Antenna device and wireless communication device

Abstract

Provided are an antenna device and a wireless communication device with which it is possible to suppress the degradation of antenna properties in beam forming. This antenna device comprises: an antenna module in which a plurality of patch antennas for emitting millimeter waves are arranged on an identical surface of a substrate; a pair of metal side walls that are disposed at both ends in the direction in which the plurality of patch antennas are arranged; and a metal front wall that is provided in the emission direction of the millimeter waves and that has formed therein a plurality of through-holes corresponding to the plurality of patch antennas. The plurality of through-holes are disposed at a wider interval as compared with the plurality of patch antennas.

Description

[Technical field]

[0001] The present invention relates to an antenna device and a wireless communication device. [Background technology]

[0002] In an antenna device that has multiple antennas that emit millimeter waves arranged in an array, a technique called "beamforming" is used in which the directivity of the emitted millimeter waves is changed by imparting a phase difference to the signals fed to each antenna.

[0003] When metal is placed in the direction of emission of the millimeter wave, the performance of the antenna is degraded. Therefore, when the above antenna device is applied to a communication device having a metal housing, a through hole is formed in the metal housing in a portion located in the direction of emission of the millimeter wave. Here, in order to compensate for the decrease in rigidity of the housing due to the formation of the through hole, multiple pillars are formed in the through hole (see Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] US Patent Application Publication No. 2017 / 0201011 [Patent Document 2] US Patent Application Publication No. 2020 / 0052376 Summary of the Invention [Problem to be solved by the invention]

[0005] By making the pillars in the through-hole thicker, the deterioration of the rigidity of the housing is suppressed, but the performance of the antenna is reduced. Also, by making the pillars in the through-hole thinner, the deterioration of the performance of the antenna is suppressed, but the rigidity of the housing is reduced. Also, when pillars are provided in the through-hole, the deterioration of the antenna performance during beamforming is significant.

[0006] An object of one aspect of the disclosed technology is to provide an antenna device and a wireless communication device that can suppress degradation of antenna performance in beamforming. [Means for solving the problem]

[0007] One aspect of the disclosed technology is exemplified by the following antenna device: This antenna device includes an antenna module in which a plurality of patch antennas that emit millimeter waves are arranged side by side on the same surface of a substrate, a pair of metallic side walls arranged at both ends in the direction in which the plurality of patch antennas are arranged, and a metallic front wall provided in the emission direction of the millimeter waves and in which a plurality of through holes corresponding to each of the plurality of patch antennas are formed, the plurality of through holes being arranged at intervals wider than the intervals between the plurality of patch antennas. Effect of the Invention

[0008] The disclosed technology can suppress degradation of antenna performance in beamforming. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram illustrating an example of an antenna device according to an embodiment. [Diagram 2] FIG. 2 is a diagram showing the configuration of the millimeter wave antenna module. [Diagram 3] FIG. 3 is a front view of the antenna device according to the embodiment. [Figure 4] FIG. 4 is an end view showing an end face taken along line AA in FIG. [Diagram 5] FIG. 5 is a diagram illustrating an example of an antenna device according to a first comparative example. [Figure 6] FIG. 6 is a first diagram comparing gains during beamforming between the antenna device according to the embodiment and the antenna device according to the first comparative example. [Figure 7] FIG. 7 is a second diagram comparing the gain during beamforming between the antenna device according to the embodiment and the antenna device according to the first comparative example. [Figure 8] FIG. 8 is a third diagram comparing the gain during beamforming between the antenna device according to the embodiment and the antenna device according to the first comparative example. [Figure 9] FIG. 9 is a fourth diagram comparing the gain during beamforming between the antenna device according to the embodiment and the antenna device according to the first comparative example. [Figure 10] FIG. 10 is a diagram illustrating an example of an antenna device according to a second comparative example. [Figure 11] FIG. 11 is a diagram comparing the gain in the front direction between the antenna device according to the embodiment and the antenna device according to the second comparative example. [Figure 12] FIG. 12 is a diagram illustrating an antenna device in which the thickness of the pillar is changed. [Figure 13] FIG. 13 is a diagram illustrating the gain of the antenna device in the front direction when the width of the through hole is changed. [Figure 14] FIG. 14 is a diagram illustrating a case where the interval between side walls is changed in the embodiment. [Figure 15] FIG. 15 is a first diagram comparing the gain of the antenna device according to the embodiment with the gain of the antenna device according to the first modified example. [Figure 16] FIG. 16 is a second diagram comparing the gain of the antenna device according to the embodiment with the gain of the antenna device according to the first modified example. [Figure 17] FIG. 17 plots the highest gain for each sidewall spacing. [Figure 18] FIG. 18 is a first diagram comparing the gain of the antenna device according to the embodiment with the gain of the antenna device according to the first modified example. [Figure 19] FIG. 19 is a second diagram comparing the gain of the antenna device according to the embodiment with the gain of the antenna device according to the first modified example. [Figure 20] FIG. 20 plots the highest gain for each sidewall spacing. [Figure 21] FIG. 21 is a first diagram illustrating variations in the shape of the through-hole. [Figure 22] FIG. 22 is a second diagram illustrating variations in the shape of the through-hole. [Figure 23] FIG. 23 is a third diagram illustrating variations in the shape of the through-hole. [Figure 24] FIG. 24 is a fourth diagram illustrating variations in the shape of the through-hole. [Diagram 25] FIG. 25 is a fifth diagram illustrating variations in the shape of the through-hole. [Figure 26] FIG. 26 is a diagram showing an example of an arrangement of patch antennas in the embodiment. [Figure 27] FIG. 27 is a first diagram illustrating a state in which millimeter wave antenna modules are stacked vertically in two stages. [Figure 28] FIG. 28 is a second diagram illustrating a state in which millimeter wave antenna modules are stacked vertically in two stages. [Figure 29] FIG. 29 is a diagram showing the antenna device illustrated in FIG. 27 as viewed from the front. [Diagram 30] FIG. 30 is a diagram showing the antenna device shown in FIG. 28 as viewed from the front. [Diagram 31] FIG. 31 is a diagram showing the gain of the antenna device when the number of through holes is changed. [Diagram 32] FIG. 32 is a first diagram showing an example in which the side wall or the front wall is used as part of an antenna other than the patch antenna. [Diagram 33] FIG. 33 is a second diagram showing an example in which the side wall or the front wall is used as part of an antenna other than the patch antenna. [Diagram 34] FIG. 34 is a diagram illustrating an example of a wireless communication device equipped with an antenna device. [Diagram 36] FIG. 36 is a first diagram showing an example in which the front wall of an antenna device is used as a part of the housing of a wireless communication device. [Diagram 35] FIG. 35 is a second diagram showing an example in which the front wall of the antenna device is used as a part of the housing of the wireless communication device. [Figure 37]FIG. 37 is a third diagram showing an example in which the front wall of the antenna device is used as a part of the housing of the wireless communication device. [Figure 38] FIG. 38 is a fourth diagram showing an example in which the front wall of the antenna device is used as a part of the housing of the wireless communication device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] <Embodiment> The configurations of the embodiments described below are examples, and the disclosed technology is not limited to the configurations of the embodiments. The antenna device according to the embodiment has, for example, the following configuration. The antenna device according to the embodiment has an antenna module in which a plurality of patch antennas that emit millimeter waves are arranged side by side on the same surface of a substrate, a pair of metallic side walls arranged at both ends in the direction in which the plurality of patch antennas are arranged, and a metallic front wall provided in the emission direction of the millimeter waves and in which a plurality of through holes corresponding to each of the plurality of patch antennas are formed. The plurality of through holes are arranged at intervals wider than the intervals between the plurality of patch antennas.

[0011] In this antenna device, a plurality of through holes corresponding to the plurality of patch antennas are formed in the front wall. The through holes are arranged at intervals wider than the plurality of patch antennas, and therefore the positions of the through holes and the patch antennas are offset from each other in a front view. Therefore, the millimeter waves emitted from the patch antennas are more likely to be reflected by the front wall compared to a case in which the positions of the through holes and the patch antennas overlap in a front view. The millimeter waves reflected by the front wall are reflected by the side walls and the substrate and emitted from the front wall. The millimeter waves reflected and emitted from the through holes are also emitted in a direction different from the front direction. This antenna device is configured to emit millimeter waves in this way, thereby suppressing a decrease in antenna performance in beamforming.

[0012] Furthermore, in this antenna device, pillars are formed between the multiple through holes on the front wall, so that the rigidity of this antenna device is increased compared to an antenna device that does not have such pillars.

[0013] The antenna device will be described in further detail below with reference to the drawings. Fig. 1 is a diagram showing an example of an antenna device 1 according to an embodiment. The antenna device 1 shown in Fig. 1 includes a millimeter wave antenna module 11, a ground substrate 12, side walls 13, 13, and a front wall 14.

[0014] The ground substrate 12 is a grounded substrate. The millimeter-wave antenna module 11 is provided on the ground substrate 12. FIG. 2 is a diagram showing a configuration of the millimeter-wave antenna module 11. The millimeter-wave antenna module 11 is a module in which four patch antennas 111 are arranged in a line on the same surface of a substrate 112 formed in a rectangular shape in a plan view. A power feed point 113 is connected to each of the patch antennas 111. Each of the patch antennas 111 receives power from the power feed point 113 and emits millimeter waves.

[0015] Returning to FIG. 1, the side walls 13, 13 are a pair of metal walls arranged at both ends in the direction in which the patch antennas 111 are arranged on the substrate 112. The front wall 14 is a metal wall provided in the direction in which the patch antennas 111 emit millimeter waves. Four through holes 141 corresponding to the respective patch antennas 111 are formed in the front wall 14. Furthermore, pillars 142 are formed between the four through holes 141. The front wall 14 and the side walls 13, 13 are formed of, for example, copper.

[0016] Here, an example of the size of the antenna device 1 and the millimeter wave antenna module 11 will be described. With reference to FIG. 1, the sizes of the antenna device 1 are, for example, as follows. The interval W1 between the side walls 13, 13 is, for example, 25 mm. The thickness T1 of the front wall 14 is, for example, 1 mm. The height H1 of the front wall 14 is, for example, 6.2 mm. The pitch (interval) W2 of the through holes 141 formed in the front wall 14 is, for example, 6.8 mm. The depth D of the side wall 13 is, for example, 5 mm. The width T2 of the side wall 13 is, for example, 1 mm. Also, with reference to FIG. 2, the sizes of the millimeter wave antenna module 11 are, for example, as follows. The width W3 of the substrate 112 is, for example, 23 mm. The height H2 of the substrate 112 is, for example, 4.2 mm. The pitch (interval) W4 of the patch antenna 111 is, for example, 5.7 mm.

[0017] Here, the depth D is approximately equal to the distance from the millimeter-wave antenna module 11 to the front wall 14. Since the radio waves emitted by the patch antenna 111 are millimeter waves (for example, a frequency of 27 GHz), it can be understood that the depth D is 0.5 times the wavelength of the millimeter waves emitted by the patch antenna 111 (0.5 wavelengths).

[0018] Fig. 3 is a front view of the antenna device 1 according to the embodiment. In Fig. 3, a portion of the patch antenna 111 that is located behind the pillar 142 is indicated by a dotted line. As described above, in the antenna device 1, the intervals at which the through holes 141 are arranged are set to be longer than the intervals at which the patch antennas 111 are arranged. Therefore, the positions of the patch antennas 111 and the through holes 141 are offset from each other when viewed from the front. Since the patch antennas 111 and the through holes 141 are arranged in this manner, at least a portion of the patch antenna 111 is hidden by the pillar 142 when viewed from the front of the antenna device 1.

[0019] Fig. 4 is an end view showing the end face taken along line AA in Fig. 3. In Fig. 4, the millimeter waves emitted from the patch antenna 111 are typically indicated by arrows. When the distance from the millimeter-wave antenna module 11 to the front wall 14 is 0.5 wavelengths, as exemplified by the circle R in Fig. 4, the radio waves emitted from the multiple patch antennas 111 are combined in phase at the through-hole 141. Therefore, the antenna device 1 has an improved gain compared to a case in which the front wall 14 and the through-hole 141 are not provided and millimeter waves are emitted from each of the patch antennas 111.

[0020] (First Comparative Example) Here, a first comparative example will be described. Fig. 5 is a diagram showing an example of an antenna device 500 according to the first comparative example. The antenna device 500 differs from the antenna device 1 according to the embodiment in that it includes a front wall 514 instead of the front wall 14. The front wall 514 is formed in a frame shape when viewed from the front of the antenna device 500. All the millimeter wave antenna modules 11 are arranged so as to fit within the frame of the front wall 514 when viewed from the front of the antenna device 500. That is, the front wall 514 differs from the front wall 14 of the antenna device 1 in that no pillar 142 is provided on the front wall 514.

[0021] 6 to 9 are diagrams comparing the gain during beamforming between the antenna device 1 according to the embodiment and the antenna device 500 according to the first comparative example. In FIG. 6 to FIG. 9, the gain of the antenna device 1 is indicated by a solid line, and the gain of the antenna device 500 is indicated by a dotted line. FIG. 6 illustrates the gain when beamforming is performed with a phase difference between the adjacent patch antenna set to 0 degrees. FIG. 7 illustrates the gain when beamforming is performed with a phase difference between the adjacent patch antenna set to 30 degrees. FIG. 8 illustrates the gain when beamforming is performed with a phase difference between the adjacent patch antenna set to 60 degrees. FIG. 9 illustrates the gain when beamforming is performed with a phase difference between the adjacent patch antenna set to 90 degrees.

[0022] 6 to 8, it can be seen that the gain of the antenna device 1 according to the embodiment is improved more than that of the antenna device 500 according to the first comparative example, regardless of the direction in which beamforming is performed. That is, the antenna device 1 according to the embodiment can suppress the deterioration of antenna performance in beamforming. In addition, it is considered that the antenna device 1 including the pillar 142 has higher rigidity than the antenna device 500 not including the pillar 142.

[0023] (Second Comparative Example) FIG. 10 is a diagram showing an example of an antenna device 600 according to a second comparative example. The antenna device 600 differs from the antenna device 500 according to the first comparative example in that the antenna device 600 does not include a side wall 13. FIG. 11 is a diagram comparing the gain in the front direction of the antenna device 1 according to the embodiment and the antenna device 600 according to the second comparative example. As can be understood by referring to FIG. 11, the antenna device 1 including the side wall 13 has an improved gain in the front direction compared to the antenna device 600 not including the side wall 13. In the antenna device 1, the radio wave emitted from the patch antenna 111 can be reflected by the side wall 13 and emitted from the through hole 141, so it is considered that such an improvement in gain is observed. In addition, it is considered that the antenna device 1 including the pillar 142 and the side wall 13 has a higher rigidity than the antenna device 600 not including the pillar 142 and the side wall 13.

[0024] From the above, it can be said that the antenna device 1 including the side wall 13, the multiple through holes 141, and the pillars 142 has improved communication performance and housing rigidity compared to the antenna device 500 and the antenna device 600.

[0025] (Change in width of through hole 141) In the antenna device 1 described above, for example, the thickness of the pillar 142 may be changed. Fig. 12 is a diagram illustrating an antenna device 1 in which the thickness of the pillar 142 is changed. In Fig. 12(A), the width W5 of the through hole 141 is set to 3.45 mm (the total width of the four through holes 141 is 13.8 mm). In Fig. 12(B), the width W5 of the through hole 141 is set to 2.3 mm (the total width of the four through holes 141 is 9.2 mm). In Fig. 12(C), the width W5 of the through hole 141 is set to 1.15 mm (the total width of the four through holes 141 is 4.6 mm).

[0026] The thickness of the pillar 142 of the antenna device 1 (and thus the width W5 of the through hole 141) can be changed in various ways as illustrated in FIG. 12. For example, the width of the through hole 141 and the pillar 142 can be determined as follows. The ratio of the interval W1 (see FIG. 1) between the side walls 13, 13 to be allocated to the pillar 142 is determined. For example, when 80% of the interval W1 is allocated to the pillar 142, the width of the pillar 142 can be calculated by multiplying the interval W1 by 0.8 and dividing the number by the number of the pillars 142 ("3" in the example of FIG. 12). In addition, the width of the through hole 141 can be calculated by multiplying the interval W1 by (1-0.8) and dividing the number by the number of the through holes 141 ("4" in the example of FIG. 12).

[0027] FIG. 13 is a diagram illustrating the gain of the antenna device 1 in the front direction when the width of the through hole 141 is changed. In FIG. 13, the vertical axis indicates the gain, and the horizontal axis indicates the total value of the width of the through hole 141. Also, in FIG. 13, the gain of the antenna device 600 according to the second comparative example is indicated by a dotted line B. FIG. 13 further illustrates a case where the center of the through hole 141 and the center of the patch antenna 111 are aligned in front view (indicated by "△ (circle)" in FIG. 13) and a case where the center of the through hole 141 and the center of the patch antenna 111 are not aligned in front view (indicated by "◯ (circle)" in FIG. 13). Note that the case where the center of the through hole 141 and the center of the patch antenna 111 are not aligned in front view corresponds to the antenna device 1 according to the embodiment.

[0028] 13, it can be seen that by not matching the center of patch antenna 111 with the center of through hole 141 (shifting the center of patch antenna 111 from the center of through hole 141), the gain in the front direction of antenna device 1 can be improved. It can also be seen that by making the total width of through hole 141 5 mm or more, the gain in the front direction can be improved compared to antenna device 600. In other words, it can be seen that by making the total width of through hole 141 0.5 wavelengths of millimeter-wave radio waves or more, the gain in the front direction can be improved compared to antenna device 600.

[0029] Fig. 14 is a diagram illustrating a case where the interval between the side walls 13, 13 is changed in the embodiment. Fig. 14 is a diagram of the antenna device 1 as viewed from above. The interval W1 between the side walls 13 is extended in the order of (A) → (B) → (C) in Fig. 14. In Fig. 14, the widths of the front wall 14 and the ground substrate 12 are also extended with the extension of the interval W1. On the other hand, the width of the millimeter wave antenna module 11 is constant in Fig. 14 (A) → (B) → (C). In other words, the pitch of the patch antenna 111 is not changed.

[0030] 15 and 16 are diagrams comparing the gain of the antenna device 1 according to the embodiment with the gain of the antenna device 500 according to the first modification. FIG. 15 illustrates the width of the pillar 142 that provides a higher gain than the antenna device 500 when the interval W1 between the side walls 13 of the antenna device 1 and the antenna device 500 is changed. In the example of FIG. 15, the width of the through hole 141 is constant even if the interval W1 is changed. FIG. 16 illustrates the width of the pillar 142 that provides a higher gain than the antenna device 500 with the interval W1 fixed at 23 mm when the interval W1 between the side walls 13 of the antenna device 1 is changed. The vertical axis of FIG. 15 and FIG. 16 indicates the width (mm) of each pillar 142, and the horizontal axis indicates the interval W1 (mm) of the side walls 13. In FIG. 15 and FIG. 16, the "x" marks indicate the width of the pillar 142 with the maximum gain at each interval W1. Moreover, Fig. 17 is a diagram in which the highest gain is plotted for each interval W1 of the side walls 13. The vertical axis of Fig. 17 represents the gain (dBi) in the front direction, and the horizontal axis represents the interval W1 (mm).

[0031] 15 and 16, when the width of the pillar 142 is in the range of 1 mm to 8 mm, the gain of the antenna device 1 often exceeds the gain of the antenna device 500. The width of the pillar 142 of 1 mm to 8 mm corresponds to 0.1 to 0.7 wavelengths in the case of a millimeter wave with a frequency of 27 GHz. Therefore, when the patch antenna 111 emits a millimeter wave with a frequency of 27 GHz, the width of each of the three pillars 142 formed between the four through holes 141 is preferably set to 0.1 to 0.7 wavelengths. That is, the interval between the through holes 141 is preferably 0.1 to 0.7 wavelengths. Also, referring to FIG. 17, the interval W1 of the side walls 13 is preferably about 23 mm to 33 mm, or about 40 mm to 44 mm. The interval W1 of the side walls 13 of 1 mm to 8 mm is preferably set to 2 to 2.9 wavelengths, or 3.6 to 3.9 wavelengths in the case of a millimeter wave with a frequency of 27 GHz.

[0032] 18 and 19 are diagrams comparing the gain of the antenna device 1 according to the embodiment and the gain of the antenna device 500 according to the first modification. FIG. 18 illustrates the width of the pillar 142 that provides a higher gain than the antenna device 500 when the interval W1 between the side walls 13 of the antenna device 1 and the antenna device 500 is changed. Here, unlike FIG. 15, FIG. 18 illustrates the width of the through hole 141 that is changed according to the change in the interval W1. That is, in the example of FIG. 18, the width of the through hole 141 is increased as the interval W1 becomes longer. FIG. 19 illustrates the width of the pillar 142 that provides a higher gain than the antenna device 500 with the interval W1 fixed at 23 mm when the interval W1 between the side walls 13 of the antenna device 1 is changed. The vertical axis of FIG. 18 and FIG. 19 indicates the width (mm) of each pillar 142, and the horizontal axis indicates the interval W1 (mm) between the side walls 13. 18 and 19, the "x" marks indicate the width of the pillar 142 at which the gain was maximized for each spacing W1. Also, Fig. 20 is a plot of the highest gain for each spacing W1 of the side walls 13. The vertical axis of Fig. 20 indicates the gain (dBi) in the front direction, and the horizontal axis indicates the spacing W1 (mm).

[0033] 18 and 19, when the width of the pillar 142 is in the range of 1 mm to 13 mm, the gain of the antenna device 1 often exceeds the gain of the antenna device 500. The width of the pillar 142 of 1 mm to 13 mm corresponds to 0.1 to 1.2 wavelengths in the case of a millimeter wave having a frequency of 27 GHz. Therefore, when the patch antenna 111 emits a millimeter wave having a frequency of 27 GHz, the width of each of the three pillars 142 formed between the four through holes 141 is preferably set to 0.1 to 1.2 wavelengths. That is, the interval between the through holes 141 is preferably 0.1 to 1.2 wavelengths. Also, referring to FIG. 20, the interval W1 of the side walls 13 is preferably about 23 mm to 45 mm. The interval W1 of the side walls 13 of 23 mm to 45 mm is preferably set to 2 to 4 wavelengths in the case of a millimeter wave having a frequency of 27 GHz.

[0034] In the embodiment described above, the patch antenna 111 and the through hole 141 are provided so as to be misaligned in a front view of the antenna device 1. That is, in a front view of the antenna device 1, at least a part of the patch antenna 111 is hidden by the pillar 142. Therefore, the millimeter wave emitted from the patch antenna 111 is more likely to be reflected by the front wall 14 compared to a case in which the entire patch antenna 111 is visible through the through hole 141 in a front view. The millimeter wave reflected by the front wall 14 is reflected by the side walls 13, 13 and the ground substrate 12 and is emitted from the patch antenna 111. The millimeter wave reflected and emitted from the through hole 141 is also emitted in a direction different from the front direction. By configuring the antenna device 1 to emit millimeter waves in this way, it is possible to suppress a decrease in antenna performance in beamforming.

[0035] Here, in the antenna device 1, the distance from the millimeter-wave antenna module 11 to the front wall 14 is set to 0.5 times the wavelength of the millimeter wave emitted by the patch antenna 111. This setting makes it possible to combine, in phase, the millimeter wave passing directly from the patch antenna 111 through the through-hole 141 and the millimeter wave emitted from the patch antenna 111, reflected by the front wall 14, the side wall 13, and the ground substrate 12, and then emitted from the patch antenna 111. Therefore, the antenna device 1 can further suppress the deterioration of antenna performance in beamforming.

[0036] Moreover, in the antenna device 1, the pillars 142 are formed between the through holes 141, so that the rigidity of the antenna device 1 can be increased compared to the antenna device 500 which is not provided with the pillars 142. Furthermore, in the antenna device 1, the side walls 13, 13 are provided, so that the rigidity of the antenna device 1 can be increased compared to the antenna device 600 which is not provided with the side walls 13, 13.

[0037] <Modification> In the antenna device 1 described above, the through hole 141 is formed in a rectangular shape in a front view. However, the shape of the through hole 141 is not limited to a rectangular shape, and may be formed in various shapes. FIGS. 21 to 25 are diagrams illustrating variations in the shape of the through hole 141. FIG. 21 illustrates a through hole 141 that is cross-shaped in a front view. FIG. 22 illustrates a through hole 141 that is square-shaped in a front view. FIG. 23 illustrates a through hole 141 that is a cross mark (tilted cross shape) in a front view. FIG. 24 illustrates a through hole 141 that is diamond-shaped in a front view. FIG. 25 illustrates a through hole 141 that is circular in a front view. By adopting the shapes illustrated in FIGS. 21 to 25 for the through hole 141, the antenna device 1 can be made compatible with orthogonal polarization. In this way, various shapes can be adopted for the through hole 141. Furthermore, in the antenna device 1, through holes 141 of different shapes may be mixed. For example, the antenna device 1 may include a cross-shaped through-hole 141 as illustrated in FIG. 21 and a diamond-shaped through-hole 141 as illustrated in FIG.

[0038] Furthermore, the patch antennas 111 are not limited to being arranged in a square shape when viewed from the front (with the top and bottom sides parallel to the top and bottom sides of the millimeter-wave antenna module 11 and the left and right sides parallel to the left and right sides of the millimeter-wave antenna module 11) as illustrated in FIG. 2, but may be arranged at an angle. FIG. 26 is a diagram showing an example of the arrangement of the patch antennas 111 in the embodiment. FIG. 26 illustrates a state in which the front wall 14 is removed in order to show the arrangement of the patch antennas 111. As illustrated in FIG. 26, each of the patch antennas 111 may be arranged in a diamond shape when viewed from the front (tilted 45 degrees from the state of FIG. 2).

[0039] Furthermore, in the antenna device 1, the millimeter-wave antenna modules 11 may be arranged in two layers, one above the other. In this case, a through hole 141 may be provided for each patch antenna 111 of the millimeter-wave antenna modules 11 arranged in two layers. Figures 27 and 28 are diagrams illustrating a state in which the millimeter-wave antenna modules 11 are arranged in two layers, one above the other. In Figures 27 and 28, upper and lower walls 15 are provided on the top and bottom of the antenna device 1 as well.

[0040] Fig. 29 is a diagram showing the antenna device 1 shown in Fig. 27 as viewed from the front. Fig. 30 is a diagram showing the antenna device 1 shown in Fig. 28 as viewed from the front. In Figs. 29 and 30, a portion hidden behind the front wall 14 in a front view is indicated by a dotted line. As shown in Fig. 29, the positional relationship between the patch antenna 111 and the through hole 141 may be set so that the vertical center of the patch antenna 111 and the vertical center of the through hole 141 substantially coincide in a front view of the antenna device 1. Also, as shown in Fig. 30, the positional relationship may be set such that the interval between the through holes 141 in the short side direction is enlarged in a front view of the antenna device 1.

[0041] In the above-described embodiment and modified example, the number of the patch antennas 111 and the number of the through holes 141 are the same, but the number of the through holes 141 may be greater than the number of the patch antennas 111. FIG. 31 is a diagram showing the gain of the antenna device 1 when the number of the through holes 141 is changed. The vertical axis of FIG. 31 indicates the gain (dBi) of the antenna device 1, and the horizontal axis indicates the total width (mm) of the through holes 141 provided in the front wall 14. In FIG. 31, graph A indicates a case where the number of the through holes 141 is two, graph B indicates a case where the number of the through holes 141 is three, graph C indicates a case where the number of the through holes 141 is four, graph D indicates a case where the number of the through holes 141 is eight, and graph E indicates a case where the number of the through holes 141 is sixteen. The horizontal dotted line F illustrates the gain of the antenna device 500.

[0042] 31, it can be seen that even if the number of through holes 141 is increased to more than four, a higher gain than that of antenna device 500 can be achieved by appropriately adjusting the total width of through holes 141. For example, when the number of through holes 141 is four, the gain of antenna device 1 can be made higher than that of antenna device 500 by setting the total width of through holes 141 to 5 mm or more. In other words, when patch antenna 111 emits millimeter waves of 27 GHz, the gain of antenna device 1 can be made higher than that of antenna device 500 as long as the total width of through holes 141 is 0.45 wavelengths or more.

[0043] In the antenna device 1, the side wall 13 and the front wall 14 may be used as part of an antenna other than the patch antenna 111. Below, a configuration in which the side wall 13 and the front wall 14 of the antenna device 1 according to the embodiment are used as part of an antenna will be described.

[0044] 32, in the antenna device 1, one side wall 13 is replaced with a side wall 13a. The side wall 13a is in contact with the front wall 14, while a gap is formed between the side wall 13a and the ground substrate 12. A power feed point 21 is disposed in the gap formed between the side wall 13a and the ground substrate 12, and power is fed to the side wall 13a. With this configuration, a loop antenna can be formed by the side wall 13a, the front wall 14, the side wall 13, and the ground substrate 12.

[0045] 33, in the antenna device 1, both side walls 13 are replaced with side walls 13a. A power feed point 21 is disposed between one of the side walls 13a and the ground substrate 12, and power is fed to the one of the side walls 13a. With this configuration, an inverted-L antenna can be formed by the side walls 13a, the front wall 14, and the side walls 13a.

[0046] 34 is a diagram showing an example of a wireless communication device 800 equipped with an antenna device 1. The wireless communication device 800 includes a housing 801 formed in a substantially rectangular shape in a plan view. The antenna devices 1 are provided on each side of the housing 801 formed in a rectangular shape in a plan view. In the wireless communication device 800, a front wall 14 of the antenna device 1 forms part of the housing 801 (part of a side wall).

[0047] 35 to 38 will explain an example in which the front wall 14 is used as part of the housing 801 of the wireless communication device 800. In the example of Fig. 36, a feed point 21 is provided on the substrate 11 between one of the side walls 13, 13 and the substrate 11. Then, an additional conductor 22 is provided which receives power from the feed point 21 and is connected to the front wall 14. Even with this configuration, a ladder loop antenna can be formed by the side walls 13, 13, the front wall 14, and the additional conductor 22.

[0048] In the example of Fig. 35, an extension portion 14a is formed by extending the front wall 14 from one of the side walls 13, 13. No through hole 141 is provided in the extension portion 14a. An additional conductor 22 is provided, which is connected to the extension portion 14a and the power feed point 21. In Fig. 35, a dotted line is drawn on the boundary between the front wall 14 and the extension portion 14a to facilitate understanding. With this configuration, a ladder loop antenna is formed by the side walls 13, 13, the front wall 14, and the additional conductor 22. The length of the extension portion 14a may be determined appropriately depending on the frequency of the radio waves that operate the ladder loop antenna.

[0049] 37, in the configuration illustrated in FIG 35, one of the side walls 13 is replaced with a side wall 13a that forms a gap 12a between the side wall 13 and the ground substrate 12. By forming the gap 12a, an inverted-F antenna is formed by the additional conductor 22, the extension portion 14a, the front wall 14, and the side wall 13a.

[0050] In the example of FIG. 38, the front wall 14 is used as a part of the housing 801 of the wireless communication device as in FIG. 35, and the extension portion 14a is also formed. The side walls 13, 13 are replaced with side walls 13a, 13a. An additional conductor 22a is provided between the extension portion 14a and the ground substrate 12, and is connected to the extension portion 14a and the ground substrate 12. A power feed point 21 is provided between one of the side walls 13a, 13a and the ground substrate 12, and power is fed from the power feed point 21 to the one side wall 13a. With this configuration, an inverted-F antenna can be formed by the additional conductor 22a, the extension portion 14a, the side wall 13a, the front wall 14, and the side wall 13a.

[0051] As described above, in the antenna device 1, not only the patch antenna 111 but also the front wall 14 and the side walls 13, 13 can be operated as antennas.

[0052] The embodiments and modifications disclosed above can be combined with each other. [Explanation of symbols]

[0053] 1. Antenna device 11. Millimeter wave antenna module 12 Ground board 12a Gap 13. Side wall 13a Side wall 14...Front wall 14a...extension part 15...Upper and lower walls 21. Power supply point 22 Additional conductor 22a Additional conductor 141...Through hole 142 Pillar 111··Patch antenna 112··Substrate 113 Power supply point 500 Antenna device 514...Front wall 600 Antenna device 800 Wireless communication devices 801··Case

Claims

1. an antenna module in which a plurality of patch antennas that emit millimeter waves are arranged side by side on the same surface of a substrate; a pair of metallic side walls disposed on both ends in a direction in which the plurality of patch antennas are arranged; a metal front wall provided in a direction in which the millimeter wave is emitted and in which a plurality of through holes corresponding to the plurality of patch antennas are formed; The interval between the through holes is set to be wider than the interval between the patch antennas. Antenna device.

2. The distance between the front wall and the substrate is half the wavelength of the millimeter wave.

2. The antenna device according to claim 1.

3. The interval between adjacent through holes is within a range of 0.1 to 0.7 wavelengths of the millimeter wave.

3. The antenna device according to claim 1 or 2.

4. The through hole is formed in a rectangular shape having a long side in a direction perpendicular to a direction in which the plurality of patch antennas are arranged, The distance between the through hole and the substrate is half the wavelength of the millimeter wave. An antenna device according to any one of claims 1 to 3.

5. The substrate is provided on a ground substrate, one of the pair of side walls is connected to the front wall and is fed with power from a feeding point provided on the ground substrate; An antenna device according to any one of claims 1 to 4.

6. the other of the pair of side walls is connected to the front wall, and a gap is formed between the other side wall and the ground substrate; 6. The antenna device according to claim 5.

7. the front wall includes an extension portion further extending from the one side wall, Further comprising a conductor connecting the ground substrate and the extension portion.

7. The antenna device according to claim 6.

8. The substrate is provided on a ground substrate, a conductor is further provided between one of the pair of side walls and the substrate, the conductor being fed from a feeding point provided on the ground substrate and connected to the front wall, An antenna device according to any one of claims 1 to 4.

9. The substrate is provided on a ground substrate, one of the pair of side walls is connected to the front wall and the ground substrate; the front wall includes an extension portion further extending from the one side wall, a conductor that is fed from a feeding point provided on the ground substrate and is connected to the extension portion, An antenna device according to any one of claims 1 to 4.

10. the other of the pair of side walls is connected to the front wall, and a gap is formed between the other side wall and the ground substrate; 10. The antenna device according to claim 9.

11. Equipped with an antenna device according to any one of claims 1 to 10, Wireless communication device.

12. The front wall is included as a part of the side surface of the housing.

12. The wireless communication device of claim 11.

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