Antenna systems, wireless relay equipment, and drones

Abstract

This invention provides an antenna system that enables omnidirectional operation in the horizontal plane while suppressing interference patterns without being affected by the drone's legs. [Solution] The antenna system is connected to a wireless device mounted on a drone body having multiple legs. The antenna system comprises a plurality of first polarization-sharing antennas provided on the outside of the first leg or its mounting part and having primary directivity in different outward directions from each other, and a plurality of second polarization-sharing antennas provided on the outside of the second leg or its mounting part and having primary directivity in different outward directions from each other. The vertical polarization ports of the plurality of first polarization-sharing antennas are connected to the first port of the wireless device, and the horizontal polarization ports of the plurality of first polarization-sharing antennas are connected to the second port of the wireless device. The vertical polarization ports of the plurality of second polarization-sharing antennas are connected to the second port of the wireless device, and the horizontal polarization ports of the plurality of second polarization-sharing 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, a drone having a wireless device and an antenna for wireless communication with the ground side and capable of flying and hovering in the air is known.

[0003] For example, Patent Document 1 discloses an antenna system having a long-shaped antenna with omnidirectionality 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. The antenna system comprises a plurality of adjacently arranged first polarization-sharing antennas provided on the horizontal outer side of 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 having primary directivity in different outward directions from each other; and a plurality of adjacently arranged second polarization-sharing antennas provided on the horizontal outer side of a second leg located on the opposite side of the drone body from the first leg, or on the horizontal outer side of the mounting portion of the second leg, and having primary directivity in different outward directions from each other. The vertical polarization port of each of the plurality of first polarization-sharing antennas is connected to the first antenna port of the wireless device, and the horizontal polarization port of each of the plurality of first polarization-sharing antennas is connected to the second antenna port of the wireless device. The vertical polarization port of each of the plurality of second polarization-sharing antennas is connected to the second antenna port of the wireless device, and the horizontal polarization port of each of the plurality of second polarization-sharing antennas is connected to the first antenna port of the wireless device.

[0006] In the antenna system, the angle formed by the directions of the principal directivity of each of the plurality of first polarization-sharing antennas may be 80 degrees or more and 100 degrees or less, and the angle formed by the directions of the principal directivity of each of the plurality of second polarization-sharing antennas may be 80 degrees or more and 100 degrees or less, or 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 principal directivity of each of the plurality of first polarization-sharing antennas and the plurality of second polarization-sharing antennas may be 40 degrees or more and 50 degrees or less, or 45 degrees or about 45 degrees.

[0007] In the antenna system described above, the plurality of first polarization-sharing antennas may be arranged horizontally, and the plurality of second polarization-sharing antennas may be arranged horizontally.

[0008] In the antenna system described above, the plurality of first polarization-sharing antennas may be arranged vertically, and the plurality of second polarization-sharing antennas may be arranged vertically.

[0009] The antenna system may include a first distribution combiner with a common terminal connected to the first antenna port of the wireless device, a second distribution combiner with a common terminal connected to the second antenna port of the wireless device, a third distribution combiner with a common terminal connected to one branch terminal of the first distribution combiner, a fourth distribution combiner with a common terminal connected to the other branch terminal of the first distribution combiner, a fifth distribution combiner with a common terminal connected to one branch terminal of the second distribution combiner, and a sixth distribution combiner with a common terminal connected to the other branch terminal of the second distribution combiner. Here, the two branch terminals of the third distribution combiner may be connected to the vertical polarization ports of the plurality of first polarization-sharing antennas, the two branch terminals of the fourth distribution combiner may be connected to the horizontal polarization ports of the plurality of second polarization-sharing antennas, the 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 the 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 described above, 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 comprises a drone body having a plurality of legs, 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 yet another aspect of this disclosure comprises a drone body having a plurality of legs, one of the antenna systems, and a wireless device to which the antenna system is connected.

[0013] The antenna system, wireless relay device, and drone of this disclosure make it possible to achieve horizontal omnidirectional antennary with suppressed interference patterns without being affected by the drone's legs. [Brief explanation of the drawing]

[0014] [Figure 1] Figure 1 is a perspective view showing an example of a drone to which the horizontal omnidirectional antenna system according to the embodiment can be applied. [Figure 2] Figure 2 is a perspective view showing an example of the installation of an omnidirectional antenna in a drone wireless relay device related to a reference example. [Figure 3] Figure 3(a) is an explanatory diagram showing an example of the position of the omnidirectional antenna during aerial service in a drone radio relay device according to a reference example. Figure 3(b) is an explanatory diagram showing an example of the position of the omnidirectional antenna in the same drone radio relay device during landing. Figure 3(c) is an explanatory diagram showing another example of the position of the omnidirectional antenna in the same drone radio relay device during landing. [Figure 4] Figure 4(a) is an explanatory diagram showing an example of the positions of multiple omnidirectional antennas distributed in a drone radio relay device according to a reference example. Figure 4(b) is an explanatory diagram showing an example of the positions of multiple omnidirectional antennas in the same drone radio relay device when it is landing. [Figure 5] Figure 5(a) is an explanatory diagram showing an example of the directional beam in the horizontal plane of one antenna according to a reference example. Figure 5(b) is an explanatory diagram showing an example of the horizontal directivity characteristics of the one antenna in Figure 5(a). [Figure 6] Figure 6(a) is an explanatory diagram showing an example of the directional beam in the horizontal plane of the four antennas in the reference example. Figure 6(b) is an explanatory diagram showing an example of the horizontal directivity characteristics of the four antennas in Figure 6(a). [Figure 7] Figure 7(a) is an explanatory diagram showing the positions of four antennas distributed on a drone according to a reference example and an example of the directional beam in the horizontal plane. Figure 7(b) is an explanatory diagram showing an example of the horizontal directivity characteristics of the four antennas in Figure 7(a). [Figure 8]FIG. 8 is a plan view showing an example of the distributed arrangement of two sets of two antennas in the antenna system according to the embodiment. [Figure 9] FIG. 9 is an explanatory view showing an example of an antenna connection circuit that connects two sets of two antennas and a wireless device in the antenna system of FIG. 8. [Figure 10] FIG. 10 is an explanatory view showing an example of the horizontal directivity characteristics of an antenna system having two sets of two antennas of FIG. 8 and the antenna connection circuit of FIG. 9. [Figure 11] FIG. 11 is an explanatory view showing another example of the horizontal directivity characteristics of an antenna system having two sets of two antennas of FIG. 8 and the antenna connection circuit of FIG. 9. [Figure 12] FIG. 12 is an explanatory view showing an example of an antenna connection circuit that connects two sets of two antennas and a wireless device in the antenna system according to the reference example. [Figure 13] FIG. 13 is an explanatory view showing an example of the horizontal directivity characteristics of an antenna system having the antenna connection circuit according to the reference example.

Embodiments for Carrying Out the Invention

[0015] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. 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 only to the shape, size, positional relationship, correspondence relationship, configuration, processing, steps, 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] An 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") provided 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, for example, stops flying (hovers) so as to be located above a target area such as a disaster occurrence location like a typhoon or earthquake or a distress occurrence location like an avalanche, and relays communication between a communication network such as a mobile communication network and terminal devices in the target area. Thereby, for example, communication such as that of mobile phones and smartphones at the disaster occurrence location can be restored earlier, or communication such as that of the mobile phones and smartphones of the distressed persons at the distress occurrence location can be relayed to support the search and rescue of the distressed persons.

[0018] The radio waves of the target transmitted or received 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 a horizontally omnidirectional antenna system according to an embodiment can be applied. In FIG. 1, the drone body 100 of the drone 10 includes a central accommodation part 101, a plurality (four in the example of FIG. 1) of arm parts 102 extending laterally from the central accommodation part 101, a plurality of landing legs (feet) 103 extending downward from the tip parts of the plurality of arm parts 102, and a plurality of propellers (including driving motors) 104 provided above the tip parts of the plurality of arm parts 102. The central accommodation part 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 radio") installed in the central housing 101 of the drone body 100 of the drone 10 is a device that performs wireless communication via a horizontal omnidirectional antenna system. When the drone 10 functions as a drone wireless relay device, the wireless device is, for example, a base station device or repeater slave unit, or other relay communication station (hereinafter also referred to as the "relay station") that performs wireless communication with a gateway station on land or at sea via a feeder link and also performs wireless communication with user devices, which are terminals on land, at sea, or in the air, via a service link. The antenna system of this embodiment may be used as a horizontal omnidirectional antenna for the service link or as a horizontal omnidirectional antenna for the feeder link. Furthermore, the wireless device installed in the drone 10 may be a wireless device that does not perform relaying.

[0021] While omnidirectional and directional antennas can be used as antennas connected to the wireless device mounted on drone 10, if a wide wireless coverage area of ​​360 degrees in the horizontal plane is desired with a single drone, it is preferable to use a lightweight, horizontally omnidirectional antenna that can be mounted on drone 10. Directional antennas can transmit radio waves over long distances, but the range of the wireless coverage area is narrowed due to the need to narrow the directionality. Also, if multiple directional antennas are used to transmit radio waves over 360 degrees in the horizontal plane, as is done with ground base stations, the weight of the wireless device and antennas increases due to the increase in the number of sectors (also called "sector cells").

[0022] On the other hand, the drone 10 has landing legs (feet) 103, and if an omnidirectional antenna is used, the legs 103 may affect the radio wave radiation characteristics. For example, as shown in Figure 2, if a long omnidirectional antenna 105 is positioned so as to extend downward from the central housing 101 located in the center of the drone 10, the four legs 103 located around the omnidirectional antenna 105 may affect the radio wave W radiation characteristics of the omnidirectional antenna 105. Therefore, when using an omnidirectional antenna 105, it is necessary to devise a way to prevent the legs 103 from affecting the radio wave W radiation characteristics (for example, a movable antenna configuration).

[0023] For example, as shown in Figure 3(a), when the drone 10 is positioned in the air and providing wireless relay services, the omnidirectional antenna 105 is positioned below the lower end of the drone 10's legs 103. When the drone 10 lands, the movable mechanism is used to swing the omnidirectional antenna 105 sideways (see Figure 3(b)) or move it upward (see Figure 3(c)) so that it does not come into contact with the ground G.

[0024] In this embodiment, a horizontal omnidirectional antenna system is configured so as not to require a movable mechanism that is structurally complex and heavy, and so as not to affect the radio wave radiation characteristics of the landing legs (feet). As an example of such a horizontal omnidirectional antenna system configuration, for example, as shown in Figures 4(a) and 4(b), multiple omnidirectional antennas 105 can be dispersed on the outer sides of each of the multiple legs 103 of the drone 10. With this configuration, as shown in Figure 4(a), the legs 103 do not affect the radio wave radiation characteristics W of the omnidirectional antennas 105 during aerial service, and as shown in Figure 4(b), the omnidirectional antennas 105 do not come into contact with the ground G when the drone 10 lands. However, when multiple antennas are dispersed on the outer sides of each of the multiple legs 103, it was found that there is a problem in that interference patterns occur 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 directional beam 111B in one direction in the horizontal plane, as shown in Figure 5(a), the antenna gain is maximum in the principal direction (θ=0 degrees) of the directional beam 111B perpendicular to the antenna surface of antenna 111, as shown in the horizontal plane directivity characteristics of Figure 5(b), and the antenna gain decreases as the angle from the principal direction increases. Antenna 111 is, for example, a patch antenna. Note that in Figure 5(b), the angle θ is the angle from the reference direction passing through the center of the antenna or antenna system in the horizontal plane (also referred to as the "azimuth angle") (the same applies to the directional characteristics figures below). In the examples of Figures 5(a) and 5(b), the reference direction is the outward direction perpendicular to the antenna surface that passes through the center of the antenna surface of antenna 111.

[0026] By combining multiple antennas 111 as shown in Figures 5(a) and 5(b), an antenna system having omnidirectional properties in the horizontal plane can be constructed as a whole. For example, as shown in Figure 6(a), four antennas (hereinafter also referred to as "four antennas") 111 to 114 are arranged close to each other such that the directional beams 111B to 114B of each antenna are in different outward directions (up and down and left and right directions in the figure), thereby constructing a four-antenna system in which the four antennas are arranged at equal angle (90-degree) intervals in the circumferential direction in the horizontal plane. The circumferential spacing (pitch) of the four antennas 111 to 114 is, for example, smaller than one wavelength (λ) of the target radio wave (typically 0.5λ to 0.7λ). This four-antenna system as a whole has omnidirectional properties in the horizontal plane, as shown in Figure 6(b).

[0027] However, it was found that when the four antennas 111-114 are dispersed and the circumferential spacing (pitch) between them becomes greater than or equal to one wavelength (λ) of the target radio wave, an interference pattern occurs in the overall horizontal omnidirectional antenna. For example, as shown in Figure 7(a), when four antennas 111-114, each having directional beams 111B-114B with outward-facing primary directivity horizontally outwards from the mounting parts (tips of the arm parts 102) 102N, 102S, 102E, and 102W of multiple leg parts 103, are dispersed, an interference pattern occurs in the overall horizontal omnidirectional antenna system consisting of the four antennas, as shown in Figure 7(b). In particular, the antenna gain drops by up to approximately -15dB around the diagonal directions between the antennas (θ = 45 degrees, 135 degrees, 225 degrees, 315 degrees in the figure).

[0028] In this embodiment, in order to prevent interference patterns from occurring in the overall horizontal omnidirectional antenna system, two adjacent polarization-sharing antennas (hereinafter also referred to as "2 antennas"), each having different outward primary directivity, are distributed at both ends of the drone body 100, separated by its center. Furthermore, the vertical polarization port and the horizontal polarization port connected to the antenna port of the wireless device are swapped between the 2 antennas located at one end of the drone body 100 and the 2 antennas located at the other end.

[0029] Figure 8 is a plan view showing an example of a distributed arrangement of two sets of two antennas 111, 112 and two antennas 113, 114 in an antenna system according to one embodiment of the present disclosure. In Figure 8, components common to Figure 1 are denoted by the same reference numerals and their descriptions are omitted. In Figure 8, the antenna system of this embodiment comprises a first set of two antennas consisting of a plurality of first polarization-sharing antennas 111, 112 arranged adjacent to each other, and a second set of two antennas consisting of a plurality of second polarization-sharing antennas 113, 114 arranged adjacent to each other. The distance between the first set of two antennas consisting of a plurality of first polarization-sharing antennas 111, 112 and the second set of two antennas consisting of a plurality of second polarization-sharing antennas 113, 114 is longer than the wavelength (λ) of the target radio wave.

[0030] The first polarization-sharing antennas 111 and 112, which constitute the first dual antenna, are each mounted on the horizontally outward side (leftward in the figure) (for example, the outer surface) of the mounting portion 102W of one of the multiple legs 103W of the drone body 100, and have primary directivity (beams) 111B and 112B in different outward directions. The multiple second polarization-sharing antennas 113 and 114, which constitute the second dual antenna, are each mounted on the horizontally outward side (rightward in the figure) (for example, the outer surface) of the mounting portion 102E of the second leg 103E, which is located on the opposite side of the drone body 100 from the first leg 103W with the center in between, and have primary directivity (beams) 113B and 114B in different outward directions.

[0031] Furthermore, the first polarization-sharing antennas 111 and 112 may be provided on the horizontally outer side (e.g., the outer surface) of the first leg portion 103W, and the second polarization-sharing antennas 113 and 114 may be provided on the horizontally outer side (e.g., the outer surface) of the second leg portion 103E. Also, the first polarization-sharing antennas 111 and 112 may be provided on the horizontally outer side (e.g., the outer surface) of the third leg portion 103N or the mounting portion 102N of the third leg portion 103N, and the second polarization-sharing antennas 113 and 114 may be provided on the horizontally outer side (e.g., the outer surface) of the fourth leg portion 103S or the mounting portion 102S of the fourth leg portion 103S.

[0032] The vertical polarization ports (hereinafter also referred to as "V ports") of each of the multiple first polarization-sharing antennas 111 and 112 are connected to the first antenna ports of the wireless device housed in the central housing, and the horizontal polarization ports (hereinafter also referred to as "H ports") of each of the multiple first polarization-sharing antennas 111 and 112 are connected to the second antenna ports of the wireless device. Furthermore, the vertical polarization ports (V ports) of each of the multiple second polarization-sharing antennas 113 and 114 are connected to the second antenna ports of the wireless device, and the horizontal polarization ports (H ports) of each of the multiple second polarization-sharing antennas 113 and 114 are connected to the first antenna ports of the wireless device.

[0033] In Figure 8, the angle (θ12) formed by the directions of the principal directivity (beams) 111B and 112B of each of the multiple 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. Similarly, the angle formed by the directions of the principal directivity (beams) 113B and 114B of each of the multiple second polarization-sharing antennas 113 and 114 is, for example, 80 degrees or more and 100 degrees or less, and may be 90 degrees. Furthermore, in Figure 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 directivity (beams) 111B, 112B, 113B, and 114B of the multiple first polarization-sharing antennas 111 and 112 and the multiple second polarization-sharing antennas 113 and 114, respectively, are, for example, 40 degrees or more and 50 degrees or less, and may be 45 degrees or approximately 45 degrees.

[0034] In Figure 8, multiple first polarization-sharing antennas 111 and 112 are arranged horizontally, and multiple second polarization-sharing antennas 113 and 114 are arranged horizontally. However, multiple first polarization-sharing antennas 111 and 112 may be arranged vertically, and multiple second polarization-sharing antennas 113 and 114 may be arranged vertically.

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

[0036] The two branch terminals of the third distribution combiner 123 are connected to the V ports of multiple first polarization-sharing antennas 111 and 112, and the two branch terminals of the fourth distribution combiner 124 are connected to the H ports of multiple second polarization-sharing antennas 113 and 114. In addition, the two branch terminals of the fifth distribution combiner 125 are connected to the H ports of multiple first polarization-sharing antennas 111 and 112, and the two branch terminals of the sixth distribution combiner 126 are connected to the V ports of multiple second polarization-sharing antennas 113 and 114.

[0037] The antenna connection circuit 120 in Figure 9 allows the V port and H port connected to the first antenna port 131 of the wireless device 130 to be swapped between the first set of two antennas, consisting of multiple first polarization-sharing antennas 111 and 112, and the second set of two antennas, consisting of multiple second polarization-sharing antennas 113 and 114. More specifically, the V ports of the first polarization-sharing antennas 111 and 112 are connected to the first antenna port 131 of the wireless device 130 via the first distribution combiner 121 and the third distribution combiner 123, and the H ports of the second polarization-sharing antennas 113 and 114 are connected via the first distribution combiner 121 and the fourth distribution combiner 124.

[0038] The antenna connection circuit 120 in Figure 9 allows the V port and H port connected to the second antenna port 132 of the wireless device 130 to be swapped between the first set of two antennas, consisting of multiple first polarization-sharing antennas 111 and 112, and the second set of two antennas, consisting of multiple second polarization-sharing antennas 113 and 114. More specifically, the H ports of the first polarization-sharing antennas 111 and 112 are connected to the second antenna port 132 of the wireless device 130 via the second distribution combiner 122 and the fifth distribution combiner 125, and the V ports of the second polarization-sharing antennas 113 and 114 are connected via the second distribution combiner 122 and the sixth distribution combiner 126.

[0039] According to the antenna connection circuit 120 in Figure 9, the V port and H port connected to the first antenna port 131 of the wireless device 130 can be swapped between the two antennas located at one end of the drone body 100 and the two antennas located at the other end, that is, between two sets of two antennas dispersed at a distance of more than one wavelength of the target radio wave, and the V port and H port connected to the second antenna port 132 of the wireless device 130 can also be swapped. As a result, as shown in Figure 10, the generation of interference patterns in the overall horizontal omnidirectional antenna system 110 can be suppressed.

[0040] According to this embodiment, by combining the two sets of two antennas distributed in Figure 8 with the antenna connection circuit 120 in Figure 9, it is possible to achieve horizontal omnidirectional antennary with suppressed interference patterns without being affected by the drone's legs.

[0041] Furthermore, in this embodiment, the antenna angles and half-width of the directivity characteristics of the multiple first polarization-sharing antennas 111, 112, the antenna angles and half-width of the directivity characteristics of the multiple second polarization-sharing antennas 113, 114, or both, may be adjusted to further suppress the generation of interference patterns. For example, by increasing the antenna angles of the first polarization-sharing antennas 111, 112 (θ12 in Figure 8) and the antenna angles of the second polarization-sharing antennas 113, 114 (θ34 in Figure 8) from 90 degrees to 100 degrees, or by widening the half-width of the directivity characteristics of the first polarization-sharing antennas 111, 112 and the second polarization-sharing antennas 113, 114 individually, the generation of interference patterns in the overall horizontal omnidirectional antenna system can be further suppressed, as shown in Figure 11.

[0042] Figure 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 an antenna system 110' according to a reference example. In Figure 12, components common to Figure 9 are denoted by the same reference numerals and their explanations are omitted. In the reference example of Figure 12, unlike Figure 9, the two branch terminals of the fourth distribution combiner 124 are connected to the V ports of the multiple 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 the multiple second polarization-sharing antennas 113 and 114.

[0043] When using the antenna connection circuit 120' shown in Figure 12, there is no swapping of the V-port and H-port connected to the first antenna port 131 of the wireless device 130 between the two antennas positioned at one end of the drone body 100 and the two antennas positioned at the other end, nor is there any swapping of the V-port and H-port connected to the second antenna port 132 of the wireless device 130. In other words, in two sets of two antennas dispersed at a distance of more than one wavelength of the target radio wave, the V-ports of the first polarization-sharing antennas 111, 112 and the second polarization-sharing antennas 113, 114 are connected to the first antenna port 131 of the wireless device 130, and the H-ports of the first polarization-sharing antennas 111, 112 and the second polarization-sharing antennas 113, 114 are connected to the second antenna port 132 of the wireless device 130. Therefore, as shown in Figure 13, an interference pattern occurs omnidirectionally in the horizontal plane of the entire antenna system 110'. In particular, the antenna gain drops by approximately -10 to -20 dB around the direction between the antennas (θ = 90 degrees and 270 degrees in the diagram).

[0044] As described above, according to this embodiment, in a drone 10 equipped with a wireless device 130 such as a drone wireless relay device, horizontal omnidirectional operation can be achieved without being affected by the legs 103 of the drone 10, and the generation of interference patterns can be suppressed.

[0045] The antenna system, drone, and drone wireless relay device disclosed herein can achieve horizontal omnidirectional operation with suppressed interference patterns without being affected by the legs 103 of the drone 10, and can secure a wide 360-degree horizontal communication area with a single drone, thereby contributing to the achievement of Sustainable Development Goal (SDG) 9, "Build resilient infrastructure, promote inclusive and sustainable industrialization and foster innovation." [Explanation of Symbols]

[0046] 10: Drone (Drone-type wireless relay device) 100: Drone body 101: Central containment area 102: Arm section 102W: Mounting part 102E: Mounting part 103: Legs 103W: 1st leg 103E:Second leg 110: Antenna System 111,112: First polarization shared antenna 111B, 112B: Directional beam 113,114: Second polarization shared antenna 113B, 114B: Directional beam 120: Antenna connection circuit 121: 1st distribution combiner 122:Second distribution combiner 123:Third distribution combiner 124:Fourth distribution combiner 125:Fifth distribution combiner 126: 6th distribution combiner 130: Radio equipment 131: First antenna port 132: Second antenna port

Claims

1. An antenna system connected to a wireless device mounted on a drone body having multiple legs, Multiple adjacent first polarization-sharing antennas are provided on the horizontal outer side of one of the multiple legs of the drone body or on the horizontal outer side of the mounting portion of the first leg, and each antenna has a primary directivity in a different outward direction. The drone comprises a plurality of adjacent second polarization-sharing antennas, each having a primary directivity in a different outward direction, which are provided on the horizontal outer side of the second leg or on the horizontal outer side of the mounting portion of the second leg, with the center of the drone body in between, opposite to the first leg, Each of the multiple first polarization-sharing antennas has a vertical polarization port connected to the first antenna port of the wireless device. Each of the aforementioned plurality of first polarization-sharing antennas has a horizontal polarization port connected to the second antenna port of the wireless device. Each of the aforementioned plurality of second polarization-sharing antennas has a vertical polarization port connected to the second antenna port of the wireless device. Each of the multiple second polarization-sharing antennas has a horizontal polarization port connected to the first antenna port of the wireless device. An antenna system characterized by the following features.

2. In the antenna system of claim 1, The angle formed by the directions of the primary directivity of each of the aforementioned multiple first polarization-sharing antennas is between 80 degrees and 100 degrees. The angle formed by the directions of the primary directivity of each of the aforementioned multiple second polarization-sharing antennas is between 80 degrees and 100 degrees. The angle between the horizontal reference direction passing through the first and second legs and the direction of the principal directivity 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 following features.

3. In the antenna system of claim 1, The aforementioned plurality of first polarization-sharing antennas are arranged in a horizontal line, The aforementioned multiple second polarization-sharing antennas are arranged in a horizontal line. An antenna system characterized by the following features.

4. In the antenna system of claim 1, The aforementioned plurality of first polarization-sharing antennas are arranged in a vertical line, The aforementioned multiple second polarization-sharing antennas are arranged in a vertical line. An antenna system characterized by the following features.

5. In the antenna system of claim 1, A first distribution combiner, to which a common terminal is connected to the first antenna port of the aforementioned wireless device, A second distribution combiner, to which a common terminal is connected to the second antenna port of the aforementioned wireless device, A third distribution combiner, in which a common terminal is connected to one of the branch terminals of the first distribution combiner, A fourth distribution combiner, to which a common terminal is connected to the other branch terminal of the first distribution combiner, A fifth distribution combiner, to which a common terminal is connected to one of the branch terminals of the second distribution combiner, The system comprises a sixth distribution combiner, the other branch terminal of the second distribution combiner having a common terminal connected to it, The two branch terminals of the third distribution combiner are connected to the vertical polarization ports of the plurality of first polarization-sharing antennas. The two branch terminals of the fourth distribution combiner are connected to the horizontal polarization ports of the plurality of second polarization-sharing antennas. The two branch terminals of the fifth distribution combiner are connected to the horizontal polarization ports of the plurality of first polarization-sharing antennas. The two branch terminals of the sixth distribution combiner are connected to the vertical polarization ports of the plurality of second polarization-sharing antennas. An antenna system characterized by the following features.

6. In the antenna system of claim 1, The distance between the plurality of first polarization-sharing antennas and the plurality of second polarization-sharing antennas is longer than the wavelength of the target radio wave. An antenna system characterized by the following features.

7. A drone-type wireless relay device, A drone body having multiple legs, An antenna system according to any one of claims 1 to 6, The aforementioned antenna system is connected to a relay station which is a wireless device, A wireless relay device characterized by comprising:

8. It's a drone, A drone body having multiple legs, An antenna system according to any one of claims 1 to 6, The wireless device to which the aforementioned antenna system is connected, A drone characterized by having the following features.

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