Patch antenna and antenna module

Abstract

A patch antenna according to the present invention comprises: a dielectric layer that has a first principal surface and a second principal surface and includes a first layer that is provided on the first principal surface side and a second layer that is provided on the second principal surface side; a patch that is provided on the first principal surface; a ground that is provided between the first layer and the second layer; at least 3 connection vias that are connected to the patch; a first via that is electrically connected within the second layer to at least 2 first connection vias of the at least 3 connection vias and reaches the second principal surface; and a second via that is electrically connected to at least 2 second connection vias of the at least 3 connection vias and reaches the second principal surface.

Description

Patch antenna and antenna module This application claims priority to Japanese Patent Application No. 2024-052649, filed on March 28, 2024, the contents of which are incorporated herein by reference. Patent Document 1 discloses a patch antenna. Patent Document 1 compares a case where one feed point is connected to a patch without branching with a case where one feed point is connected to a microstrip line, which is then branched in two directions and then connected to a patch. Patent Document 1 discloses that in the former case, when the phase is 90° or 270°, a current flows along the X direction, which is associated with the intended linear polarization, and when the phase is 0° or 180°, a current flows along the Y direction, which is associated with the undesired cross polarization. Patent Document 1 discloses that in the latter case, when the phase is 0° or 180°, a current flows along the X direction, which is associated with the intended linear polarization, and when the phase is 90° or 270°, a current does not flow along the Y direction, which is associated with the undesired cross polarization.

[0064] ,

[0075] ,

[0081] , Figure 1, Figures 7A to 7D, Figure 8 and Figures 12A to 12D). Furthermore, Patent Document 1 discloses that each of the two feed points is connected to a microstrip line, and the microstrip line is branched in two directions and then connected to the patch. The two feed points are connected to two adjacent sides of the patch, respectively (

[0064] ,

[0084] and Figure 18). Patent Document 2 discloses an antenna module. In this antenna module, an antenna element is arranged on an internal layer or on the upper surface of a dielectric substrate, and a ground electrode is arranged on an internal layer of the dielectric substrate. The layer on which the ground electrode is arranged is the internal layer on which the antenna element is arranged or a layer below the surface. Furthermore, a high-frequency signal is supplied to a first feed point and a second feed point. The second feed point is formed at a position symmetrical to the position where the first feed point is formed with respect to the center of the antenna element. This makes it possible to improve the degree of separation between main polarization and cross polarization (

[0003] ,

[0020] ,

[0022] ,

[0023] ,

[0024] ,

[0029] and [Figure 2]). International Publication No. 2021 / 197400 International Publication No. 2020 / 075434 In order to increase the amount of information transmitted by radio waves transmitted and received by a patch antenna, it is effective to have the patch antenna transmit and receive two polarized waves. However, when two polarized waves are transmitted and received by a patch antenna, the isolation between the ports through which the two signals are input and output is reduced. If crosstalk occurs between the two signals, noise will be mixed into the two signals, degrading the quality of the two signals. Patent Documents 1 and 2 do not provide a sufficient solution to this problem. In view of this problem, an object of one aspect of the present disclosure is to provide a patch antenna and an antenna module that can increase isolation between ports through which two signals are input and output when, for example, two polarized waves are transmitted and received, and can suppress crosstalk between the two signals. A patch antenna of a first aspect of the present disclosure comprises: a dielectric layer having a first main surface and a second main surface on the side opposite to the first main surface, the dielectric layer comprising a first layer arranged on the side where the first main surface is located and a second layer arranged on the side where the second main surface is located; a patch arranged on the first main surface; a ground arranged between the first layer and the second layer; three or more connection vias arranged in the dielectric layer and connected to the patch; a first via that is electrically connected in the second layer to a first two or more connection vias that are included in the three or more connection vias and arranged along a first straight line in a planar view, and that reaches the second main surface; and a second via that is electrically connected to a second two or more connection vias that are included in the three or more connection vias and arranged along a second straight line that is perpendicular to the first straight line in the planar view, and that reaches the second main surface. An antenna module of a second aspect of the present disclosure comprises a patch antenna of the first aspect of the present disclosure, a circuit for sending signals to the first via and the second via or receiving signals from the first via and the second via, and wiring for electrically connecting the first via and the second via to the circuit. 2. A perspective view schematically illustrating a patch antenna of the first embodiment. A top view schematically illustrating a portion of the patch antenna of the first embodiment. A cross-sectional view schematically illustrating a cross section of a portion of the patch antenna of the first embodiment, taken along the line III-III illustrated in FIG. 2. A cross-sectional view schematically illustrating a cross section of a portion of the patch antenna of the first embodiment, taken along the line IV-IV illustrated in FIG. 2. A cross-sectional view schematically illustrating a cross section of a portion of the patch antenna of the first embodiment, taken along the line V-V illustrated in FIG. 2. A cross-sectional view schematically illustrating a cross section of a portion of the patch antenna of the first embodiment, taken along the line VI-VI illustrated in FIG. 2. S-parameter S of the patch antenna of the first embodiment. １１ 10 is a graph showing the simulation results of the frequency characteristics of the patch antenna of the first embodiment. ２１1 is a graph showing a simulation result of frequency characteristics of a patch antenna according to a first embodiment, a top view of the patch antenna according to the first embodiment, and an S parameter S of the patch antenna according to the first embodiment, where the distance from the via to the connection via is 800 μm. １１ 10 is a graph showing the simulation results of the frequency characteristics of the patch antenna of the comparative example. ２１ 10 is a graph showing a simulation result of frequency characteristics of the patch antenna according to the second embodiment; １１ 10 is a graph showing the simulation results of the frequency characteristics of the patch antenna according to the second embodiment. ２１ 10 is a graph showing the simulation results of the frequency characteristics of the patch antenna according to the second embodiment. １１ 10 is a graph showing the simulation results of the frequency characteristics of the patch antenna according to the second embodiment. ２１ 10 is a graph showing a simulation result of frequency characteristics of the patch antenna according to the third embodiment; FIG. 11 is a top view schematically showing a part of the patch antenna according to the third embodiment; FIG. 12 is a graph showing an S parameter S of the patch antenna according to the second modification of the first embodiment; １１ 10 is a graph showing a simulation result of the frequency characteristics of the patch antenna according to the second modification of the first embodiment. ２１ 22 is a graph showing simulation results of frequency characteristics of the antenna module of the fifth embodiment. FIG. 23 is a cross-sectional view schematically illustrating the antenna module of the third embodiment. FIG. 24 is a top view schematically illustrating the antenna module of the fifth embodiment. FIG. 25 is a cross-sectional view schematically illustrating a cross section of the antenna module of the fifth embodiment taken along the cutting line XXII-XXII depicted in FIG. 21. FIG. 26 is a top view schematically illustrating the first branch wiring provided in the antenna module of the first modified example of the fifth embodiment. FIG. 27 is a top view schematically illustrating the second branch wiring provided in the antenna module of the first modified example of the fifth embodiment. FIG. 28 is an S parameter S of the patch antenna provided in the antenna module of the fifth embodiment. １１ 10 is a graph showing a simulation result of the frequency characteristics of the patch antenna provided in the antenna module of the fifth embodiment.２１ 10 is a graph showing a simulation result of the frequency characteristics of the patch antenna provided in the antenna module of the fifth embodiment. １１ 10 is a graph showing a simulation result of the frequency characteristics of the patch antenna provided in the antenna module of the fifth embodiment. ２１ 10 is a graph showing a simulation result of the frequency characteristics of the patch antenna provided in the antenna module of the fifth embodiment. １１ 10 is a graph showing a simulation result of the frequency characteristics of the patch antenna provided in the antenna module of the fifth embodiment. ２１ 10 is a graph showing a simulation result of the frequency characteristics of Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the drawings, the same or equivalent elements are designated by the same reference numerals, and redundant description will be omitted. 1. First embodiment 1.1 Patch antenna FIG. 1 is a perspective view schematically illustrating a patch antenna according to a first embodiment. FIG. 2 is a top view schematically illustrating a portion of the patch antenna according to the first embodiment. FIG. 3 is a cross-sectional view schematically illustrating a cross section of a portion of the patch antenna according to the first embodiment, taken along the line III-III in FIG. 2. FIG. 4 is a cross-sectional view schematically illustrating a cross section of a portion of the patch antenna according to the first embodiment, taken along the line IV-IV in FIG. 2. FIG. 5 is a cross-sectional view schematically illustrating a cross section of a portion of the patch antenna according to the first embodiment, taken along the line V-V in FIG. 2. FIG. 6 is a cross-sectional view schematically illustrating a cross section of a portion of the patch antenna according to the first embodiment, taken along the line VI-VI in FIG. 2. The patch antenna 1 of the first embodiment shown in Figures 1 to 6 transmits radio waves according to an input signal and outputs a signal according to the received radio waves. The patch antenna 1 is incorporated into a communication module. The patch antenna 1 may also be incorporated into a device other than a communication module. The patch antenna 1 can provide a small and thin antenna when the frequency of the radio waves to be transmitted and received is high. 1 to 6, the patch antenna 1 includes a dielectric layer 11, a patch 12, a first ground 13, a second ground 14, a plurality of connection vias 15, a first via 16, a second via 17, a first path 18, and a second path 19. In the patch antenna 1 of the first embodiment, the plurality of connection vias 15 is four connection vias. The plurality of connection vias 15 may be three or less or five or more connection vias. The dielectric layer 11 has a first main surface 11a and a second main surface 11b. The first main surface 11a and the second main surface 11b are on opposite sides of each other. The first main surface 11a and the second main surface 11b extend in the X direction DX and the Y direction DY. The X direction DX and the Y direction DY are perpendicular to each other. 1 and 3 to 6, the dielectric layer 11 includes a first layer 21 and a second layer 22. The first layer 21 and the second layer 22 are stacked in the thickness direction of the dielectric layer 11. The first layer 21 is disposed on the side where the first main surface 11a is located. The second layer 22 is disposed on the side where the second main surface 11b is located. The patch 12 is disposed on the first principal surface 11a. The patch 12 has a film-like shape and serves as a patch surface. The patch 12 has a square shape in a plan view. Therefore, the patch 12 has first two sides 12a and second two sides 12b in a plan view. The first two sides 12a face each other, are parallel to each other, are spaced apart in the X direction DX, and extend in the Y direction DY. The second two sides 12b face each other, are parallel to each other, are spaced apart in the Y direction DY, and extend in the X direction DX. The first two sides 12a and second two sides 12b are perpendicular to each other. The patch 12 is made of a conductor. The conductor is a metal or the like. The first ground 13 is disposed between the first layer 21 and the second layer 22. The first ground 13 has a film-like shape and serves as a ground surface. A plurality of anti-pads 13a are formed on the first ground 13. In the first embodiment, the number of anti-pads 13a is four. Each of the plurality of anti-pads 13a has a circular shape in a plan view. Each of the plurality of anti-pads 13a may have a shape other than a circular shape. The area consisting of the ground arrangement area where the first ground 13 is disposed and the plurality of anti-pad formation areas where the plurality of anti-pads 13a are respectively formed includes the patch arrangement area where the patch 12 is disposed in a plan view. As a result, the patch 12 faces the first ground 13 and the plurality of anti-pads 13a across the dielectric layer 11. As a result, the patch 12 is electromagnetically coupled to the first ground 13 and forms an antenna. The area consisting of the ground placement area and the multiple anti-pad formation areas is preferably the entire area between the first layer 21 and the second layer 22. The first ground 13 is made of a conductor, such as a metal. The second ground 14 is disposed on the second main surface 11b. A first anti-pad 14a and a second anti-pad 14b are formed on the second ground 11b. The second ground 14 has a film-like shape and serves as a ground surface. The second ground 14 is made of a conductor. The conductor is a metal or the like. The first anti-pad 14a and the second anti-pad 14b each have a circular shape in a plan view. The first anti-pad 14a and the second anti-pad 14b may each have a shape other than a circular shape. The second ground 14 is electrically connected to the first ground 13. The second ground 14 is supplied with the same ground potential as that supplied to the first ground 13. Each of the multiple connection vias 15 has a linear shape. Each of the multiple connection vias 15 is disposed within the dielectric layer 11, extends in the thickness direction of the dielectric layer 11, and reaches the first main surface 11a. Each of the multiple connection vias 15 is disposed across the first layer 21 and the second layer 22. One end of each of the multiple connection vias 15 is located between the boundary between the first layer 21 and the second layer 22 and the second main surface 11b. The other end of each of the multiple connection vias 15 is located on the first main surface 11a, in the patch placement region in plan view. As a result, each of the multiple connection vias 15 is connected to the patch 12. In the first embodiment, the multiple connection vias 15 preferably pass through the centers of the multiple anti-pads 13a, respectively. The multiple connection vias 15 are made of a conductor. The conductor is a metal or the like. The plurality of connection vias 15 includes two or more first connection vias 31 and two or more second connection vias 32. In the first embodiment, the first two or more connection vias 31 are two connection vias, and the second two or more connection vias 32 are two connection vias. The first two or more connection vias 31 may be three or more connection vias, and the second two or more connection vias 32 may be three or more connection vias. The first two or more connection vias 31 are arranged at a first interval along a first straight line L1 extending in the Y direction DY in a plan view, and are spaced apart from one another in the Y direction DY. The second two or more connection vias 32 are arranged at a second interval along a second straight line L2 extending in the X direction DX in a plan view, and are spaced apart from one another in the X direction DX. The first straight line L1 is parallel to the first two sides 12a. The second straight line L2 is parallel to the second two sides 12b. The first straight line L1 and the second straight line L2 are perpendicular to each other. The first interval and the second interval are the same. The first two or more connection vias 31 include a first connection via 41 and a second connection via 42, and the second two or more connection vias 32 include a third connection via 43 and a fourth connection via 44. The first two or more connection vias 31 and the second two or more connection vias 32 do not include a common via. Therefore, the first connection via 41 closest to the third connection via 43 and the fourth connection via 44 in the first connection via 41 and the second connection via 42, and the third connection via 43 closest to the first connection via 41 and the second connection via 42 in the third connection via 43 and the fourth connection via 44, are different vias. Therefore, the third connection via 43 and the fourth connection via 44 are electrically insulated from the first connection via 41 and the second connection via 42. The first two or more connection vias 31 and the second two or more connection vias 32 may include a common via, and the first connection via 41 and the third connection via 43 may be a common via. If the first connection via 41 and the third connection via 43 are common vias, the number of the plurality of connection vias 15 can be reduced. Hereinafter, the center line of the patch 12 in the Y direction DY will be referred to as a first center line C1, and the center line of the patch 12 in the X direction DX will be referred to as a second center line C2. The first connection via 41 and the second connection via 42 are respectively arranged on one side and the other side of the first center line C1 in a plan view. The first connection via 41 and the second connection via 42 are respectively arranged on one side of the second center line C2. The third connection via 43 and the fourth connection via 44 are respectively arranged on one side and the other side of the second center line C2 in a plan view. The third connection via 43 and the fourth connection via 44 are arranged on one side of the first center line C1. The first via 16 has a linear shape. The first via 16 is disposed in the dielectric layer 11, extends in the thickness direction of the dielectric layer 11, and reaches the second main surface 11b. The first via 16 is disposed in the second layer 22. One end of the first via 16 is located between the boundary between the first layer 21 and the second layer 22 and the second main surface 11b. The other end of the first via 16 is located on the second main surface 11b and is located within the first antipad 14a in a plan view, preferably at the center of the first antipad 14a. The first via 16 is made of a conductor. The conductor is a metal or the like. This allows a signal to be input between the other end of the first via 16 and the second ground 14. Furthermore, a signal can be output from between the other end of the first via 16 and the second ground 14. This allows the other end of the first via 16 and the second ground 14 to be used as a first port. The first via 16 is disposed on the first center line C1. The second via 17 has a linear shape. The second via 17 is disposed in the dielectric layer 11, extends in the thickness direction of the dielectric layer 11, and reaches the second main surface 11b. The second via 17 is disposed in the second layer 22. One end of the second via 17 is located between the boundary between the first layer 21 and the second layer 22 and the second main surface 11b. The other end of the second via 17 is located on the second main surface 11b and is located within the second antipad 14b in a plan view, preferably at the center of the second antipad 14b. The second via 17 is made of a conductor. The conductor is a metal or the like. This allows a signal to be input between the other end of the second via 17 and the second ground 14. Furthermore, a signal can be output from between the other end of the second via 17 and the second ground 14. This allows the other end of the second via 17 and the first ground 13 to be used as a second port. The second via 17 is disposed on the second center line C2. The first path 18 has a linear shape. The first path 18 is disposed in the dielectric layer 11. The first path 18 is disposed in the second layer 22. One end of the first path 18 is connected to one end of the first connection via 41. The other end of the first path 18 is connected to one end of the second connection via 42. An intermediate portion of the first path 18 is connected to one end of the first via 16. The first path 18 extends in the plane direction of the dielectric layer 11 and in the Y direction DY. As a result, the first path 18 electrically connects the first connection via 41 and the second connection via 42 to the first via 16 in the second layer 22. As a result, the other end of the first via 16 is electrically connected to the patch 12 via the first via 16, the first path 18, the first connection via 41, and the second connection via 42. This allows a signal input to the first port to be transmitted from between the other end of the first via 16 and the second ground 14 to between the patch 12 and the first ground 13. Also, a signal output from the first port can be transmitted from between the patch 12 and the first ground 13 to between the other end of the first via 16 and the second ground 14. A transmission line consisting of the first via 16, the first path 18, the first connection via 41, and the second connection via 42 extends from the second main surface 11b to a branch point in the second layer 22, branches into two at the branch point, and extends from the branch point to the first two feed points 51 of the patch 12. When the first two or more connection vias 31 are four or more connection vias, the transmission line branches at branch points in each of the layers included in the plurality of layers to reach the first four or more feed points. The distance DX in the X direction from the second center line C2 to the first two feed points 51 affects the feed point impedance of the first two feed points 51. The distance DX in the X direction is set so that the feed point impedance of the first two feed points 51 becomes the port impedance. The port impedance is usually 50 Ω. The first path 18 includes a first branch path 61 and a second branch path 62. The first branch path 61 branches off from one end of the first via 16 and is connected to one end of the first connecting via 41. The second branch path 62 branches off from one end of the first via 16 and is connected to one end of the second connecting via 42. In the patch antenna 1 of the first embodiment, the first length of the first branch path 61 and the second length of the second branch path 62 are the same. The second path 19 has a linear shape. The second path 19 is disposed in the dielectric layer 11. The second path 19 is disposed in the second layer 22. One end of the second path 19 is connected to one end of the third connection via 43. The other end of the second path 19 is connected to one end of the fourth connection via 44. An intermediate portion of the second path 19 is connected to one end of the second via 17. The second path 19 extends in the surface direction of the dielectric layer 11 and in the X direction DX. As a result, the second path 19 electrically connects the third connection via 43 and the fourth connection via 44 to the second via 17. As a result, the other end of the second via 17 is electrically connected to the patch 12 via the second via 17, the second path 19, the third connection via 43, and the fourth connection via 44. This allows a signal input to the second port to be transmitted from between the other end of the second via 17 and the second ground 14 to between the patch 12 and the first ground 13. Also, a signal output from the second port can be transmitted from between the patch 12 and the first ground 13 to between the other end of the second via 17 and the second ground 14. A transmission line consisting of the second via 17, the second path 19, the third connection via 43, and the fourth connection via 44 extends from the second main surface 11b to a branch point in the dielectric layer 11, branches into two at the branch point, and extends from the branch point to the second two feed points 52 of the patch 12. When the second two or more connection vias 32 are four or more connection vias, the transmission line branches at branch points in each of the layers included in the plurality of layers to reach the second four or more feed points. The distance in the Y direction DY from the first center line C1 to the second two feed points 52 affects the feed point impedance of the second two feed points 52. The distance in the Y direction DY is set so that the feed point impedance of the second two feed points 52 becomes the port impedance. The port impedance is typically 50 Ω. The second path 19 includes a third branch path 63 and a fourth branch path 64. The third branch path 63 branches from one end of the second via 17 and is connected to one end of the third connecting via 43. The fourth branch path 64 branches from one end of the second via 17 and is connected to one end of the fourth connecting via 44. In the patch antenna 1 of the first embodiment, the third length of the third branch path 63 and the fourth length of the fourth branch path 64 are the same. When the stripline is disposed on the first principal surface 11a and the end of the stripline is connected to the side of the patch 12, it is difficult to use the feed point impedance as the port impedance. However, when the ends of the first connection via 41, the second connection via 42, the third connection via 43, and the fourth connection via 44 are connected within the plane of the patch 12, it is easy to use the feed point impedance as the port impedance. The port impedance is usually 50 Ω. 1.2 Transmission and reception of X-polarized and Y-polarized waves When a signal is input to the first port, a first current J1 shown in FIG. 2 flows through the patch 12, and a first electric field E1 shown in FIG. 6 is excited in the dielectric layer 11. The direction of the first current J1 is aligned with the X direction DX. The direction of the first electric field E1 is aligned with a direction inclined from the thickness direction of the dielectric layer 11 toward the X direction DX. Furthermore, radio waves are transmitted from electric fields excited near the first two sides 12a, which are included in the excited first electric field E1. The direction of the electric field of the transmitted radio waves is aligned with the X direction DX in a planar view. Therefore, the transmitted radio waves are X-polarized. The reason that the direction of the first current J1 is aligned with the X direction DX and the direction of the first electric field E1 is aligned with a direction inclined from the thickness direction of the dielectric layer 11 toward the X direction DX is because the first two feed points 51 arranged in the Y direction DY are used. When only one feed point is used, the first current J1 flows radially and the first electric field E1 is excited radially. When a signal is input to the second port, a second current J2 shown in FIG. 2 flows through the patch 12, and a second electric field E2 shown in FIG. 5 is excited in the dielectric layer 11. The direction of the second current J2 is aligned with the Y direction DY in a plan view. The direction of the second electric field E2 is aligned with a direction inclined from the thickness direction of the dielectric layer 11 toward the Y direction DY. Furthermore, radio waves are transmitted from electric fields excited near the second two sides 12b, which are included in the excited second electric field E2. The direction of the electric field of the transmitted radio waves is aligned with the Y direction DY. Therefore, the transmitted radio waves are Y-polarized. The reason why the direction of the second current J2 is aligned with the Y direction DY and the direction of the second electric field E2 is aligned with a direction inclined from the thickness direction of the dielectric layer 11 toward the Y direction DY is because two second feed points 52 arranged in the X direction DX are used. If only one feed point is used, a second current J2 flows radially and a second electric field E2 is excited radially. When the patch antenna 1 receives an X-polarized wave, a first current J1 shown in FIG. 2 flows through the patch 12, and a first electric field E1 shown in FIG. 6 is applied to the dielectric layer 11. As a result, the electric fields applied to the positions where the first two feed points 51 are located are in phase. As a result, the signals generated at the first two feed points 51 reinforce each other. As a result, a signal is output from the first port. However, the electric fields applied to the positions where the second two feed points 52 are located are in phase with each other. As a result, the signals generated at the second two feed points 52 weaken each other. As a result, no signal is output from the second port. When the patch antenna 1 receives a Y-polarized wave, a second current J2 shown in FIG. 2 flows through the patch 12, and a second electric field E2 shown in FIG. 5 is applied to the dielectric layer 11. As a result, the electric fields applied to the positions where the second two feed points 52 are located are in phase. As a result, the signals generated at the second two feed points 52 reinforce each other. As a result, a signal is output from the second port. However, the electric fields applied to the positions where the first two feed points 51 are located are in phase with each other. As a result, the signals generated at the first two feed points 51 weaken each other. As a result, no signal is output from the first port. These facts mean that the isolation between the first port and the second port of the patch antenna 1 (hereinafter referred to as "inter-port isolation") is high. When the inter-port isolation of the patch antenna 1 is high, it is possible to suppress the occurrence of crosstalk between the two signals input and output to the first port and the second port when the patch antenna 1 transmits and receives X-polarized waves and Y-polarized waves. The effective wavelength of the radio waves transmitted and received by the patch antenna 1 at the position where the patch 12 is disposed is determined by the dielectric material constituting the first layer 21 and the thickness of the first layer 21. The dielectric material and the thickness are adjusted according to the required gain and size. The distance between the first two sides 12 a and the distance between the second two sides 12 b are set to ½ of the effective wavelength of the radio waves transmitted and received by the patch antenna 1. This allows the patch antenna 1 to resonate with X-polarized waves and Y-polarized waves having a specific frequency, thereby allowing the patch antenna 1 to efficiently transmit and receive X-polarized waves and Y-polarized waves of the specific frequency. 1.3 S-parameters S-parameters S of a two-port circuit having a first port and a second port １１ and S ２２ corresponds to the reflectance. Since the first port and the second port differ only in the polarization they handle, S １１ and S ２２ have the same value. Therefore, in the following, S １１ Only the S-parameters S of the patch antenna 1 are discussed. １１ A small value of σ means that the radiation efficiency of the patch antenna 1 is high. The frequency band that can be used for communication is generally within the range of the S parameter S of the patch antenna 1. １１ is a frequency band in which the noise level is -10 dB or less. S-parameter S in a two-port circuit having a first port and a second port ２１ and S １２ corresponds to the transmittance. Since the first port and the second port differ only in the polarization they handle, S ２１ and S １２have the same value. Therefore, in the following, S ２１ Only the S-parameters S of the patch antenna 1 are discussed. ２１ A small value means that the isolation between the ports of the patch antenna 1 is high. The desired S parameter S of the patch antenna 1 is ２１ is -15 dB or less, and the more desirable S parameter S of the patch antenna 1 ２１ is less than -20 dB. 1.4 Positions in the thickness direction of the first and second paths The first path 18 and the second path 19 are not located in the first layer 21 sandwiched between the patch 12 and the first ground 13, but in the second layer 22 sandwiched between the first ground 13 and the second ground 14. This prevents the first path 18 and the second path 19 from constituting a small antenna, and even if the first path 18 and the second path 19 are electromagnetically coupled to the first ground 13 and the second ground 14, almost no radio waves are radiated outside the gap between the first ground 13 and the second ground 14. In other words, the first path 18 and the second path 19 can function solely as a transmission line. This prevents the small antenna formed by the first path 18 and the second path 19 from interfering with the transmission and reception of radio waves by the antenna formed by the patch 12. This increases the radiation efficiency of the patch antenna 1. The first path 18, the first ground 13, and the second ground 14 constitute a first transmission line. The constituted first transmission line is a first stripline and preferably has the same characteristic impedance as the feed impedance, for example, 50 Ω. The second path 19, the first ground 13, and the second ground 14 constitute a second transmission line. The constituted second transmission line is a second stripline and preferably has the same characteristic impedance as the feed impedance, for example, 50 Ω. This makes it possible to reduce losses in the first path 18 and the second path. 1.5 Effect of distance from via to connecting via FIG. 7 shows the S parameter S of the patch antenna of the first embodiment. １１ 8 is a graph showing the simulation results of the frequency characteristics of the patch antenna of the first embodiment. ２１ 9 is a graph showing a simulation result of frequency characteristics of the patch antenna according to the first embodiment, in which the distance from the via to the connection via is 800 μm. 7 and 8, the lengths of the first two sides 12a and the second two sides 12b of the patch 12 are 2.7 mm, the distance in the X direction DX from the second center line C2 to the first via 16, the first connecting via 41, and the second connecting via 42, and the distance in the Y direction DY from the first center line C1 to the second via 17, the third connecting via 43, and the fourth connecting via 44 are 0.9 mm in plan view, the dielectric material constituting the dielectric layer 11 is MCL-HS100 manufactured by Resonac Corporation (Minato-ku, Tokyo, Japan), and the thickness of the first layer 21 is The figure shows simulation results when the thickness of the second layer 22 is 725 μm, the thickness of the second layer 22 is 210 μm, the radius of the multiple antipads 13 a is 350 μm in a planar view, the radius of the first antipad 14 a and the second antipad 14 b is 350 μm in a planar view, the radius r of the first connection via 41, the second connection via 42, the third connection via 43 and the fourth connection via 44 is 20 μm in a planar view, and the radius R of the first via 16 and the second via 17 is 75 μm in a planar view. 7 and 8 show simulation results when the distance L, which is the Y-direction DY distance from the first via 16 to the first connecting via 41, the Y-direction DY distance from the first via 16 to the second connecting via 42, the X-direction DX distance from the second via 17 to the third connecting via 43, and the X-direction DX distance from the second via 17 to the fourth connecting via 44, is 200 μm, 400 μm, 600 μm, and 800 μm in plan view. As shown in FIG. 7, the S parameter S of the patch antenna 1 １１The minimum value of becomes significantly smaller when the distance L is increased to 800 μm. That is, the radiation efficiency of the patch antenna 1 becomes significantly higher when the distance L is increased to 800 μm. The reason why the radiation efficiency of the patch antenna 1 becomes significantly higher when the distance L is increased to 800 μm is that when the distance L is increased to 800 μm, as shown in FIG. 9 , the antipads through which the first connection via 41 and the third connection via 43 pass are connected, so that the first connection via 41 and the third connection via 43 pass through the same antipad 13 a, and the area of ​​the region removed by the antipad 13 a through which the first connection via 41 and the third connection via 43 pass becomes smaller. S parameter S of patch antenna 1 １１ In the frequency characteristics of １１ The deeper the dip, the higher the radiation efficiency of the patch antenna 1. However, the S parameter S １１ In the frequency characteristics of １１ The deeper the dip, the stronger the electric field excited between the patch 12 and the first ground 13. Therefore, the signal output from a port different from the port to which the signal is input becomes stronger. This reduces the isolation between the ports of the patch antenna 1. For this reason, in the evaluation of the patch antenna 1, the S parameter S of the patch antenna 1 is １１ The S parameter S of the patch antenna 1 in a frequency band where ２１ or the S parameter S of the patch antenna 1 ２１ The S parameter S of the patch antenna 1 in a frequency band where １１ The smaller the value of is, the better the evaluation. 1.6 Comparison of branching and non-branching FIG. 10 shows the S-parameters S of the patch antenna of the comparative example. １１ 11 is a graph showing the simulation results of the frequency characteristics of the patch antenna of the comparative example. ２１ 10 is a graph showing a simulation result of the frequency characteristics of The patch antenna of the comparative example differs from the patch antenna 1 of the first embodiment in that it does not have the first connecting via 41, the second connecting via 42, the third connecting via 43, the fourth connecting via 44, the first path 18 and the second path 19, and the first via 16 and the second via 17 are directly connected to the patch 12. 10 and 11 show simulation results when the radius R of the first via 16 and the second via 17 is 25 μm, 40 μm, 50 μm, and 75 μm in plan view. Table 1 shows the S parameters S of the patch antenna of Comparative Example 1 and the patch antenna 1 of Example 1. １１ The minimum value of the S parameter S １１ The S parameter S at the lower limit frequency of the frequency band where ２１ and the S parameter S at the upper limit frequency of the frequency band ２１ Indicates the value of In the patch antenna of Comparative Example 1, the radius R is 75 μm. The configuration of the patch antenna 1 of Example 1 is as follows: S parameter S １１ is the S parameter S of the patch antenna of Comparative Example 1 １１ It is determined to be close to. From Table 1, the S parameter S of the patch antenna 1 of Example 1 is １１ The minimum value of the S parameter S of the patch antenna of Comparative Example 1 is １１ and the S parameter S of the patch antenna 1 of Example 1 is smaller than the minimum value of ２１ The value of the S parameter S of the patch antenna of Comparative Example 1 ２１ That is, it can be seen that the radiation efficiency of the patch antenna 1 of Example 1 is higher than the radiation efficiency of the patch antenna of Comparative Example 1, and the inter-port isolation of the patch antenna 1 of Example 1 is higher than the inter-port isolation of the patch antenna of Comparative Example 1. 2. Second embodiment The following describes the differences between the second embodiment and the first embodiment. For points that are not described, the second embodiment also employs the same configuration as that employed in the first embodiment. FIG. 12 is a top view schematically illustrating a part of the patch antenna according to the second embodiment. In the patch antenna 1 of the first embodiment, as shown in Figure 2, the first via 16 is arranged on the first center line C1 in a planar view, and the second via 17 is arranged on the second center line C2 in a planar view. In contrast, in the patch antenna 2 of the second embodiment, as shown in FIG. 12 , the first via 16 is arranged on the other side of the first center line C1 in a plan view, and the second via 17 is arranged on the other side of the second center line C2 in a plan view. This separates the first via 16 and the second via 17 from each other. This weakens the electromagnetic field coupling between the first via 16 and the second via 17. This increases the inter-port isolation of the patch antenna 2. When the first via 16 is arranged on the other side of the first center line C1 and the distance from the first via 16 to the first connecting via 41 and the distance from the first via 16 to the second connecting via 42 are different from each other, the phases of the signals fed to the first two feeding points 51 are different from each other. When the second via 17 is positioned on the other side of the second center line C2 and the distance from the second via 17 to the third connecting via 43 and the distance from the second via 17 to the fourth connecting via 44 are different from each other, the phases of the signals supplied to the second two power supply points 52 are different from each other. Furthermore, in the patch antenna 1 of the first embodiment, as shown in Figure 2, the first length of the first branch path 61 and the second length of the second branch path 62 are the same, and the third length of the third branch path 63 and the fourth length of the fourth branch path 64 are the same. 12 , in the patch antenna 2 of the second embodiment, the second length of the second branch path 62 may be shorter than the first length of the first branch path 61, and the fourth length of the fourth branch path 64 may be shorter than the third length of the third branch path 63. This brings the first two feed points 51 closer to the first via 16, and the second two feed points 52 closer to the second via 17. This makes it possible to reduce losses in the second branch path 62 and the fourth branch path 64, and to increase the radiation efficiency of the patch antenna 2. In the patch antenna 1 of the first embodiment, as shown in FIG. 2, the first connection via 41 and the third connection via 43 pass through two different anti-pads 13a. In contrast to this, in the patch antenna 2 of the second embodiment, as shown in FIG. 12, the first connection via 41 and the third connection via 43 pass through the same single anti-pad 13a. FIG. 13 shows the S parameter S of the patch antenna of the second embodiment. １１ 14 is a graph showing the simulation results of the frequency characteristics of the patch antenna according to the second embodiment. ２１ 10 is a graph showing a simulation result of the frequency characteristics of 13 and 14 show simulation results when the distance L is 800 μm, the first two feed points 51 are at the same distance from the first center line C1, and the second two feed points 52 are at the same distance from the second center line C2. Figures 13 and 14 show simulation results when the deviation S_parallel, which is the deviation amount to the other side of the first center line C1 of the first via 16 and the deviation amount to the other side of the second center line C2 of the second via 17, is -200 μm, -100 μm, 0 μm, 100 μm, and 200 μm. As shown in FIG. 13, the S parameter S of the patch antenna 2 １１The minimum value of is small when the displacement amount S_parallel is 0 μm, 100 μm, and 200 μm. That is, the radiation efficiency of the patch antenna 1 is high when the displacement amount S_parallel is 0 μm, 100 μm, and 200 μm. As shown in FIG. 14, the S parameter S of the patch antenna 2 ２１ The inter-port isolation of the patch antenna 2 is also small when the displacement amount S_parallel is 0 μm, 100 μm, and 200 μm. That is, the inter-port isolation of the patch antenna 2 is high when the displacement amount S_parallel is 0 μm, 100 μm, and 200 μm. FIG. 15 shows the S parameter S of the patch antenna of the second embodiment. １１ 16 is a graph showing the simulation results of the frequency characteristics of the patch antenna according to the second embodiment. ２１ 10 is a graph showing a simulation result of the frequency characteristics of 15 and 16 show the simulation results when the deviation amount S_parallel is 100 μm. 15 and 16 show simulation results when the length difference ΔL, which is the difference between the second length of the second branch path 62 and the first length of the first branch path 61 and the difference between the fourth length of the fourth branch path 64 and the third length of the third branch path 63, is −300 μm, −200 μm, and −100 μm. As shown in FIG. 15, the S parameter S of the patch antenna 2 １１ The minimum value of is smallest when the length difference ΔL is −200 μm. That is, the radiation efficiency of the patch antenna 2 is highest when the length difference ΔL is −200 μm. This means that the radiation efficiency of the patch antenna 2 is highest when the first two feed points 51 are arranged symmetrically with respect to the first center line C1 and the second two feed points 52 are arranged symmetrically with respect to the second center line C2. As shown in FIG. 16, the S parameter S of the patch antenna 2 ２１is smallest when the length difference ΔL is −200 μm. That is, the inter-port isolation of patch antenna 2 is highest when the length difference ΔL is −200 μm. The reason for this is that when the length difference ΔL is −200 μm, the amplitudes of the Y-polarized signals generated at the first two feed points 51 are the same, and the amplitudes of the X-polarized signals generated at the second two feed points 52 are the same. Table 2 shows the S parameters S of the patch antenna 2 of Example 2. １１ The minimum value of the S parameter S １１ The S parameter S at the lower limit frequency of the frequency band where ２１ and the S parameter S at the upper limit frequency of the frequency band ２１ Indicates the value of The configuration of the patch antenna 2 of Example 2 is as follows: １１ is the S parameter S of the patch antenna of Comparative Example 1 １１ In the patch antenna 2 of the second embodiment, the amount of deviation S_parallel is −100 μm, and the length difference ΔL is −200 μm. From Tables 1 and 2, the S parameter S of the patch antenna 2 of Example 2 is １１ The minimum value of the S parameter S of the patch antenna of Comparative Example 1 is １１ and the S parameter S of the patch antenna 2 of Example 2 is smaller than the minimum value of ２１ is the S parameter S of the patch antenna of Comparative Example 1 ２１ That is, it can be seen that the radiation efficiency of the patch antenna 2 of Example 2 is higher than the radiation efficiency of the patch antenna of Comparative Example 1, and the inter-port isolation of the patch antenna 2 of Example 2 is higher than the inter-port isolation of the patch antenna of Comparative Example 1. When the deviation amount S_parallel is −200 μm or −100 μm, the S parameter S of the patch antenna 2 is １１ and S-parameter S ２１becomes larger, but the S parameter S of the patch antenna 2 １１ The S parameter S of the patch antenna 2 in the frequency band where ２１ The variation in the inter-port isolation is reduced. Therefore, when a small variation in the inter-port isolation is more important than the radiation efficiency and the high inter-port isolation of the patch antenna 2, the deviation S_parallel may be set to -200 μm or -100 μm. When the variation in the inter-port isolation of the patch antenna 2 is reduced in this way, it becomes unnecessary to set the circuit constant according to the frequency when suppressing leakage components on the side of the circuit connected to the patch antenna 2. This makes it possible to simplify the circuit, reduce the size of the circuit, and suppress the power consumption of the circuit. 3. Third embodiment The following describes the differences between the third embodiment and the first embodiment. For points that are not described, the third embodiment also employs the same configuration as that employed in the first embodiment. FIG. 17 is a top view schematically illustrating a part of the patch antenna according to the third embodiment. In the patch antenna 1 of the first embodiment, as shown in Figure 2, the first via 16 is arranged along a first straight line L1 in a planar view, and the second via 17 is arranged along a second straight line L2 in a planar view. 17 , in the patch antenna 3 of the third embodiment, the first via 16 is shifted from the first straight line L1 in a direction approaching the second center line C2 in a plan view, and the second via 17 is shifted from the second straight line L2 in a direction approaching the first center line C1 in a plan view. Therefore, the first via 16 is disposed between the first straight line L1 and the second center line C2 in a plan view, and the second via 17 is disposed between the second straight line L2 and the first center line C1 in a plan view. This brings the first via 16 and the second via 17 closer to each other. When the first via 16 is shifted in a direction away from the second center line C2 of the patch 12 in a plan view, and the second via 17 is shifted in a direction away from the first center line C1 in a plan view, the area of ​​the first ground 13 that strongly contributes to the transmission and reception of radio waves is removed by the anti-pad 13a. As a result, the radiated energy decreases, and the directivity pattern of the patch antenna 3 is distorted. FIG. 18 shows the S parameter S of the patch antenna according to the second modification of the first embodiment. １１ 19 is a graph showing the simulation results of the frequency characteristics of the patch antenna according to the second modification of the first embodiment. ２１ 10 is a graph showing a simulation result of the frequency characteristics of 18 and 19 show the simulation results when the length difference ΔL is 0 μm and the deviation amount S_parallel is 0 μm. Figures 18 and 19 show simulation results when the deviation S_perp, which is the deviation of the first via 16 from the first straight line L1 in the direction toward the center of the patch 12 and the deviation S_perp of the second via 17 from the second straight line L2 in the direction toward the center of the patch 12, is -100 μm, 0 μm, and 100 μm. As shown in FIG. 18, the S parameter S of the patch antenna 3 １１ The minimum value of θ_perp decreases as the shift amount S_perp increases. That is, the radiation efficiency of the patch antenna 3 increases as the shift amount S_perp increases. As shown in FIG. 19, the S parameter S of the patch antenna 3 ２１ The S parameter S of the patch antenna 3 is almost independent of the deviation S_perp. ２１is almost independent of the deviation S_perp because the lengths of the first branch path 61, the second branch path 62, the third branch path 63, and the fourth branch path 64 are relatively short compared to the overall length of the transmission line. Also, even if the deviation S_perp changes, the state in which there is no difference between the first length of the first branch path 61 and the second lengths of the second branch path 62 and 64 remains unchanged, and the state in which there is no difference between the third length of the third branch path 63 and the fourth length of the fourth branch path 64 remains unchanged. Table 3 shows the S parameters S of the patch antenna 3 of Example 3. １１ The minimum value of the S parameter S １１ The S parameter S at the lower limit frequency of the frequency band where ２１ and the S parameter S at the upper limit frequency of the frequency band ２１ Indicates the value of The configuration of the patch antenna 3 of Example 3 is as follows: １１ is the S parameter S of the patch antenna of Comparative Example 1 １１ In the patch antenna 3 of Example 3, the deviation amount S_perp is 100 μm. From Tables 1 and 3, the S parameter S of the patch antenna 3 of Example 3 １１ The minimum value of the S parameter S of the patch antenna of Comparative Example 1 is １１ and the S parameter S of the patch antenna 3 of Example 3 is smaller than the minimum value of ２１ The value of the S parameter S of the patch antenna of Comparative Example 1 ２１ That is, it can be seen that the radiation efficiency of the patch antenna 3 of Example 3 is higher than the radiation efficiency of the patch antenna of Comparative Example 1, and the inter-port isolation of the patch antenna 3 of Example 3 is higher than the inter-port isolation of the patch antenna of Comparative Example 1. 4. Fourth embodiment FIG. 20 is a cross-sectional view schematically illustrating the antenna module of the fourth embodiment. As shown in FIG. 20, the antenna module 4 of the fourth embodiment includes a patch antenna 101, a second dielectric layer 102, an integrated circuit chip 103, vias 104, a wiring layer 105, vias 106, and bumps 107. The patch antenna 101 is the patch antenna 1, 2 or 3 of the first, second or third embodiment. The integrated circuit chip 103 is disposed on the second dielectric layer 102. The integrated circuit chip 103 contains a circuit. The contained circuit sends signals to the first via 16 and the second via 17 and receives signals from the first via 16 and the second via 17. Part or all of the circuit may be replaced with a discrete circuit. The dielectric layer 11, which serves as the first dielectric layer of the patch antenna 101, is disposed on one main surface of the second ground 14. The second dielectric layer 102 is disposed on the other main surface of the second ground 14. The via 104, the wiring layer 105, and the via 106 are disposed in the second dielectric layer 102. The bump 107 is disposed on the second dielectric layer 102. The wiring consisting of the via 104 , the wiring layer 105 , the via 106 and the bump 107 electrically connects the first via 16 and the second via 17 to the circuit built in the integrated circuit chip 103 . The patch antenna 101, the second dielectric layer 102, the via 104, the wiring layer 105, and the via 106 constitute a monolithic antenna module substrate. The antenna module 4 may include a plurality of patch antennas 101 . 5. Fifth embodiment Fig. 21 is a top view schematically illustrating the antenna module of the fifth embodiment. Fig. 22 is a cross-sectional view schematically illustrating the cross section of the antenna module of the fifth embodiment taken along the cutting line XXII-XXII in Fig. 21. As shown in FIGS. 21 and 22, the antenna module 5 of the fifth embodiment includes a patch antenna 111. The patch antenna 111 differs from the patch antenna 1 of the first embodiment or the patch antenna 2 of the second embodiment in the following points. 21 and 22, the patch antenna 111 includes a wiring layer 121. The wiring layer 121 includes a first branch wiring 131, a second branch wiring 132, and a ground pattern 133. For convenience of illustration, the ground pattern 133 is not shown in FIG. The wiring layer 121 is disposed in the second layer 22. The wiring layer 121 extends in the planar direction of the patch antenna 111 and the dielectric layer 11, and is used for routing wiring in a direction parallel to the planar direction. The first branch wiring 131 is connected to one end of the first two or more connection vias 31 and one end of the first via 16. The second branch wiring 132 is connected to one end of the second two or more connection vias 32 and one end of the second via 17. In this way, the first branch wiring 131 electrically connects the first two or more connection vias 31 to the first via 16. The second branch wiring 132 electrically connects the second two or more connection vias 32 to the second via 17. 21 , the first branch wiring 131 has a first branch 141. The second branch wiring 132 has a second branch 142. Therefore, the first branch wiring 131 includes a first pre-branch wiring 151 and first two post-branch wirings 152 and 153. The second branch wiring 132 includes a second pre-branch wiring 161 and second two post-branch wirings 162 and 163. The first pre-branch wiring 151 reaches the first via 16 to the first branch point 154. The first two post-branch wirings 152 and 153 reach the first two or more connection vias 31 from the first branch point 154. As a result, the first pre-branch wiring 151 is electrically connected to the first via 16. The first two post-branch wirings 152 and 153 are electrically connected to the first two or more connection vias 31. The first two post-branch wirings 152 and 153 branch directly from the first pre-branch wiring 151. As a result, the first pre-branch wiring 151 and the first two post-branch wirings 152 and 153 are electrically connected to each other. As a result, the first branch wiring 131 electrically connects the first two or more connection vias 31 to the first via 16. The second pre-branch wiring 161 reaches the second branch point 164 from the second via 17. The second two post-branch wirings 162 and 163 reach the second two or more connection vias 32 from the second branch point 164. As a result, the second pre-branch wiring 161 is electrically connected to the second via 17. The second two post-branch wirings 162 and 163 are electrically connected to the second two or more connection vias 32. The second two post-branch wirings 162 and 163 branch directly from the second pre-branch wiring 161. As a result, the second pre-branch wiring 161 and the second two post-branch wirings 162 and 163 are electrically connected to each other. As a result, the second branch wiring 132 electrically connects the second two or more connection vias 32 to the second via 17. The first two post-branching wirings 152 and 153 extend from the first branch point 154 to the first connection via 41 and the second connection via 42 included in the first two or more connection vias 31, respectively. As a result, the first two post-branching wirings 152 and 153 are electrically connected to the first connection via 41 and the second connection via 42, respectively. The second two post-branching wirings 162 and 163 extend from the second branch point 164 to the third connection via 43 and the fourth connection via 44 included in the second two or more connection vias 32, respectively. As a result, the second two post-branching wirings 162 and 163 are electrically connected to the third connection via 43 and the fourth connection via 44, respectively. By providing the first branch wiring 131 electrically connecting the first two or more connection vias 31 to the first via 16 and the second branch wiring 132 electrically connecting the second two or more connection vias 32 to the second via 17 in the wiring layer 121 arranged in the second layer 22, the wiring layer 121 can function as a branch layer having branches for distributing signals. This makes it unnecessary to provide a branch layer separate from the wiring layer 121 in the antenna module 5. This makes it possible to increase inter-port isolation without increasing the number of layers. The first two branched wirings 152 and 153 preferably have the same wiring length. The second two branched wirings 162 and 163 preferably have the same wiring length. This allows the phases of signals fed to the first two feed points 51 to be the same. Also, the phases of signals fed to the second two feed points 52 can be the same. This allows for increased inter-port isolation. The first two post-branch wirings 152 and 153 are arranged on the side of the first straight line L1 opposite to the side where the second center line C2 is located in a plan view. The second two post-branch wirings 162 and 163 are arranged on the side of the second straight line L2 opposite to the side where the first center line C1 is located in a plan view. This makes it possible to prevent the first branch wiring 131 and the second branch wiring 132 from interfering with each other. The first pre-branch wiring 151, the first ground 13, and the second ground 14 constitute a first pre-branch transmission line. The constituted first pre-branch transmission line is a stripline and preferably has the same characteristic impedance as the port impedance, for example, 50 Ω. The first two post-branch wirings 152 and 153, the first ground 13, and the second ground 14 constitute a first post-branch transmission line. The first post-branch transmission line is a stripline and preferably has a characteristic impedance twice the characteristic impedance of the first pre-branch transmission line, for example, 100 Ω. This makes it possible to match the combined impedance of the characteristic impedances of the first two post-branch transmission lines constituted by the first two post-branch wirings 152 and 153 with the characteristic impedance of the first pre-branch transmission line constituted by the first pre-branch wiring 151. This allows the first pre-branch transmission line and the first two post-branch transmission lines to be matched with each other at the first branch point 154. This reduces loss in the first branch wiring 131. The second pre-branch wiring 161, the first ground 13, and the second ground 14 constitute a second pre-branch transmission line. The constituted second pre-branch transmission line is a stripline and preferably has the same characteristic impedance as the port impedance, for example, 50 Ω. Each of the second two post-branch wirings 162 and 163, the first ground 13, and the second ground 14 constitutes a second post-branch transmission line. The second post-branch transmission line is a stripline and preferably has a characteristic impedance twice the characteristic impedance of the second pre-branch transmission line, for example, 100 Ω. This allows the combined impedance of the characteristic impedances of the second two post-branch transmission lines formed by the second two post-branch wirings 162 and 163 to match the characteristic impedance of the second pre-branch transmission line formed by the second pre-branch wiring 161. This allows the second pre-branch transmission line and the second two post-branch transmission lines to be matched with each other at the second branch point 164.This makes it possible to reduce loss in the second branch wiring 132 . The first branch 141 of the first branch wiring 131 has a Y-shape. The first pre-branch wiring 151 extends along a straight line near the first branch point 154. The first pre-branch wiring 151 may extend along a bent line or a curved line near the first branch point 154. Each of the first two post-branch wirings 152 and 153 extends along a straight line near the first branch point 154. Each of the first two post-branch wirings 152 and 153 may extend along a bent line or a curved line near the first branch point 154. The second branch 142 of the second branch wiring 132 has a Y-shape. The second pre-branch wiring 161 extends along a straight line near the second branch point 164. The second pre-branch wiring 161 may extend along a bent line or a curved line near the second branch point 164. Each of the second two post-branch wirings 162 and 163 extends along a straight line near the second branch point 164. Each of the second two post-branch wirings 162 and 163 may extend along a bent line or a curved line near the second branch point 164. 23 and 24 are top views schematically illustrating a first branch wiring and a second branch wiring provided in the antenna module of the first modified example of the fifth embodiment, respectively. 23 , in the first modified example of the fifth embodiment, the first two post-branch wirings 152 and 153 extend along curved lines that convex toward each other near the first branch point 154. Furthermore, as shown in FIG. 24 , the second two post-branch wirings 162 and 163 extend along curved lines that convex toward each other near the second branch point 155. Therefore, when the directions in which the first two post-branch wirings 152 and 153 extend near the first branch point 154 are directions D12 and D13, respectively, and the direction in which the first pre-branch wiring 151 extends near the first branch point 154 is direction D11, the angles that the directions D12 and D13 form with the direction D11 in the first modified example of the fifth embodiment are smaller than those in the fifth embodiment. Furthermore, if the directions in which the second two post-branch wirings 162 and 163 extend near the second branch point 155 are directions D22 and D23, respectively, and the direction in which the second pre-branch wiring 161 extends near the second branch point 155 is direction D21, the angle that directions D22 and D23 make with direction D21 in the first variant of the fifth embodiment is smaller than the angle in the fifth embodiment. FIG. 25 shows the S parameter S of the patch antenna provided in the antenna module of the fifth embodiment. １１ 26 is a graph showing the simulation results of the frequency characteristics of the patch antenna provided in the antenna module of the fifth embodiment. ２１ 10 is a graph showing a simulation result of the frequency characteristics of 25 and 26 , the distance L′ in the Y direction DY from the first branch point 154 to the first connection via 41, the distance L′ in the Y direction DY from the first branch point 154 to the second connection via 42, the distance L′ in the X direction DX from the second branch point 164 to the third connection via 43, and the distance L′ in the X direction DX from the second branch point 164 to the fourth connection via 44 are 800 μm, and the distances L′ in the X direction DX from the first branch point 154 to the first connection via 41, the distance L′ in the X direction DX from the first branch point 154 to the second connection via 42, the distance L′ in the Y direction DY from the second branch point 164 to the third connection via 43, and the distance L′ in the Y direction DX from the second branch point 164 to the fourth connection via 44 are 800 μm. Simulation results are shown for the case where the distance Div_length, which is the Y-direction DY distance from the first wiring 151 to the second wiring 161, is 250 μm, the characteristic impedance of the stripline formed by the first pre-branch wiring 151 and the stripline formed by the second pre-branch wiring 161 (hereinafter referred to as the "characteristic impedance before branching") is 50 Ω, and the characteristic impedances of the striplines formed by the first two post-branch wirings 152 and 153 and the second two post-branch wirings 162 and 163 (hereinafter referred to as the "characteristic impedance after branching") are 50 Ω and 100 Ω, respectively. The characteristic impedance of the stripline formed by wiring was set to 50 Ω by setting the width of the wiring to 60 μm. The characteristic impedance of the stripline formed by wiring was set to 100 Ω by setting the width of the wiring to 30 μm. As shown in FIG. 25, the S parameter S when the characteristic impedance after branching is 100Ω １１ The minimum value of the S parameter S when the characteristic impedance after branching is 50Ω １１ In addition, when the characteristic impedance after branching is 100Ω, the S parameter S １１ S parameter S in the frequency band where ２１ The value of is the S parameter S in the frequency band when the characteristic impedance after branching is 50Ω. ２１From this, it can be seen that by setting the characteristic impedance after branching to 100Ω, which is twice the characteristic impedance before branching, 50Ω, the radiation efficiency of the patch antenna 111 can be increased without reducing the isolation between the ports of the patch antenna 111. FIG. 27 shows the S parameter S of the patch antenna provided in the antenna module of the fifth embodiment. １１ 28 is a graph showing the simulation results of the frequency characteristics of the patch antenna provided in the antenna module of the fifth embodiment. ２１ 10 is a graph showing a simulation result of the frequency characteristics of 27 and 28 show simulation results for a case where the distance L' is 800 μm, the distance Div_length is 1500 μm, 1250 μm, 1000 μm, 750 μm, 500 μm, and 250 μm, the characteristic impedance before branching is 50 Ω, and the characteristic impedance after branching is 100 Ω. The characteristic impedance of the stripline formed by wiring was set to 50 Ω by setting the width of the wiring to 60 μm. The characteristic impedance of the stripline formed by wiring was set to 100 Ω by setting the width of the wiring to 30 μm. As shown in FIG. 27, when the distance Div_length is longer than −750 μm, the S parameter S １１ When the distance Div_length is long, the minimum value of the S parameter S １１ It is considered that the reason why the minimum value of becomes large is that the loss in the first branch wiring 131 and the second branch wiring 132 increases. Therefore, when the distance Div_length is long, the strength of the signals fed to the first two feed points 51 and the second two feed points 52 becomes weaker. Furthermore, when the distance Div_length is long, the area occupied by the wiring layer 121 must be increased, or the first branch wiring 131 and the second branch wiring 132 must be brought closer to each other. Even when the distance Div_length is shorter than −750 μm, the S parameter S １１ When the distance Div_length is short, the minimum value of the S parameter S １１ The reason why the minimum value of increases is thought to be that the angles that the directions D12 and D13 make with the direction D11 increase, and the angles that the directions D22 and D23 make with the direction D21 increase, so that the signal transmitted by the first branch wiring 131 is more likely to be reflected at the first branch point 154, and the signal transmitted by the second branch wiring 132 is more likely to be reflected at the second branch point 164. For this reason, when the distance Div_length is short, the intensities of the signals fed to the first two feed points 51 and the second two feed points 52 become weaker. Table 4 shows the S parameters S of the patch antenna 111 of each of Examples 5-1, 5-2, 5-3, and 5-4. １１ , the minimum value of the S parameter S of the patch antenna 111 of each embodiment １１ The S parameter S of the patch antenna 111 of each embodiment at the lower limit frequency of the frequency band where ２１ and the S parameter S of the patch antenna 111 of each embodiment at the upper limit frequency of the frequency band. ２１ Indicates the value of In Examples 5-1, 5-2, 5-3, and 5-4, the distance Div_length is 1000 μm, 750 μm, 500 μm, and 250 μm, respectively. From Table 4, the S parameters S of the patch antenna 111 of Examples 5-1, 5-2, 5-3, and 5-4 are １１ The minimum value of the S parameter S of the patch antenna of Comparative Example 1 is １１ and the S parameter S of the patch antenna 111 of Examples 5-1, 5-2, 5-3, and 5-4 is smaller than the minimum value of ２１ is the S parameter S of the patch antenna of Comparative Example 1 ２１That is, it can be seen that the radiation efficiency of the patch antennas 111 of Examples 5-1, 5-2, 5-3, and 5-4 is higher than the radiation efficiency of the patch antenna of Comparative Example 1, and that the inter-port isolation of the patch antennas 111 of Examples 5-1, 5-2, 5-3, and 5-4 is higher than the inter-port isolation of the patch antenna of Comparative Example 1. FIG. 29 shows the S parameter S of the patch antenna provided in the antenna module of the fifth embodiment. １１ 30 is a graph showing the simulation results of the frequency characteristics of the patch antenna provided in the antenna module of the fifth embodiment. ２１ 10 is a graph showing a simulation result of the frequency characteristics of 29 and 30 show simulation results for cases where the distance L' is 800 μm, 600 μm, and 400 μm, the distance Div_length is 250 μm, the characteristic impedance before branching is 50 Ω, and the characteristic impedance after branching is 100 Ω. The characteristic impedance of the stripline formed by wiring was set to 50 Ω by setting the width of the wiring to 60 μm. The characteristic impedance of the stripline formed by wiring was set to 100 Ω by setting the width of the wiring to 30 μm. As shown in FIG. 29, the S parameter S of the patch antenna 111 is １１ becomes smaller as the distance L' becomes longer. Therefore, the distance L' is preferably made longer. Table 5 shows the S parameters S of the patch antenna 111 of Example 5-5. １１ the minimum value of the S parameter S21 of the patch antenna 111 of Example 5-5 at the lower limit frequency of the frequency band in which the S parameter S11 of the patch antenna 111 of Example 5-5 is −10 dB or less, and the S parameter S21 of the patch antenna 111 of Example 5-5 at the upper limit frequency of the frequency band ２１ Indicates the value of In Example 5-5, the distance L' is 400 μm. From Table 5, the S parameters of the patch antenna 111 of Example 5-5 when the distance L' is 400 μm are １１ The minimum value of the S parameter S of the patch antenna of Comparative Example 1 is １１ , and the S parameter S of the patch antenna 111 of Example 5-5 when the distance L' is 400 μm. ２１ is the S parameter S of the patch antenna of Comparative Example 1 ２１ That is, it can be seen that the radiation efficiency of the patch antenna 111 of Example 5-5 is comparable to the radiation efficiency of the patch antenna of Comparative Example 1, and that the inter-port isolation of the patch antenna 111 of Example 5-5 is higher than the inter-port isolation of the patch antenna of Comparative Example 1. 21 and 22 , the antenna module 5 of the fifth embodiment includes a dielectric layer 171, a wiring layer 172, first bumps 173, second bumps 174, and an integrated circuit chip 175. The wiring layer 172 includes a first wiring 181 and a second wiring 182. The integrated circuit chip 175 includes a first terminal 191 and a second terminal 192. The dielectric layer 11, which serves as the first dielectric layer, is disposed on one main surface of the second ground 14. The dielectric layer 11 has a first main surface 11a and a second main surface 11b. The second main surface 11b is located on the opposite side to the first main surface 11a and is in contact with one main surface of the second ground 14. The dielectric layer 171, which serves as the second dielectric layer, is disposed on the other main surface of the second ground 14. The dielectric layer 171 has a first main surface 171a and a second main surface 171b. The second main surface 171b is located on the opposite side to the first main surface 171a and is in contact with the other main surface of the second ground 14. Each of the first via 16 and the second via 17 is disposed across the second layer 22 and the dielectric layer 171, extends in the thickness direction of the second layer 22 and the dielectric layer 171, and reaches the first main surface 171 a of the dielectric layer 171. The wiring layer 172 is disposed on the first main surface 171 a. The integrated circuit chip 175 is disposed on the wiring layer 172. The first wiring 181 and the second wiring 182 are directly connected to the first via 16 and the second via 17, respectively. In the antenna module 5, the first pre-branch wiring 151 and the second pre-branch wiring 161 can be routed in the wiring layer 121 in a direction parallel to the surface direction of the patch antenna 111, and therefore there is no need to provide a layer other than the wiring layer 121 in order to route the first pre-branch wiring 151 and the second pre-branch wiring 161 in a direction parallel to the surface direction of the patch antenna 111. This makes it possible to reduce the number of layers provided in the antenna module 5. The integrated circuit chip 175 has a built-in circuit. The built-in circuit sends signals to the first via 16 and the second via 17 and receives signals from the first via 16 and the second via 17. The signals sent to the first via 16 and the second via 17 are output from the first terminal 191 and the second terminal 192. The signals received from the first via 16 and the second via 17 are input to the first terminal 191 and the second terminal 192. The integrated circuit chip 175 is mounted on the wiring layer 172. The first terminal 191 and the second terminal 192 are connected to the first wiring 181 and the second wiring 182 via the first bump 173 and the second bump 174, respectively. As a result, the first terminal 191 and the second terminal 192 are electrically connected to the first wiring 181 and the second wiring 182, respectively. In the fifth embodiment, the first terminal 191 and the second terminal 192 through which signals are input and output are provided on the integrated circuit chip 175. However, the first terminal 191 and the second terminal 192 through which signals are input and output may be provided on at least one circuit element other than the integrated circuit chip 175. The present disclosure is not limited to the above-described embodiments, and may be replaced with a configuration that is substantially the same as the configuration shown in the above-described embodiments, a configuration that has the same effect, or a configuration that can achieve the same purpose.

Claims

1. A patch antenna comprising: a dielectric layer having a first main surface and a second main surface on the side opposite to the first main surface, the dielectric layer comprising a first layer arranged on the side where the first main surface is located and a second layer arranged on the side where the second main surface is located; a patch arranged on the first main surface; a ground arranged between the first layer and the second layer; three or more connection vias arranged in the dielectric layer and connected to the patch; a first via that is electrically connected in the second layer to a first two or more connection vias that are included in the three or more connection vias and arranged along a first straight line in a planar view, and that reaches the second main surface; and a second via that is electrically connected to a second two or more connection vias that are included in the three or more connection vias and arranged along a second straight line that is perpendicular to the first straight line in the planar view, and that reaches the second main surface.

2. The patch antenna according to claim 1, wherein the second via is electrically connected to the second two or more connection vias within the second layer.

3. The patch antenna according to claim 1, wherein the patch has first two sides that are opposite and parallel to each other in the plan view and second two sides that are opposite and parallel to each other and perpendicular to the first two sides, the first straight line is parallel to the first two sides, and the second straight line is parallel to the second two sides.

4. The patch antenna according to claim 1, wherein a connection via included in the first two or more connection vias and a connection via included in the second two or more connection vias pass through the same anti-pad formed in the ground.

5. The patch antenna according to claim 1, further comprising a first path disposed in the second layer and electrically connecting the first two or more connection vias to the first via, the first path constituting a first transmission line having the same characteristic impedance as a feeding impedance.

6. The patch antenna according to claim 5, wherein the ground is a first ground, and a second ground is disposed on the second main surface, and the first transmission line is a first stripline constituted by the first path, the first ground, and the second ground.

7. The patch antenna according to claim 2, further comprising a second path disposed in the second layer and electrically connecting the second two or more connection vias to the second via, the second path constituting a second transmission line having the same characteristic impedance as the feeding impedance.

8. The patch antenna according to claim 7, wherein the ground is a first ground, and a second ground is disposed on the second main surface, and the second transmission line is a second stripline constituted by the second path, the first ground, and the second ground.

9. The patch antenna according to claim 1, wherein the first two or more connection vias include a first connection via and a second connection via, and the second two or more connection vias include a third connection via and a fourth connection via.

10. The patch antenna described in claim 9, wherein the first straight line and the second straight line extend in a first direction and a second direction, respectively; the first connection via, the third connection via, and the fourth connection via are arranged on one side of a first center line of the patch in the first direction in the planar view; the first connection via, the second connection via, and the third connection via are arranged on one side of a second center line of the patch in the second direction in the planar view; the second connection via is arranged on the other side of the first center line in the planar view; the fourth connection via is arranged on the other side of the second center line in the planar view; the first via is arranged on the other side of the first center line in the planar view; and the second via is arranged on the other side of the second center line in the planar view.

11. The patch antenna described in claim 10, comprising: a first branch path branching from the first via and connected to the first connection via, the first branch path having a first length; a second branch path branching from the first via and connected to the second connection via, the second branch path having a second length shorter than the first length; a third branch path branching from the second via and connected to the third connection via, the third length; and a fourth branch path branching from the second via and connected to the fourth connection via, the fourth length shorter than the third length.

12. A patch antenna as described in claim 1, further comprising a wiring layer disposed within the second layer and extending in the plane direction of the dielectric layer, the wiring layer comprising a first branch wiring electrically connecting the first two or more connection vias to the first via and having a first branch.

13. The patch antenna according to claim 12, wherein the wiring layer includes a second branch wiring that electrically connects the second two or more connection vias to the second via and has a second branch.

14. The patch antenna described in claim 12, wherein the first branch wiring comprises a first pre-branch wiring electrically connected to the first via, and first two post-branch wirings branching from the first pre-branch wiring and electrically connected to the first two or more connection vias, the first pre-branch wiring constituting a first pre-branch transmission line, and each of the first two post-branch wirings constituting a first post-branch transmission line having a characteristic impedance twice the characteristic impedance of the first pre-branch transmission line.

15. The patch antenna described in claim 13, wherein the second branch wiring comprises a second pre-branch wiring electrically connected to the second via, and two second post-branch wirings branching from the second pre-branch wiring and electrically connected to the second two or more connection vias, the second pre-branch wiring constituting a second pre-branch transmission line, and each of the second two post-branch wirings constituting a second post-branch transmission line having a characteristic impedance twice the characteristic impedance of the second pre-branch transmission line.

16. An antenna module comprising: a patch antenna according to any one of claims 1 to 15; a circuit for sending signals to the first via and the second via, or for receiving signals from the first via and the second via; and wiring for electrically connecting the first via and the second via to the circuit.

17. The antenna module according to claim 16, wherein the patch antenna is the patch antenna according to claim 12, and further comprises at least one circuit element having a first terminal and a second terminal electrically connected to the first via and the second via, respectively.

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