Antenna Device

Abstract

To form a wide communication area in a midair-floating type communication device.SOLUTION: An antenna device mounted on a midair-floating type communication device includes: a first array antenna that has a plurality of annularly arranged antenna elements and forms a first communication area on the ground; and a second array antenna that has a plurality of annularly arranged antenna elements and forms a second communication area outside the first communication area.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to an antenna device. [Background technology]

[0002] Airborne relay devices such as High Altitude Platform Stations (HAPS) are known.

[0003] As an antenna device mounted on a floating relay device, a phased array antenna capable of beamforming is known. Patent Document 1 discloses a hexagonal pyramid-shaped antenna device equipped with multiple planar array antennas in FIG. [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] JP 2020-080459 A Summary of the Invention [Problem to be solved by the invention]

[0005] For airborne repeater devices such as HAPS, it is desirable to create a wider communication area.

[0006] A non-limiting embodiment of the present disclosure contributes to providing an antenna device that forms a wide communication area in an airborne communication device. [Means for solving the problem]

[0007] One embodiment of the present disclosure is an antenna device mounted on an airborne communication device, comprising a first array antenna arranged in a ring shape to form a first communication area on the ground, and a second array antenna arranged in a ring shape to form a second communication area outside the first communication area.

[0008] These comprehensive or specific aspects may be realized as a system, an apparatus, a method, an integrated circuit, a computer program, or a recording medium, or may be realized as any combination of a system, an apparatus, a method, an integrated circuit, a computer program, and a recording medium. Effect of the Invention

[0009] According to an embodiment of the present disclosure, a wide communication area can be formed in an airborne relay device.

[0010] Further advantages and benefits of an embodiment of the present disclosure will become apparent from the specification and drawings. Such advantages and / or benefits may be provided by some of the embodiments and features described in the specification and drawings, respectively, but not necessarily all of them may be provided to obtain one or more identical features. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 shows an example of the configuration of a communication system according to a first embodiment. [Diagram 2] A perspective view of the antenna device to be installed on HAPS [Figure 3A] Side view of a planar array antenna [Figure 3B] Side view of a planar array antenna [Figure 4] Front view of a planar array antenna [Diagram 5] A diagram showing an example of the block configuration of a planar array antenna [Figure 6] Diagram showing an example of HAPS block configuration [Figure 7] Diagram explaining the area formed by antenna groups [Figure 8A] FIG. 1 is a diagram for explaining an example of antenna group control. [Figure 8B] FIG. 1 is a diagram for explaining an example of antenna group control. [Figure 9] 1 is a flowchart illustrating an example of the operation of the antenna device. [Figure 10] FIG. 3 is a top view of the antenna device shown in FIG. [Figure 11] FIG. 13 is a perspective view of an antenna device according to a second embodiment; [Figure 12] FIG. 13 is a perspective view of an antenna device according to a third embodiment; [Figure 13] FIG. 13 is a block diagram showing an example of the configuration of an antenna device according to a fourth embodiment; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, the embodiments of the present disclosure will be described in detail with reference to the drawings as appropriate. However, more detailed explanation than necessary may be omitted. For example, detailed explanation of already well-known matters or duplicate explanation of substantially the same configuration may be omitted. This is to avoid the following explanation becoming unnecessarily redundant and to facilitate understanding by those skilled in the art.

[0013] It should be noted that the accompanying drawings and the following description are provided to enable those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter described in the claims.

[0014] (First embodiment) 1 is a diagram showing an example of the configuration of a communication system 1 according to a first embodiment. As shown in FIG. 1, the communication system 1 includes a HAPS 11 and ground stations 12 and 13.

[0015] The HAPS 11 is an air vehicle such as a UAV (unmanned aerial vehicle) or an unmanned balloon equipped with a relay device. The HAPS 11 relays communication between a ground station 12 and a ground station 13 that are fixed on the ground.

[0016] The service area A11 indicates an area in which communication is possible with the HAPS 11. The HAPS 11 stays in the air while flying at a high altitude of, for example, about 20 km along a circular HAPS route R11, and forms the service area A11 on the ground. The HAPS route R11 is determined, for example, so that the ground stations 12 and 13 are located within the service area A11.

[0017] While flying along HAPS route R11, HAPS11 constantly establishes link L11 with ground station 12 within service area A11 and link L12 with ground station 13, and provides (relays) a wireless communication link between ground station 12 and ground station 13.

[0018] The HAPS may be referred to as an airborne relay device, relay station, radio station, or communication device. The ground station may be referred to as a base station, radio station, or communication device. The service area may be referred to as a communication area or area.

[0019] Furthermore, the HAPS route R11 does not have to be circular. For example, the HAPS route R11 may be in the shape of a figure eight.

[0020] Fig. 2 is a perspective view of the antenna device 20 mounted on the HAPS 11. As shown in Fig. 2, the antenna device 20 has planar array antennas 21-24 (second array antennas) and planar array antennas 31-34 (first array antennas). The antenna device 20 is disposed, for example, at the bottom of the unmanned aerial vehicle.

[0021] The planar array antennas 21-24, 31-34 are arranged in a ring shape. The planar array antennas 21-24, 31-34 are arranged so that the normal to the antenna surface (the surface on which the antenna element 41 shown in FIG. 4 is formed) faces downward with respect to the horizontal direction. In other words, the antenna surfaces of the planar array antennas 21-24, 31-34 face toward the ground when the HAPS 11 is floating in the air. As the planar array antennas 21-24, 31-34 are arranged in a ring shape, the antenna elements formed on the antenna surfaces of the planar array antennas 21-24, 31-34 are also arranged in a ring shape.

[0022] The depression angle of the antenna plane of each of the planar array antennas 21-24 is the same. The depression angle of the antenna plane of each of the planar array antennas 31-34 is the same. Hereinafter, "the same" includes "approximately the same" unless otherwise specified. In addition, hereinafter, "the depression angle of the antenna plane of the planar array antenna" may be expressed as "the depression angle of the planar array antenna". In addition, hereinafter, the depression angle will be referred to as the tilt angle.

[0023] Fig. 3A is a side view of the planar array antenna 21. Fig. 3B is a side view of the planar array antenna 31.

[0024] A dotted line X1 in Fig. 3A indicates a normal line to the planar array antenna 21. The normal line to the planar array antenna 21 faces downward relative to the horizontal direction. The planar array antenna 21 has a tilt angle TA1 as shown in Fig. 3A.

[0025] As described above, the planar array antennas 21 to 24 have the same tilt angle. Therefore, the planar array antennas 22 to 24 also have the tilt angle TA1.

[0026] The dotted line X2 in Fig. 3B indicates the normal line of the planar array antenna 31. The normal line of the planar array antenna 31 faces downward relative to the horizontal direction. The planar array antenna 31 has a tilt angle TA2 as shown in Fig. 3B. The tilt angle TA2 is greater than the tilt angle TA1 of the planar array antenna 21.

[0027] As described above, the planar array antennas 31 to 34 have the same tilt angle. Therefore, the planar array antennas 32 to 34 also have a tilt angle TA2.

[0028] The inclination angle TA2 is less than 90 degrees. Therefore, the antenna planes of the planar array antennas 31 to 34 do not face directly downward. The antenna planes of the planar array antennas 31 to 34 having an inclination angle TA1 smaller than the inclination angle TA2 also do not face directly downward.

[0029] Hereinafter, the planar array antennas 21 to 24 having the same tilt angle TA1 may be referred to as antenna group G1, and the planar array antennas 31 to 34 having the same tilt angle TA2 may be referred to as antenna group G2.

[0030] Returning to the explanation of Fig. 2, the planar array antennas 21 to 24 and 31 to 34 are arranged such that the inclination angles of adjacent planar array antennas 21 to 24 and 31 to 34 are different from each other.

[0031] 2 from above, the planar array antenna 31 having a tilt angle TA2 is disposed to the left of the planar array antenna 21 having a tilt angle TA1. The planar array antenna 22 having a tilt angle TA1 is disposed to the left of the planar array antenna 31 having a tilt angle TA2. That is, the planar array antennas 21-24 of the antenna group G1 and the planar array antennas 31-34 of the antenna group G2 are disposed alternately in a circular pattern.

[0032] Fig. 4 is a front view of the planar array antenna 21. As shown in Fig. 4, the planar array antenna 21 has a plurality of antenna elements 41 arranged vertically and horizontally. The antenna element 41 is, for example, a dual-polarized patch antenna compatible with vertically polarized waves and horizontally polarized waves.

[0033] Hereinafter, the coordinates (position) of the antenna element 41 in the planar array antenna 21 will be indicated as P(m,n). m indicates the position of the antenna element 41 in the vertical direction. n indicates the position of the antenna element 41 in the horizontal direction. m is an integer between 1 and M inclusive. n is an integer between 1 and N inclusive.

[0034] In addition, P(M, N) shown in FIG. 4 is M=N=8 in the example of the planar array antenna 21 shown in FIG.

[0035] Although an example of the configuration of the planar array antenna 21 has been described with reference to FIG. 4, the planar array antennas 22 to 24 and 31 to 34 also have the same configuration as the planar array antenna 21 shown in FIG.

[0036] Fig. 5 is a diagram showing an example of a block configuration of the planar array antenna 21. As shown in Fig. 5, the planar array antenna 21 has M x N RF (Radio Frequency) units 51-1, 51-2, ..., 5M-N, a baseband (BB) unit 63, and an I / F (Interface) unit 64.

[0037] The RF unit 51-1 includes the antenna element 41 of P(1,1) shown in FIG.

[0038] The transceiver 61 up-converts the H polarized (vertical polarized) signal output from the baseband unit 63 to a radio frequency and outputs it to the P(1,1) antenna element 41. The transceiver 61 also down-converts the H polarized signal received by the P(1,1) antenna element 41 and outputs it to the baseband unit 63.

[0039] The transceiver 62 up-converts the V-polarized (horizontal polarized) signal output from the baseband unit 63 to a radio frequency and outputs it to the P(1,1) antenna element 41. The transceiver 62 also down-converts the V-polarized signal received by the P(1,1) antenna element 41 and outputs it to the baseband unit 63.

[0040] The RF units 51-2, ..., 5M-N have the same configuration as the RF unit 51-1, except that the RF unit 5m-n has P(m,n) antenna elements 41.

[0041] The baseband unit 63 is connected to the RF units 51-1, 51-2, ..., 5M-N via the interfaces of TRXBB-V / H(1,1), TRXBB-V / H(1,2), ..., TRXBB-V / H(M,N) that transmit and receive digital baseband signals. The baseband unit 63 performs baseband processing on signals received from the I / F unit 64 and outputs the signals to the RF units 51-1, 51-2, ..., 5M-N. The baseband unit 63 also performs baseband processing on signals output from the RF units 51-1, 51-2, ..., 5M-N and outputs the signals to the I / F unit 64.

[0042] Although an example of the block configuration of the planar array antenna 21 has been described with reference to FIG. 5, the planar array antennas 22 to 24 and 31 to 34 also have the same block configuration as the planar array antenna 21 shown in FIG.

[0043] Fig. 6 is a diagram showing an example of a block configuration of the HAPS 11. As shown in Fig. 6, the HAPS 11 includes the antenna device 20 shown in Fig. 2, a signal processing unit 72, and an I / F unit 73.

[0044] The antenna device 20 has planar array antennas 21-24 and 31-34 shown in Fig. 2. The planar array antennas 21-24 are arranged at a tilt angle TA1, and belong to antenna group G1 as shown in Fig. 6. The planar array antennas 31-34 are arranged at a tilt angle TA2, and belong to antenna group G2 as shown in Fig. 6. The antenna device 20 also has a control unit 71 not shown in Fig. 2.

[0045] The control unit 71 is connected to the I / F unit 64 of the planar array antenna 21 described in Fig. 5. As described in Fig. 5, the planar array antennas 22 to 24 and 31 to 34 also have an I / F unit similar to the I / F unit 64 of the planar array antenna 21 and are connected to the control unit 71.

[0046] Based on the position information and attitude information of the antenna device 20 and the position information of the ground station 12, the control unit 71 determines whether to communicate with the ground station 12 using antenna group G1 or antenna group G2.

[0047] When the control unit 71 determines that communication with the ground station 12 is to be performed using the antenna group G1, it communicates with the ground station 12 using one of the planar array antennas 21-24 of the antenna group G1. When the control unit 71 determines that communication with the ground station 12 is to be performed using the antenna group G2, it communicates with the ground station 12 using the planar array antennas 31-34 of the antenna group G2. The control unit 71 also performs the same determination and control as above in communication with the ground station 13.

[0048] The signal processing unit 72 has a ground station processing unit 72a and a ground station processing unit 72b, and performs regenerative relay processing of signals.

[0049] For example, the ground station processing unit 72a outputs a signal received from the ground station 12 from the TX terminal of the ground station processing unit 72a and outputs it to the RX terminal of the ground station processing unit 72b. The ground station processing unit 72b transmits the signal of the ground station 12 input to the RX terminal to the ground station 13. The ground station processing unit 72b outputs a signal received from the ground station 13 from the TX terminal of the ground station processing unit 72b and outputs it to the RX terminal of the ground station processing unit 72a. The ground station processing unit 72a transmits the signal of the ground station 13 input to the RX terminal to the ground station 12.

[0050] 6 indicates a control signal transmitted and received between the antenna device 20 and the signal processing unit 72. Channel 1 TRX indicates a signal received from the ground station 12 and a signal to be transmitted to the ground station 12. Channel 2 TRX indicates a signal received from the ground station 13 and a signal to be transmitted to the ground station 13.

[0051] Position information and attitude information of the HAPS 11 are input to the I / F unit 73. For example, a global navigation satellite system (GNSS) device is connected to the I / F unit 73, and a GNSS signal is input. Also, for example, an inertial sensor is connected to the I / F unit 73, and an attitude signal such as an acceleration signal or an angular velocity signal is input. As will be described later, the position information and attitude information of the HAPS 11, together with position information of the ground stations 12 and 13, are used to control the antenna groups G1 and G2.

[0052] Fig. 7 is a diagram for explaining the areas formed by antenna group G1 and antenna group G2. Fig. 7 shows the service area A11 explained in Fig. 1.

[0053] An area A21 between a solid-line circle C1 and a solid-line circle C2 shown in FIG. 7 indicates the communication area formed (provided) by the planar array antennas 21 to 24 of the antenna group G1.

[0054] An area A22 between a solid-line circle C1 and a solid-line circle C3 shown in FIG. 7 indicates a communication area formed by the planar array antennas 31 to 34 of the antenna group G2.

[0055] Therefore, the service area A11 provided by HAPS11 is made up of an area A21 and an area A22.

[0056] 3A and 3B, the inclination angle TA1 of the planar array antennas 21-24 of the antenna group G1 is smaller (shallower) than the inclination angle TA2 of the planar array antennas 31-34 of the antenna group G2. Therefore, the area A21 is formed outside the area A22.

[0057] The planar array antennas 21-24 of the antenna group G1 are arranged, for example, so that the normal to the antenna plane faces the boundary X11 that equally divides the area A21. This allows the region (area A21) covered by the swing width (upper limit angle and lower limit angle in the tilt angle direction of BF) in the tilt angle direction of BF (beamforming) to be approximately equally divided at the boundary X11.

[0058] The planar array antennas 31 to 34 of the antenna group G2 are arranged, for example, so that the normals of the antenna planes face the boundary X12 that equally divides the area A22. This allows the region (area A22) covered by the swing width in the tilt angle direction of BF to be approximately equally divided at the boundary X12.

[0059] In this way, when the planar array antennas 21 to 24 and 31 to 34 are arranged so as to equally divide the area A21 and the area A22, the antenna device 20 can suppress the degradation of the BF performance.

[0060] The planar array antennas 21 to 24 of the antenna group G1 and the planar array antennas 31 to 34 of the antenna group G2 are not limited to being arranged to equally divide the areas A21 and A22.

[0061] Moreover, since area A22 is closer to the rotation of HAPS 11 than area A21 and has a smaller free propagation loss, the area of ​​area A22 may be relatively larger. This makes the distribution of transmission power for each area uniform.

[0062] 8A and 8B are diagrams for explaining examples of control of antenna group G1 and antenna group G2. In Fig. 8A and Fig. 8B, the same components as those in Fig. 7 are denoted by the same reference numerals.

[0063] As shown in FIG. 8A, when the ground station 12 is located within the area A21, the HAPS 11 selects the planar array antenna that faces the ground station 12 in the azimuth direction from among the planar array antennas 21-24 of the antenna group G1 that forms the area A21.

[0064] For example, the HAPS 11 selects a planar array antenna among the planar array antennas 21 to 24 of the antenna group G1, the normal of the antenna plane of which is oriented in a direction within a range of ±45 degrees in the azimuth direction based on the ground station 12. The HAPS 11 performs BF control on the selected planar array antenna, and directs the beam toward the ground station 12.

[0065] As shown in FIG. 8B, when the ground station 12 is located within the area A22, the HAPS 11 selects the planar array antenna that faces the ground station 12 in the azimuth direction from among the planar array antennas 31 to 34 of the antenna group G2 that forms the area A22.

[0066] For example, the HAPS 11 selects a planar array antenna from among the planar array antennas 31 to 34 of the antenna group G2, the normal to the antenna plane of which is oriented in a direction within a range of ±45 degrees in the azimuth direction based on the ground station 12. The HAPS 11 performs BF control on the selected planar array antenna, and directs the beam toward the ground station 12.

[0067] Although an example of control of antenna group G1 and antenna group G2 for ground station 12 has been described above, HAPS 11 performs similar control for ground station 13 as well.

[0068] Furthermore, the angular range in the azimuth direction based on the ground station 12 is not limited to ±45 degrees. The angular range in the azimuth direction based on the ground station 12 may be changed depending on the number of planar array antennas. For example, if the number of planar array antennas is large, the angular range in the azimuth direction based on the ground station 12 becomes smaller.

[0069] Fig. 9 is a flowchart illustrating an example of the operation of the antenna device 20. The control unit 71 of the antenna device 20 starts the process of the flowchart shown in Fig. 9, for example, when the HAPS 11 starts turning at a target location where it is hovering in the air.

[0070] The control unit 71 acquires position information of the HAPS 11, position information of the ground stations 12 and 13, and attitude information of the HAPS 11 (S1).

[0071] The control unit 71 acquires position information and attitude information of the HAPS 11 via the I / F unit 73. The position information of the ground stations 12, 13 is stored in advance in a storage device such as a memory included in the control unit 71, for example, before the HAPS 11 starts flying. The position information includes, for example, latitude, longitude, and altitude.

[0072] The control unit 71 determines whether the ground station 12 is located in area A21 or area A22 based on the position information and attitude information of the HAPS 11 acquired in S1 and the position information of the ground stations 12 and 13 (S2).

[0073] That is, the control unit 71 determines whether the ground station 12 is located in the area A21 formed by the planar array antennas 21-24 of the antenna group G1, or whether the ground station 12 is located in the area A22 formed by the planar array antennas 31-34 of the antenna group G2.

[0074] When the control unit 71 determines that the ground station 12 is located in the area A21 formed by the planar array antennas 21-24 of the antenna group G1 ("area A21" in S2), it executes BF control toward the ground station 12 using the planar array antennas 21-24 (S3a-S7a). When the control unit 71 determines that the ground station 12 is located in the area A22 formed by the planar array antennas 31-34 of the antenna group G2 ("area A22" in S2), it executes BF control toward the ground station 12 using the planar array antennas 31-34 (S3b-S7b).

[0075] Hereinafter, the processes (S3a to S7a) performed when the control unit 71 determines that the ground station 12 is located in the area A21 formed by the planar array antennas 21 to 24 of the antenna group G1 will be described.

[0076] The control unit 71 acquires (S3a) the position information of the HAPS 11, the position information of the ground stations 12 and 13, and the attitude information of the HAPS 11. Note that the control unit 71 acquires the position information of the HAPS 11, the position information of the ground stations 12 and 13, and the attitude information of the HAPS 11 by a process similar to the process of S1.

[0077] Based on the position information and attitude information of HAPS 11 acquired in S3a and the position information of the ground stations 12, 13, the control unit 71 selects, from among the planar array antennas 21-24 of the antenna group G1, a planar array antenna whose normal to the antenna plane is oriented within a predetermined angle range from the azimuth angle direction based on the ground station 12 (S4a).

[0078] The control unit 71 uses the planar array antenna selected in S4a to calculate the weight of the BF to face the direction of the ground station 12 (S5a). The control unit 71 calculates the direction of the BF toward the ground station 12 based on the position information and attitude information of the HAPS 11 acquired in S3a and the position information of the ground stations 12 and 13.

[0079] The control unit 71 controls (forms) the BF in the planar array antenna selected in S4a by using the weight calculated in S5a (S6a).

[0080] The control unit 71 determines whether or not a predetermined time has elapsed (S7a).

[0081] When the control unit 71 determines that the predetermined time has not elapsed ("No" in S7a), the control unit 71 shifts the process to S3a. That is, the control unit 71 performs BF control using the planar array antennas 21 to 24 of the antenna group G1.

[0082] On the other hand, if the control unit 71 determines that the predetermined time has elapsed ("Yes" in S7a), the process proceeds to S1. Then, in S2, the control unit 71 determines whether the ground station 12 is located in area A21 or area A22.

[0083] In other words, the frequency of determining whether the ground station 12 is located in area A21 or area A22 in the tilt angle direction (processing of S2) is less than the frequency of BF control (S3a to S6a). This is because the fluctuation in the tilt angle direction of the ground station 12 relative to the HAPS 11 is small even when the HAPS 11 rotates in the air.

[0084] It should be noted that steps S3b to S7b are BF control processes in the planar array antennas 31 to 34 of the antenna group G2, and are similar to the processes S3a to 37a, so that the description thereof will be omitted.

[0085] The control unit 71 also executes the process of the flowchart in FIG.

[0086] An example of the weight calculation in S5a will be described. The control unit 71 calculates the direction of the ground station 12 relative to the antenna surface of the planar array antenna selected in S4a based on the position information and attitude information of the HAPS 11 and the position information of the ground station 12. That is, the control unit 71 calculates the beam direction "r0" to be formed by the planar array antenna selected in S4a. Then, the control unit 71 performs BF control using the weight "w0" that directs the beam to the calculated beam direction "r0" by using each of the M×N RF units (see, for example, RF units 51-1, 51-2, ..., 5M-N in FIG. 5) of the planar array antenna selected in S4a.

[0087] The weight w0(m,n) used in the RF unit of P(m,n) is calculated using the value of equation (1). Here, p(m,n) indicates the vector from the center of the antenna plane to the antenna element P(m,n). j indicates the imaginary unit. k indicates the wave number at the frequency used. r0 is a vector indicating the beam direction. ur0 is a unit vector in the r0 direction.

[0088] w0(m,n)=exp(-j×k×(ur0·p(m,n))) (1)

[0089] Through the above processing, the antenna device 20 can perform BF control that follows the changes in position and attitude of the HAPS 11.

[0090] As described above, the antenna device 20 mounted on HAPS11 has planar array antennas 31-34 arranged in a ring shape and forming area A22 on the ground, and planar array antennas 21-24 arranged in a ring shape and forming area A21 outside area A22.

[0091] In this way, the antenna device 20 forms the area A22 with the planar array antennas 31-34, and forms the area A21 outside of that with the planar array antennas 31-34, thereby forming a wide communication area.

[0092] Furthermore, the antenna device 20 does not have a planar array antenna with an antenna surface facing directly downward. In other words, the antenna device 20 does not have an antenna element on its bottom surface (surface facing the ground). This eliminates the need for polarization control by yaw rotation of the HAPS 11 in the antenna device 20.

[0093] For example, a planar array antenna with its antenna surface facing straight down rotates at the same angle as the yaw rotation of the HAPS 11. As a result, the polarized waves of the communication path with the ground stations 12 and 13 rotate according to the yaw rotation of the HAPS 11. In order to form a stable communication path in a planar array antenna with its antenna surface facing straight down, polarization control that follows the yaw-rotating polarized waves is required, which makes the BF control complicated.

[0094] In contrast, the antenna device 20 does not have a planar array antenna whose antenna surface faces directly downward. The antenna device 20 covers an area formed by a planar array antenna whose antenna surface faces directly downward, for example, by the planar array antennas 31 to 34 of the antenna group G2. This makes it unnecessary for the antenna device 20 to perform polarization control by yaw rotation of the HAPS 11.

[0095] In addition, in Fig. 4, an example of a planar array antenna with 8 x 8 antenna elements is shown as an example, but the number of antenna elements is not limited to this. The number of antenna elements (M x N) may be determined according to the line design between the HAPS 11 and the ground station.

[0096] Furthermore, a planar array antenna with different numbers of vertical and horizontal axes (M ≠ N) may be used for the antenna device 20. The control unit 71 calculates the weights using equation (1) according to the positions P(m, n) of the antenna elements, thereby enabling BF control that follows the changes in position and attitude of the HAPS 11.

[0097] Furthermore, the planar array antennas 21 to 24 and 31 to 34 may be configured as digital phased arrays, which allows the antenna device 20 to control the BF with higher accuracy than when the planar array antennas 21 to 24 and 31 to 34 are configured as analog phased arrays.

[0098] Furthermore, the planar array antennas 21 to 24 and 31 to 34 may be configured as analog phased arrays, which allows the antenna device 20 to consume less power than when the planar array antennas 21 to 24 and 31 to 34 are configured as digital phased arrays.

[0099] The planar array antennas 21-24 and 31-34 may be configured with an analog phased array and a digital phased array. This allows the antenna device 20 to reduce power consumption with the analog phased array, while compensating for the BF that cannot be controlled with high precision with the analog phased array with the digital phased array.

[0100] Furthermore, the array antenna does not have to be a planar array antenna, and the antenna surface of the array antenna may be a curved surface.

[0101] The antenna device 20 divides the service area A11 into concentric areas A21 and A22 by the planar array antennas 21-24 and 31-34 of the antenna groups G1 and G2, which have different inclination angles of the antenna planes. The antenna device 20 is set so that the antenna planes of the planar array antennas 21-24 of the antenna group G1 in the inclination angle direction equally divide the area A21. The antenna device 20 is set so that the antenna planes of the planar array antennas 31-34 of the antenna group G2 in the inclination angle direction equally divide the area A22. The antenna device 20 selects the antenna groups G1 and G2 to be BFed based on the areas A21 and A22 where the ground stations 12 and 13 are located. The antenna device 20 calculates the beam direction and weight based on the coordinates (position) and attitude of the HAPS and the positions of the ground stations, and performs BF control using the planar array antennas of the selected antenna group.

[0102] This allows the antenna device 20 to perform BF control following changes in the position and attitude of the HAPS 11. Furthermore, the antenna device 20 divides the service area A11 into areas A21 and A22 using planar array antennas 21-24 and 31-34 of antenna groups G1 and G2 with different tilt angles, thereby reducing the swing angle width of the BF in the tilt angle direction and suppressing gain deviation due to the angle difference of the antenna plane relative to the ground stations 12 and 13. Furthermore, the antenna device 20 can reduce the dynamic range of the BF and reduce power consumption. Note that since the HAPS 11 drives onboard equipment with limited power capacity of onboard batteries, solar cells, etc., reducing power consumption is important.

[0103] (Variation 1) In the first modification, when the ground station 12 is located near the boundary between the areas A21 and A22 (for example, near the circle C1 in FIG. 7), the antenna device 20 does not execute BF control by the planar array antenna based on the antenna group G1, G2 determination. That is, when the ground station 12 is located near the boundary between the areas A21 and A22, the antenna device 20 does not distinguish between the antenna groups G1 and G2, and selects a planar array antenna to be subjected to BF control from the planar array antennas 21-24 and 31-34.

[0104] Fig. 10 is a top view of the antenna device 20 shown in Fig. 2. In Fig. 10, the same components as those in Fig. 2 are denoted by the same reference numerals.

[0105] For example, after the process of S1 described in FIG. 9, the control unit 71 of the antenna device 20 determines whether or not the ground station 12 is located within a predetermined distance from the boundary between the areas A21 and A22 (for example, the circle C1 in FIG. 7).

[0106] If the control unit 71 determines that the ground station 12 is not located within a predetermined distance from the boundary between the areas A21 and A22, it executes the processes from S2 onward described with reference to FIG.

[0107] On the other hand, if the control unit 71 determines that the ground station 12 is located within a predetermined distance from the boundary between the areas A21 and A22, it acquires the position information of the HAPS 11, the position information of the ground stations 12 and 13, and the attitude information of the HAPS 11.

[0108] Based on the acquired position information and attitude information of HAPS 11 and position information of ground stations 12, 13, the control unit 71 selects from the planar array antennas 21-24 and the planar array antennas 31-34 the planar array antenna whose normal to the antenna plane is oriented within a predetermined angle range in the azimuth direction based on the ground station 12.

[0109] That is, the control unit 71, without distinguishing between antenna groups G1 and G2, selects from among the planar array antennas 21-24 and the planar array antennas 31-34 a planar array antenna whose antenna plane normal faces within a predetermined angle range (angle ranges AZ21-AZ24, AZ31-AZ34 shown in Figure 10) in the azimuth direction based on the ground station 12.

[0110] For example, it is assumed that the ground station 12 is located within a predetermined distance from the boundary between the areas A21 and A22, and within the angular range AZ23 shown in FIG.

[0111] The control unit 71 calculates the weight of the BF for pointing in the direction of the ground station 12 using the selected planar array antenna.

[0112] The control unit 71 controls the BF in the selected planar array antenna using the calculated weights.

[0113] The control unit 71 determines whether a predetermined time has elapsed, and if the predetermined time has not elapsed, executes a planar array antenna selection process that does not distinguish between the antenna groups G1 and G2. If the predetermined time has elapsed, the control unit 71 determines whether the ground station 12 is located within a predetermined distance from the boundary between the areas A21 and A22.

[0114] The above process enables the antenna device 20 to suppress an increase in power consumption, and also enables efficient BF control.

[0115] For example, near the boundary between areas A21 and A21, the antenna groups G1 and G2 with good gains fluctuate frequently due to changes in the attitude of the HAPS 11, while the difference in antenna gain between the antenna groups G1 and G2 is not large. Therefore, as described above, when the ground station 12 is located near the boundary between areas A21 and A21, the antenna device 20 does not distinguish between the antenna groups G1 and G2, and selects a planar array antenna to be subjected to BF control from among the planar array antennas 21-24 and 31-34. In this way, the antenna device 20 prevents a state in which a group antenna with low antenna gain is selected for a predetermined time (see S7a and S7b in FIG. 9), and suppresses an increase in power consumption. Furthermore, the antenna device 20 can perform efficient BF control.

[0116] As described above, the control unit 71 determines whether the ground stations 12, 13 are located within a predetermined distance from the boundary between area A21 and area A22, and if it determines that the ground stations 12, 13 are located within the predetermined distance, it selects an array antenna facing the ground stations 12, 13 from among the planar array antennas 21-24, 31-34. Then, the control unit 71 performs BF control toward the ground stations 12, 13 using the selected planar array antenna. This allows the antenna device 20 to reduce power consumption and perform efficient BF control.

[0117] (Second embodiment) 11 is a perspective view of an antenna device 80 according to the second embodiment. As shown in FIG.

[0118] The planar array antennas 81 to 84 have, for example, the tilt angle TA1 shown in Fig. 3A. The planar array antennas 81 to 84 form an antenna group G1.

[0119] The planar array antennas 86 to 89 have, for example, the tilt angle TA2 shown in Fig. 3B. The planar array antennas 86 to 89 form an antenna group G2.

[0120] The planar array antennas 81 to 84 of the antenna group G1 are disposed above the planar array antennas 86 to 89 of the antenna group G2.

[0121] The antenna device 80 can reduce the horizontal footprint by arranging planar array antennas of antenna groups with different tilt angles in the vertical direction. Furthermore, when the mounting conditions of the HAPS 11 limit the horizontal footprint, the antenna device 80 can be easily mounted on the HAPS 11.

[0122] The control unit of the antenna device 80 executes the same process as that shown in the flowchart of Fig. 9. The control unit of the antenna device 80 performs BF control that follows the changes in position and attitude of the HAPS 11 by using the weights in equation (1) that correspond to the positions of the antenna elements.

[0123] As described above, the planar array antennas 81 to 84 are arranged above the planar array antennas 86 to 89. This allows the antenna device 80 to perform BF control that follows changes in the position and attitude of the HAPS 11, and reduces the area occupied in the horizontal direction.

[0124] The planar array antennas 81 to 84 may be disposed below the planar array antennas 86 to 89.

[0125] Furthermore, the number of the planar array antennas 81 to 84 in the antenna group G1 does not have to be the same as the number of the planar array antennas 86 to 89 in the antenna group G2.

[0126] 11, one planar array antenna having a tilt angle TA1 may be disposed between each of the planar array antennas 81 to 84 of the antenna group G1. For example, the number of planar array antennas in the antenna group G1 may be eight, and the number of planar array antennas in the antenna group G2 may be four.

[0127] (Third embodiment) 12 is a perspective view of an antenna device 90 according to the third embodiment. As shown in FIG.

[0128] Array antenna 91 has planar subarray antennas 91a to 91d as shown in Fig. 12. Each of subarray antennas 91a to 91d is formed with, for example, the same number of antenna elements.

[0129] The bottom subarray antenna 91a has the largest inclination angle. The second bottom subarray antenna 91b has the second largest inclination angle. The third bottom subarray antenna 91c has the third largest inclination angle. The top subarray antenna 91d has the smallest inclination angle. That is, the inclination angles of the subarray antennas 91a to 91d decrease as they move upward.

[0130] Like the array antenna 91, the array antennas 92 to 94 also have sub-array antennas.

[0131] The bottommost subarray antenna of each of the array antennas 91-94 constitutes antenna group G1, forming a first communication area. The second lowest subarray antenna of each of the array antennas 91-94 constitutes antenna group G2, forming a second communication area outside the first communication area. The third lowest subarray antenna of each of the array antennas 91-94 constitutes antenna group G3, forming a third communication area outside the second communication area. The fourth lowest subarray antenna of each of the array antennas 91-94 constitutes antenna group G4, forming a fourth communication area outside the third communication area.

[0132] The control unit of the antenna device 90 selects an antenna group that corresponds to the positions of the ground stations 12, 13 in the tilt angle direction. The control unit performs BF control on the sub-array antennas of the selected antenna group using the weights of equation (1).

[0133] As described above, each of the array antennas 91 to 94 has a sub-array antenna that forms a different communication area on the ground. This enables the antenna device 90 to reduce the number of operating RF units (for example, see RF units 51-1, 51-2, ..., 5M-N in FIG. 5) and reduce power consumption.

[0134] Although FIG. 12 shows an example of a configuration in which the tilt angle of the subarray antenna increases from the top, the subarray antenna may be configured so that the tilt angle increases from the bottom.

[0135] (Fourth embodiment) Fig. 13 is a diagram showing an example of a block configuration of an antenna device 20 according to a fourth embodiment. As shown in Fig. 13, the antenna device 20 includes an RF unit 101, SWs (switches) 103a and 103b, a TX-H line (H-polarized wave transmission line) 104a, an RX-H line (H-polarized wave reception line) 104b, a TX-V (V-polarized wave transmission line) line 105a, an RX-V (V-polarized wave reception line) line 105b, an RF-BB conversion unit 106, and a baseband unit 111.

[0136] The RF unit 101 includes P(m,n) antenna elements 41 and RF sections 102a and 102b. Each of the RF sections 102a and 102b includes a duplexer, a power amplifier (PA), and a low noise amplifier (LNA).

[0137] The duplexer of the RF unit 102a is connected to the H polarization terminal of the antenna element 41. The PA of the RF unit 102a is connected to the TX-H line 104a when SW103a is turned on. The LNA of the RF unit 102a is connected to the RX-H line 104b when SW103a is turned on.

[0138] The duplexer of the RF unit 102b is connected to the V polarization terminal of the antenna element 41. The PA of the RF unit 102b is connected to the TX-V line 105a when SW103b is turned on. The LNA of the RF unit 102b is connected to the RX-V line 105b when SW103b is turned on.

[0139] The RF-BB conversion unit 106 includes an up-converter 107a, a digital-to-digital converter (DAC) 108a, a down-converter 109a, and an analog-to-digital converter (ADC) 110a. The RF-BB conversion unit 106 also includes an up-converter 107b, a DAC 108b, a down-converter 109b, and an ADC 110b.

[0140] When SW 103a is turned on, upconverter 107a is connected to TX-H line 104a. Therefore, when SW 103a is turned on or off, the PA of RF unit 102a is connected to or disconnected from upconverter 107a.

[0141] When SW 103a is turned on, downconverter 109a is connected to RX-H line 104b. Therefore, the LNA of RF unit 102a is connected to downconverter 109a or disconnected from downconverter 109a by turning SW 103a on and off.

[0142] When SW 103b is turned on, upconverter 107b is connected to TX-V line 105a. Therefore, when SW 103b is turned on or off, the PA of RF unit 102b is connected to or disconnected from upconverter 107b.

[0143] When SW 103b is turned on, downconverter 109b is connected to RX-V line 105b. Therefore, the LNA of RF unit 102b is connected to downconverter 109b or disconnected from downconverter 109b by turning SW 103b on and off.

[0144] The H polarized transmission digital signal output from the baseband unit 111 is converted to an analog signal by the DAC 108a. The analog signal is converted to a signal in the RF frequency band by the up-converter 107a.

[0145] The V-polarized transmission digital signal output from the baseband unit 111 is converted to an analog signal by the DAC 108b. The analog signal is converted to a signal in the RF frequency band by the up-converter 107b.

[0146] The H polarized reception signal transmitted through the RX-H line 104b is converted to a baseband signal by the downconverter 109a. The baseband signal is converted to an H polarized reception digital signal by the ADC 110a. The H polarized reception digital signal is output to the baseband unit 111.

[0147] The H polarized reception signal transmitted through the RX-H line 105b is converted to a baseband signal by the downconverter 109b. The baseband signal is converted to an H polarized reception digital signal by the ADC 110b. The H polarized reception digital signal is output to the baseband unit 111.

[0148] The baseband unit 111 performs baseband processing of signals to be transmitted to the ground stations 12 and 13. The baseband unit 111 also performs baseband processing of signals received from the ground stations 12 and 13.

[0149] The antenna device 20 has M×N RF-BB conversion units 106. That is, the antenna device 20 has the same number of RF-BB conversion units 106 as the number of antenna elements in one planar array antenna. RF units 101 having antenna elements positioned correspondingly in each of the planar array antennas 21-24, 31-34 are connected to the RF-BB conversion units 106, the number of which is the same as the number of antenna elements in one planar array antenna, via SW.

[0150] For example, the RF unit 101 having the antenna element P(1,1) of the planar array antennas 21-24, 31-34 is connected to the 1-1 RF-BB conversion unit 106 via a SW. The RF unit 101 having the antenna element P(1,2) of the planar array antennas 21-24, 31-34 is connected to the 1-2 RF-BB conversion unit 106 via a SW. The RF unit 101 having the antenna element P(1,3) of the planar array antennas 21-24, 31-34 is connected to the 1-3 RF-BB conversion unit 106 via a SW. Similarly, the RF unit 101 having the antenna element P(M,N) of the planar array antennas 21-24, 31-34 is connected to the MN RF-BB conversion unit 106 via a SW.

[0151] Then, for example, the M×N RF units of the planar array antenna selected in S4a and S4b in FIG. 9 are connected to the M×N RF-BB conversion units 106 by on / off control of the SW.

[0152] That is, the M×N RF-BB conversion units 106 are connected to the M×N antenna elements (RF units) in the planar array antenna selected from the planar array antennas 21-24, 31-34 via SW.

[0153] In the BF control, the control unit 71 selects the planar array antennas 21-24, 31-34. The control unit 71 switches the connection of the TX signal and the RX signal to the RF unit corresponding to the selected planar array antenna by SW103a, 103b. For example, the control unit 71 switches the SW103a, 103b on and off according to the selection of the planar array antenna by S4a, 4b in FIG. 9. As a result, beams in the directions of the ground stations 12, 13 are formed.

[0154] As described above, in the antenna device 20, the RF-BB converter 106 that converts the frequency of a signal is shared among the antenna elements of the planar array antennas 21 to 24 and 31 to 34. This allows the antenna device 20 to reduce power consumption.

[0155] Although the block configuration example of the antenna device 20 has been described above, the block configuration example of FIG.

[0156] In the above-described embodiments, the notation "... part" used for each component may be replaced with other notations such as "... circuit", "... assembly", "... device", "... unit", or "... module".

[0157] Although the embodiments have been described above with reference to the drawings, the present disclosure is not limited to such examples. It is clear that a person skilled in the art can come up with various modified or altered examples within the scope of the claims. It is understood that such modified or altered examples also belong to the technical scope of the present disclosure. In addition, the components in the embodiments may be arbitrarily combined within the scope of the present disclosure.

[0158] The present disclosure can be realized by software, hardware, or software in cooperation with hardware. Each functional block used in the description of the above embodiment may be realized partially or entirely as an LSI, which is an integrated circuit, and each process described in the above embodiment may be controlled partially or entirely by one LSI or a combination of LSIs. The LSI may be composed of individual chips, or may be composed of one chip so as to include some or all of the functional blocks. The LSI may have input and output of data. Depending on the degree of integration, the LSI may be called an IC, a system LSI, a super LSI, or an ultra LSI.

[0159] The method of integration is not limited to LSI, and may be realized by a dedicated circuit, a general-purpose processor, or a dedicated processor. Also, after LSI manufacturing, a programmable FPGA (Field Programmable Gate Array) or a reconfigurable processor that can reconfigure the connections and settings of circuit cells inside the LSI may be used. The present disclosure may be realized as digital processing or analog processing.

[0160] Furthermore, if a new integrated circuit technology that can replace LSI appears due to the progress of semiconductor technology or a derivative technology, it is possible to integrate the functional blocks using that technology. The application of biotechnology is also a possibility. [Industrial Applicability]

[0161] The present disclosure can be applied to a relay device that floats in the air and relays communications between terrestrial radio stations. [Explanation of symbols]

[0162] 1. Communication Systems 11 HAPS 12,13 Ground Station 20 Antenna device 21~24,31~34 Planar array antenna 41 Antenna element 51-1, 51-2, …, 5M-N RF unit 61,62 Transmitter / Receiver 63 Baseband section 64 I / F section 71 Control Unit 72 Signal Processing Section 72a, 72b Ground station processing section 73 I / F section 80 Antenna equipment 81-84, 86-89 Planar array antennas 90 Antenna equipment 91~94 Array Antenna 91a~91d Subarray antennas

Claims

1. An antenna device mounted on an airborne communication device, a first array antenna arranged in a ring shape to form a first communication area on the ground; a second array antenna arranged in a ring shape and forming a second communication area outside the first communication area; a control unit that determines whether the ground station is located in the first communication area or the second communication area based on position information and attitude information of the antenna device and position information of a ground station; An antenna device having the above configuration.

2. the first array antenna includes a plurality of first planar array antennas having a first depression angle; the second array antenna includes a plurality of second planar array antennas having a second depression angle; 2. The antenna device according to claim 1.

3. The plurality of first planar array antennas and the plurality of second planar array antennas are arranged alternately in a circular shape.

3. The antenna device according to claim 2.

4. the second planar array antennas are disposed above or below the first planar array antennas; 3. The antenna device according to claim 2.

5. The control unit is When it is determined that the ground station is located in the first communication area, performing beamforming control toward the ground station using the first array antenna; When it is determined that the ground station is located in the second communication area, the second array antenna is used to perform beamforming control toward the ground station.

2. The antenna device according to claim 1.

6. The control unit is determining whether the ground station is located within a predetermined distance from a boundary between the first communication area and the second communication area; When it is determined that the ground station is located within the predetermined distance, an array antenna that faces the ground station is selected from the first array antenna and the second array antenna; Using the selected array antenna, perform beamforming control toward the ground station.

2. The antenna device according to claim 1.

7. a frequency converter that converts a frequency of a signal is shared between antenna elements in each of the plurality of first planar array antennas and antenna elements in each of the plurality of second planar array antennas; 3. The antenna device according to claim 2.

8. The first array antenna and the second array antenna are configured as digital phased arrays.

2. The antenna device according to claim 1.

9. The first array antenna and the second array antenna are configured as analog phased arrays.

2. The antenna device according to claim 1.

10. The first array antenna and the second array antenna are configured as an analog phased array and a digital phased array.

2. The antenna device according to claim 1.

11. An antenna device mounted on an airborne communication device, a first subarray antenna arranged in a ring shape to form a first communication area on the ground; an array antenna having a second subarray antenna arranged in a ring shape and forming a second communication area outside the first communication area; a control unit that determines whether the ground station is located in the first communication area or the second communication area based on position information and attitude information of the antenna device and position information of a ground station; An antenna device having the above configuration.

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