Antenna system, wireless relay device, and drone

Abstract

Provided is an antenna system capable of realizing omnidirectionality in a horizontal plane in which the generation of an interference pattern is suppressed without being affected by the legs of a drone. **Solution**: The antenna system is connected to a wireless device mounted on a drone body having a plurality of legs. The antenna system includes a plurality of first polarization multiplexing antennas provided outside the first leg or its mounting portion and having main directivities in different outward directions from each other, and a plurality of second polarization multiplexing antennas provided outside the second leg or its mounting portion and having main directivities in different outward directions from each other. The vertical polarization ports of the plurality of first polarization multiplexing antennas are connected to the first port of the wireless device, and the horizontal polarization ports of the plurality of first polarization multiplexing antennas are connected to the second port of the wireless device. The vertical polarization ports of the plurality of second polarization multiplexing antennas are connected to the second port of the wireless device, and the horizontal polarization ports of the plurality of second polarization multiplexing antennas are connected to the first port of the wireless device.

Description

Technical Field

[0001] The present invention relates to an antenna system having an antenna of a wireless device such as a relay station, a wireless relay device, and a drone.

Background Art

[0002] Conventionally, there is known a drone that has a wireless device and an antenna for wireless communication with the ground side and can fly and hover in the air.

[0003] For example, Patent Document 1 discloses an antenna system having a long-shaped omnidirectional antenna and a drone-type wireless relay device.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Means for Solving the Problems

[0005] An antenna system according to one aspect of the present disclosure is an antenna system connected to a wireless device mounted on a drone body having a plurality of legs. This antenna system is provided on the outer side in the horizontal direction of any one of the plurality of legs of the drone body or on the outer side in the horizontal direction of the mounting portion of the first leg, and is provided with a plurality of first polarization multiplexing antennas arranged adjacent to each other and having main directivities in different outward directions. It also includes a plurality of second polarization multiplexing antennas provided on the outer side in the horizontal direction of a second leg located on the opposite side of the first leg with the center of the drone body in between or on the outer side in the horizontal direction of the mounting portion of the second leg, and arranged adjacent to each other and having main directivities in different outward directions. The vertical polarization ports of each of the plurality of first polarization multiplexing antennas are connected to the first antenna port of the wireless device, and the horizontal polarization ports of each of the plurality of first polarization multiplexing antennas are connected to the second antenna port of the wireless device. The vertical polarization ports of each of the plurality of second polarization multiplexing antennas are connected to the second antenna port of the wireless device, and the horizontal polarization ports of each of the plurality of second polarization multiplexing antennas are connected to the first antenna port of the wireless device.

[0006] In the antenna system, the angle formed by the directions of the main directivities of each of the plurality of first polarization multiplexing antennas may be 80 degrees or more and 100 degrees or less, the angle formed by the directions of the main directivities of each of the plurality of second polarization multiplexing antennas may be 80 degrees or more and 100 degrees or less, or may be 90 degrees or about 90 degrees. The angle formed by the horizontal reference line passing through the first leg and the second leg and the directions of the main directivities of each of the plurality of first polarization multiplexing antennas and the plurality of second polarization multiplexing antennas may be 40 degrees or more and 50 degrees or less, or may be 45 degrees or about 45 degrees.

[0007] In the antenna system, the plurality of first polarization multiplexing antennas may be arranged side by side in the horizontal direction, and the plurality of second polarization multiplexing antennas may be arranged side by side in the lateral direction.

[0008] In the antenna system, the plurality of first polarization sharing antennas may be arranged side by side in the vertical direction, and the plurality of second polarization sharing antennas may be arranged side by side in the vertical and horizontal directions.

[0009] In the antenna system, a first distribution combiner having a common terminal connected to a first antenna port of the wireless device, a second distribution combiner having a common terminal connected to a second antenna port of the wireless device, a third distribution combiner having a common terminal connected to one branch terminal of the first distribution combiner, a fourth distribution combiner having a common terminal connected to the other branch terminal of the first distribution combiner, a fifth distribution combiner having a common terminal connected to one branch terminal of the second distribution combiner, and a sixth distribution combiner having a common terminal connected to the other branch terminal of the second distribution combiner may be provided. Here, two branch terminals of the third distribution combiner may be connected to the vertical polarization ports of the plurality of first polarization sharing antennas, two branch terminals of the fourth distribution combiner may be connected to the horizontal polarization ports of the plurality of second polarization sharing antennas, two branch terminals of the fifth distribution combiner may be connected to the horizontal polarization ports of the plurality of first polarization sharing antennas, and two branch terminals of the sixth distribution combiner may be connected to the vertical polarization ports of the plurality of second polarization sharing antennas.

[0010] In the antenna system, the distance between the plurality of first polarization sharing antennas and the plurality of second polarization sharing antennas may be longer than the wavelength of the target radio wave.

[0011] A drone-type wireless relay device according to another aspect of the present disclosure includes a drone body having a plurality of legs, any one of the antenna systems, and a relay station as a wireless device to which the antenna system is connected.

[0012] A drone according to still another aspect of the present disclosure includes a drone body having a plurality of legs, any one of the antenna systems, and a wireless device to which the antenna system is connected.

[0013] According to the antenna system, wireless relay device, and drone of the present disclosure, it is possible to achieve horizontal omnidirectionality in which the generation of an interference pattern is suppressed without being affected by the legs of the drone.

Brief Description of the Drawings

[0014]

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Embodiments for Carrying Out the Invention

[0015] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Note that each figure in the drawings only schematically shows the shape, size, positional relationship, correspondence relationship, configuration, processing, steps, procedures, etc. to the extent that the content of the present disclosure can be understood. Therefore, the present disclosure is not limited to only the shapes, sizes, positional relationships, correspondence relationships, configurations, processing, steps, and procedures illustrated in each figure. Also, the numerical values exemplified in the present disclosure are only preferred examples, and thus the present disclosure is not limited to the exemplified numerical values.

[0016] The antenna system according to an embodiment of the present disclosure is a horizontally omnidirectional antenna system suitable for mounting on a drone, which has a simple structure, does not require a movable part that becomes a heavy member, and the landing legs (feet) do not affect the radiation characteristics of radio waves. Further, the device according to the embodiment described in this document is, for example, a drone and a drone-type wireless relay device (hereinafter referred to as "drone wireless relay device") equipped with the above-mentioned horizontally omnidirectional antenna system.

[0017] The drone wireless relay device can be made to function as a temporary or emergency repeater (slave unit) or base station (eNodeB) that hovers (stops in flight) so as to be located above a target area such as a disaster occurrence location such as a typhoon or earthquake or a distress occurrence location such as an avalanche, and relays communication between a communication network such as a mobile communication network and a terminal device in the target area. Thereby, for example, communication of a mobile phone or a smartphone at a disaster occurrence location can be restored early, or communication of a mobile phone or a smartphone of a person in distress at a distress occurrence location can be relayed to support the search and rescue of the person in distress.

[0018] The radio waves targeted for transmission or reception by the antenna system of the present disclosure are, for example, microwaves, millimeter waves, or sub-millimeter waves of 300 MHz or higher.

[0019] FIG. 1 is a perspective view showing an example of a drone 10 to which the horizontally omnidirectional antenna system according to the embodiment can be applied. In FIG. 1, the drone body 100 of the drone 10 includes a central housing portion 101, a plurality (four in the example of FIG. 1) of arm portions 102 extending laterally from the central housing portion 101, a plurality of landing legs (feet) 103 extending downward from the tip portions of the plurality of arm portions 102, and a plurality of propellers (including driving motors) 104 provided above the tip portions of the plurality of arm portions 102. The central housing portion 101 has a wireless device connected to the antenna system of the embodiment, a battery for supplying power to each part, and the like. Note that the overall configuration of the drone body 100 is not limited to the configuration of FIG. 1.

[0020] The wireless device (also referred to as the "drone wireless radio") provided in the central accommodation part 101 of the drone main body 100 of the drone 10 is a device that performs wireless communication via an omnidirectional antenna system in the horizontal plane. When the drone 10 functions as a drone wireless relay device, the wireless device is, for example, a relay communication station such as a base station device or a repeater slave unit that wirelessly communicates with a gateway station on the ground or at sea via a feeder link and wirelessly communicates with a terminal, which is a user device on the ground, at sea, or in the air, via a service link (hereinafter also referred to as a "relay station"). The antenna system of the present embodiment may be used as an omnidirectional antenna in the horizontal plane of the service link or may be used as an omnidirectional antenna in the horizontal plane of the feeder link. Further, the wireless device provided in the drone 10 may be a wireless device that does not perform relaying.

[0021] As for the antenna connected to the wireless device mounted on the drone 10, it is conceivable to mount an omnidirectional antenna or a directional antenna. However, when it is desired to secure a wide wireless coverage area within a 360-degree range in the horizontal plane with a single drone, it is desirable to use a lightweight omnidirectional antenna in the horizontal plane that can be mounted on the drone 10. Although a directional antenna can radiate radio waves far away, the range of the wireless coverage area becomes narrow due to the narrowed directivity. Also, when using a plurality of directional antennas like a ground base station to radiate radio waves within a 360-degree range in the horizontal plane, the weight of the wireless device and the antenna increases due to an increase in the number of sectors (also referred to as "sector cells").

[0022] On the other hand, the drone 10 has landing legs (feet) 103, and when using an omnidirectional antenna, the legs 103 may affect the radiation characteristics of radio waves. For example, as shown in FIG. 2, when a long omnidirectional antenna 105 is arranged so as to extend downward from the central accommodation part 101 located at the center of the drone 10, the four legs 103 located around the omnidirectional antenna 105 may affect the radiation characteristics of the radio wave W of the omnidirectional antenna 105. Therefore, when using the omnidirectional antenna 105, a measure (for example, an antenna movable configuration) is required so that the legs 103 do not affect the radiation characteristics of the radio wave W.

[0023] For example, when the drone 10 is positioned in the air and providing a wireless relay service as shown in FIG. 3(a), the omnidirectional antenna 105 is located below the lower end of the leg portion 103 of the drone 10. When the drone 10 lands, the omnidirectional antenna 105 is swung laterally (see FIG. 3(b)) or moved upward (see FIG. 3(c)) by a movable mechanism so that it does not contact the ground G.

[0024] In this embodiment, there is no need for a movable mechanism that has a complex structure and is a weight member, and an antenna system that is omnidirectional in the horizontal plane is configured so that the landing legs (feet) do not affect the radiation characteristics of radio waves. As a configuration example of such an antenna system that is omnidirectional in the horizontal plane, for example, as shown in FIGS. 4(a) and 4(b), a plurality of omnidirectional antennas 105 can be dispersedly arranged on the outer sides of each of the plurality of leg portions 103 of the drone 10. According to this configuration, as shown in FIG. 4(a), the leg portion 103 does not affect the radiation characteristics of the radio wave W of the omnidirectional antenna 105 during the in-air service, and as shown in FIG. 4(b), the omnidirectional antenna 105 does not contact the ground G when the drone 10 lands. However, when a plurality of antennas are dispersedly arranged on the outer sides of each of the plurality of leg portions 103, it has been found that there is a problem that an interference pattern occurs in the antenna directivity characteristics of the entire drone, as shown below.

[0025] Here, for example, in the case of a single antenna (hereinafter also referred to as "1-antenna") 111 having a directive beam 111B in one direction in the horizontal plane as shown in Fig. 5(a), as shown in the horizontal plane directivity characteristic of Fig. 5(b), the antenna gain is maximized in the main direction (θ = 0 degrees) of the directive beam 111B perpendicular to the antenna surface of the antenna 111, and the antenna gain decreases as the angle from the main direction increases. The antenna 111 is, for example, a patch antenna. Note that in Fig. 5(b), the angle θ is the angle (also referred to as "azimuth angle") from the reference direction passing through the center of the antenna or the antenna system in the horizontal plane (the same applies to the following figures showing directivity characteristics). The reference direction in the examples of Figs. 5(a) and 5(b) is the outward direction perpendicular to the antenna surface passing through the center of the antenna surface of the antenna 111.

[0026] By combining a plurality of the antennas 111 in Figs. 5(a) and 5(b), an antenna system having omnidirectionality in the horizontal plane can be configured as a whole. For example, as shown in Fig. 6(a), four antennas (hereinafter also referred to as "4-antenna") 111 to 114 are arranged close to each other so that the directive beams 111B to 114B of the respective antennas are in different outward directions (the vertical and horizontal directions in the figure), whereby a 4-antenna antenna system in which the 4 antennas are arranged at equal angular intervals (90 degrees) in the circumferential direction in the horizontal plane can be configured. The circumferential interval (pitch) of the 4 antennas 111 to 114 is, for example, smaller than one wavelength (λ) of the target radio wave (typically, 0.5λ to 0.7λ). This 4-antenna antenna system has omnidirectionality in the horizontal plane as a whole as shown in Fig. 6(b).

[0027] However, when the four antennas 111 to 114 are dispersedly arranged such that the circumferential interval (pitch) between the four antennas 111 to 114 is equal to or greater than one wavelength (λ) of the target radio wave, it has been found that an interference pattern occurs in the overall horizontal plane omnidirectionality. For example, as shown in FIG. 7(a), when the four antennas 111 to 114 having the directional beams 111B to 114B with an outward main directivity are dispersedly arranged on the outer sides in the horizontal direction of the attachment portions (the tip portions of the arm portions 102) 102N, 102S, 102E, and 102W of the plurality of leg portions 103, an interference pattern occurs in the overall horizontal plane omnidirectionality of the antenna system composed of the four antennas as shown in FIG. 7(b). In particular, around the diagonal directions (θ = 45 degrees, 135 degrees, 225 degrees, and 315 degrees in the figure) between the antennas, the antenna gain drops by about -15 dB at most.

[0028] In the present embodiment, two polarization - sharing antennas (hereinafter also referred to as "two antennas") arranged adjacent to each other and having main directivities in different outward directions are dispersedly arranged at both ends with the center of the drone body 100 in between, so that an interference pattern does not occur in the overall horizontal plane omnidirectionality of the antenna system. Further, between the two antennas arranged at one end of the drone body 100 and the two antennas arranged at the other end, the vertical - polarization port and the horizontal - polarization port connected to the antenna port of the wireless device are interchanged.

[0029] FIG. 8 is a plan view showing an example of the dispersed arrangement of two sets of two antennas 111, 112 and two antennas 113, 114 in the antenna system according to an embodiment of the present disclosure. Note that the components common to FIG. 1 described above in FIG. 8 are denoted by the same reference numerals, and the description thereof is omitted. In FIG. 8, the antenna system of the present embodiment includes a first two - antenna composed of a plurality of first polarization - sharing antennas 111, 112 arranged adjacent to each other, and a second two - antenna composed of a plurality of second polarization - sharing antennas 113, 114 arranged adjacent to each other. The distance between the first two - antenna composed of the plurality of first polarization - sharing antennas 111, 112 and the second two - antenna composed of the plurality of second polarization - sharing antennas 113, 114 is longer than the wavelength (λ) of the target radio wave.

[0030] The first polarization multiplexing antennas 111 and 112 that constitute the first two antennas are respectively provided on the horizontal outer side (the left outer side in the figure) (for example, the outer surface) of the mounting portion 102W of one of the plurality of leg portions 103 of the drone body 100, i.e., the first leg portion 103W, and have main directivities (beams) 111B and 112B in different outward directions. The plurality of second polarization multiplexing antennas 113 and 114 that constitute the second two antennas are respectively provided on the horizontal outer side (the right outer side in the figure) (for example, the outer surface) of the mounting portion 102E of the second leg portion 103E that is located on the side opposite to the first leg portion 103W with the center of the drone body 100 in between, and have main directivities (beams) 113B and 114B in different outward directions.

[0031] Note that the first polarization multiplexing antennas 111 and 112 may be provided on the horizontal outer side (for example, the outer surface) of the first leg portion 103W, and the second polarization multiplexing antennas 113 and 114 may be provided on the horizontal outer side (for example, the outer surface) of the second leg portion 103E. Also, the first polarization multiplexing antennas 111 and 112 may be provided on the horizontal outer side (for example, the outer surface) of the third leg portion 103N or the horizontal outer side (for example, the outer surface) of the mounting portion 102N of the third leg portion 103N, and the second polarization multiplexing antennas 113 and 114 may be provided on the horizontal outer side (for example, the outer surface) of the fourth leg portion 103S or the horizontal outer side (for example, the outer surface) of the mounting portion 102S of the fourth leg portion 103S.

[0032] The vertical polarization ports (hereinafter also referred to as "V ports") of the plurality of first polarization multiplexing antennas 111 and 112 are connected to the first antenna port of the wireless device housed in the central housing portion, and the horizontal polarization ports (hereinafter also referred to as "H ports") of the plurality of first polarization multiplexing antennas 111 and 112 are connected to the second antenna port of the wireless device. Also, the vertical polarization ports (V ports) of the plurality of second polarization multiplexing antennas 113 and 114 are connected to the second antenna port of the wireless device, and the horizontal polarization ports (H ports) of the plurality of second polarization multiplexing antennas 113 and 114 are connected to the first antenna port of the wireless device.

[0033] In FIG. 8, the angle (θ12) formed by the directions of the main directivities (beams) 111B and 112B of the plurality of first polarization-sharing antennas 111 and 112 is, for example, 80 degrees or more and 100 degrees or less, and may be 90 degrees or approximately 90 degrees. Also, the angle formed by the directions of the main directivities (beams) 113B and 114B of the plurality of second polarization-sharing antennas 113 and 114 is, for example, 80 degrees or more and 100 degrees or less, and may be 90 degrees. Further, in FIG. 8, the angles θ1, θ2, θ3, and θ4 formed by the horizontal reference line A passing through the first leg portion 103W and the second leg portion 103E and the directions of the main directivities (beams) 111B, 112B, 113B, and 114B of the plurality of first polarization-sharing antennas 111 and 112 and the plurality of second polarization-sharing antennas 113 and 114 are, for example, 40 degrees or more and 50 degrees or less, and may be 45 degrees or approximately 45 degrees.

[0034] In FIG. 8, the plurality of first polarization-sharing antennas 111 and 112 are arranged side by side in the horizontal direction, and the plurality of second polarization-sharing antennas 113 and 114 are arranged side by side in the horizontal direction. However, the plurality of first polarization-sharing antennas 111 and 112 may be arranged side by side in the vertical direction, and the plurality of second polarization-sharing antennas 113 and 114 may be arranged side by side in the vertical direction.

[0035] FIG. 9 is an explanatory diagram showing an example of an antenna connection circuit 120 that connects two sets of two antennas in the antenna system 110 of FIG. 8 to a wireless device. In FIG. 9, the antenna connection circuit 120 includes a first distribution combiner 121 having a common terminal connected to a first antenna port 131 of the wireless device 130, and a second distribution combiner 122 having a common terminal connected to a second antenna port 132 of the wireless device 130. Further, the antenna connection circuit 120 includes a third distribution combiner 123 having a common terminal connected to one branch terminal of the first distribution combiner 121, and a fourth distribution combiner 124 having a common terminal connected to the other branch terminal of the first distribution combiner 121. Also, the antenna connection circuit 120 includes a fifth distribution combiner 125 having a common terminal connected to one branch terminal of the second distribution combiner 122, and a sixth distribution combiner 126 having a common terminal connected to the other branch terminal of the second distribution combiner 122.

[0036] The two branch terminals of the third distributor / combiner 123 are connected to the V ports of a plurality of first polarization-common antennas 111 and 112, and the two branch terminals of the fourth distributor / combiner 124 are connected to the H ports of a plurality of second polarization-common antennas 113 and 114. Also, the two branch terminals of the fifth distributor / combiner 125 are connected to the H ports of a plurality of first polarization-common antennas 111 and 112, and the two branch terminals of the sixth distributor / combiner 126 are connected to the V ports of a plurality of second polarization-common antennas 113 and 114.

[0037] With the antenna connection circuit 120 in FIG. 9, it is possible to swap the V port and the H port connected to the first antenna port 131 of the wireless device 130 between the first two-antennas composed of a plurality of first polarization-common antennas 111 and 112 and the second two-antennas composed of a plurality of second polarization-common antennas 113 and 114. More specifically, the V ports of the first polarization-common antennas 111 and 112 are connected to the first antenna port 131 of the wireless device 130 via the first distributor / combiner 121 and the third distributor / combiner 123, and the H ports of the second polarization-common antennas 113 and 114 are connected via the first distributor / combiner 121 and the fourth distributor / combiner 124.

[0038] With the antenna connection circuit 120 in FIG. 9, it is possible to swap the V port and the H port connected to the second antenna port 132 of the wireless device 130 between the first two-antennas composed of a plurality of first polarization-common antennas 111 and 112 and the second two-antennas composed of a plurality of second polarization-common antennas 113 and 114. More specifically, the H ports of the first polarization-common antennas 111 and 112 are connected to the second antenna port 132 of the wireless device 130 via the second distributor / combiner 122 and the fifth distributor / combiner 125, and the V ports of the second polarization-common antennas 113 and 114 are connected via the second distributor / combiner 122 and the sixth distributor / combiner 126.

[0039] According to the antenna connection circuit 120 of FIG. 9, between the two antennas arranged at one end of the drone body 100 and the two antennas arranged at the other end, that is, between two sets of two antennas that are dispersedly arranged more than one wavelength apart from the target radio wave, the V port and the H port connected to the first antenna port 131 of the wireless device 130 can be swapped, and the V port and the H port connected to the second antenna port 132 of the wireless device 130 can be swapped. Thereby, as shown in FIG. 10, the generation of the interference pattern in the overall horizontal plane non-directionality of the antenna system 110 can be suppressed.

[0040] According to the present embodiment, by combining the two sets of two dispersedly arranged antennas of FIG. 8 and the antenna connection circuit 120 of FIG. 9, it is possible to realize a horizontal plane non-directionality in which the generation of the interference pattern is suppressed without being affected by the legs of the drone.

[0041] Also, in the present embodiment, the antenna angles and the half-value widths of the directivity characteristics of the plurality of first polarization-sharing antennas 111 and 112, the antenna angles and the half-value widths of the directivity characteristics of the plurality of second polarization-sharing antennas 113 and 114, or both of them may be adjusted so as to further suppress the generation of the interference pattern. For example, by increasing the antenna angles (θ12 in FIG. 8) of the first polarization-sharing antennas 111 and 112 and the antenna angles (θ34 in FIG. 8) of the second polarization-sharing antennas 113 and 114 from 90 degrees to 100 degrees, or by widening the half-value widths of the directivity characteristics of the first polarization-sharing antennas 111 and 112 and the second polarization-sharing antennas 113 and 114 alone, as shown in FIG. 11, the generation of the interference pattern in the overall horizontal plane non-directionality of the antenna system can be further suppressed.

[0042] FIG. 12 is an explanatory diagram showing an example of an antenna connection circuit 120' that connects two sets of two antennas and a wireless device 130 in the antenna system 110' according to the reference example. In FIG. 12, the same reference numerals are given to the configurations common to FIG. 9 described above, and the description thereof is omitted. In the reference example of FIG. 12, unlike FIG. 9 described above, the two branch terminals of the fourth distribution combiner 124 are connected to the V ports of a plurality of second polarization-sharing antennas 113 and 114, and the two branch terminals of the sixth distribution combiner 126 are connected to the H ports of a plurality of second polarization-sharing antennas 113 and 114.

[0043] When the antenna connection circuit 120' of FIG. 12 is used, there is no swapping of the V port and the H port connected to the first antenna port 131 of the wireless device 130 between the two antennas arranged at one end of the drone body 100 and the two antennas arranged at the other end. Also, there is no swapping of the V port and the H port connected to the second antenna port 132 of the wireless device 130. That is, in two sets of two antennas that are dispersedly arranged more than one wavelength apart from the target radio wave, the respective V ports of the first polarization-sharing antennas 111 and 112 and the second polarization-sharing antennas 113 and 114 are connected to the first antenna port 131 of the wireless device 130, and the respective H ports of the first polarization-sharing antennas 111 and 112 and the second polarization-sharing antennas 113 and 114 are connected to the second antenna port 132 of the wireless device 130. Therefore, as shown in FIG. 13, an interference pattern is generated in the omnidirectionality in the horizontal plane of the entire antenna system 110'. In particular, around the directions between the antennas (θ = 90 degrees and 270 degrees in the figure), the antenna gain drops by about -10 to -20 dB at most.

[0044] As described above, according to the present embodiment, in the drone 10 including the wireless device 130 such as a drone wireless relay device, it is possible to realize an omnidirectionality in the horizontal plane in which the generation of the interference pattern is suppressed without being affected by the legs 103 of the drone 10.

[0045] The antenna system, drone, and drone wireless relay device of the present disclosure can achieve omnidirectionality in the horizontal plane with the generation of interference patterns suppressed without being affected by the legs 103 of the drone 10, and can secure a wide communication area of 360 degrees in the horizontal direction with a single drone, thus contributing to the achievement of Sustainable Development Goal (SDG) 9, "Build the infrastructure for industry and innovation."

Explanation of Signs

[0046] 10: Drone (drone-type wireless relay device) 100: Drone body 101: Central accommodation part 102: Arm part 102W: Attachment part 102E: Attachment part 103: Legs 103W: First leg 103E: Second leg 110: Antenna system 111, 112: First polarization sharing antenna 111B, 112B: Directive beam 113, 114: Second polarization sharing antenna 113B, 114B: Directive beam 120: Antenna connection circuit 121: First distribution combiner 122: Second distribution combiner 123: Third distribution combiner 124: Fourth distribution combiner 125: Fifth distribution combiner 126: Sixth distribution combiner 130: Wireless device 131: First antenna port 132: Second antenna port

Claims

1. An antenna system connected to a wireless device mounted on a drone body having a plurality of legs, provided on the horizontal outer side of any one of the plurality of legs of the drone body or on the horizontal outer side of the mounting portion of the first leg, and a plurality of first polarization sharing antennas arranged adjacent to each other and having main directivities in different outward directions, provided on the horizontal outer side of the second leg located on the opposite side of the first leg with the center of the drone body in between or on the horizontal outer side of the mounting portion of the second leg, and a plurality of second polarization sharing antennas arranged adjacent to each other and having main directivities in different outward directions, and comprising: the vertical polarization ports of the plurality of first polarization sharing antennas are connected to the first antenna port of the wireless device, the horizontal polarization ports of the plurality of first polarization sharing antennas are connected to the second antenna port of the wireless device, the vertical polarization ports of the plurality of second polarization sharing antennas are connected to the second antenna port of the wireless device, the horizontal polarization ports of the plurality of second polarization sharing antennas are connected to the first antenna port of the wireless device, An antenna system characterized by the above.

2. In the antenna system of Claim 1, the angle formed by the direction of the main directivity of each of the plurality of first polarization sharing antennas is 80 degrees or more and 100 degrees or less, the angle formed by the direction of the main directivity of each of the plurality of second polarization sharing antennas is 80 degrees or more and 100 degrees or less, the angle formed by the horizontal reference direction passing through the first leg and the second leg and the direction of the main directivity of each of the plurality of first polarization sharing antennas and the plurality of second polarization sharing antennas is 40 degrees or more and 50 degrees or less, An antenna system characterized by the above.

3. In the antenna system of Claim 1, the plurality of first polarization sharing antennas are arranged side by side in the horizontal direction, the plurality of second polarization sharing antennas are arranged side by side in the horizontal direction, An antenna system characterized by the above.

4. In the antenna system of Claim 1, the plurality of first polarization sharing antennas are arranged side by side in the vertical direction, the plurality of second polarization sharing antennas are arranged side by side in the vertical direction, An antenna system characterized by the above.

5. In the antenna system of Claim 1, a first distribution combiner having a common terminal connected to the first antenna port of the wireless device, a second distribution combiner having a common terminal connected to the second antenna port of the wireless device; a third distribution combiner having a common terminal connected to one branch terminal of the first distribution combiner; a fourth distribution combiner having a common terminal connected to the other branch terminal of the first distribution combiner; a fifth distribution combiner having a common terminal connected to one branch terminal of the second distribution combiner; a sixth distribution combiner having a common terminal connected to the other branch terminal of the second distribution combiner, and two branch terminals of the third distribution combiner are connected to the vertical polarization ports of the plurality of first polarization shared antennas; two branch terminals of the fourth distribution combiner are connected to the horizontal polarization ports of the plurality of second polarization shared antennas; two branch terminals of the fifth distribution combiner are connected to the horizontal polarization ports of the plurality of first polarization shared antennas; two branch terminals of the sixth distribution combiner are connected to the vertical polarization ports of the plurality of second polarization shared antennas, An antenna system characterized by the above.

6. In the antenna system of Claim 1, the distance between the plurality of first polarization shared antennas and the plurality of second polarization shared antennas is longer than the wavelength of the target radio wave, An antenna system characterized by the above.

7. A drone-type wireless relay device, a drone body having a plurality of legs, the antenna system according to any one of Claims 1 to 6, and a relay station as a wireless device to which the antenna system is connected, A wireless relay device characterized by comprising the above.

8. A drone, a drone body having a plurality of legs, the antenna system according to any one of Claims 1 to 6, and a wireless device to which the antenna system is connected, A drone characterized by comprising the above.

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