects the first side portion 411a-2 and the second side portion 411b, similar to the third side portion 411c-2. The third side portions 411e-1 and 411e-2 are not linear along the second direction, but are linear extending in a direction intersecting the first direction without being perpendicular thereto. In particular, the angles of the third side portions 411e-1 and 411e-2 with respect to the first side portions 411a-1 and 411a-2 are obtuse angles.

[0099] The third side 411e-1 is obtained by chamfering the corner between the first side 411a-1 and the third side 411c-1 in the above embodiment. Similarly, the third side 411e-2 is obtained by chamfering the corner between the first side 411a-2 and the third side 411c-2 in the above embodiment.

[0100] Such third side portions 411e-1 and 411e-2 can reduce the change in width w of the line portion 41 compared to the third side portions 411c-1 and 411c-2. This means that the change in impedance due to the change in width w of the line portion 41 can be reduced. Therefore, it is possible to reduce the reflection of signals on the transmission line 4, and the deterioration of the transmission characteristics of the transmission line 4 can be reduced.

[0101] The second side 412 includes fourth side portions 412a-1 and 412a-2, a fifth side portion 412b, and sixth side portions 412e-1 and 412e-2.

[0102] The sixth side portion 412e-1 connects the fourth side portion 412a-1 and the fifth side portion 412b, similar to the sixth side portion 412c-1. The sixth side portion 412e-2 connects the fourth side portion 412a-2 and the fifth side portion 412b, similar to the sixth side portion 412c-2. The sixth side portions 412e-1 and 412e-2 are not linear along the second direction, but are linear extending in a direction intersecting the first direction without being perpendicular thereto. In particular, the sixth side portions 412e-1 and 412e-2 form obtuse angles with respect to the fourth side portions 412a-1 and 412a-2.

[0103] The sixth side 412e-1 is obtained by chamfering the corner between the fourth side 412a-1 and the sixth side 412c-1 in the above embodiment. Similarly, the sixth side 412e-2 is obtained by chamfering the corner between the fourth side 412a-2 and the sixth side 412c-2 in the above embodiment.

[0104] Such sixth sides 412e-1 and 412e-2 can reduce the change in width w of the line portion 41 compared to the sixth sides 412c-1 and 412c-2. This means that the change in impedance due to the change in width w of the line portion 41 can be reduced. Therefore, it is possible to reduce the reflection of signals on the transmission line 4, and the deterioration of the transmission characteristics of the transmission line 4 can be reduced.

[0105] Here, if the corners of the first side portions 411a-1, 411a-2 and the third side portions 411c-1, 411c-2 of the antenna substrate 1 are simply chamfered to form the third side portions 411e-1, 411e-2, the first side portions 411a-1, 411a-2 are shorter than the antenna substrate 1, and the capacitance between the line portion 41C and the radiation electrode 3 is reduced. Therefore, in the third modification, in order to make the capacitance between the line portion 41C and the radiation electrode 3 equal to the capacitance between the line portion 41 and the radiation electrode 3, the lengths of the first side portions 411a-1, 411a-2 are maintained, but the second side portion 411b and the fifth side portion 412b facing the second side portion 411b are shortened. This narrows the range in which the line portion 41C protrudes on the opposite side to the radiation electrode 3, making it easier to secure space for arranging other components.

[0106] In the antenna substrate 1C described above, the side (first side) 411C on the radiation electrode 3 side of the line portion 41C includes first side portions 411a-1, 411a-2 along the first direction in which the distance between the radiation electrode 3 and the line portion 41C is the smallest, a second side portion 411b along the first direction in which the distance between the radiation electrode 3 and the line portion 41C is the largest, and third side portions 411e-1, 411e-2 connecting the first side portions 411a-1, 411a-2 and the second side portion 411b, and the third side portions 411e-1, 411e-2 are straight lines that intersect without being perpendicular to the first direction. This configuration makes it possible to reduce reflection of signals on the transmission line 4C and reduce deterioration of the transmission characteristics of the transmission line 4C. Furthermore, this configuration makes it possible to narrow the range in which the line portion 41C protrudes on the opposite side to the radiation electrode 3, making it easier to secure space for arranging other components.

[0107] In the third modification, the line portion 41C may include at least one of the third side portions 411e-1 and 411e-2. That is, the line portion 41C may include the third side portions 411c-1 and 411e-2, or may include the third side portions 411e-1 and 411c-2. The line portion 41C does not necessarily have to include the sixth side portions 412e-1 and 412e-2, and may include the sixth side portions 412c-1 and 412c-2.

[0108] [2.4 Variation 4] Fig. 14 is an enlarged view of a main portion of an antenna substrate 1D according to Modification 4. Like the antenna substrate 1, the antenna substrate 1D includes a dielectric substrate 2, radiation electrodes 3 and 6, transmission lines 4C and 7, a ground electrode 5, and a connector 8. The dielectric substrate 2, radiation electrode 6, transmission line 7, ground electrode 5, and connector 8 are the same as those of the antenna substrate 1, so Figs. 1 to 4 will be referred to for these as necessary.

[0109] The line portion 41D of the transmission line 4D has a first side 413 and a second side 414. The first side 413 and the second side 414 are both sides in the width direction (Y direction) of the dielectric substrate 2. In particular, the first side 413 is the side on the radiating electrode 3 side, and the second side 414 is the side opposite to the radiating electrode 3.

[0110] The first side 413 includes a first side portion 413a, a second side portion 413b, a third side portion 413c, and a fourth side portion 413d.

[0111] The first side portion 413a and the second side portion 413b are linear and extend along the first direction (X direction). In the line portion 41D, the distance between the radiating electrode 3 and the line portion 41D is minimum at the first side portion 413a and the second side portion 413b. In the first side portion 413a, the distance between the radiating electrode 3 and the line portion 41D is minimum at the first end portion 31a of the radiating electrode 3. In the second side portion 413b, the distance between the radiating electrode 3 and the line portion 41D is minimum at the second end portion 31b of the radiating electrode 3.

[0112] The third side portion 413c extends from the first side portion 413a toward the second side portion 413b such that the distance between the radiation electrode 3 and the line portion 41D gradually increases. The third side portion 413c is linear and extends in a direction intersecting the first direction (X direction) without being perpendicular to the first direction. In particular, the angle of the third side portion 413c with respect to the first side portion 413a is an obtuse angle.

[0113] The fourth side 413d extends from the third side 413c toward the second side 413b such that the distance between the radiation electrode 3 and the line portion 41D gradually decreases. The fourth side 413d is linear and extends in a direction intersecting the first direction (X direction) without being perpendicular to it. In particular, the angle of the fourth side 413d with respect to the second side 413b is an obtuse angle.

[0114] In the line portion 41D, a distance g1 between the first side portion 413a and the second side portion 413b and the radiation electrode 3 is the minimum value of the distance between the radiation electrode 3 and the line portion 41D. A distance g2 between the intersection of the third side portion 413c and the fourth side portion 413d and the radiation electrode 3 is the maximum value of the distance between the radiation electrode 3 and the line portion 41D.

[0115] Such third side portion 413c and fourth side portion 413d can reduce the change in width w of the line portion 41D compared to the antenna substrate 1 of the embodiment. Therefore, it is possible to reduce the reflection of a signal on the transmission line 4D, and to reduce the deterioration of the transmission characteristics of the transmission line 4.

[0116] The second side 414 includes a fifth side portion 414a, a sixth side portion 414b, a seventh side portion 414c, and an eighth side portion 414d.

[0117] The fifth side 414a, the sixth side 414b, the seventh side 414c, and the eighth side 414d are parallel to and face the first side 413a, the second side 413b, the third side 413c, and the fourth side 413d, respectively. As a result, the distance between the first side 413a and the fifth side 414a, the distance between the second side 413b and the sixth side 414b, the distance between the third side 413c and the seventh side 414c, and the distance between the fourth side 413d and the eighth side 414d are equal to each other, and define the width w of the line portion 41D. That is, the width w is uniform in the line portion 41D. This allows a further reduction in the reflection of the signal in the transmission line 4D, and further reduces the deterioration of the transmission characteristics of the transmission line 4.

[0118] In the antenna substrate 1D described above, the side (first side) 413 of the line portion 41D on the radiation electrode 3 side includes a first side portion 413a along the first direction where the distance between the radiation electrode 3 and the line portion 41D is minimum at the first end portion 31a of the radiation electrode 3, a second side portion 413b along the first direction where the distance between the radiation electrode 3 and the line portion 41D is minimum at the second end portion 31b of the radiation electrode 3, a third side portion 413c where the distance between the radiation electrode 3 and the line portion 41D gradually increases from the first side portion 413a toward the second side portion 413b, and a fourth side portion 413d where the distance between the radiation electrode 3 and the line portion 41D gradually decreases from the third side portion 413c toward the second side portion 413b. This configuration makes it possible to reduce reflection of signals on the transmission line 4D and reduce deterioration of the transmission characteristics of the transmission line 4D.

[0119] [2.5 Variation 5] Fig. 15 is an enlarged view of a main portion of an antenna substrate 1E according to Modification 5. Like the antenna substrate 1, the antenna substrate 1E includes a dielectric substrate 2, radiation electrodes 3 and 6, transmission lines 4E and 7, a ground electrode 5, and a connector 8. The dielectric substrate 2, radiation electrode 6, transmission line 7, ground electrode 5, and connector 8 are the same as those of the antenna substrate 1, so Figs. 1 to 4 will be referred to for these as necessary.

[0120] A line portion 41E of the transmission line 4E has a first side 411E and a second side 412E.

[0121] The first side 411E includes first side portions 411a-1 and 411a-2, a second side portion 411b, third side portions 411c-1 and 411c-2, fourth side portions 411f-1 and 411f-2, and fifth side portions 411g-1 and 411g-2.

[0122] The fourth sides 411f-1 and 411f-2 are linear and extend in the first direction (X direction). The fourth sides 411f-1 and 411f-2 do not face the radiation electrode 3 in the width direction (Y direction) of the dielectric substrate 2. The fourth side 411f-1 is on the opposite side to the second side 411b with respect to the first side 411a-1. The fourth side 411f-2 is on the opposite side to the second side 411b with respect to the first side 411a-2. The distance between the fourth sides 411f-1 and 411f-2 and the radiation electrode 3 in the second direction is equal to the distance g2 between the second side 411b and the radiation electrode 3.

[0123] The fifth side portion 411g-1 connects the first side portion 411a-1 and the fourth side portion 411f-1. The fifth side portion 411g-2 connects the first side portion 411a-2 and the fourth side portion 411f-2. The fifth sides 411g-1 and 411g-2 are linear and extend along the width direction (Y direction) of the dielectric substrate 2.

[0124] The second side 412E is a straight line extending in the first direction (X direction).

[0125] In the line portion 41E, the first side portion 411a-1, the third side portion 411c-1, and the fifth side portion 411g-1 form a portion protruding toward the first end portion 31a of the radiation electrode 3, and the first side portion 411a-2, the third side portion 411c-2, and the fifth side portion 411g-2 form a portion protruding toward the second end portion 31b of the radiation electrode 3. On the other hand, the second side portion 411b and the third side portions 411c-1 and 411c-2 form portions recessed with respect to the radiation electrode 3.

[0126] Therefore, in the antenna substrate 1E, the side (first side 411E) of the line portion 41E on the radiation electrode 3 side is recessed at a portion (second side 411b) corresponding to the intermediate portion 31c more than at portions (first side portions 411a-1, 411a-2) corresponding to the first end portion 31a and the second end portion 31b. In other words, the first side 411E of the line portion 41E is nonlinear, with a distance g2 between the line portion 41 and the radiation electrode 3 at the intermediate portion 31c being greater than a distance g1 between the line portion 41 and the radiation electrode 3 at the first end portion 31a and the second end portion 31b. Therefore, in the line portion 41E, the distance between the radiation electrode 3 and the line portion 41E is minimum at the first end portion 31a and the second end portion 31b of the radiation electrode 3 in the first direction, and is maximum at the intermediate portion 31c between the first end portion 31a and the second end portion 31b of the radiation electrode 3 in the first direction. This allows the line portion 41E and the radiation electrode 3 to be capacitively coupled at two points, the first end 31a and the second end 31b of the radiation electrode 3. Therefore, degradation of the transmission characteristics can be reduced while reducing the distance between the radiation electrode 3 and the transmission line 4E.

[0127] In the antenna substrate 1E described above, the side (first side 411E) of the line portion 41E on the radiation electrode 3 side is non-linear in that the distance g2 between the line portion 41 and the radiation electrode 3 at the intermediate portion 31c is greater than the distance g1 between the line portion 41 and the radiation electrode 3 at the first end 31a and the second end 31b. This configuration can reduce degradation in transmission characteristics while reducing the distance between the radiation electrode 3 and the transmission line 4E.

[0128] [2.6 Variation 6] Fig. 16 is an enlarged view of a main portion of an antenna substrate 1F according to Modification 6. The antenna substrate 1F includes a dielectric substrate 2, radiation electrodes 3F and 6, transmission lines 4F and 7, a ground electrode 5, and a connector 8. The dielectric substrate 2, radiation electrode 6, transmission line 7, ground electrode 5, and connector 8 are similar to those of the antenna substrate 1, so Figs. 1 to 4 will be referred to for these as necessary.

[0129] A line portion 41F of the transmission line 4F has a first side 411F and a second side 412F. The first side 411F and the second side 412F are linear and extend in a first direction (X direction).

[0130] The radiating electrode 3F has a first side 31F, a second side 32, a third side 33, and a fourth side 34. Unlike the first side 31 of the radiating electrode 3 according to the embodiment, the first side 31F is not a straight line extending along the longitudinal direction (X direction) of the dielectric substrate 2. The first side 31F includes a first end 31a, a second end 31b, a middle portion 31c, and connecting portions 31d and 31e.

[0131] The first end 31a and the second end 31b are closer to the line portion 41F of the transmission line 4F than the intermediate portion 31c. A distance g1 between the first end 31a and the second end 31b and the line portion 41F is smaller than a distance g2 between the intermediate portion 31c and the line portion 41F. The distance g1 is the minimum value of the distance between the radiating electrode 3F and the line portion 41F, and the distance g2 is the maximum value of the distance between the radiating electrode 3F and the line portion 41F.

[0132] The connecting portions 31d and 31e are portions that connect the first end portion 31a and the second end portion 31b to the intermediate portion 31c, and are linear and extend in the width direction of the dielectric substrate 2 (Y direction).

[0133] Therefore, in the antenna substrate 1F, the side (first side 31F) of the radiation electrode 3F on the line portion 41F side is recessed in the middle portion 31c from the first end 31a and the second end 31b. In other words, the first side 31F of the radiation electrode 3F is nonlinear in that the distance g2 between the line portion 41F and the radiation electrode 3F at the middle portion 31c is larger than the distance g1 between the line portion 41F and the radiation electrode 3F at the first end 31a and the second end 31b. Therefore, in the radiation electrode 3F, the distance between the radiation electrode 3F and the line portion 41F is smallest at the first end 31a and the second end 31b of the radiation electrode 3F in the first direction and is largest at the middle portion 31c between the first end 31a and the second end 31b of the radiation electrode 3F in the first direction. This allows the line portion 41F and the radiation electrode 3F to be capacitively coupled at two points, the first end 31a and the second end 31b of the radiation electrode 3F. Therefore, degradation of the transmission characteristics can be reduced while reducing the distance between the radiation electrode 3F and the transmission line 4F.

[0134] In the antenna substrate 1F described above, the side (first side 31F) of the radiation electrode 3F on the line portion 41F side is nonlinear such that the distance g2 between the line portion 41F and the radiation electrode 3F at the intermediate portion 31c is greater than the distance g1 between the line portion 41F and the radiation electrode 3F at the first end 31a and the second end 31b. This configuration can reduce the degradation of the transmission characteristics while reducing the distance between the radiation electrode 3F and the transmission line 4F. In addition, since it is not necessary to change the width w of the transmission line 4F, it is possible to reduce the reflection of the signal on the transmission line 4F, and reduce the degradation of the transmission characteristics of the transmission line 4F.

[0135] [2.7 Variation 7] Fig. 17 is an enlarged view of a main portion of an antenna substrate 1G according to Modification 7. The antenna substrate 1G includes a dielectric substrate 2, radiating electrodes 3F and 6, transmission lines 4 and 7, a ground electrode 5, and a connector 8. The dielectric substrate 2, the radiating electrode 6, the transmission line 7, the ground electrode 5, and the connector 8 are similar to those of the antenna substrate 1, so Figs. 1 to 4 will be referred to for these as necessary.

[0136] In the transmission line 4, the side (first side 411) of the line portion 41 on the radiation electrode 3F side has a shape in which a portion (second side 411b) corresponding to the intermediate portion 31c is recessed more than portions (first sides 411a-1, 411a-2) corresponding to the first end 31a and the second end 31b. In other words, the first side 411 of the line portion 41 is nonlinear in which a distance g2 between the line portion 41 and the radiation electrode 3F at the intermediate portion 31c is larger than a distance g1 between the line portion 41 and the radiation electrode 3F at the first end 31a and the second end 31b.

[0137] In the radiation electrode 3F, the side (first side 31F) on the line portion 41F side of the radiation electrode 3F has a shape in which the middle portion 31c is recessed more than the first end portion 31a and the second end portion 31b. In other words, the first side 31F of the radiation electrode 3F is nonlinear in that the distance g2 between the line portion 41F and the radiation electrode 3F at the middle portion 31c is larger than the distance g1 between the line portion 41F and the radiation electrode 3F at the first end portion 31a and the second end portion 31b.

[0138] In the antenna substrate 1G, both the line portion 41 and the radiation electrode 3F are nonlinear such that the distance g2 between the line portion 41F and the radiation electrode 3F at the intermediate portion 31c is greater than the distance g1 between the line portion 41F and the radiation electrode 3F at the first end 31a and the second end 31b. Therefore, the distance g2 between the line portion 41 and the radiation electrode 3F at the intermediate portion 31c can be greater than when only one of the line portion 41 and the radiation electrode 3F is nonlinear as described above. Therefore, it is not necessary to increase the distance between the radiation electrode 3F and the transmission line 4 in order to increase the distance g2.

[0139] In the antenna substrate 1G described above, both the side of the line portion 41 on the radiation electrode 3F side (first side 411) and the side of the radiation electrode 3F on the line portion 41 side (first side 31F) are non-linear in that the distance g2 between the line portion 41 and the radiation electrode 3F at the intermediate portion 31c is greater than the distance g1 between the line portion 41 and the radiation electrode 3F at the first end 31a and the second end 31b. This configuration can reduce degradation in transmission characteristics while reducing the distance between the radiation electrode 3F and the transmission line 4. In particular, it is not necessary to increase the distance between the radiation electrode 3F and the transmission line 4 in order to increase the distance g2.

[0140] [2.8 Variation 8] Fig. 18 is a plan view of an antenna substrate 1H according to Modification 8. The antenna substrate 1H includes a dielectric substrate 2, radiating electrodes 3 and 6, transmission lines 4H and 7H, a ground electrode 5, and a connector 8. The dielectric substrate 2, the radiating electrodes 3 and 6, the ground electrode 5, and the connector 8 are similar to those of the antenna substrate 1, so Figs. 1 to 5 will be referred to for these as necessary.

[0141] The transmission lines 4H and 7H are not disposed on the main surface 2a of the dielectric substrate 2. Therefore, the line portions 41, 42, and 43 of the transmission line 4H are not at the same position as the radiation electrode 3 in the normal direction of the dielectric substrate 2.

[0142] Fig. 19 is a cross-sectional view of an antenna substrate 1H according to Modification 8. As shown in Fig. 19, a transmission line 4H is provided as an intermediate layer of a dielectric substrate 2. As a result, line portions 41, 42, and 43 of the transmission line 4H are located between the radiation electrode 3 and the ground electrode 5 in the normal direction of the dielectric substrate 2.

[0143] In the transmission line 4H, the line portion 43 extends from the tip of the line portion 42 to a position where it overlaps with the radiation electrode 6, and is connected to the radiation electrode 6 by a via hole 44. The position of the via hole 71 in the radiation electrode 3 corresponds to the position of the power feeding point of the radiation electrode 6.

[0144] In the antenna substrate 1H as well, the line portion 41 extends in a first direction perpendicular to the normal direction of the dielectric substrate 2 and is spaced apart from the radiation electrode 3 in a second direction intersecting the first direction. In this modification, the second direction is not the width direction (Y direction) of the dielectric substrate 2, unlike the embodiment. However, in this modification as well, as described in the embodiment, the side (first side 411) of the line portion 41 on the radiation electrode 3 side has a shape in which the portion (second side 411b) corresponding to the intermediate portion 31c is recessed more than the portions (first side portions 411a-1, 411a-2) corresponding to the first end portion 31a and the second end portion 31b. Therefore, in this modification as well, the distance between the radiation electrode 3 and the line portion 41 is smallest at the first end portion 31a and the second end portion 31b and is largest at the intermediate portion 31c. That is, as shown in Figures 18 and 19, the distance g2 between the line portion 41 and the radiation electrode 3 at the intermediate portion 31c is greater than the distance g1 between the line portion 41 and the radiation electrode 3 at the first end portion 31a and the second end portion 31b.

[0145] This allows the line portion 41 and the radiation electrode 3 to be capacitively coupled at two points, the first end 31a and the second end 31b of the radiation electrode 3. This can generate a loop-shaped current path surrounding the gap between the second side portion 411b of the line portion 41 and the middle portion 31c of the radiation electrode 3. This allows the current to flow in a loop between the line portion 41 and the radiation electrode 3 even when the current passes through the transmission line 4H, so that the amount of current leaking from the transmission line 4H through the radiation electrode 3 to the transmission line 7H can be reduced. As a result, it is possible to ensure isolation between the transmission line 4H and the radiation electrode 3. Therefore, it is possible to reduce the deterioration of the transmission characteristics while reducing the distance between the radiation electrode 3 and the transmission line 4H.

[0146] Like the transmission line 4H, the transmission line 7H is not disposed on the main surface 2a of the dielectric substrate 2. The transmission line 7H is provided as an intermediate layer of the dielectric substrate 2, and is disposed on the dielectric substrate 2 between the main surface 2a and the ground electrode 5. The transmission line 7H is connected to the radiating electrode 3 by a via hole 71. The position of the via hole 71 in the radiating electrode 3 corresponds to the position of the feeding point of the radiating electrode 3.

[0147] [2.9 Other Modifications] In one modified example, the shapes of the dielectric substrate 2 and the ground electrode 5 are not particularly limited. Three or more radiating electrodes may be arranged on the dielectric substrate 2. The ground electrode 5 may be provided separately for each of the radiating electrodes 3 and 6. The connector 8 is not essential, and a coaxial cable or the like may be directly connected to the transmission lines 4 and 7.

[0148] In one modified example, the shape of the radiation electrodes 3, 6 is not limited to the rectangular shape as in the embodiment. The shape of the radiation electrodes 3, 6 does not necessarily have to be rectangular, and may be a quadrangle such as a trapezoid or a parallelogram, or may be a circle.

[0149] In one modified example, the radiating electrodes 3, 6 do not necessarily have to be arranged on the main surface 2a of the dielectric substrate 2. The radiating electrodes 3, 6 may be arranged on an inner layer (intermediate layer) of the dielectric substrate 2. The ground electrode 5 does not necessarily have to be arranged on the rear surface 2b of the dielectric substrate 2. The radiating electrodes 3, 6 and the ground electrode 5 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 interposed therebetween.

[0150] In one modified example, the frequency band used for wireless communication in the antenna substrate 1 is not particularly limited. The frequency band may be selected from well-known frequency bands such as a frequency band for wireless communication by Wi-Fi, a frequency band for wireless communication by UWB, a frequency band for Bluetooth (registered trademark), a frequency band for wireless communication by Wi-Fi, a mid-band of the 2G (second generation mobile communication) standard, a low-band of the 4G (fourth generation mobile communication) standard, and a low-band of the 5G (fifth generation mobile communication) standard. Examples of the frequency band for wireless communication by Wi-Fi include a frequency band around 2.4 GHz (for example, 2.4 GHz to 2.5 GHz) and a frequency band around 5 GHz (for example, 5.15 GHz to 5.8 GHz). The 2G standard is, for example, 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 in various communication standards such as wireless LAN, specific low power radio, and short-distance wireless communication.

[0151] [3. Aspects] As is apparent from the above embodiment and modifications, the present disclosure includes the following aspects.

[0152] [Aspect 1] a dielectric substrate having a dielectric layer; a radiation electrode and a ground electrode facing each other with at least a part of the dielectric layer interposed therebetween; a transmission line on the dielectric substrate; Equipped with the transmission line includes a line portion extending in a first direction perpendicular to a normal direction of the dielectric substrate and spaced apart from the radiation electrode in a second direction intersecting the first direction; a distance between the radiation electrode and the line portion is smallest at a first end and a second end of the radiation electrode in the first direction and is largest at an intermediate portion between the first end and the second end of the radiation electrode in the first direction, a minimum value of the distance between the radiation electrode and the line portion is smaller than a width of the line portion; Antenna board.

[0153] [Aspect 2] The wavelength corresponding to the frequency band supported by the radiation electrode is λ, Let d be the distance between a first point at which the distance between the line portion and the radiation electrode at the first end of the radiation electrode is minimum and a second point at which the distance between the line portion and the radiation electrode at the second end of the radiation electrode is minimum, d is within λ / 4±40%; 2 is an antenna substrate according to embodiment 1;

[0154] [Aspect 3] The size of the radiation electrode in the first direction is D, Let d be the distance between a first point at which the distance between the line portion and the radiation electrode at the first end of the radiation electrode is minimum and a second point at which the distance between the line portion and the radiation electrode at the second end of the radiation electrode is minimum, d is within D / 2±40%; The antenna substrate according to embodiment 1 or 2.

[0155] [Aspect 4] The wavelength corresponding to the frequency band supported by the radiation electrode is λ, Let d be the distance between a first point at which the distance between the line portion and the radiation electrode at the first end of the radiation electrode is minimum and a second point at which the distance between the line portion and the radiation electrode at the second end of the radiation electrode is minimum, d is greater than 3λ / 20 and less than λ / 2; The antenna substrate according to any one of the first to third embodiments.

[0156] [Aspect 5] The size of the radiation electrode in the first direction is D, Let d be the distance between a first point at which the distance between the line portion and the radiation electrode at the first end of the radiation electrode is minimum and a second point at which the distance between the line portion and the radiation electrode at the second end of the radiation electrode is minimum, d is greater than 3D / 10 and less than D, The antenna substrate according to any one of the first to fourth embodiments.

[0157] [Aspect 6] a maximum distance between the radiation electrode and the line portion is smaller than a width of the line portion; The antenna substrate according to any one of embodiments 1 to 5.

[0158] [Aspect 7] at least in a range between both ends of the radiation electrode in the first direction as viewed from a thickness direction of the dielectric substrate, the line portion and the radiation electrode have shapes that are line symmetrical with respect to a straight line that passes through a center of the radiation electrode in the first direction and is perpendicular to the first direction. The antenna substrate according to any one of the first to sixth embodiments.

[0159] [Aspect 8] the line portion is located at the same position as the radiation electrode in the normal direction of the dielectric substrate; The antenna substrate according to any one of the first to seventh embodiments.

[0160] [Aspect 9] At least in a range between both ends of the radiation electrode in the first direction as viewed from a thickness direction of the dielectric substrate, the line portion and the radiation electrode are not symmetrical with respect to a straight line that passes through a center of the radiation electrode in the first direction and is perpendicular to the first direction. The antenna substrate according to any one of the first to eighth embodiments.

[0161] [Aspect 10] a power supply point of the radiation electrode is located on an opposite side of a line passing through a midpoint of a line segment connecting a first point, at which a distance between the line portion and the radiation electrode at the first end of the radiation electrode is minimum, and a second point, at which a distance between the line portion and the radiation electrode at the second end of the radiation electrode is minimum, with respect to a center of the radiation electrode in the first direction. The antenna substrate according to any one of embodiments 1 to 9.

[0162] [Aspect 11] At least one of an edge of the line portion on the radiation electrode side and an edge of the radiation electrode on the line portion side is nonlinear such that a distance between the line portion and the radiation electrode at the intermediate portion is greater than a distance between the line portion and the radiation electrode at the first end portion and the second end portion. The antenna substrate according to any one of embodiments 1 to 10.

[0163] [Aspect 12] The side of the line portion on the radiation electrode side is a first side portion along the first direction in which the distance between the radiation electrode and the line portion is minimum; a second side portion along the first direction in which the distance between the radiation electrode and the line portion is maximum; a third side portion connecting the first side portion and the second side portion; Including, The third side portion has an arc shape with a radius of 1 / 10 or more of the width of the line portion. The antenna substrate according to any one of embodiments 1 to 11.

[0164] [Aspect 13] The side of the line portion on the radiation electrode side is a first side portion along the first direction in which the distance between the radiation electrode and the line portion is minimum; a second side portion along the first direction in which the distance between the radiation electrode and the line portion is maximum; a third side portion connecting the first side portion and the second side portion; Including, The third side portion is a straight line that intersects with the first direction without being perpendicular to the first direction. The antenna substrate according to any one of embodiments 1 to 11.

[0165] [Aspect 14] The side of the line portion on the radiation electrode side is a first side portion along the first direction in which the distance between the radiation electrode and the line portion is minimum at the first end portion of the radiation electrode; a second side portion along the first direction in which the distance between the radiation electrode and the line portion is minimum at the second end portion of the radiation electrode; a third side portion in which the distance between the radiation electrode and the line portion gradually increases from the first side portion toward the second side portion; a fourth side portion in which the distance between the radiation electrode and the line portion gradually decreases from the third side portion toward the second side portion; Including, The antenna substrate according to any one of embodiments 1 to 11.

[0166] [Aspect 15] The antenna substrate according to any one of the first to fourth aspects is provided. Antenna module.

[0167] [Aspect 16] 16. The antenna module of claim 15, Communications equipment.

[0168] Aspects 2 to 14 are optional elements and are not essential. [Industrial Applicability]

[0169] 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 constituting a patch antenna, an antenna module, and a communication device. [Explanation of symbols]

[0170] 1, 1A, 1B, 1C, 1D, 1E, 1F, 1G, 1H Antenna board 2. Dielectric substrate 20 Dielectric layer 3, 3F 1st radiation electrode (radiation electrode) 31, 31F, Side 1 31a First end 31b Second end 31c middle part 4, 4B, 4C, 4D, 4E, 4F, 4H Second transmission line (transmission line) 41, 41B, 41C, 41D, 41E, 41F Track section 411, 411B, 411C, 411E, 411F First side (side of the line section facing the radiation electrode) 411a-1, 411a-2 1st side 411b 2nd side 411c-1, 411c-2 3rd side 411d-1, 411d-2 Third side 411e-1, 411e-2 Third side 413 First side (side of the line section facing the radiation electrode) 413a First side 413b 2nd side 413c Third side 413d Fourth side 5 Ground electrode 10 Antenna Module 100 Communication equipment

Claims

1. a dielectric substrate having a dielectric layer; a radiation electrode and a ground electrode facing each other with at least a part of the dielectric layer interposed therebetween; a transmission line on the dielectric substrate; Equipped with the transmission line includes a line portion extending in a first direction perpendicular to a normal direction of the dielectric substrate and spaced apart from the radiation electrode in a second direction intersecting the first direction, a distance between the radiation electrode and the line portion is smallest at a first end and a second end of the radiation electrode in the first direction and is largest at an intermediate portion between the first end and the second end of the radiation electrode in the first direction, a minimum value of the distance between the radiation electrode and the line portion is smaller than a width of the line portion; Antenna board.

2. The wavelength corresponding to the frequency band supported by the radiation electrode is λ, Let d be the distance between a first point at which the distance between the line portion and the radiation electrode at the first end of the radiation electrode is minimum and a second point at which the distance between the line portion and the radiation electrode at the second end of the radiation electrode is minimum. d is within λ / 4±40%; The antenna substrate of claim 1 .

3. The size of the radiation electrode in the first direction is D, Let d be the distance between a first point at which the distance between the line portion and the radiation electrode at the first end of the radiation electrode is minimum and a second point at which the distance between the line portion and the radiation electrode at the second end of the radiation electrode is minimum. d is within D / 2±40%; The antenna substrate of claim 1 .

4. The wavelength corresponding to the frequency band supported by the radiation electrode is λ, Let d be the distance between a first point at which the distance between the line portion and the radiation electrode at the first end of the radiation electrode is minimum and a second point at which the distance between the line portion and the radiation electrode at the second end of the radiation electrode is minimum. d is greater than 3λ / 20 and less than λ / 2; The antenna substrate of claim 1 .

5. The size of the radiation electrode in the first direction is D, Let d be the distance between a first point at which the distance between the line portion and the radiation electrode at the first end of the radiation electrode is minimum and a second point at which the distance between the line portion and the radiation electrode at the second end of the radiation electrode is minimum. d is greater than 3D / 10 and less than D; The antenna substrate of claim 1 .

6. a maximum value of the distance between the radiation electrode and the line portion is smaller than a width of the line portion; The antenna substrate of claim 1 .

7. at least in a range between both ends of the radiation electrode in the first direction as viewed from a thickness direction of the dielectric substrate, the line portion and the radiation electrode have shapes that are line symmetrical with respect to a straight line that passes through a center of the radiation electrode in the first direction and is perpendicular to the first direction. The antenna substrate of claim 1 .

8. the line portion is located at the same position as the radiation electrode in the normal direction of the dielectric substrate; The antenna substrate of claim 1 .

9. At least in a range between both ends of the radiation electrode in the first direction as viewed from a thickness direction of the dielectric substrate, the line portion and the radiation electrode are not symmetrical with respect to a straight line that passes through a center of the radiation electrode in the first direction and is perpendicular to the first direction. The antenna substrate of claim 1 .

10. a power supply point of the radiation electrode is located on an opposite side of a line passing through a midpoint of a line segment connecting a first point, at which a distance between the line portion and the radiation electrode at the first end of the radiation electrode is minimum, and a second point, at which a distance between the line portion and the radiation electrode at the second end of the radiation electrode is minimum, with respect to a center of the radiation electrode in the first direction. The antenna substrate of claim 1 .

11. At least one of an edge of the line portion on the radiation electrode side and an edge of the radiation electrode on the line portion side is nonlinear such that a distance between the line portion and the radiation electrode at the intermediate portion is greater than a distance between the line portion and the radiation electrode at the first end portion and the second end portion. The antenna substrate of claim 1 .

12. The side of the line portion on the radiation electrode side is a first side portion along the first direction in which the distance between the radiation electrode and the line portion is minimum; a second side portion along the first direction in which the distance between the radiation electrode and the line portion is maximum; a third side portion connecting the first side portion and the second side portion; Including, The third side portion has an arc shape with a radius of 1 / 10 or more of the width of the line portion. The antenna substrate of claim 1 .

13. The side of the line portion on the radiation electrode side is a first side portion along the first direction in which the distance between the radiation electrode and the line portion is minimum; a second side portion along the first direction in which the distance between the radiation electrode and the line portion is maximum; a third side portion connecting the first side portion and the second side portion; Including, The third side portion is a straight line that intersects with the first direction without being perpendicular to the first direction. The antenna substrate of claim 1 .

14. The side of the line portion on the radiation electrode side is a first side portion along the first direction in which the distance between the radiation electrode and the line portion is minimum at the first end portion of the radiation electrode; a second side portion along the first direction in which the distance between the radiation electrode and the line portion is minimum at the second end portion of the radiation electrode; a third side portion in which the distance between the radiation electrode and the line portion gradually increases from the first side portion toward the second side portion; a fourth side portion in which the distance between the radiation electrode and the line portion gradually decreases from the third side portion toward the second side portion; Including, The antenna substrate of claim 1 .

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

16. 16. A method for manufacturing an antenna comprising: Communications equipment.

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