Antenna and wireless communications device

Abstract

Provided is an antenna comprising: a first substrate on which is formed a first conductor extending on a first surface; a second substrate on which is formed a second conductor that is electrically connected to the first conductor and extends on the first surface serving as a potential reference for the first conductor; and a casing that accommodates the first substrate and the second substrate. A dielectric material is provided on the surface side of the first conductor opposite from the surface thereof facing the second conductor.

Description

Antenna and wireless communication device

[0001] The present disclosure relates to an antenna and a wireless communication device.

[0002] In recent years, an antenna that is capable of good communication even when placed on a metal plate has become known (see, for example, Patent Document 1).

[0003] International Publication No. 2018 / 174026

[0004] The antenna of the present disclosure comprises a first substrate on which a first conductor extending over a first surface is formed, a second substrate on which a second conductor extending over the first surface is formed and is electrically connected to the first conductor and serves as a potential reference for the first conductor, and a housing that houses the first substrate and the second substrate, and has a dielectric material on the side of the first conductor opposite the side facing the second conductor.

[0005] A wireless communication device of the present disclosure includes the antenna of the present disclosure.

[0006] FIG. 1 is a diagram illustrating an overview of an antenna unit according to a first example of the first embodiment. FIG. 2 is a diagram illustrating an example of a configuration of a first conductor according to the first example of the first embodiment. FIG. 3 is a diagram illustrating an example of a configuration of a second conductor according to the first example of the first embodiment. FIG. 4 is a diagram illustrating an overview of an antenna unit according to a second example of the first embodiment. FIG. 5 is a diagram illustrating an example of a configuration of a first conductor according to the second example of the first embodiment. FIG. 6 is a diagram illustrating an example of a configuration of a second conductor according to the second example of the first embodiment. FIG. 7 is a diagram illustrating an example of a configuration of a first modified example of a first conductor according to the second example of the first embodiment. FIG. 8 is a diagram illustrating an example of a configuration of a second modified example of a first conductor according to the second example of the first embodiment. FIG. 9 is a diagram illustrating an example of a configuration of an antenna according to the first embodiment. FIG. 10 is a diagram illustrating an arrangement pattern of upper conductors according to the first embodiment. FIG. 11 is a diagram illustrating an arrangement pattern of upper conductors according to a comparative example. FIG. 12 is a diagram illustrating the overall radiation efficiency of the antenna according to the first embodiment. FIG. 13 is a diagram illustrating the influence of a housing of the antenna according to the first embodiment on the overall radiation efficiency. FIG. 14 is a diagram illustrating the overall radiation efficiency of radio waves when a housing is provided for the antenna according to the first embodiment. FIG. 15 is a diagram for explaining the influence of the housing of the antenna according to the first embodiment on the overall radiation efficiency. FIG. 16 is a diagram for explaining the overall radiation efficiency of radio waves when there is a housing for an antenna according to a modified example of the first embodiment. FIG. 17 is a diagram showing a configuration example of an antenna according to a modified example of the second embodiment. FIG. 18 is a diagram showing a configuration example of an antenna according to a modified example of the second embodiment. FIG. 19 is a perspective view showing a method of fixing a housing and a metal member according to a first example of the third embodiment. FIG. 20 is a top view showing a method of fixing a housing and a metal member according to the first example of the third embodiment. FIG. 21 is a perspective view showing a method of fixing a housing and a metal member according to a first comparative example of the third embodiment. FIG. 22 is a top view showing a method of fixing a housing and a metal member according to a first comparative example of the third embodiment. FIG. 23 is a perspective view showing a method of fixing a housing and a metal member according to a second example of the third embodiment. FIG. 24 is a top view showing a method of fixing a housing and a metal member according to a second example of the third embodiment. FIG. 25 is a perspective view showing a method of fixing a housing and a metal member according to a second comparative example of the third embodiment.Fig. 26 is a top view showing a method of fixing a housing and a metal member according to a second comparative example of the third embodiment Fig. 27 is a block diagram showing an example of the configuration of a wireless communication device according to a fourth embodiment.

[0007] Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings. Note that the present invention is not limited to this embodiment, and in the following embodiments, the same components are designated by the same reference numerals, and redundant explanations will be omitted.

[0008] In the following description, an XYZ Cartesian coordinate system is set, and the positional relationship of each part will be described with reference to this XYZ Cartesian coordinate system. The direction parallel to the X axis in a horizontal plane is defined as the X-axis direction, the direction parallel to the Y axis in the horizontal plane perpendicular to the X axis is defined as the Y-axis direction, and the direction parallel to the Z axis perpendicular to the horizontal plane is defined as the Z-axis direction. Furthermore, the plane including the X axis and Y axis will be referred to as the XY plane as appropriate, the plane including the X axis and Z axis will be referred to as the XZ plane as appropriate, and the plane including the Y axis and Z axis will be referred to as the YZ plane as appropriate. The XY plane is parallel to the horizontal plane. The XY plane, XZ plane, and YZ plane are perpendicular to each other.

[0009] [First embodiment] (Antenna unit of first example) An overview of an antenna unit according to a first example of the present disclosure will be described using Fig. 1, Fig. 2, and Fig. 3. Fig. 1 is a diagram showing an overview of an antenna unit according to the first example of the first embodiment. Fig. 2 is a diagram showing a configuration example of a first conductor according to the first example of the first embodiment. Fig. 3 is a diagram showing a configuration example of a second conductor according to the first example of the first embodiment.

[0010] As shown in Fig. 1, the antenna unit 1a includes a first substrate 11, a second substrate 12, an upper conductor 21, an upper conductor 22, an upper conductor 23, a lower conductor 31, connecting conductors 41-1, 41-2, connecting conductors 42-1, 42-2, and a power supply conductor 43. Fig. 1 is a cross-sectional view of the antenna unit 1a in the long side direction. The antenna unit 1a can be mounted on, for example, a metal plate 2. The antenna unit 1a is a single-band type antenna.

[0011] The antenna unit 1a is configured to be capable of radiating circularly polarized waves. The antenna unit 1a is configured to exhibit an artificial magnetic conductor character (ARTC) for electromagnetic waves of a predetermined frequency incident on the XY plane of the antenna unit 1a from the positive side of the Z axis. In this disclosure, the artificial magnetic conductor character refers to the character of a surface where the phase difference between the incident wave and the reflected wave is 0 degrees. On a surface having the artificial magnetic conductor character, the phase difference between the incident wave and the reflected wave is -90 degrees to +90 degrees in the operating frequency band. This also applies to the following antenna units.

[0012] The first substrate 11 extends in the XY plane. The first substrate 11 is, for example, a dielectric substrate. The first substrate 11 is formed in a rectangular shape, but is not limited to this.

[0013] The second substrate 12 extends in the XY plane. The second substrate 12 is located away from the first substrate 11 in the Z-axis direction. The second substrate 12 faces the first substrate 11. The second substrate 12 is, for example, a dielectric substrate. The second substrate 12 is formed in a rectangular shape, but is not limited to this.

[0014] The top conductors 21, 22, and 23 are provided on the first substrate 11. The top conductors 21, 22, and 23 are also referred to as first conductors. As shown in FIG. 2 , the top conductors 21, 22, and 23 are provided at intervals along the X-axis direction. The top conductor 21 is provided on the left side. The top conductor 23 is provided on the right side. The top conductor 22 is provided between the top conductors 21 and 23. For example, the area of ​​the top conductor 21 and the area of ​​the top conductor 23 are the same. The area of ​​the top conductor 22 is larger than the areas of the top conductors 21 and 23. The top conductors 21, 22, and 23 are each formed in a rectangular shape, but this is not a limitation. The top conductors 21, 22, and 23 are conductors that transmit and receive radio waves.

[0015] The bottom conductor 31 is provided on the second substrate 12. The bottom conductor 31 is provided, for example, on the upper and lower surfaces of the second substrate 12. The bottom conductor 31 provided on the upper surface of the second substrate 12 and the bottom conductor 31 provided on the lower surface of the second substrate 12 are electrically connected, for example, via a via. The bottom conductor 31 is also called a second conductor. As shown in FIG. 3 , the bottom conductor 31 is formed in a rectangular shape, but is not limited to this. The bottom conductor 31 has a feeding point 311. The bottom conductor 31 and the feeding point 311 are not electrically connected. The bottom conductor 31 is a conductor that serves as a reference potential. The reference potential is, for example, ground, but is not limited to this.

[0016] One end of the connection conductor 41-1 and the connection conductor 41-2 is electrically connected to the top conductor 21. The other end of the connection conductor 41-1 and the connection conductor 41-2 is electrically connected to the bottom conductor 31. That is, the connection conductor 41-1 and the connection conductor 41-2 are configured to electrically connect the top conductor 21 and the bottom conductor 31, respectively. The connection conductors 41-1 and 41-2 are provided along the Y-axis direction. The connection conductors 41-1 and 41-2 are each, for example, a columnar body extending in the Z-axis direction.

[0017] One end of the connection conductor 42-1 and the connection conductor 42-2 is electrically connected to the top conductor 23. The other end of the connection conductor 42-1 and the connection conductor 42-2 is electrically connected to the bottom conductor 31. That is, the connection conductor 42-1 and the connection conductor 42-2 are configured to electrically connect the top conductor 23 and the bottom conductor 31, respectively. The connection conductors 42-1 and 42-2 are provided along the Y-axis direction. The connection conductors 42-1 and 42-2 are each, for example, a columnar body extending in the Z-axis direction.

[0018] One end of the power supply conductor 43 is electrically connected to the upper conductor 21. The other end of the power supply conductor 43 is electrically connected to the power supply point 311. That is, the power supply conductor 43 is configured to electrically connect the upper conductor 21 and the power supply point 311. The power supply conductor 43 is, for example, a columnar body extending in the Z-axis direction. The power supply conductor 43 supplies power supplied from, for example, an external device to the upper conductor 21. The power supply conductor 43 supplies power from, for example, the upper conductor 21 to the external device.

[0019] (Antenna unit of second example) An overview of an antenna unit according to a second example of the present disclosure will be described using Fig. 4, Fig. 5, and Fig. 6. Fig. 4 is a diagram showing an overview of an antenna unit according to a second example of the first embodiment. Fig. 5 is a diagram showing a configuration example of a first conductor according to the second example of the first embodiment. Fig. 6 is a diagram showing a configuration example of a second conductor according to the second example of the first embodiment.

[0020] 4 to 6, the antenna unit 1b includes a first substrate 11, a second substrate 12, an upper conductor 21A, an upper conductor 22A, an upper conductor 23A, an upper conductor 24A, an upper conductor 25A, an upper conductor 26A, a lower conductor 31, connecting conductors 41-1, 41-2, 42-1, 42-2, a power supply conductor 43, and connecting conductors 44-1 and 44-2. The antenna unit 1b is a multi-band antenna.

[0021] The top conductor 21A, the top conductor 22A, the top conductor 23A, the top conductor 24A, the top conductor 25A, and the top conductor 26A are provided on the first substrate 11. The top conductor 21A, the top conductor 22A, the top conductor 23A, the top conductor 24A, the top conductor 25A, and the top conductor 26A are also referred to as first conductors.

[0022] The top conductor 21A, the top conductor 22A, and the top conductor 23A are spaced apart from one another along the X-axis direction. The top conductor 21A is provided on the left side. The top conductor 23A is provided on the right side. The top conductor 22A is provided between the top conductors 21A and 23A. The top conductor 22A has a notch 221A in the center. The area of ​​the top conductor 21A and the area of ​​the top conductor 23A are, for example, the same. The area of ​​the top conductor 22A is larger than the areas of the top conductors 21 and 23. The top conductors 21A, 22A, and 23A are each formed in a rectangular shape, but are not limited to this.

[0023] The top conductor 24A, the top conductor 25A, and the top conductor 26A are spaced apart from one another along the X-axis direction. The top conductor 24A is spaced apart from the top conductor 21A along the Y-axis direction. The top conductor 25A is spaced apart from the top conductor 22A along the Y-axis direction. The top conductor 26A is spaced apart from the top conductor 23A along the Y-axis direction. The top conductor 24A is located on the left side. The top conductor 26A is located on the right side. The top conductor 25A is located between the top conductors 24A and 25A. The top conductor 25A has a notch 251A in its center. The top conductor 24A has the same shape as the top conductor 21A. The top conductor 25A has the same shape as the top conductor 22A. The top conductor 26A has the same shape as the top conductor 23A.

[0024] One end of the connection conductor 41-1 is electrically connected to the upper conductor 21A. The other end of the connection conductor 41-1 is electrically connected to the lower conductor 31. In other words, the connection conductor 41-1 is configured to electrically connect the upper conductor 21A and the lower conductor 31.

[0025] One end of the connection conductor 41-2 is electrically connected to the upper conductor 24A. The other end of the connection conductor 41-2 is electrically connected to the lower conductor 31. In other words, the connection conductor 41-2 is configured to electrically connect the upper conductor 24A and the lower conductor 31.

[0026] One end of the connection conductor 42-1 is electrically connected to the upper conductor 23A. The other end of the connection conductor 42-1 is electrically connected to the lower conductor 31. In other words, the connection conductor 42-1 is configured to electrically connect the upper conductor 23A and the lower conductor 31.

[0027] One end of the connection conductor 42-2 is electrically connected to the upper conductor 26A. The other end of the connection conductor 42-2 is electrically connected to the lower conductor 31. In other words, the connection conductor 42-2 is configured to electrically connect the upper conductor 26A and the lower conductor 31.

[0028] One end of the connection conductor 44-1 is electrically connected to the upper conductor 22A. The other end of the connection conductor 44-1 is electrically connected to the lower conductor 31. In other words, the connection conductor 44-1 is configured to electrically connect the upper conductor 22A and the lower conductor 31. The connection conductor 44-1 is, for example, a columnar body extending in the Z-axis direction.

[0029] One end of the connection conductor 44-2 is electrically connected to the upper conductor 25A. The other end of the connection conductor 44-2 is electrically connected to the lower conductor 31. In other words, the connection conductor 44-2 is configured to electrically connect the upper conductor 25A and the lower conductor 31. The connection conductor 44-2 is, for example, a columnar body extending in the Z-axis direction.

[0030] (First Modification of Antenna Unit of Second Example) A first modification of the antenna unit of the second example will be described. The shape of the first conductor of the antenna unit of the second example is not limited to the example shown in Fig. 5. Fig. 7 is a diagram showing a configuration example of a first modification of the first conductor according to the second example of the first embodiment.

[0031] The configuration of the first modified example of the first conductor according to the second example is the same as the shape of the first conductor according to the first example.

[0032] One end of each of the connection conductors 41-1 and 41-2 is electrically connected to the top conductor 21. The other end of each of the connection conductors 41-1 and 41-2 is electrically connected to the bottom conductor 31.

[0033] One end of each of the connection conductors 42-1 and 42-2 is electrically connected to the top conductor 23. The other end of each of the connection conductors 42-1 and 42-2 is electrically connected to the bottom conductor 31.

[0034] One end of each of the connection conductors 44-1 and 44-2 is electrically connected to the top conductor 22. The other end of each of the connection conductors 44-1 and 44-2 is electrically connected to the bottom conductor 31.

[0035] As shown in FIG. 7, by electrically connecting the top conductor 21, the top conductor 22, and the top conductor 23 with the bottom conductor 31, a multi-band antenna can be realized.

[0036] (Second Modification of Antenna Unit of Second Example) Fig. 8 is a diagram showing a configuration example of a second modification of the first conductor according to the second example of embodiment 1. As shown in Fig. 8, the second modification of the first conductor according to the second example has an upper conductor 21, an upper conductor 22B, and an upper conductor 23.

[0037] The top conductor 22B differs from the top conductor 22 shown in FIG. 7 in that it has a hole 221B in the center. The size of the hole 221B may be changed as desired depending on the design. One end of each of the connection conductors 44-1 and 44-2 is electrically connected to the top conductor 22B. The other end of each of the connection conductors 44-1 and 44-2 is electrically connected to the bottom conductor 31.

[0038] As shown in FIG. 8, by electrically connecting the top conductor 21, the top conductor 22B, and the top conductor 23 with the bottom conductor 31, a multi-band antenna can be realized.

[0039] [Antenna] A configuration example of the antenna according to the first embodiment will be described with reference to Fig. 9. Fig. 9 is a diagram showing a configuration example of the antenna according to the first embodiment.

[0040] As shown in FIG. 9 , the antenna 100 includes an antenna unit 1, a metal plate 2, and a housing 3. The metal plate 2 and the housing 3 form a housing. The metal plate 2 is a type of first housing unit. The housing 3 is a type of second housing unit. The antenna unit 1 has a configuration similar to that of the antenna unit 1b shown in FIG. 4 . For ease of explanation, the configuration of the upper conductor is assumed to be the configuration shown in FIG. 7 . The antenna unit 1 is shown without the power supply conductor 43. The antenna unit 1 is disposed on the metal plate 2. The metal plate 2 is electrically connected to the bottom conductor 31. The metal plate 2 and the bottom conductor 31 are bonded together, for example, with double-sided tape or adhesive containing a dielectric material. The top and side surfaces of the antenna unit 1 are covered with the housing 3. The housing 3 is made of a dielectric material such as resin. The housing 3 and the first substrate 11 are bonded together, for example, with double-sided tape or adhesive containing a dielectric material.

[0041] In this embodiment, the antenna unit 1 is configured to improve the communication characteristics of the antenna 100. In the following, the antenna 100 will be described as having a multi-band type antenna unit, but it may also have a single-band type antenna unit.

[0042] (Top Conductor) The arrangement pattern of the top conductor according to the first embodiment will be described with reference to Fig. 10 and Fig. 11. Fig. 10 is a diagram showing the arrangement pattern of the top conductor according to the first embodiment. Fig. 11 is a diagram showing the arrangement pattern of the top conductor according to a comparative example.

[0043] 10 , in the first embodiment, the top conductor 21, the top conductor 22, and the top conductor 23 are provided on the surface of the first substrate 11 that faces the second substrate 12. In other words, the top conductor 21, the top conductor 22, and the top conductor 23 are provided inside the first substrate 11.

[0044] 11 , in the comparative example, the top conductor 21, the top conductor 22, and the top conductor 23 are provided on the surface of the first substrate 11 opposite to the surface facing the second substrate 12. In other words, the top conductor 21, the top conductor 22, and the top conductor 23 are provided on the outside of the first substrate 11.

[0045] Fig. 12 is a diagram for explaining the overall radiation efficiency of the antenna according to the first embodiment, in which the horizontal axis represents frequency [GHz (gigahertz)] and the vertical axis represents overall radiation efficiency [dB].

[0046] Graph 101 shows the overall radiation efficiency of the antenna unit 1 when the top conductor 21, the top conductor 22, and the top conductor 23 are provided inside the first substrate 11. Graph 102 shows the overall radiation efficiency of the antenna unit 1 when the top conductor 21, the top conductor 22, and the top conductor 23 are provided outside the first substrate 11.

[0047] When each upper conductor is provided on the outside of the first substrate 11, the distance to the lower conductor 31 increases, and therefore the capacitance component formed by each upper conductor and lower conductor 31 increases. As a result, as shown in graphs 101 and 102, when each upper conductor is provided on the outside, the frequency characteristics shift to the lower frequency side compared to when each upper conductor is provided on the inside.

[0048] When each upper conductor is provided inside the first substrate 11, the gain when radiating radio waves along the +Z-axis direction of the antenna unit 1 is, for example, +2.3 [dBi (decibels)]. When each upper conductor is provided outside the first substrate 11, the gain when radiating radio waves along the +Z-axis direction of the antenna unit 1 is, for example, +2.0 [dBi]. This is because radio waves have the property of easily passing through materials with high dielectric constants, and when each upper conductor is provided inside the first substrate 11, the first substrate 11, which has a high dielectric constant, is located outside the each upper conductor that radiates radio waves, making it easier to radiate radio waves.

[0049] Therefore, in the first embodiment, it is preferable to provide each upper conductor on the inner side of the first substrate 11 .

[0050] (Influence of Housing) As described above, the antenna unit 1 is used with its top and side surfaces covered by the housing 3. Therefore, the housing 3 may affect the overall radiation efficiency of radio waves. Fig. 13 is a diagram for explaining the influence of the housing of the antenna according to the first embodiment on the overall radiation efficiency.

[0051] 13, the housing 3 is located outside the first substrate 11. The dielectric constant of the first substrate 11 is, for example, 4.3. The dielectric constant of the housing 3 is, for example, 3.1.

[0052] Fig. 14 is a diagram for explaining the overall radiation efficiency of radio waves when there is a housing for the antenna according to the first embodiment, where the horizontal axis represents frequency [GHz] and the vertical axis represents overall radiation efficiency [dB].

[0053] Graph 103 shows the radiation efficiency of the antenna unit 1 when each upper conductor is provided inside the first substrate 11 having a dielectric constant of 4.3 and when the housing 3 is not located outside the first substrate 11. Graph 104 shows the overall radiation efficiency of the antenna unit 1 when each upper conductor is provided inside the first substrate 11 having a dielectric constant of 4.3 and when the housing 3 having a dielectric constant of 3.1 is located outside the first substrate 11. Graph 105 shows the overall radiation efficiency of the antenna unit 1 when each upper conductor is provided inside the first substrate 11 having a dielectric constant of 4.3 and when the housing 3 having a dielectric constant of 5.0 is located outside the first substrate 11.

[0054] When the housing 3 is located outside the first substrate 11, the dielectric constant increases, and the capacitance component created between each upper conductor increases. As a result, as shown in graphs 103 to 105, when the housing 3 is located outside the first substrate 11, the frequency characteristics shift to the lower range compared to when the housing 3 is not located outside the first substrate 11. As shown in graphs 104 and 105, even if the dielectric constant of the housing 3 changes, the amount of shift is almost the same. Therefore, since the change in characteristics is small in response to variations in the dielectric constant of the housing material, it is advantageous (meritorious) from the perspective of variation to have each upper conductor located inside the first substrate 11.

[0055] When the housing 3 is not located outside the first substrate, the gain when radiating radio waves along the +Z-axis direction of the antenna unit 1 is, for example, +2.3 dBi. When the housing 3 is not located outside the first substrate, the gain when radiating radio waves in a direction at 30 degrees relative to the +Z-axis direction of the antenna unit 1 is, for example, +1.2 dBi. When a housing 3 with a dielectric constant of 3.1 is located outside the first substrate, the gain when radiating radio waves along the +Z-axis direction of the antenna unit 1 is, for example, +2.2 dBi. When the housing 3 is not located outside the first substrate, the gain when radiating radio waves in a direction at 30 degrees relative to the +Z-axis direction of the antenna unit 1 is, for example, +1.1 dBi. When a housing 3 with a dielectric constant of 5.0 is located outside the first substrate, the gain when radiating radio waves along the +Z-axis direction of the antenna unit 1 is, for example, +2.1 dBi. When the housing 3 is not positioned outside the first board, the gain when radiating radio waves in a direction 30 degrees from the +Z axis direction of the antenna unit 1 is, for example, +1.1 [dBi].

[0056] That is, even if each upper conductor is disposed inside the first substrate 11 and the housing 3 is located outside the first substrate 11, the direction of high dielectric constant for each upper surface conductor is the same, so there is little effect on the gain when radiating radio waves. In addition, the dielectric constant of the housing 3 also has little effect on the gain when radiating radio waves. Therefore, in the first embodiment, the antenna unit 1 can be housed in a housing 3 made of any dielectric material.

[0057] (Antenna Modification) When the antenna unit 1 is accommodated in the housing 3, the upper conductors may be provided on the outside of the first substrate 11. FIG. 15 is a diagram for explaining the influence of the housing of the antenna according to the first embodiment on the overall radiation efficiency. As shown in FIG. 15, the upper conductors 21, 22, and 23 of the antenna unit 1A are provided on the outside of the first substrate 11. In the example shown in FIG. 15, the housing 3 is located on the upper conductors 21, 22, and 23. In this case, the housing 3 and the upper conductors 21, 22, and 23 are adhered to each other with, for example, double-sided tape or an adhesive containing a dielectric material.

[0058] 16 is a diagram for explaining the overall radiation efficiency of radio waves when there is a housing for the antenna according to the modified example of the first embodiment, in which the horizontal axis represents frequency [GHz] and the vertical axis represents overall radiation efficiency [dB].

[0059] Graph 106 shows the radiation efficiency of antenna unit 1A when each upper conductor is provided outside first substrate 11 having a dielectric constant of 4.3 and when housing 3 is not located outside first substrate 11. Graph 107 shows the overall radiation efficiency of antenna unit 1A when each upper conductor is provided outside first substrate 11 having a dielectric constant of 4.3 and when housing 3 having a dielectric constant of 3.1 is located outside first substrate 11. Graph 108 shows the overall radiation efficiency of antenna unit 1A when each upper conductor of first substrate 11 having a dielectric constant of 4.3 is provided outside and housing 3 having a dielectric constant of 5.0 is located outside first substrate 11.

[0060] When the housing 3 is located outside the first substrate 11, the dielectric constant between the top and bottom of each upper conductor increases, and the capacitance component created between each upper conductor increases. As a result, as shown in graphs 106 to 108, when the housing 3 is located outside the first substrate 11, the frequency characteristics shift to the lower range compared to when the housing 3 is not located outside the first substrate 11. As shown in graphs 106 and 108, the greater the dielectric constant of the housing 3, the greater the amount of shift. In other words, variations in the dielectric constant of the material of the housing 3 significantly change the characteristics (which is a disadvantage).

[0061] When the housing 3 is not located outside the first substrate, the gain when the antenna unit 1A radiates radio waves along the +Z-axis direction is, for example, +2.0 dBi. When the housing 3 is not located outside the first substrate, the gain when the antenna unit 1A radiates radio waves in a direction at 30 degrees relative to the +Z-axis direction is, for example, +0.7 dBi. When the housing 3 having a dielectric constant of 3.1 is located outside the first substrate, the gain when the antenna unit 1A radiates radio waves along the +Z-axis direction is, for example, +2.0 dBi. When the housing 3 is not located outside the first substrate, the gain when the antenna unit 1A radiates radio waves in a direction at 30 degrees relative to the +Z-axis direction is, for example, +0.9 dBi. When the housing 3 having a dielectric constant of 5.0 is located outside the first substrate, the gain when the antenna unit 1 radiates radio waves along the +Z-axis direction is, for example, +1.9 dBi. When the housing 3 is not positioned outside the first board, the gain when radiating radio waves in a direction at 30 degrees with respect to the +Z axis direction of the antenna unit 1 is, for example, +0.8 [dBi].

[0062] That is, when the upper conductors are provided on the outside of the first substrate 11, positioning the housing 3 on the outside makes it easier for radio waves to travel to the outside because there are parts with high dielectric constants on the outside of each upper conductor, and the gain in the upward direction when radiating radio waves is improved compared to metal. In other words, by having a dielectric material in the direction opposite to the direction of the lower conductor 31 of each upper conductor, the gain when radiating radio waves is improved.

[0063] Second Embodiment An example of the configuration of an antenna according to the second embodiment will be described with reference to Fig. 17. Fig. 17 is a diagram showing an example of the configuration of an antenna according to the second embodiment.

[0064] As shown in FIG. 17, the antenna 100A differs from the antenna 100 shown in FIG. 9 in that it further includes a capacitor 61 and a capacitor 62.

[0065] The capacitor 61 has one end electrically connected to the upper conductor 21 and the other end electrically connected to the upper conductor 22. That is, the capacitor 61 adds capacitance between the upper conductor 21 and the upper conductor 22.

[0066] The capacitor 62 has one end electrically connected to the upper conductor 22 and the other end electrically connected to the upper conductor 23. That is, the capacitor 62 adds capacitance between the upper conductor 22 and the upper conductor 23.

[0067] That is, by adjusting the capacitances of the capacitors 61 and 62, the characteristics of the antenna 100A can be easily adjusted.

[0068] [Modification of Second Embodiment] A configuration example of an antenna according to a modification of the second embodiment will be described with reference to Fig. 18. Fig. 18 is a diagram showing a configuration example of an antenna according to a modification of the second embodiment.

[0069] As shown in FIG. 18, the antenna 100B differs from the antenna 100 shown in FIG. 9 in that it further includes a capacitive conductor 71 and a capacitive conductor 72.

[0070] The capacitive conductor 71 is provided on the surface opposite to the surface on which the upper conductors are provided, and faces the upper conductors 21 and 22. That is, capacitance is added between the capacitive conductor 71 and the upper conductors 21 and 22.

[0071] The capacitive conductor 72 is provided on the surface opposite to the surface on which the upper conductors are provided, and faces the upper conductors 22 and 23. That is, capacitance is added between the capacitive conductor 72 and the upper conductors 22 and 23.

[0072] That is, the capacitance between the capacitive conductors 71 and 72 and the respective upper conductors can be adjusted by adjusting the sizes of the capacitive conductors 71 and 72. Therefore, the characteristics of the antenna 100B can be easily adjusted.

[0073] In the antenna 100B, as shown in FIG. 17, a capacitor 61 may be provided between the top conductor 21 and the top conductor 22, and a capacitor 62 may be provided between the top conductor 22 and the top conductor 23.

[0074] [Third Embodiment] (First Example) A method of fixing a housing and a metal member according to a first example of the third embodiment will be described using Fig. 19, Fig. 20, Fig. 21, and Fig. 22. Fig. 19 is a perspective view showing the method of fixing a housing and a metal member according to the first example of the third embodiment. Fig. 20 is a top view showing the method of fixing a housing and a metal member according to the first example of the third embodiment. Fig. 21 is a perspective view showing the method of fixing a housing and a metal member according to a first comparative example of the third embodiment. Fig. 22 is a top view showing the method of fixing a housing and a metal member according to the first comparative example of the third embodiment.

[0075] As shown in FIGS. 19 to 22 , in the antenna 100C, the metal plate 2 and the housing 3 are fixed by fixing portions 81, 82, 83, and 84. The fixing portions 81 and 82 are arranged along the short sides of the metal plate 2 and the housing 3. The fixing portions 83 and 84 are arranged along the short sides of the metal plate 2 and the housing 3. That is, in the third embodiment, two sets of fixing portions are arranged along the short sides of the metal plate 2 and the housing 3. The fixing portions 81 to 84 are, for example, screws made of a metal material. In the following description, it is assumed that the fixing portions 81 to 84 are screws made of a metal material. As shown in FIGS. 19 to 22 , the upper conductor 20 provided on the first substrate 11 includes a plurality of conductors, and slits 201 are formed between each conductor.

[0076] As shown in Figure 20, in the first example of the third embodiment, the fixing portions 81 to 84 fix the metal plate 2 and the housing 3 at a position that is off the extension line 110 of the slit 201 in the long side direction of the upper conductor 20.

[0077] As shown in Figure 22, in the first comparative example of the third embodiment, the fixing portions 81 to 84 fix the metal plate 2 and the housing 3 at a position on the extension line 110 of the slit 201 in the long side direction of the upper conductor 20.

[0078] When the metal plate 2 and the housing 3 are fixed to each other without using the fixing portions 81 to 84, the gain of the antenna 100C when radiating radio waves along the +Z-axis direction is, for example, +2.1 [dBi]. In this case, the gain of the antenna 100C when radiating radio waves in a direction at 30 degrees from the +Z-axis direction is, for example, +1.0 [dBi]. In this case, the gain of the antenna 100C when radiating radio waves in a direction at 60 degrees from the +Z-axis direction is, for example, -1.5 [dBi].

[0079] 19 and 20 , in the first example of the third embodiment, the gain of the antenna 100C when radiating radio waves along the +Z-axis direction is, for example, +1.9 [dBi]. In this case, the gain of the antenna 100C when radiating radio waves in a direction at an angle of 30 degrees from the +Z-axis direction is, for example, +0.9 [dBi]. In this case, the gain of the antenna 100C when radiating radio waves in a direction at an angle of 60 degrees from the +Z-axis direction is, for example, −1.7 [dBi].

[0080] 21 and 22 , in the first comparative example of the third embodiment, the gain when the antenna 100C radiates radio waves along the +Z-axis direction is, for example, +1.9 [dBi]. In this case, the gain when the antenna 100C radiates radio waves in a direction at an angle of 30 degrees from the +Z-axis direction is, for example, +0.8 [dBi]. In this case, the gain when the antenna 100C radiates radio waves in a direction at an angle of 60 degrees from the +Z-axis direction is, for example, −1.7 [dBi].

[0081] That is, when two of the fixed portions 81 to 84 are arranged along the short sides of the metal plate 2 and the housing 3, respectively, and the metal plate 2 and the housing 3 are fixed together, the characteristics hardly change depending on the positions at which the fixed portions 81 to 84 are arranged. This is because the two short sides of the antenna portion accommodated in the housing 3 function as a pair of electric walls, and even if a metal member is arranged outside the electric walls, the effect of the metal member on the antenna characteristics is small. Therefore, when two of the fixed portions 81 to 84 are arranged along the short sides of the metal plate 2 and the housing 3, respectively, the fixed portions 81 to 84 can be arranged in any positions.

[0082] (Second Example) A method of fixing a housing and a metal member according to a second example of the third embodiment will be described using Fig. 23, Fig. 24, Fig. 25, and Fig. 26. Fig. 23 is a perspective view showing a method of fixing a housing and a metal member according to the second example of the third embodiment. Fig. 24 is a top view showing a method of fixing a housing and a metal member according to the second example of the third embodiment. Fig. 25 is a perspective view showing a method of fixing a housing and a metal member according to a second comparative example of the third embodiment. Fig. 26 is a top view showing a method of fixing a housing and a metal member according to the second comparative example of the third embodiment.

[0083] 23 to 26 , in the second example of the third embodiment and the second comparative example, the fixing portion 81 and the fixing portion 83 are arranged along the longitudinal direction of the metal plate 2 and the housing 3. The fixing portion 82 and the fixing portion 84 are arranged along the longitudinal direction of the metal plate 2 and the housing 3. That is, in the third embodiment, two sets of fixing portions are arranged along the longitudinal direction of the metal plate 2 and the housing 3. The fixing portions 81 to 84 are, for example, screws made of a metal material.

[0084] As shown in Figure 24, in the second example of the third embodiment, the fixing portions 81 to 84 fix the metal plate 2 and the housing 3 at a position that is off the extension line 120 of the slit 201 in the long side direction of the upper conductor 20.

[0085] As shown in Figure 26, in the second comparative example of the third embodiment, the fixing portions 81 to 84 fix the metal plate 2 and the housing 3 at a position on the extension line 120 of the slit 201 in the long side direction of the upper conductor 20.

[0086] 23 and 24 , in the second example of the third embodiment, the gain of the antenna 100C when radiating radio waves along the +Z-axis direction is, for example, +1.9 [dBi]. In this case, the gain of the antenna 100C when radiating radio waves in a direction at 30 degrees from the +Z-axis direction is, for example, +0.7 [dBi]. In this case, the gain of the antenna 100C when radiating radio waves in a direction at 60 degrees from the +Z-axis direction is, for example, −2.9 [dBi].

[0087] 25 and 26 , in the second comparative example of the third embodiment, the gain when the antenna 100C radiates radio waves along the +Z-axis direction is, for example, +2.0 [dBi]. In this case, the gain when the antenna 100C radiates radio waves in a direction at an angle of 30 degrees from the +Z-axis direction is, for example, +0.8 [dBi]. In this case, the gain when the antenna 100C radiates radio waves in a direction at an angle of 60 degrees from the +Z-axis direction is, for example, −3.5 [dBi].

[0088] That is, when two of the fixed portions 81 to 84 are arranged along the longitudinal direction of the metal plate 2 and the housing 3 to fix the metal plate 2 and the housing 3, if the fixed portions 81 to 84 are arranged on the extension line 120, the antenna characteristics will be worse than when the fixed portions 81 to 84 are not arranged on the extension line 120. This is because the upper conductor 20 is designed to spread the electric field in the longitudinal direction, and the electric field spreads greatly from the slit 201, but the spread of the electric field is hindered by the fixed portions 81 to 84. Therefore, when two of the fixed portions 81 to 84 are arranged along the longitudinal direction of the metal plate 2 and the housing 3, it is desirable to arrange the fixed portions 81 to 84 in positions other than on the extension line 120 of the slit 201 of the upper conductor 20.

[0089] [Modification of Third Embodiment] A modification of the third embodiment will be described. In the third embodiment, the metal plate 2 and the housing 3 are fixed to each other with screws made of a metal material, but the present disclosure is not limited to this.

[0090] In a modification of the third embodiment, for example, the fixing portions 81 to 84 may be screws made of an insulating material. In this case, the fixing portions 81 to 84 can be arranged at any positions to fix the metal plate 2 and the housing 3 together.

[0091] In a modified example of the third embodiment, for example, the metal plate 2 and the housing 3 may have a structure that allows them to be fitted together, and the metal plate 2 and the housing 3 may be fixed together by fitting them together.

[0092] [Fourth embodiment] (Wireless communication device) A wireless communication device according to a fourth embodiment will be described with reference to Fig. 27. Fig. 27 is a block diagram showing an example of the configuration of a wireless communication device according to the fourth embodiment.

[0093] 27, the wireless communication device 200 includes an antenna 100, a memory 210, a controller 220, a sensor 230, and a battery 240. The memory 210, the controller 220, the sensor 230, and the battery 240 are also called a communication unit.

[0094] Memory 210 includes, for example, a semiconductor memory. Memory 210 may be configured to function as a work memory for controller 220. Memory 210 may be included in controller 220. Memory 210 may store a program describing the processing content that realizes each function of wireless communication device 200, information used by wireless communication device 200, and the like.

[0095] The controller 220 includes, for example, a processor. The controller 220 may include one or more processors. The processor may include a general-purpose processor that loads a specific program to execute a specific function, and a dedicated processor specialized for a specific process. The dedicated processor may include an application-specific IC. An application-specific IC is also called an ASIC (Application Specific Integrated Circuit). The processor may include a programmable logic device. A programmable logic device is also called a PLD (Programmable Logic Device). A PLD may include an FPGA (Field-Programmable Gate Array). The controller 220 may be either a SoC (System-on-a-Chip) or a SiP (System in a Package) in which one or more processors work together. The controller 220 may store various information or programs for operating each component of the wireless communication device 200 in the memory 210.

[0096] The controller 220 may be configured to generate a transmission signal to be transmitted from the wireless communication device 200. The controller 220 may be configured, for example, to acquire measurement data from a sensor. The controller 220 may be configured to generate a transmission signal in response to the measurement data. The controller 220 may be configured to transmit a baseband signal to the antenna 100.

[0097] The sensor 230 includes various sensors. The sensor 230 may include, for example, a speed sensor, a vibration sensor, an acceleration sensor, a gyro sensor, a rotation angle sensor, an angular velocity sensor, a geomagnetic sensor, a magnet sensor, a temperature sensor, a humidity sensor, an air pressure sensor, a light sensor, an illuminance sensor, a UV sensor, a gas sensor, a gas concentration sensor, an atmosphere sensor, a level sensor, an odor sensor, a pressure sensor, an air pressure sensor, a contact sensor, a wind sensor, an infrared sensor, a human presence sensor, a displacement sensor, an image sensor, a weight sensor, a smoke sensor, a liquid leakage sensor, a vital sign sensor, a battery remaining amount sensor, and an ultrasonic sensor. The sensor 230 may also include a GNSS (Global Navigation Satellite System) sensor that acquires current location information of the wireless communication device 200.

[0098] Battery 240 may be configured to provide power to wireless communication device 200. Battery 240 may be configured to provide power to at least one of memory 210, controller 220, and sensor 230. Battery 240 includes at least one of a primary battery and a secondary battery.

[0099] Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the contents of these embodiments. Furthermore, the above-described components include those that can be easily imagined by a person skilled in the art, those that are substantially the same, and those that are within the so-called equivalent range. Furthermore, the above-described components can be combined as appropriate. Furthermore, various omissions, substitutions, or modifications of the components can be made without departing from the spirit of the above-described embodiments.

[0100] The present disclosure may also have the following configurations. (1) An antenna comprising: a first substrate on which a first conductor extending over a first surface is formed; a second substrate on which a second conductor extending over the first surface is formed, the second conductor being electrically connected to the first conductor and serving as a potential reference for the first conductor; and a housing accommodating the first substrate and the second substrate, the housing having a dielectric material on a surface of the first conductor opposite to a surface facing the second conductor. (2) The antenna described in (1), in which the first conductor is formed on a surface of the first substrate facing the second substrate. (3) The antenna described in (1), in which the first conductor is formed on a surface of the first conductor opposite to a surface facing the second substrate. (4) The antenna described in any one of (1) to (3), in which the first conductor is formed by a plurality of conductors arranged at intervals from each other. (5) The antenna according to (4), wherein the plurality of conductors include at least three conductors, a third conductor, a fourth conductor, and a fifth conductor, which are arranged at intervals from each other along the longitudinal direction of the first substrate. (6) The antenna according to (5), wherein at least one of the third conductor, the fourth conductor, and the fifth conductor is formed by a plurality of conductors which are arranged at intervals from each other along the short direction of the first substrate. (7) The antenna according to any one of (4) to (6), wherein capacitors are connected between the plurality of conductors. (8) The antenna according to any one of (4) to (7), wherein a sixth conductor is formed on a surface opposite to the surface on which the first conductor is formed so as to face at least a portion of the first conductor. (9) The antenna described in any one of (1) to (8), wherein the housing includes: a first housing portion formed using a metal material and in which the second substrate is installed; and a second housing portion formed using a dielectric material and formed so as to cover the side and top surfaces of the first substrate and the second substrate.(10) The antenna according to (9), wherein the first housing part and the second housing part are fixed with a plurality of screws made of a metal material, and the plurality of screws fix the first housing part and the second housing part along the longitudinal direction of the housing and at positions that do not overlap on extensions of gaps between the plurality of conductors formed on the first substrate. (11) The antenna according to (9), wherein the first housing part and the second housing part are fixed with a plurality of screws made of a metal material, and the plurality of screws fix the first housing part and the second housing part along the lateral direction of the housing. (12) The antenna according to (9), wherein the first housing part and the second housing part are fixed with a plurality of screws made of an insulating material. (13) The antenna according to any one of (1) to (12), wherein the second substrate and the second conductor are formed of metal plates. (14) A wireless communication device including the antenna according to any one of (1) to (13).

[0101] DESCRIPTION OF SYMBOLS 1, 1a, 1b, 1A Antenna section 2 Metal plate 3 Housing 11 First board 12 Second board 20, 21, 22, 23, 21A, 22A, 23A, 24A, 25A, 26A Upper conductor 31 Lower conductor 41-1, 41-2, 42-1, 42-2, 44-1, 44-2 Connection conductor 43 Power supply conductor 61, 62 Capacitor 71, 72 Capacitance conductor 81, 82, 83, 84 Fixed section 100, 100A, 100B, 100C Antenna 200 Wireless communication device 210 Memory 220 Controller 230 Sensor 240 Battery

Claims

1. An antenna comprising: a first substrate having a first conductor extending over a first surface; a second substrate having a second conductor extending over the first surface and electrically connected to the first conductor, the second conductor serving as a potential reference for the first conductor; and a housing that houses the first substrate and the second substrate, the antenna comprising: a dielectric material on the side of the first conductor opposite to the side facing the second conductor.

2. The antenna according to claim 1, wherein the first conductor is formed on a surface of the first substrate facing the second substrate.

3. The antenna according to claim 1, wherein the first conductor is formed on a surface of the first conductor opposite to a surface facing the second substrate.

4. The antenna according to claim 1 or 2, wherein the first conductor is formed of a plurality of conductors arranged at intervals from each other.

5. The antenna as described in claim 4, wherein the plurality of conductors include at least three conductors, a third conductor, a fourth conductor and a fifth conductor, arranged at intervals from each other along the longitudinal direction of the first substrate.

6. The antenna as described in claim 5, wherein at least one of the third conductor, the fourth conductor and the fifth conductor is formed of a plurality of the conductors arranged at intervals from each other along the short side direction of the first substrate.

7. The antenna according to claim 4, wherein a capacitor is connected between the plurality of conductors.

8. The antenna according to claim 4, wherein a sixth conductor is formed on the surface opposite to the surface on which the first conductor is formed so as to face at least a portion of the first conductor.

9. The antenna described in claim 4, wherein the housing comprises: a first housing portion formed using a metal material and in which the second substrate is mounted; and a second housing portion formed using a dielectric material and configured to cover the sides and top of the first substrate and the second substrate.

10. The antenna described in claim 9, wherein the first housing part and the second housing part are fixed together by a plurality of screws formed of a metal material, and the plurality of screws fix the first housing part and the second housing part together along the longitudinal direction of the housing and at positions that do not overlap with extensions of gaps between the plurality of conductors formed on the first board.

11. The antenna described in claim 9, wherein the first housing part and the second housing part are fixed together by a plurality of screws formed of a metal material, and the plurality of screws fix the first housing part and the second housing part together at positions along the short side direction of the housing.

12. The antenna according to claim 9, wherein the first housing portion and the second housing portion are fixed together by a plurality of screws made of an insulating material.

13. The antenna according to claim 1 or 2, wherein the second substrate and the second conductor are formed of metal plates.

14. A wireless communication device comprising the antenna of claim 1.

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