Antenna device, beamforming method, and program

Abstract

To provide an antenna device capable of improving the design freedom of the wavefront generated by an array feed unit or the wavefront synthesized by the array receiver in a combination of a lens antenna or parabolic antenna and an array feeding part or an array receiving part, and a beam forming method.SOLUTION: An antenna device 100 includes: an array feeding unit 111 in which multiple antenna elements that radiate electromagnetic waves are arranged; and a lens 110 that refracts electromagnetic waves. The array feeding unit 111 excites multiple antenna elements with a complex excitation amplitude the electromagnetic wave is made to travel as a plane wave in a given direction after being refracted by lens 110.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This disclosure relates to an antenna device, a beamforming method, and a program, and more particularly to an antenna device, a beamforming method, and a program for performing beamforming. [Background technology]

[0002] International efforts are underway to develop the infrastructure and technologies necessary for the commercialization of High-Altitude Platform Stations (HAPS), and their widespread adoption is expected. In particular, there are high expectations for fixed communication systems utilizing HAPS, such as the ability to secure redundant backhaul routes via the airspace. At WRC-19 (World Radiocommunication Conference 2019), it was announced that high-speed, high-capacity HAPS systems would be realized in conjunction with 5G networks using the 38GHz band allocated to HAPS (see, for example, Non-Patent Document 1). Since HAPS orbits in a circle in the stratosphere at an altitude of around 20km, it is necessary to track them using beamforming so that the beam (radiation directivity) is directed towards the ground station. Conversely, ground stations also need to track HAPS using beamforming so that their beams are directed towards the HAPS.

[0003] Antenna devices used in ground stations can include aperture antennas and phased array antennas. Aperture antennas are broadly classified into horn antennas using waveguides, parabolic antennas using reflection, and lens antennas using refraction. Aperture antennas make it easy to form a large aperture and configure a high-gain antenna, but they have the drawback of requiring the antenna device's orientation to be constantly mechanically driven to track HAPS, resulting in high power consumption for the drive. On the other hand, phased array antennas make it easy to track HAPS by controlling the beam direction by controlling the excitation phase of the antenna elements, but they have the drawback of requiring a large number of antenna elements to form a large aperture and configure a high-gain antenna.

[0004] Non-patent document 2 describes a system that combines a lens antenna with an electronically controllable array power supply unit, and further controls the entire system with a mechanically driven gimbal, aiming to reduce side lobes to mitigate interference with other wireless devices and to reduce power consumption during tracking control.

[0005] Patent Document 1 discloses an antenna device that includes a circular array for each mode of OAM (Orbital Angular Momentum) and combines it with a lens so that the radiation angle of the maximum gain for each mode is the same.

[0006] Patent Document 2 discloses an antenna system comprising multiple lens sets arranged in an array, where each lens set combines one lens with multiple feeding elements. In each lens set, the beam differs for each feeding element, and the antenna system performs coarse beam control depending on which feeding element is being fed. Furthermore, the antenna system performs precise beam control by controlling the signals that are fed to the feeding elements of each of the multiple lens sets.

[0007] Patent Document 3 describes a design and manufacturing flow for a parabolic antenna mounted on a geostationary satellite, specifically for changing the radiation gain of a particular region during rainfall attenuation, etc. The parabolic antenna and array feeding section are designed and manufactured so that the radiation gain of a particular region can be changed by changing the excitation amplitude and phase of the array feeding section combined with the parabolic antenna. During operation after manufacturing, when changing the radiation gain of a particular region during rainfall attenuation, etc., the radiation gain of the particular region is changed based on the specified excitation amplitude value and / or excitation phase value for each array element. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Japanese Patent Publication No. 2017-228856 [Patent Document 2] Japanese Patent Publication No. 2019-220995 [Patent Document 3] Japanese Patent Publication No. 2014-143525 [Non-patent literature]

[0009] [Non-Patent Document 1] Suzuki et al., "Development of a 38GHz Band Wireless Communication System in Collaboration with a 5G Network using a High-Altitude Platform (HAPS) - Study on High-Speed, High-Capacity Backhaul Lines for 5G Networks -", ​​2021 IEICE General Conference, B-3-1 (March 2021) [Non-Patent Document 2] Tsuji et al., "Development of a 38GHz Band Wireless Communication System in Collaboration with a 5G Network using a High Altitude Platform (HAPS) - Examination of a 38GHz Band Ground Station Antenna System for HAPS -", 2021 IEICE General Conference, B-3-4 (March 2021) [Overview of the project] [Problems that the invention aims to solve]

[0010] However, the aforementioned conventional technologies do not demonstrate a method for generating wavefronts that improves the design flexibility of antenna devices (lens antennas or parabolic antennas and array feeding sections) in these combinations, and therefore there is room for improvement.

[0011] Non-limiting embodiments of this disclosure contribute to providing an antenna device and beamforming method that can improve the design freedom of the wavefront generated by the array feeding unit or the wavefront synthesized by the array receiving unit in a combination of a lens antenna or parabolic antenna and an array feeding unit or an array receiving unit. [Means for solving the problem]

[0012] An antenna device according to one embodiment of the present disclosure comprises an array feeding unit in which a plurality of antenna elements that radiate electromagnetic waves are arranged, and a lens that refracts the electromagnetic waves, wherein the array feeding unit excites the plurality of antenna elements with a complex excitation amplitude that causes the electromagnetic waves to propagate as plane waves in a predetermined direction after being refracted by the lens.

[0013] An antenna device according to one embodiment of the present disclosure comprises an array receiving unit in which a plurality of antenna elements are arranged, and a lens that refracts an incoming electromagnetic wave and irradiates it onto the array receiving unit, wherein the array receiving unit weights the plurality of antenna elements with a complex amplitude that causes the electromagnetic wave before refracting by the lens to be incident on the lens as a plane wave from a predetermined direction, and synthesizes the wavefronts of the electromagnetic wave after refracting by the lens.

[0014] An antenna device according to one embodiment of the present disclosure comprises an array feeding unit in which a plurality of antenna elements that radiate electromagnetic waves are arranged, and a reflector that reflects the electromagnetic waves, wherein the array feeding unit excites the plurality of antenna elements with a complex excitation amplitude that causes the electromagnetic waves to propagate as plane waves in a predetermined direction after being reflected by the reflector.

[0015] An antenna device according to one embodiment of the present disclosure comprises an array receiving unit in which a plurality of antenna elements are arranged, and a reflecting mirror that reflects incoming electromagnetic waves and irradiates the array receiving unit, wherein the array receiving unit weights the plurality of antenna elements with a complex amplitude that causes the electromagnetic waves before being reflected by the reflecting mirror to be incident on the reflecting mirror as plane waves from a predetermined direction, and synthesizes the wavefronts of the electromagnetic waves after they have been reflected by the reflecting mirror.

[0016] A beamforming method according to one embodiment of the present disclosure is a beamforming method using an antenna device comprising an array feeding unit in which a plurality of antenna elements are arranged and a lens, wherein the plurality of antenna elements radiate electromagnetic waves, and the array feeding unit excites the plurality of antenna elements with a complex excitation amplitude such that the electromagnetic waves are refracted by the lens and propagated as plane waves in a predetermined direction.

[0017] A beamforming method according to one embodiment of the present disclosure is a beamforming method using an antenna device comprising an array receiving unit having a plurality of antenna elements arranged in a row and a lens, wherein the array receiving unit weights the plurality of antenna elements by a complex amplitude such that the incoming electromagnetic wave before being refracted by the lens is incident on the lens as a plane wave from a predetermined direction, and the array receiving unit synthesizes the wavefronts of the electromagnetic wave after it has been refracted by the lens.

[0018] A beamforming method according to one embodiment of the present disclosure is a beamforming method using an antenna device comprising an array feeding unit in which a plurality of antenna elements are arranged and a reflector, wherein the plurality of antenna elements radiate electromagnetic waves, and the array feeding unit excites the plurality of antenna elements with a complex excitation amplitude such that the electromagnetic waves are propagated as plane waves in a predetermined direction after being reflected by the reflector.

[0019] A beamforming method according to one embodiment of the present disclosure is a beamforming method using an antenna device comprising an array receiving unit having a plurality of antenna elements arranged thereon and a reflector, wherein the array receiving unit weights the plurality of antenna elements with a complex amplitude such that the incoming electromagnetic wave before being reflected by the reflector is incident on the reflector as a plane wave from a predetermined direction, and the array receiving unit synthesizes the wavefronts of the electromagnetic wave after it has been reflected by the reflector.

[0020] These comprehensive or specific embodiments may be implemented as systems, devices, methods, integrated circuits, computer programs, or recording media, or as any combination of systems, devices, methods, integrated circuits, computer programs, and recording media. [Effects of the Invention]

[0021] According to one embodiment of the present disclosure, the array power supply unit excites a plurality of antenna elements with a complex excitation amplitude, which is generated when electromagnetic waves are refracted by a lens and then propagate as plane waves in a predetermined direction. , By performing beam shaping (which may also be called beam forming), it becomes possible to improve aperture efficiency and suppress radiation outside the lens, and in the combination of the lens and the array feeding unit, the design freedom of the wavefront generated by the array feeding unit can be improved.

[0022] Further advantages and effects of one embodiment of this disclosure will be made apparent from the specification and drawings. Such advantages and / or effects are provided by several embodiments and features described in the specification and drawings, but not all of them are necessarily provided in order to obtain one or more identical features. [Brief explanation of the drawing]

[0023] [Figure 1] This figure shows an example of the basic configuration and basic operation of the antenna device in Embodiment 1 of this disclosure. [Figure 2] This figure shows an example of a beam shift method for the array power supply unit in Embodiment 1. [Figure 3] This figure shows an example of the detailed basic operation of the antenna device assuming the ideal light-gathering characteristics of the lens in Embodiment 1. [Figure 4] A diagram illustrating an example of the excitation amplitude of the array power supply unit in Embodiment 1. [Figure 5] A diagram illustrating an example of wavefront shaping for beam shifting by the array power supply unit in Embodiment 1. [Figure 6]This figure shows an example of the effect on the aperture efficiency of wavefront shaping using a two-dimensional planar array in Embodiment 1. [Figure 7] This figure shows an example of the effect on improving the degree of freedom of the F / D ratio (focal length / diameter) of wavefront shaping using a two-dimensional planar array in Embodiment 1. [Figure 8] This figure shows an example of the configuration of the array power supply unit in Embodiment 1. [Figure 9] This figure shows an example of the configuration of the array receiver unit for the receiving function in Embodiment 1. [Figure 10A] This figure shows an example of the effect when the arrangement of the array power supply unit in Embodiment 2 of this disclosure is shifted from the focal plane of the lens. [Figure 10B] This figure shows an example of the effect when the arrangement of the array power supply unit in Embodiment 2 of this disclosure is shifted from the focal plane of the lens. [Figure 11] This figure shows an example of the basic configuration and basic operation of the antenna device in Embodiment 3 of this disclosure. [Modes for carrying out the invention]

[0024] The embodiments of this disclosure will be described in detail below, with appropriate reference to the drawings. However, some unnecessarily detailed explanations may be omitted. For example, detailed explanations of already well-known matters and redundant explanations of substantially identical configurations may be omitted. This is to avoid the following explanation becoming unnecessarily verbose and to facilitate understanding by those skilled in the art.

[0025] The attached drawings and the following description are provided for the benefit of those skilled in the art to fully understand this disclosure and are not intended to limit the subject matter described in the claims.

[0026] (Embodiment 1) Figure 1 shows an example of the basic configuration and basic operation of the antenna device 100 in Embodiment 1 of the present disclosure. The antenna device 100 comprises a lens 110 and an array power supply unit 111.

[0027] The lens 110 refracts the electromagnetic waves emitted by the array power supply unit 111.

[0028] The array power supply unit 111 includes two-dimensionally arranged antenna elements that emit electromagnetic waves, and generates and radiates a transmission beam (towards the lens 110).

[0029] As shown in Figure 1, the basic operation of the array power supply unit 111 is, for example, to generate a wavefront radiated from a virtual radiation position of the lens 110. Outside the lens The radiated power oppressed The goal is to perform beam shaping in this manner.

[0030] Figure 2 shows the beam shift method of the array feeding unit 111 in the antenna device 100 in Embodiment 1.

[0031] The array power supply unit 111 generates a wavefront with a virtually shifted radiation position, as shown in Figure 2, by having a control unit (for example, a control unit 129 described later) within the array power supply unit 111 control the excitation phase of the antenna elements. Outside the lens The radiated power oppressed The beam is shaped in this way, thereby achieving beam shift.

[0032] To explain the operating principle of the antenna device 100, we will first describe the excitation amplitude of the array feeding section 111, assuming the ideal focusing characteristics of the lens. Next, we will describe general lens characteristics. Here, ideal focusing characteristics refer to the phase conversion characteristics in which a spherical wave radiated from the focal point is converted into a plane wave upon passing through the lens. Furthermore, the lens is assumed to be a thin, circular plane with no transmission loss.

[0033] Figure 3 shows an example of the detailed basic operation of the antenna device 100, assuming the ideal light-gathering characteristics of the lens in the antenna device 100.

[0034] In FIG. 3, a lens having ideal light-condensing characteristics is shown as lens 110a. As shown in FIG. 3, in a rectangular coordinate system, the focal point of the lens 110a is set as the origin, the main axis of the lens 110a is set as the z-axis, and the lens surface is arranged parallel to the x-y plane. Let D be the diameter of the lens and F be the focal length, the coordinates (x l ,y l ,z l ) are represented by the following formula (1). [Math.]]

[0035] The lens 110a refracts a spherical wave s(x,y,z) emitted from the focal point and converts it into a plane wave p(x,y,z) propagating in the z-axis direction. The spherical wave s(x,y,z) and the plane wave p(x,y,z) are respectively represented by the following formula (2) and formula (3). [Math.]] [Math.]] Here, k is the wave number and ψ is the phase delay.

[0036] The conversion characteristic f(x l ,y l ,z l ) of the lens on the lens surface (x l ,y l ,z l ) is represented by the following formula (4). [Math.]] Since it is not necessary to consider the phase delay here, the phase delay term included in formula (4) may be set to 0 and omitted as shown in formula (5). [Math.]]

[0037] Figure 4 is a diagram illustrating the excitation amplitude of the array feeding section 111 in the antenna device 100.

[0038] As the array power supply unit 111, for example, a planar array antenna in which antenna elements are arranged at equal intervals in two dimensions may be used, as described above. The electric field E(r,θ,φ) of the electromagnetic wave radiated from one antenna element is expressed using spherical coordinates as shown in equation (6).

number

number

number

number

[0039] position(x e ,y e ,z e The complex excitation amplitude of the antenna element at ) is E0(x e ,y e ,z e Let's assume that the electric field E(x,y,z) at position (x,y,z) of the electromagnetic wave radiated from the array power supply unit 111 is expressed as the sum of the electric fields of the electromagnetic waves radiated from all antenna elements, as shown in equation (10).

number

number

[0040] If you want to obtain a desired electric field distribution E(x,y,z) by array feeding, the array feeding unit 111 feeds each antenna element according to equation (12) E0(x e ,y e ,z e Find (or determine or calculate) the obtained E0(x e ,y e ,z e Each antenna element can be excited using the following method.

number

number

[0041] The calculations described above may be performed by a control unit (for example, a control unit 129 described later) included in the array power supply unit 111, or by another functional unit.

[0042] Figure 5 is a diagram illustrating the wavefront shaping performed by the array feeding unit 111 in the antenna device 100 for beam shifting.

[0043] As shown in Figure 5, consider the case where a plane wave (beam) radiated from lens 110a is beamformed in the (θ,φ) direction. If the unit vector in the beam direction is expressed as in equation (14), then the plane wave propagating in the (θ,φ) direction can be expressed as in equation (16) or equation (17) using the coordinate vector shown in equation (15).

number

number

number

number

[0044] Lens surface (x l ,y l ,z l In ), a plane wave p propagates in the (θ,φ) direction. θ,φ (x l ,y l ,z l In order to emit ), the wavefront s, which can be expressed as in equation (18) with respect to the lens, θ,φ (x l ,y l ,z l ) should be injected.

number

[0045] incident wavefront s θ,φ (x l ,y l ,z l To obtain the complex excitation amplitude E0(x) obtained by equation (19), the array power supply unit 111 uses the complex excitation amplitude E0(x) obtained by equation (19). e ,y e ,z e Each antenna element should be excited by the following: However, the excitation amplitude E0(x) obtained by equation (19) e ,y e ,ze Since the transmission power is a relative value between antenna elements, it is desirable to normalize the transmission power of each antenna element so that the sum of the transmission powers of all antenna elements equals a predetermined transmission power.

number

[0046] The above is an example of the details of the basic operation of the antenna device 100 assuming the light-gathering characteristics of an ideal lens 110a. In the case of a typical lens 110 with aberrations and thickness, the lens conversion characteristic f(x l ,y l ,z l ) should be calculated or measured in advance, or the incident plane (x) near the incident surface of lens 110 l ,y l ,z l ) Desired wavefront characteristics s θ,φ (x l ,y l ,z l By pre-calculating or measuring the corresponding complex excitation amplitude E0(x e ,y e ,z e ) can be calculated.

[0047] Figure 6 shows an example of the effect of wavefront shaping on aperture efficiency in a two-dimensional planar array (array power supply unit 111). In this example, the lens diameter D is 600 mm and the focal length F is 750 mm.

[0048] Figure 6(a) shows the case where the above wavefront shaping is performed on a 32x32 element two-dimensional planar array, and Figure 6(b) shows the case where the above wavefront shaping is not performed on a 4x4 element planar array and it is excited with equal phase and equal amplitude.

[0049] The left side of Figure 6 shows the amplitude values ​​of the real part of the complex excitation amplitude. The right side of Figure 6 shows the radiation characteristics, and the dashed lines around ±20° represent the positions of both ends of the lens diameter. It can be seen that by performing the above wavefront shaping, the gain within the lens diameter is high and flat, improving the aperture efficiency and thus the antenna gain. It can also be seen that by performing the above wavefront shaping, unwanted radiation outside the lens is suppressed.

[0050] As described above, by appropriately controlling the complex excitation amplitude that excites the multiple antenna elements of the array feeding unit 111 in the combination of the lens 110 and the array feeding unit 111, a desired beam shape can be obtained according to the conversion characteristics of the lens, and tracking by beamforming becomes possible. Furthermore, antenna gain can be improved and unwanted radiation can be suppressed.

[0051] Figure 7 shows an example of the effect on improving the degree of freedom of the F / D ratio (focal length / diameter) of wavefront shaping in a two-dimensional planar array (array power supply unit 111).

[0052] As shown in the figure, when excitation is performed with equal phase and equal amplitude without wavefront shaping, the range of F / D ratio in which a large gain can be obtained is narrow, and this range varies depending on the number of antenna elements. On the other hand, when wavefront shaping is performed, the range in which a large gain can be obtained is wide, and it is possible to maintain a high gain in the region of a small F / D ratio (i.e., miniaturization of the antenna device 100 is possible), and especially when the number of antenna elements is large (in the case of 32x32 elements), it is possible to maintain a high gain even in the region of a large F / D ratio. From the above, it can be seen that the degree of freedom of the F / D ratio can be improved by wavefront shaping.

[0053] Figure 8 shows an example of the configuration of the array power supply unit 111. The array power supply unit 111 comprises N complex amplitude multiplier units 120-1 to 120-N, N high-frequency conversion units 121-1 to 121-N, N antenna elements 125-1 to 125-N, and a control unit 129. The complex amplitude multiplier units 120-1 to 120-N may each be referred to as complex amplitude excitation units 120-1 to 120-N.

[0054] Each of the N complex amplitude multiplier units 120-1 to 120-N is connected to the lens surface (x l ,y l ,z l In ), a plane wave p propagates in the (θ,φ) direction. θ,φ (x l ,y l ,z l The transmitted baseband signal is given a complex excitation amplitude E0(x) such that it radiates ). e ,y e ,z e ) multiplied by (i.e., complex excitation amplitude E0(x e ,y e ,z e The baseband signal is excited by the transmitter and output to N high-frequency conversion units 121-1 to 121-N.

[0055] Each of the N high-frequency conversion units 121-1 to 121-N converts the excited transmit baseband signal input from the N complex amplitude multiplier units 120-1 to 120-N into a high-frequency signal to be transmitted and outputs it to the N antenna elements 125-1 to 125-N.

[0056] The control unit 129 controls the overall processing of the array feeding unit 111. For example, the control unit 129 controls N complex amplitude multipliers 120-1 to 120-N, N high-frequency converters 121-1 to 121-N, and N antenna elements 125-1 to 125-N to perform the processing described above. For example, the control unit 129 may control N complex amplitude multipliers 120-1 to 120-N, N high-frequency converters 121-1 to 121-N, and N antenna elements 125-1 to 125-N to perform the processing described above by executing a program stored in a storage unit (e.g., memory; not shown). In other words, such a program may cause the control unit 129 to control the array feeding unit 111, which has N antenna elements 135-1 to 135-N, to perform the beamforming method according to the present disclosure. Furthermore, as described above, the control unit 129 controls the complex excitation amplitude E0(x) of each antenna element. e ,y e ,z e You may calculate ).

[0057] In this way, the array power supply unit 111 controls the wavefront of the electromagnetic wave incident on the lens 110 so that the radiation characteristics of the electromagnetic wave after refraction by the lens 110 become a desired beam shape. Specifically, the array power supply unit 111 controls the wavefront of the electromagnetic wave after refraction by the lens 110 so that the wavefront becomes a plane wave p θ,φ (x l ,y l ,z l The complex excitation amplitude E0(x) is propagated as a plane wave in a predetermined direction. e ,y e ,z e The N antenna elements 125-1 to 125-N are excited using ).

[0058] With the above configuration, it is possible to provide an antenna device 100 that improves the design freedom of the wavefront generated by the array power supply unit 111 when the lens 110 and the array power supply unit 111 are combined.

[0059] The above describes the transmission function of the antenna device 100, but the receiving function of the antenna device 100 can also be realized using the same principle. For this purpose, the antenna device 100 may further be equipped with an array receiving unit 112.

[0060] The lens 110 refracts the incoming electromagnetic waves and irradiates the array receiving unit 112 with them.

[0061] The array receiving unit 112 includes two-dimensionally arranged antenna elements that receive incoming electromagnetic waves refracted by the lens 110, corresponding to the array feeding unit 111.

[0062] Figure 9 shows an example of the configuration of the array receiving unit 112. The array receiving unit 112 comprises N antenna elements 135-1 to 135-N, N high-frequency conversion units 131-1 to 131-N, N complex amplitude multiplication units 130-1 to 130-N, an adder 132, and a control unit 139, corresponding to the array power supply unit 111.

[0063] Each of the N antenna elements 135-1 to 135-N receives an electromagnetic wave (high-frequency signal) and outputs the received signal to the N high-frequency converters 135-1 to 131-N.

[0064] Each of the N high-frequency converters 131-1 to 131-N converts the high-frequency signal input from the corresponding one of the N antenna elements 135-1 to 135-N into a baseband signal, and outputs the converted signal to the N complex amplitude multipliers 130-1 to N.

[0065] Each of the N complex amplitude multipliers 130-1 to N is arranged on the lens surface (x l ,y l ,z l ), such that a plane wave p incident from the (θ,φ) direction θ,φ (x l ,y l ,z l ) is incident, multiplies the baseband signal by the complex amplitude E0(x e ,y e ,z e ) (that is, multiplies the baseband signal by the complex excitation amplitude E0(x e ,y e ,z e ) in the transmission function) and outputs the resulting signal to the adder 132.

[0066] The adder 132 adds the N multiplied baseband signals input from the N complex amplitude multipliers 130-1 to N (that is, synthesizes the wavefront of the electromagnetic wave after being refracted by the lens 110), thereby achieving the desired wavefront characteristic s θ,φ (x l ,y l ,z l ) at the antenna elements 135-1 to 135-N.

[0067] The control unit 139 controls the overall processing of the array receiver 112. For example, the control unit 139 controls the N antenna elements 135-1 to 135-N, the N high-frequency conversion units 131-1 to 131-N, the N complex amplitude multiplication units 130-1 to 130-N, and the adder 132 to perform the processing described above. For example, the control unit 139 may control the N antenna elements 135-1 to 135-N, the N high-frequency conversion units 131-1 to 131-N, the N complex amplitude multiplication units 130-1 to 130-N, and the adder 132 to perform the processing described above by executing a program stored in the storage unit (e.g., memory; not shown) of the antenna device 100. In other words, such a program may cause the control unit 139 to control the array receiver 112, which has N antenna elements 135-1 to 135-N, to perform the beamforming method according to the present disclosure. Furthermore, as described above, the control unit 139 controls the complex (excitation) amplitude E0(x) of each antenna element. e ,y e ,z e You may calculate ).

[0068] In this way, the array receiver 112 combines the wavefronts of the electromagnetic waves irradiated from the lens 110 so that the reception characteristics of the electromagnetic waves before they are refracted by the lens 110 result in a desired beam shape. Specifically, the array receiver 112 combines the wavefronts of the electromagnetic waves before they are refracted by the lens 110 so that they are a plane wave p from a predetermined direction. θ,φ (x l ,y l ,z l The complex amplitude E0(x) is directed into lens 110 as follows: e ,y e ,z e ) The baseband signals received through N antenna elements 135-1 to 135-N are weighted (in other words, the electromagnetic waves before being refracted by lens 110 are plane waves p from a predetermined direction) θ,φ (x l ,y l ,z l The complex amplitude E0(x) is incident on lens 110 as follows: e ,y e ,z eThe N antenna elements 135-1 to 135-N are weighted, and the wavefronts of the electromagnetic waves after refraction by the lens 110 are combined.

[0069] With the above configuration, it is possible to provide an antenna device 100 that improves the design freedom of the wavefront synthesized by the array receiver 112 in the combination of the lens 110 and the array receiver 112.

[0070] (Embodiment 2) Figures 10A and 10B show an example of the effect of shifting the arrangement of the array power supply unit 111 from the focal plane of the lens 110 in a two-dimensional planar array. In this example, the diameter D of the lens 110 is 600 mm and the focal length F is 300 mm.

[0071] Figure 10A(a) shows the maximum power per element relative to the total transmitted power, and Figure 10A(b) shows the gain. In this embodiment, only the case where wavefront shaping is performed is illustrated. The horizontal axis in Figures 10A(a) and 10A(b) indicates the position where the array power supply unit 111 is located. 0 on the horizontal axis indicates that the array power supply unit 111 is located at the focal plane of the lens 110. The rightward direction (positive direction) indicates the case where the array power supply unit 111 is closer to the lens 110 from its focal plane, and the leftward direction (negative direction) indicates the case where the array power supply unit 111 is further away from the lens 110 from its focal plane.

[0072] As shown in Figure 10A(a), it can be seen that for all antenna element configurations from 4x4 to 32x32, the maximum power per element can be reduced by shifting the arrangement of the array feed unit 111 away from the focal plane of the lens 110.

[0073] Figures 10B(a) and 10B(b) show the amplitude of array power supply when the horizontal axis (offset value) of Figure 10A(a) is 0 mm and when the horizontal axis (offset value) of Figure 10A(a) is 30 mm, respectively. As shown in Figure 10B, it can be seen that the arrangement of the array power supply unit 111 is offset from the focal plane of the lens 110 to avoid the concentration of power on some elements.

[0074] On the other hand, as shown in Figure 10A(b), the range of offsets over which gain can be maintained varies depending on the number of antenna elements, but it can be seen that this range expands as the number of antenna elements increases.

[0075] Based on the above, when the arrangement of the array power supply unit 111 is offset from the focal plane of the lens 110, it is possible to provide an antenna device 100 that, using the same process as in Embodiment 1, can avoid the concentration of power on some elements while maintaining gain in the combination of the lens 110 and the array power supply unit 111.

[0076] Furthermore, even when the arrangement of the array receiving unit 112 is offset from the focal plane of the lens 110, the same processing as in Embodiment 1 can be used to provide an antenna device 100 that can avoid power concentration on some elements while maintaining gain in the combination of the lens 110 and the array receiving unit 112.

[0077] (Embodiment 3) Figure 11 shows an example of the basic configuration and basic operation of the antenna device 300 in Embodiment 3 of this disclosure. Since the antenna device 300 has the same configuration as the antenna device 100 in Embodiment 1, the same configuration will not be described. The antenna device 300 is configured as a parabolic antenna and includes a parabolic reflector 310 and an array feeding unit 111.

[0078] The parabolic reflector 310 reflects electromagnetic waves emitted by the array power supply unit 111.

[0079] The array power supply unit 111 in this embodiment is the same as the array power supply unit 111 in Embodiment 1. However, the array power supply unit 111 includes two-dimensionally arranged antenna elements that radiate electromagnetic waves, and generates a transmission beam (towards the parabolic reflector 310 instead of the lens 110) for radiation.

[0080] The parabolic reflector 310 exhibits a conversion characteristic f(x) due to reflection. l ,y l ,z l ) has a function that converts the wavefront s(x,y,z) generated by the array power supply unit 111 into a plane wave p(x,y,z) propagating in the z-axis direction.

[0081] Similar to Embodiment 1, in this embodiment as well, the array power supply unit 111 controls the wavefront of the electromagnetic waves incident on the parabolic reflector 310 so that the radiation characteristics of the electromagnetic waves after reflection by the parabolic reflector 310 become a desired beam shape. Specifically, the array power supply unit 111 controls the wavefront of the electromagnetic waves after reflection by the parabolic reflector 310 to form a plane wave p in a predetermined direction (for example, a direction parallel to the z-axis). θ,φ (x l ,y l ,z l The complex excitation amplitude E0(x) is used to propagate the vibration. e ,y e ,z e The N antenna elements 125-1 to 125-N are excited using ).

[0082] Furthermore, the antenna device 300 may also include an array receiving unit 112.

[0083] The parabolic reflector 310 reflects the incoming electromagnetic waves and irradiates the array receiving unit 112 with them.

[0084] The array receiving unit 112 in this embodiment is the same as the array receiving unit 112 in Embodiment 1. However, the array receiving unit 112 includes two-dimensionally arranged antenna elements that receive incoming electromagnetic waves reflected by the parabolic reflector 310, instead of the lens 110.

[0085] Similar to Embodiment 1, in this embodiment as well, the array receiving unit 112 synthesizes the wavefronts of the electromagnetic waves irradiated from the parabolic reflector 310 so that the reception characteristics of the electromagnetic waves before they are reflected by the parabolic reflector 310 result in a desired beam shape. Specifically, the array receiving unit 112 synthesizes the wavefronts of the electromagnetic waves before they are reflected by the parabolic reflector 310 so that they are plane waves from a predetermined direction p θ,φ (x l ,y l ,z l The complex amplitude E0(x) is incident on the parabolic reflector 310 as e ,y e ,z e The N antenna elements 135-1 to 135-N are weighted, and the wavefronts of the electromagnetic waves after they have been reflected by the parabolic reflector 310 are combined.

[0086] Therefore, with the configuration of the antenna device 300 shown in Figure 11, it is possible to provide an antenna device 300 that, in the same manner as in Embodiment 1, makes it possible to improve the design freedom of the wavefront generated by the array feeding unit 111 in the combination of the parabolic reflector 310 and the array feeding unit 111. Also, in the same manner as in Embodiment 1, it is possible to provide an antenna device 300 that, in the same manner as in Embodiment 1, makes it possible to improve the design freedom of the wavefront synthesized by the array receiving unit 112 in the combination of the parabolic reflector 310 and the array receiving unit 112. Also, in the same manner as in Embodiment 2, it is possible to provide an antenna device 300 that, in the same manner as in Embodiment 2, makes it possible to avoid the concentration of power on some elements while maintaining gain in the combination of the parabolic reflector 310 and the array feeding unit 111. Also, in the same manner as in Embodiment 2, it is possible to provide an antenna device 300 that, in the same manner as in Embodiment 2, makes it possible to avoid the concentration of power on some elements while maintaining gain in the combination of the parabolic reflector 310 and the array receiving unit 112.

[0087] (1) In embodiments 1 to 3, a full digital beamforming configuration was used as shown in Figure 8, but the disclosure is not limited thereto, and hybrid beamforming or full digital beamforming configurations may also be used. In these cases as well, the same effects as described above can be obtained.

[0088] (2) In embodiments 1 to 3, an example was described in which the array power supply unit 111 is equipped with a control unit 129 and the array receiving unit 112 is equipped with a control unit 139, but the disclosure is not limited to this example. For example, instead of the array power supply unit 111 being equipped with a control unit 129 and the array receiving unit 112 being equipped with a control unit 139, the antenna devices 100 and 300 may be equipped with a control unit 129 and a control unit 139 outside the array power supply unit 111 and the array receiving unit 112. In this case, the control unit 129 and the control unit 139 may be an integrated control unit. These control units may be processors, for example.

[0089] (3) In embodiments 1 to 3, the notation "...part" used for each component may be replaced with other notations such as "...circuitry", "...assembly", "...device", "...unit", or "...module".

[0090] (4) This disclosure may relate to implementations using hardware and software. The above embodiments may be implemented or executed using a computing device (processor). The computing device or processor may be, for example, a main processor / general-purpose processor, a digital signal processor (DSP), an ASIC (application-specific integrated circuit), an FPGA (field-programmable gate array), or other programmable logic devices. The above embodiments may be executed or realized by a combination of these devices.

[0091] (5) Embodiments 1 to 3 may be implemented by a mechanism of software modules executed by a processor or directly by hardware. A combination of software modules and hardware implementations is also possible. The software modules may be stored in various types of computer-readable storage media, such as RAM, EPROM, EEPROM, flash memory, registers, hard disks, CD-ROMs, DVDs, etc.

[0092] (Summary of the embodiments) An antenna device according to one embodiment of the present disclosure comprises an array feeding unit in which a plurality of antenna elements that radiate electromagnetic waves are arranged, and a lens that refracts the electromagnetic waves, wherein the array feeding unit excites the plurality of antenna elements with a complex excitation amplitude that causes the electromagnetic waves to propagate as plane waves in a predetermined direction after being refracted by the lens.

[0093] A beamforming method according to one embodiment of the present disclosure is a beamforming method using an antenna device comprising an array feeding unit in which a plurality of antenna elements are arranged and a lens, wherein the plurality of antenna elements radiate electromagnetic waves, and the array feeding unit excites the plurality of antenna elements with a complex excitation amplitude such that the electromagnetic waves are refracted by the lens and propagated as plane waves in a predetermined direction.

[0094] With the above configuration, the array power supply unit excites multiple antenna elements with a complex excitation amplitude, which causes the electromagnetic waves to propagate as plane waves in a predetermined direction after being refracted by the lens. , By shaping the lens, it becomes possible to improve aperture efficiency and suppress radiation outside the lens, thereby increasing the design freedom of the wavefront generated by the array power supply unit in the combination of the lens and the array power supply unit.

[0095] An antenna device according to one embodiment of the present disclosure comprises an array feeding unit in which a plurality of antenna elements that radiate electromagnetic waves are arranged, and a reflector that reflects the electromagnetic waves, wherein the array feeding unit excites the plurality of antenna elements with a complex excitation amplitude that causes the electromagnetic waves to propagate as plane waves in a predetermined direction after being reflected by the reflector.

[0096] A beamforming method according to one embodiment of the present disclosure is a beamforming method using an antenna device comprising an array feeding unit in which a plurality of antenna elements are arranged and a reflector, wherein the plurality of antenna elements radiate electromagnetic waves, and the array feeding unit excites the plurality of antenna elements with a complex excitation amplitude such that the electromagnetic waves are propagated as plane waves in a predetermined direction after being reflected by the reflector.

[0097] With the above configuration, the array power supply unit excites multiple antenna elements with a complex excitation amplitude that causes electromagnetic waves to propagate as plane waves in a predetermined direction after being reflected by the reflector. , By performing frame shaping, it becomes possible to improve aperture efficiency and suppress radiation outside the reflector, and in the combination of the reflector and the array feed unit, the design freedom of the wavefront generated by the array feed unit can be improved.

[0098] An antenna device according to one embodiment of the present disclosure comprises an array receiving unit in which a plurality of antenna elements are arranged, and a lens that refracts an incoming electromagnetic wave and irradiates it onto the array receiving unit, wherein the array receiving unit weights the plurality of antenna elements with a complex amplitude that causes the electromagnetic wave before refracting by the lens to be incident on the lens as a plane wave from a predetermined direction, and synthesizes the wavefronts of the electromagnetic wave after refracting by the lens.

[0099] A beamforming method according to one embodiment of the present disclosure is a beamforming method using an antenna device comprising an array receiving unit having a plurality of antenna elements arranged in a row and a lens, wherein the array receiving unit weights the plurality of antenna elements by a complex amplitude such that the incoming electromagnetic wave before being refracted by the lens is incident on the lens as a plane wave from a predetermined direction, and the array receiving unit synthesizes the wavefronts of the electromagnetic wave after it has been refracted by the lens.

[0100] With the above configuration, the array receiver weights multiple antenna elements by the complex amplitude of the incoming electromagnetic wave that is incident on the lens as a plane wave from a predetermined direction before being refracted by the lens, and synthesizes the wavefronts of the electromagnetic wave after it has been refracted by the lens. , By shaping the lens, it becomes possible to improve aperture efficiency and suppress incident light from outside the lens, thereby increasing the design freedom of the wavefront synthesized by the array receiver when combining the lens and the array receiver.

[0101] An antenna device according to one embodiment of the present disclosure comprises an array receiving unit in which a plurality of antenna elements are arranged, and a reflecting mirror that reflects incoming electromagnetic waves and irradiates the array receiving unit, wherein the array receiving unit weights the plurality of antenna elements with a complex amplitude that causes the electromagnetic waves before being reflected by the reflecting mirror to be incident on the reflecting mirror as plane waves from a predetermined direction, and synthesizes the wavefronts of the electromagnetic waves after they have been reflected by the reflecting mirror.

[0102] A beamforming method according to one embodiment of the present disclosure is a beamforming method using an antenna device comprising an array receiving unit having a plurality of antenna elements arranged thereon and a reflector, wherein the array receiving unit weights the plurality of antenna elements with a complex amplitude such that the incoming electromagnetic wave before being reflected by the reflector is incident on the reflector as a plane wave from a predetermined direction, and the array receiving unit synthesizes the wavefronts of the electromagnetic wave after it has been reflected by the reflector.

[0103] With the above configuration, the array receiver weights multiple antenna elements by the complex amplitude of the incoming electromagnetic wave that is incident on the reflector as a plane wave from a predetermined direction before being reflected by the reflector, and synthesizes the wavefronts of the electromagnetic wave after it has been reflected by the reflector. , By performing frame shaping, it becomes possible to improve aperture efficiency and suppress incidence from outside the reflector, thereby increasing the design freedom of the wavefront synthesized by the array receiver in the combination of the reflector and the array receiver. [Industrial applicability]

[0104] This disclosure can be applied not only to HAPS but also to beamforming technology in wireless transmission. [Explanation of Symbols]

[0105] 100, 300 antenna equipment 110 Lens 111 Array power supply unit 112 Array Receiver 120, 130 Complex amplitude multiplication section 121, 131 High-frequency conversion section 125, 135 antenna elements 129, 139 Control Unit 132 Addition section 310 Parabolic reflector

Claims

1. An array power supply unit in which multiple antenna elements that emit electromagnetic waves are arranged, A lens that refracts the aforementioned electromagnetic waves, Equipped with, The array power supply unit excites the plurality of antenna elements with a complex excitation amplitude that causes the electromagnetic wave to propagate as a plane wave in a predetermined direction after being refracted by the lens. Antenna device.

2. A control unit calculates the complex excitation amplitude based on the conversion characteristics of the lens or predetermined wavefront characteristics at the incident surface, which have been calculated or measured in advance. Furthermore, The control unit controls the array feeding unit to excite the plurality of antenna elements with the complex excitation amplitude. The antenna device according to claim 1.

3. The array power supply unit is positioned at a location offset from the focal plane of the lens. The antenna device according to claim 1 or 2.

4. An array receiving unit in which multiple antenna elements are arranged, A lens that refracts the incoming electromagnetic waves and irradiates them onto the array receiving unit, Equipped with, The array receiving unit weights the signals received by the plurality of antenna elements with complex amplitudes corresponding to plane waves from a predetermined direction, and synthesizes the wavefronts of the electromagnetic waves after they have been refracted by the lens. Antenna device.

5. An array power supply unit in which multiple antenna elements that emit electromagnetic waves are arranged, A reflector that reflects the aforementioned electromagnetic waves, Equipped with, The array power supply unit excites the plurality of antenna elements with a complex excitation amplitude that causes the electromagnetic waves to propagate as plane waves in a predetermined direction after being reflected by the reflector. Antenna device.

6. An array receiving unit in which multiple antenna elements are arranged, A reflector that reflects incoming electromagnetic waves and irradiates them onto the array receiving unit, Equipped with, The array receiving unit weights the signals received by the plurality of antenna elements with complex amplitudes corresponding to plane waves from a predetermined direction, and synthesizes the wavefronts of the electromagnetic waves after they have been reflected by the reflector. Antenna device.

7. A beamforming method using an antenna device comprising an array feeding unit in which multiple antenna elements are arranged and a lens, The aforementioned plurality of antenna elements emit electromagnetic waves, The array power supply unit excites the plurality of antenna elements with a complex excitation amplitude such that the electromagnetic wave is refracted by the lens and then propagates as a plane wave in a predetermined direction. Beamforming method.

8. A beamforming method using an antenna device comprising an array receiving unit in which multiple antenna elements are arranged and a lens, The array receiving unit weights the signals received by the plurality of antenna elements with complex amplitudes corresponding to plane waves from a predetermined direction, and synthesizes the wavefronts of the electromagnetic waves after they have been refracted by the lens. Beamforming method.

9. A beamforming method using an antenna device comprising an array feeding section with multiple antenna elements arranged in a row and a reflector, The aforementioned plurality of antenna elements emit electromagnetic waves, The array power supply unit excites the plurality of antenna elements with a complex excitation amplitude that causes the electromagnetic waves to propagate as plane waves in a predetermined direction after being reflected by the reflector. Beamforming method.

10. A beamforming method using an antenna device comprising an array receiving unit in which multiple antenna elements are arranged and a reflector, The array receiving unit weights the signals received by the plurality of antenna elements with complex amplitudes corresponding to plane waves from a predetermined direction, and synthesizes the wavefronts of the electromagnetic waves after they have been reflected by the reflector. Beamforming method.

11. A program for causing a control unit of the antenna device to control the plurality of antenna elements and the array feeding unit to perform the beamforming method described in claim 7 or 9.

12. A program for causing a control unit of the antenna device to control the array receiving unit to perform the beamforming method described in claim 8 or 10.

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