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] A phased array antenna capable of beamforming is known as an antenna device mounted on a floating relay device. Patent Document 1 discloses a hexagonal pyramidal antenna device equipped with multiple planar array antennas in Figure 30. [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] Japanese Patent Application Publication No. 2020-080459 Summary of the Invention [Problem to be solved by the invention]

[0005] Airborne repeaters such as HAPS are expected to provide a wider communication area.

[0006] Non-limiting examples of the present disclosure contribute 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, which has 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. [Effects 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 explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a diagram illustrating an example of the configuration of a communication system according to a first embodiment. [Figure 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 [Figure 5] 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 the antenna group [Figure 8A] A diagram explaining an example of antenna group control [Figure 8B] A diagram explaining an example of antenna group control [Figure 9] Flowchart for explaining an example of operation of the antenna device [Figure 10] FIG. 3 is a top view of the antenna device shown in FIG. [Figure 11] FIG. 10 is a perspective view of an antenna device according to a second embodiment; [Figure 12] FIG. 10 is a perspective view of an antenna device according to a third embodiment. [Figure 13] FIG. 10 is a block diagram illustrating an example of the configuration of an antenna device according to a fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, 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 redundant explanation of substantially identical configurations may be omitted. This is to avoid unnecessary redundancy in the following explanation and to facilitate understanding by those skilled in the art.

[0013] 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 the 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 communications between a ground station 12 and a ground station 13, both of which 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) wireless communication links between ground station 12 and ground station 13.

[0018] Note that HAPS may be referred to as an airborne relay device, relay station, radio station, or communication device. Ground stations may be referred to as base stations, radio stations, or communication devices. Service areas may be referred to as communication areas or areas.

[0019] Furthermore, HAPS route R11 does not have to be circular. For example, HAPS route R11 may be shaped like 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 to 24 (second array antennas) and planar array antennas 31 to 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 and 31-34 are arranged in a ring shape. The planar array antennas 21-24 and 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 and 31-34 face toward the ground when the HAPS 11 is floating in the air. As the planar array antennas 21-24 and 31-34 are arranged in a ring shape, the antenna elements formed on the antenna surfaces of the planar array antennas 21-24 and 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 to 24 is the same. The depression angle of the antenna plane of each of the planar array antennas 31 to 34 is the same. Note that "same" includes "substantially the same" unless otherwise specified. Also, 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." Also, hereinafter, the depression angle will be referred to as the tilt angle.

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

[0024] 3A indicates the normal to the planar array antenna 21. The normal to the planar array antenna 21 points 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 a tilt angle TA1.

[0026] The dotted line X2 in Fig. 3B indicates the normal to the planar array antenna 31. The normal to the planar array antenna 31 points downward relative to the horizontal. 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 tilt angle TA2 is less than 90 degrees. Therefore, the antenna planes of the planar array antennas 31 to 34 do not point directly downward. The antenna planes of the planar array antennas 31 to 34 having a tilt angle TA1 smaller than the tilt angle TA2 also do not point 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 so that the tilt 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 arranged 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 arranged 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 arranged 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 in vertical and horizontal directions. The antenna elements 41 are, for example, dual-polarized patch antennas 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 represented as P(m, n). m represents the position of the antenna element 41 in the vertical direction. n represents 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 the example of the planar array antenna 21 shown in FIG. 4, P(M, N) is M=N=8.

[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 × 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 has the antenna element 41 of P(1,1) shown in FIG.

[0038] The transceiver 61 up-converts the H polarized (vertically 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 interfaces 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] 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.

[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 an inclination angle TA1 and belong to antenna group G1 as shown in Fig. 6. The planar array antennas 31-34 are arranged at an inclination 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 I / F units similar to the I / F unit 64 of the planar array antenna 21, and are connected to the control unit 71.

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

[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 to 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 to 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 from the ground station 12 input to the RX terminal to the ground station 13. The ground station processing unit 72b outputs the 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 from 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 attitude signals such as acceleration signals and angular velocity signals are 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] 7 is a diagram illustrating the areas formed by antenna group G1 and antenna group G2, and shows the service area A11 described in FIG.

[0053] An area A21 sandwiched between a solid circle C1 and a solid 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 sandwiched between a solid circle C1 and a solid circle C3 shown in FIG. 7 indicates the 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 area A21 and area A22.

[0056] 3A and 3B, the tilt angle TA1 of the planar array antennas 21-24 of the antenna group G1 is smaller (shallower) than the tilt 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 normals to the antenna planes face the boundary X11 that equally divides the area A21. This allows the area (area A21) covered by the swing range (upper and lower limit angles in the tilt angle direction of BF (beamforming)) in the tilt angle direction to be divided approximately equally 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 to 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 divided into approximately equal parts 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 a decrease in 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] Furthermore, area A22 may be relatively larger than area A21 because the eccentric distance from the turning point of HAPS 11 is shorter and the free propagation loss is smaller. This allows the distribution of transmission power to each area to be uniform.

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

[0063] As shown in Figure 8A, when the ground station 12 is located within area A21, HAPS11 selects the planar array antenna that faces the ground station 12 in the azimuth direction from among the planar array antennas 21 to 24 of antenna group G1 that forms area A21.

[0064] For example, the HAPS 11 selects a planar array antenna from among the planar array antennas 21 to 24 of the antenna group G1, the normal to the antenna plane of which is oriented in a direction within a range of ±45 degrees in the azimuth direction relative to 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 Figure 8B, when the ground station 12 is located within area A22, HAPS11 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 antenna group G2 that form 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 relative to 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 the antenna group G1 and the antenna group G2 for the ground station 12 has been described above, the HAPS 11 also performs similar control for the ground station 13.

[0068] Furthermore, the angular range in the azimuth direction relative to the ground station 12 is not limited to ±45 degrees. The angular range in the azimuth direction relative to 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 relative to the ground station 12 becomes smaller.

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

[0070] 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 (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 and 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 to 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 to 34 of the antenna group G2.

[0074] When the control unit 71 determines that the ground station 12 is located in 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 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] The following describes the processing (S3a to S7a) 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.

[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 HAPS11 acquired in S3a and the position information of ground stations 12 and 13, the control unit 71 selects from among the planar array antennas 21 to 24 of antenna group G1 a planar array antenna whose normal to the antenna surface is oriented within a predetermined angle range from the azimuth angle direction based on 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 point toward 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 using the weight calculated in S5a (S6a).

[0080] The control unit 71 determines whether a predetermined time has elapsed (S7a).

[0081] If the control unit 71 determines that the predetermined time has not elapsed ("No" in S7a), the control unit 71 proceeds 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 control unit 71 shifts the process 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 lower than the frequency of BF control (S3a to S6a). This is because even when the HAPS 11 rotates in the air, fluctuations in the tilt angle direction of the ground station 12 relative to the HAPS 11 are small.

[0084] 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 of S3a to 37a, so a 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 plane 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. The control unit 71 then performs BF control using the weight "w0" that directs the beam toward 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) represents the vector from the center of the antenna surface to the antenna element P(m,n). j represents the imaginary unit. k represents 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 the position and attitude of the HAPS 11.

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

[0091] In this way, the antenna device 20 forms the area A22 with the planar array antennas 31 to 34, and forms the area A21 outside of that with the planar array antennas 31 to 34, so that a wide communication area can be formed.

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

[0093] For example, a planar array antenna with its antenna surface facing directly downward rotates at the same angle as the yaw rotation of the HAPS 11. As a result, the polarization of the communication path with the ground stations 12 and 13 rotates in accordance with the yaw rotation of the HAPS 11. To form a stable communication path in a planar array antenna with its antenna surface facing directly downward, polarization control that follows the yaw-rotating polarization is required, which makes 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 uses, for example, the planar array antennas 31 to 34 of the antenna group G2 to cover the area formed by a planar array antenna whose antenna surface faces directly downward. This eliminates the need for the antenna device 20 to control polarization by yaw rotation of the HAPS 11.

[0095] 4 shows an example of a planar array antenna with 8 × 8 antenna elements, but the number of antenna elements is not limited to this. The number of antenna elements (M × N) may be determined according to the link design between the HAPS 11 and the ground station.

[0096] Furthermore, a planar array antenna with different numbers of vertical and horizontal elements (M≠N) may be used for the antenna device 20. The control unit 71 calculates the weights using equation (1) according to the position P(m, n) of the antenna elements, thereby enabling BF control that follows changes in the 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 precision 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 to 24 and 31 to 34 may be configured with analog phased arrays and digital phased arrays. This allows the antenna device 20 to reduce power consumption with the analog phased array, while using the digital phased array to compensate for the BF that cannot be controlled with high precision with the analog 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 also divides the service area A11 into concentric areas A21 and A22 using planar array antennas 21-24 and 31-34 of antenna groups G1 and G2, which have different inclination angles of the antenna planes. The antenna device 20 is set so that the orientations of 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 orientations of 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 perform BF 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 that follows changes in the position and attitude of the HAPS 11. Furthermore, by dividing 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, the antenna device 20 can reduce the BF swing angle width in the tilt angle direction and suppress gain deviation due to the angle difference between the antenna plane and the ground stations 12 and 13. Furthermore, the antenna device 20 can reduce the dynamic range of the BF and reduce power consumption. Since the HAPS 11 operates onboard equipment with limited power capacity from onboard batteries and solar cells, 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 using the planar array antenna based on the determination of the antenna groups G1 and G2. In other words, 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 the ground station 12 is located within a predetermined distance from the boundary between areas A21 and A22 (for example, 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 onwards 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 the position information of ground stations 12 and 13, the control unit 71 selects from among the planar array antennas 21 to 24 and the planar array antennas 31 to 34 the planar array antenna whose normal to the antenna surface is oriented within a predetermined angle range in the azimuth direction based on the ground station 12.

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

[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. 10. In this case, the control unit 71 selects the planar array antenna 23.

[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 weight.

[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 without distinguishing 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 of the areas A21 and A22.

[0114] The above process allows the antenna device 20 to suppress an increase in power consumption. Also, the antenna device 20 can perform efficient BF control.

[0115] For example, near the boundary between areas A21 and A21, the antenna groups G1 and G2 with high gain frequently change due to changes in the attitude of the HAPS 11, while the difference in antenna gain between antenna group G1 and antenna group 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 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. This prevents the antenna device 20 from selecting a group antenna with low antenna gain for a predetermined period of time (see S7a and S7b in FIG. 9), thereby suppressing 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 arranged 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 horizontal footprint is limited due to the mounting conditions of the HAPS 11, the antenna device 80 can be easily mounted on the HAPS 11.

[0122] The control unit of the antenna device 80 executes the same processing as that shown in the flowchart of Fig. 9. The control unit of the antenna device 80 performs BF control that follows changes in the 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 placed 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 placed 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] 12, the array antenna 91 has planar subarray antennas 91a to 91d. Each of the subarray antennas 91a to 91d has, for example, the same number of antenna elements formed therein.

[0129] The tilt angle of the bottom subarray antenna 91a is the largest. The tilt angle of the second bottom subarray antenna 91b is the second largest. The tilt angle of the third bottom subarray antenna 91c is the third largest. The tilt angle of the top subarray antenna 91d is the smallest. That is, the tilt angles of the subarray antennas 91a to 91d become smaller as they go up.

[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 to 94 forms antenna group G1, which forms a first communication area. The second-lowest subarray antenna of each of the array antennas 91 to 94 forms antenna group G2, which forms a second communication area outside the first communication area. The third-lowest subarray antenna of each of the array antennas 91 to 94 forms antenna group G3, which forms a third communication area outside the second communication area. The fourth-lowest subarray antenna of each of the array antennas 91 to 94 forms antenna group G4, which forms 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 and 13 in the tilt angle direction. The control unit performs BF control on the subarray 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 allows the antenna device 90 to reduce the number of operating RF units (see, for example, RF units 51-1, 51-2, ..., 5M-N in FIG. 5), thereby reducing 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) 13 is a diagram showing an example of a block configuration of an antenna device 20 according to the 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 which 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 upconverter 107a, a DAC (Digital to Digital Converter) 108a, a downconverter 109a, and an ADC (Analog-to-Digital Converter) 110a. The RF-BB conversion unit 106 also includes an upconverter 107b, a DAC 108b, a downconverter 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 and off, the PA of RF unit 102a is connected to upconverter 107a and disconnected from upconverter 107a.

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

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

[0143] When SW103b is turned on, downconverter 109b is connected to RX-V line 105b. Therefore, when SW103b is turned on and off, the LNA of RF unit 102b is connected to downconverter 109b or disconnected from downconverter 109b.

[0144] The H polarized wave transmission digital signal output from the baseband unit 111 is converted into an analog signal by the DAC 108a, and the analog signal is converted into a signal in the RF frequency band by the upconverter 107a.

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

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

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

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

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

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

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

[0154] As described above, in the antenna device 20, the RF-BB conversion unit 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 "... circuitry," "... 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 conceive of various modifications or alterations within the scope of the claims. It is understood that such modifications or alterations also fall within the technical scope of the present disclosure. Furthermore, the components in the embodiments may be combined in any manner without departing from the spirit of the present disclosure.

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

[0159] The integrated circuit method is not limited to LSI, but may be realized by a dedicated circuit, a general-purpose processor, or a dedicated processor. Also, a field programmable gate array (FPGA) that can be programmed after LSI manufacturing, or a reconfigurable processor that can reconfigure the connections and settings of circuit cells within the LSI, may be used. The present disclosure may be realized as digital processing or analog processing.

[0160] Furthermore, if an integrated circuit technology that can replace LSI emerges due to advances in semiconductor technology or other derivative technologies, it is natural that such technology can be used to integrate functional blocks. 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 antenna 90 Antenna equipment 91~94 Array Antenna 91a~91d Subarray antennas

Claims

1. An antenna device mounted on a floating 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 different from 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:

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; 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 pattern; The antenna device according to claim 2 .

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

5. The control unit 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. The antenna device according to claim 1 .

6. The control unit further determining whether the ground station is located within a predetermined distance from the 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, selecting an array antenna facing the ground station from among the first array antenna and the second array antenna; performing beamforming control toward the ground station using the selected array antenna; The antenna device according to claim 1 .

7. a frequency converter for converting 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; The antenna device according to claim 2 .

8. the first array antenna and the second array antenna are configured as digital phased arrays; The antenna device according to claim 1 .

9. the first array antenna and the second array antenna are configured as analog phased arrays; 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, The antenna device according to claim 1 .

11. An antenna device mounted on a floating 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 different from 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:

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