A two-dimensional multi-beam antenna

Abstract

The application provides a two-dimensional multi-beam antenna, and belongs to the technical field of radio frequency communication, comprising: four orthogonal couplers, input ports of the four orthogonal couplers being used for receiving input signals; four phase shifters, inputs of the four phase shifters being connected with output ports of the four orthogonal couplers; two one-dimensional 4*4 Butler matrices, inputs of the two one-dimensional 4*4 Butler matrices being connected with outputs of the phase shifters, the two one-dimensional 4*4 Butler matrices being symmetrically placed along an x axis; an antenna array, the antenna array being connected with outputs of the two one-dimensional 4*4 Butler matrices; the orthogonal couplers and the phase shifters are used for providing a fixed phase difference between adjacent output ports in a y direction, and the two one-dimensional 4*4 Butler matrices are used for providing a fixed phase difference between adjacent output ports in an x direction, so that a beam forming network in two dimensions is realized. The application can realize as many beams as possible in two dimensions with a simple network structure, and the freedom of beam pointing is improved.

Description

Technical Field

[0001] This invention belongs to the field of radio frequency communication technology, and specifically relates to a two-dimensional multi-beam antenna. Background Technology

[0002] With the rapid growth of wireless communication technology, the network capacity of wireless communication systems has been severely limited. In order to improve the utilization of spectrum resources and increase channel capacity, multi-beam antennas have been widely used in satellite communication systems, personal communication systems, and wireless local area networks.

[0003] Butler matrix-based multibeamforming networks are the core components of multibeam antennas, offering simple structure and flexible beam switching. They can effectively control the phase distribution of the antenna array, thereby achieving different beam directions. Compared to one-dimensional antenna arrays, two-dimensional antenna arrays offer more flexible beam pointing and produce more symmetrical radiation patterns. Traditional phased arrays are costly due to the use of multiple phase shifters.

[0004] Therefore, research on how to achieve as many beams as possible in two dimensions with a simpler network structure is of great significance. Summary of the Invention

[0005] In order to achieve as many beams as possible in two dimensions, the present invention provides a two-dimensional multi-beam antenna.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A two-dimensional multi-beam antenna, comprising:

[0008] A two-dimensional 8-port Butler matrix, which includes:

[0009] Four orthogonal couplers, whose input terminals are used to receive input signals;

[0010] Four phase shifters, the input terminals of which are connected to the output ports of the four quadrature couplers;

[0011] Two one-dimensional 4×4 Butler matrices are connected to the output of a phase shifter, and the two one-dimensional 4×4 Butler matrices are placed symmetrically along the x-axis.

[0012] The antenna array is connected to the outputs of two one-dimensional 4×4 Butler matrices.

[0013] By utilizing the orthogonal coupler and phase shifter to provide a fixed phase difference between adjacent output ports in the y-direction, and by utilizing the two one-dimensional 4×4 Butler matrices to provide a fixed phase difference between adjacent output ports in the x-direction, a beamforming network in two dimensions is realized. The antenna array is used to obtain beams with different directions under the excitation of different input ports, thereby realizing beam scanning.

[0014] Furthermore, the one-dimensional 4×4 Butler matrix includes:

[0015] Two single-stage orthogonal couplers, the input terminals of which are connected to the output terminals of the phase shifter;

[0016] A first-stage cross junction, whose input is connected to the output of two first-stage quadrature couplers;

[0017] Two 45° phase shifters are connected to the output of the first-stage quadrature coupler.

[0018] Two secondary orthogonal couplers, whose input terminals are respectively connected to the output terminals of the two 45° phase shifters and to the output terminal of the primary cross junction;

[0019] Two 0° phase shifters have their input terminals connected to the output terminals of the two secondary orthogonal couplers, and their output terminals are connected to the input terminals of the antenna array.

[0020] The second-level cross junction has its input connected to the output of two second-level orthogonal couplers, and its output connected to the input of the antenna array.

[0021] Furthermore, it also includes: an interconnection adapter structure for inputting the received input signal to the eight input ports of the four orthogonal couplers;

[0022] The interconnection and transition structure includes:

[0023] The first copper-based micro coaxial line has its inner conductor's output terminal connected to the input port of the orthogonal coupler;

[0024] A copper cylinder is disposed within the first copper-based micro coaxial line, with the lower part of the copper cylinder connected to one end of the inner conductor of the copper-based micro coaxial line; the top of the copper cylinder extends out to form the outer conductor of the first copper-based micro coaxial line.

[0025] Furthermore, the interconnection structure also includes: a pad disposed on the top of the copper cylinder, wherein the cross-sectional area of ​​the pad is larger than that of the copper cylinder;

[0026] The outer conductor of the first copper-based micro coaxial line forms a circular coaxial line at its end together with the pad and the copper cylinder.

[0027] Furthermore, it also includes:

[0028] Multiple release holes are periodically located on the outer wall of the outer conductor of the first copper-based micro coaxial line.

[0029] Furthermore, the antenna array includes:

[0030] Multiple air-back cavity patch antenna elements, wherein the air-back cavity patch antenna elements include:

[0031] The second copper-based microcoaxial line includes an inner conductor and an outer conductor that are nested together; the input end of the inner conductor is connected to the output end of the one-dimensional 4×4 Butler matrix.

[0032] A radiating patch, the bottom of which is connected to the output end of the inner conductor of the copper wire;

[0033] An air cavity is used to form an antenna together with a radiating patch, and its exterior is connected to the outer conductor of a second copper-based microcoaxial line.

[0034] The bottom of the air back cavity is provided with two medium supports.

[0035] Furthermore, the top of the radiation patch has two slits.

[0036] Furthermore, the outer wall of the outer conductor of the first copper-based micro coaxial line is periodically provided with multiple release holes of the same size, with the size of the release holes being 0.2mm×0.2mm×0.2mm.

[0037] Furthermore, the input and output ports of the orthogonal coupler are 8-layer copper-based micro coaxial cables with an inner conductor width of 0.33 mm; the series arm of the orthogonal coupler is an 8-layer copper-based micro coaxial cable with an inner conductor width of 0.48 mm and an inner conductor length of 1.02 mm; the parallel arm of the orthogonal coupler is an 8-layer copper-based micro coaxial cable with an inner conductor width of 0.33 mm and an inner conductor length of 0.95 mm.

[0038] The series arm has an electrical length of λ / 4 and a characteristic impedance of 50 / 2, while the parallel arm has a characteristic impedance of 50Ω.

[0039] The two-dimensional multi-beam antenna provided by this invention has the following beneficial effects:

[0040] This invention is based on a one-dimensional Butler matrix, which combines orthogonal couplers and phase shifters placed in different directions. The orthogonal couplers and phase shifters provide a fixed phase difference between adjacent output ports in the y-direction, while the one-dimensional 4×4 Butler matrix provides a fixed phase difference between adjacent output ports in the x-direction, thus realizing a beamforming network in two dimensions. This two-dimensional Butler matrix can realize multiple beams in two dimensions, improving the degree of freedom of beam pointing. Attached Figure Description

[0041] To more clearly illustrate the embodiments and design schemes of the present invention, the accompanying drawings required for this embodiment will be briefly described below. The drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0042] Figure 1 This is a schematic diagram of the W-band Butler matrix-fed two-dimensional multi-beam antenna according to an embodiment of the present invention;

[0043] Figure 2 This is a schematic diagram of the interconnection and switching structure in this invention;

[0044] Figure 3 These are the S-parameter simulation results of the interconnection and transition structure in this invention;

[0045] Figure 4 These are the simulation results of the S-parameters of the two-dimensional Butler matrix in this invention;

[0046] Figure 5 This is a schematic diagram and simulation results of the return loss of the air cavity patch antenna element in this invention;

[0047] Figure 6 This is the simulation result of the radiation pattern of the air cavity patch antenna element in this invention;

[0048] Figure 7 This invention relates to the return loss of the W-band Butler matrix-fed two-dimensional multibeam antenna.

[0049] Figure 8 This invention relates to the multi-beam 3D radiation pattern of a W-band Butler matrix-fed two-dimensional multi-beam antenna. Detailed Implementation

[0050] To enable those skilled in the art to better understand and implement the technical solutions of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and should not be construed as limiting the scope of protection of the present invention.

[0051] Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. In the description of this invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "connected" or "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances. In the description of this invention, unless otherwise stated, "a plurality of" means two or more, which will not be elaborated further here.

[0052] Example:

[0053] This invention provides a two-dimensional multi-beam antenna, specifically as follows: Figure 1 As shown, the beamforming network includes: a two-dimensional 8-port Butler matrix comprising: four orthogonal couplers with eight input ports for receiving input signals; four phase shifters with their inputs connected to the output ports of the four orthogonal couplers; two one-dimensional 4×4 Butler matrices with their inputs connected to the outputs of the phase shifters, the two one-dimensional 4×4 Butler matrices being symmetrically placed along the x-axis; and an antenna array connected to the outputs of the two one-dimensional 4×4 Butler matrices. By utilizing the orthogonal couplers and phase shifters to provide a fixed phase difference between adjacent output ports in the y-direction, and simultaneously utilizing the two one-dimensional 4×4 Butler matrices to provide a fixed phase difference between adjacent output ports in the x-direction, a two-dimensional beamforming network is achieved. The antenna array is used to obtain beams pointing in different directions under the excitation of different input ports, thus realizing beam scanning.

[0054] The following are specific embodiments of the present invention:

[0055] like Figures 1-8 As shown, this invention relates to a two-dimensional multi-beam antenna. The multi-beam antenna array includes interconnecting transition structures 101-108, a two-dimensional 8-port Butler matrix 200, and an air-back cavity patch antenna array 300. The interconnecting transition structures connect to the input terminals of the two-dimensional Butler matrix; the two-dimensional Butler matrix serves as the array antenna feed circuit, and its output ports are directly connected to the air-back cavity patch antenna to feed the array antenna; the array antenna can obtain beams with different directions under excitation at different input terminals, thereby achieving beam scanning. The array antenna and its feed circuit are designed using micro-nano fabrication technology based on chemical additive manufacturing.

[0056] Example 1:

[0057] like Figure 2 (a) is a schematic diagram of the interconnection and transition structure. Figure 2 (b) is a partial enlarged view of the interconnection and transition structure.

[0058] like Figure 2 As shown, the interconnect structure includes a first copper-based microcoaxial cable, comprising an inner conductor 109, a copper outer conductor 110, a copper cylinder 111, pads 112, several release holes 114, and several dielectric support strips 115. The pads use the 8th layer of metal, with a radius of 0.252 mm and a height of 0.1 mm. The pads can achieve vertical interconnection and high-density packaging through metal solder balls, and are vertically connected to the lower cylinders of concentricity but different diameters. The copper cylinder 111 uses the 6th-7th layer of metal, with a radius of 0.2 mm and a height of 0.2 mm, and is connected to the inner conductor of the copper-based microcoaxial cable through a cylindrical connector to achieve signal transition from other structures to the copper-based microcoaxial cable. Through the copper cylinder 111 and the pads 112, the interconnect structure can achieve good mode conversion and smooth impedance transition.

[0059] The W-band (75GHz–110GHz) is an important atmospheric window band in the millimeter-wave spectrum. Compared to low-frequency bands, W-band communication systems offer advantages such as wider usable bandwidth, larger channel capacity, and easier miniaturization of components. However, in this band, the dielectric loss of traditional transmission lines increases, and inter-line coupling and radiation effects become more pronounced, limiting the integration and miniaturization of millimeter-wave systems. The interconnection structure, combined with the inherent planar and vertical design capabilities of a three-dimensional multilayer metal structure, enables vertical interconnection between copper-based microcoaxial lines and itself, as well as other transmission lines, breaking through the self-encapsulation technology of copper-based microcoaxial lines. This structure utilizes double-section cylindrical pads to achieve excellent mode conversion and impedance matching, solving the problems of high interconnection complexity and high loss in existing technologies.

[0060] Example 2:

[0061] like Figure 2 As shown, the inner conductor 110 of the first copper-based microcoaxial cable uses the 4th and 5th metal layers, with a width of 0.33 mm and a height of 0.2 mm. This inner conductor is connected to a double-section diameter stepped cylinder via a cylindrical connector at the end. The copper outer conductor smoothly transitions into a cylindrical cavity at the end, with a radius of 0.58 mm, which, together with the double-section diameter stepped cylinder, forms a section of circular coaxial cable. Several release holes 114 of the same size are periodically opened on the outer wall of the copper-based microcoaxial cable to release photoresist. The size of the release holes is 0.3 mm × 0.3 mm × 0.3 mm. A support strip 115 is used to support the inner conductor 109.

[0062] like Figure 2 As shown, the copper cylinder 111 and pad 112 achieve good mode conversion and impedance matching of signals from other structures to the copper-based micro coaxial line. In the 90-100GHz frequency band, the return loss of the interconnect structure is better than 26.2dB, and the insertion loss is better than 0.052dB.

[0063] like Figure 1 As shown in (d), the two-dimensional 8-port Butler matrix 200 includes four orthogonal couplers 201, 202, 203, and 204, four phase shifters 205, 206, 207, and 208, and two one-dimensional 4×4 Butler matrices 209 and 210. The eight input ports of the four orthogonal couplers 201, 202, 203, and 204 are connected to interconnection transition structures 101-108, and their output ports are connected to transmission lines 205, 206, 207, and 208 that constitute the phase shifters. These phase shifters are connected to the input ports of the orthogonal couplers above and the input ports of the two one-dimensional 4×4 Butler matrices 209 and 210 below. The two-dimensional 8-port Butler matrix utilizes the orthogonal couplers and the phase shifters shown to provide a fixed phase difference between adjacent output ports in the y-direction, and simultaneously utilizes the one-dimensional 4×4 Butler matrix to provide a fixed phase difference between adjacent output ports in the x-direction, thereby realizing a beamforming network in two dimensions.

[0064] like Figure 1 As shown, the four orthogonal couplers are traditional branch-line couplers, with equal power allocated to the two output ports and a 90° phase difference. This branch-line coupler is implemented using an 8-layer copper-based microcoaxial cable. The input and output ports are connected to 50Ω transmission lines, implemented using copper-based microcoaxial cables with an inner conductor width of 0.33mm. The series arm has an electrical length of λ / 4 and a characteristic impedance of 50 / 2, implemented using copper-based microcoaxial cables with an inner conductor width of 0.48mm and a length of 1.02mm. The parallel arm has a characteristic impedance of 50Ω, implemented using copper-based microcoaxial cables with an inner conductor width of 0.33mm and a length of 0.95mm. Several release holes of the same size (0.2mm × 0.2mm × 0.2mm) are periodically opened on the outer wall of the outer conductor of the copper-based microcoaxial cable to release photoresist. Support bars are used to support the inner conductor.

[0065] like Figure 1 As shown, the four phase shifters 205, 206, 207, and 208 are each composed of two transmission lines leading from the output ports of their respective quadrature couplers. These two transmission lines are implemented using an 8-layer copper-based microcoaxial cable, and the difference in their electrical lengths is the phase shift angle t of the phase shifter. Since the quadrature coupler and the phase shifter are on the same path, a phase difference of ±90°-t between adjacent ports can be generated in the y-axis direction. In this embodiment, the two transmission lines constituting the phase shifter have the same electrical length, meaning the phase shift angle of the phase shifter is 0. Therefore, the phase difference between adjacent ports in the y-axis direction is ±90°.

[0066] like Figure 1As shown in (d), the one-dimensional 4×4 Butler matrix 209 includes four orthogonal couplers 211, 212, 216, and 217 in two stages, two 45° phase shifters 213 and 214, and two cross-connections 215 and 220 in two stages. The first-stage orthogonal coupler consists of two orthogonal couplers 211 and 212. Its input port is connected to a transmission line of phase shifters 205, 206, 207, and 208, and its output port is connected to the main line structure of the two 45° phase shifters and the first-stage cross-connection, respectively. This orthogonal coupler is completely identical to the branch line couplers 201, 202, 203, and 204, and will not be described further.

[0067] like Figure 1 As shown in (d), the 45° phase shifter uses copper-based microcoaxial coupling lines 213 and 214 as the main structure, and the first-stage cross-junction 215 as the reference structure. Its four output ports are connected to the input ports of the second-stage orthogonal coupler. The 45° phase shifter is designed with 8 layers of copper-based microcoaxial lines, and the cross-junction 215 is implemented by cascading two branch line couplers. The relative phase shift between the output phase of the coupling line and the output phase of the cross-junction is defined as follows: when the relative phase shift is 45°, the length of the coupling line is 1.1 mm, and the spacing between the coupling lines is 0.1 mm.

[0068] like Figure 1 As shown in (d), the output ports of the second-stage orthogonal couplers 216 and 217 are connected to the input ports of the two coupled transmission lines 218 and 219 and the second-stage cross-connection 220. The branch line couplers that make up the second-stage orthogonal couplers are exactly the same as those of the first stage and will not be described again. The relative displacement between the output phase of coupled transmission lines 218 and 219 and the output phase of the second-stage cross-connection 220 is 0°. At this time, the length of the coupled lines is 0.9 mm and the spacing between the coupled lines is 0.1 mm.

[0069] like Figure 1 As shown, two one-dimensional 4×4 Butler matrices 209 and 210 are placed symmetrically along the x-axis and have identical internal structures.

[0070] Figure 4 (a) represents the avoidance loss of power supply to different input ports of a two-dimensional 8-port Butler matrix. Figure 4 (b) shows the phase characteristics of the two-dimensional Butler matrix when fed by different input ports. Figure 4 (c) represents the amplitude of different output ports when input ports 101 and 103 are powered. Figure 4 (d) represents the amplitude of different output ports when input ports 102 and 104 are powered.

[0071] like Figure 4As shown, the center frequency of the two-dimensional 8-port Butler matrix is ​​94GHz. In the 93-95GHz frequency band, the return loss of each input port fed separately is better than 19.32dB. When the input ports are 101 and 103, the output amplitude of each output port is -9.85dB±0.69dB; when the input ports are 102 and 104, the output amplitude of each output port is -9.85dB±0.68dB; the overall output amplitude is around -9.85dB, and the imbalance is within ±0.69dB.

[0072] like Figure 4 As shown, within the 93-95GHz frequency band, when the input ports are 101, 103, 105, and 107, the phase differences between adjacent output ports in the x-axis direction are 45±5.39°, -135±6.55°, 135±5.80°, and -45±5.46°, respectively. The overall phase imbalance is within ±6.55°. The phase differences for other ports are not detailed due to symmetry. In the y-axis direction, when ports 101, 103, 105, and 107 are fed, the phase difference between adjacent ports is 90±2.5°; when ports 2, 4, 6, and 8 are fed, the phase difference between adjacent ports is -90±2.37°.

[0073] Example 3:

[0074] like Figure 5 (a) is a schematic diagram of an air cavity patch antenna element. Figure 5 (b) shows the simulation results of return loss.

[0075] like Figure 5 As shown, the air-back cavity patch antenna element includes a second copper-based microcoaxial cable 309, 310, a radiating patch 311, an air-back cavity 312, a patch support 313, several support bars 314, and several release holes 315. The copper-based microcoaxial cable feed line, connected to the output port of the two-dimensional Butler matrix 200, extends vertically upwards and connects to the bottom of the radiating patch 311. The air-back cavity 312, which together with the radiating patch forms the antenna radiation, is connected to the outer conductor 310 of the copper-based microcoaxial cable. Two dielectric supports 313 at its bottom support the radiating patch to ensure the mechanical strength of the antenna element. Several release holes 315 of the same size are periodically opened on the outer wall of the copper-based microcoaxial cable outer conductor 310 to release photoresist. The size of the release holes is 0.2mm × 0.2mm × 0.2mm. The support bars 314 support the inner conductor.

[0076] like Figure 5As shown, the copper-based microcoaxial cable has a characteristic impedance of 50Ω and is implemented using an 8-layer metal design. The radiating patch and air cavity that make up the antenna are implemented using an 8-10 layer metal design. Gaps are left between the patch structure and the four outer walls of the air cavity, and a 0.1mm height difference exists to improve the antenna's gain and bandwidth. The radiating patch measures 1.09mm × 0.9mm, and the air cavity measures 1.08mm × 1.4mm. The radiating patch has an E-shaped structure with two slots loaded on it to improve impedance matching and frequency tuning.

[0077] Figure 6 (a) shows the E-plane radiation pattern of the air cavity patch antenna element. Figure 6 (b) is the H-plane orientation pattern.

[0078] like Figure 6 As shown, the antenna center frequency is 94GHz, and the bandwidth with a return loss better than 10dB is 3.94% (i.e., the operating frequency is 92.3-96.0GHz). At the antenna's operating center frequency of 94GHz, the gain of a single antenna reaches 7.19dBi, and the sidelobe level is -15.53dBi, indicating that the antenna sidelobes are relatively low.

[0079] like Figure 6 As shown, the distance between adjacent antenna elements needs to be reasonably selected. Based on comprehensive analysis, the antenna spacing dx and dy in both the vertical and horizontal directions are taken as 0.5λ. The output port of the Butler matrix is ​​coplanarly connected to the feed section of the air-cavity patch antenna. Since the output port spacing is different from the antenna array spacing, transmission lines of the same length are needed to ensure that the phase characteristics of the feed port remain unchanged. This two-dimensional beam scanning network can achieve 8-beam scanning.

[0080] like Figure 7 As shown, within the 93-95 GHz frequency band, the maximum beam offset angle in the θ direction is 44°. The beam pointing angles corresponding to ports 101-108 are (22°, 300°), (22°, 60°), (42°, 210°), (44°, 146°), (44°, 326°), (44°, 34°), (22°, 240°), and (22°, 120°), respectively. The maximum antenna gain can reach 14.988 dBi. The return loss is better than 17.40 dB in the 93-95 GHz band. The overall beam scanning network size is 36.81 mm × 38.13 mm × 1 mm, and the antenna efficiency is 83.13%.

[0081] In summary, this invention proposes a design method for a two-dimensional multi-beam antenna based on copper-based microcoaxial lines. It leverages the inherent planar and vertical design capabilities of three-dimensional multilayer metal structures to study the design method of vertical interconnection structures between copper-based microcoaxial lines and themselves, as well as other transmission lines. This breakthrough overcomes the self-encapsulation technology of copper-based microcoaxial lines, solving the problems of high interconnection structure complexity and high loss. Based on a one-dimensional Butler matrix, this invention combines orthogonal couplers and phase shifters placed in different directions to propose a design method for a two-dimensional Butler matrix with a simple network structure and flexible output phase switching. Utilizing the low-loss characteristics of copper-based microcoaxial lines in the W-band and the vertical design capabilities of multilayer metal structures, this invention proposes a high-gain, low-profile air-back cavity patch antenna. Finally, this invention proposes a Butler-fed two-dimensional multi-beam antenna with a simple network structure, realizing multiple beams in two dimensions and improving the freedom of beam pointing. Compared to traditional beamforming networks, this invention has the advantages of high integration, high efficiency, low loss, and flexible beam pointing, showing promising prospects in the field of microwave communication.

[0082] The above embodiments are merely preferred embodiments of the present invention, and the scope of protection of the present invention is not limited thereto. Any simple changes or equivalent substitutions of the technical solutions that can be obviously obtained by those skilled in the art within the scope of the technology disclosed in the present invention shall fall within the scope of protection of the present invention.

Claims

1. A two-dimensional multi-beam antenna, characterized by include: A two-dimensional 8-port Butler matrix, which includes: Four orthogonal couplers, whose input terminals are used to receive input signals; Four phase shifters, the input terminals of which are connected to the output ports of the four quadrature couplers; Two one-dimensional 4×4 Butler matrices are connected to the output of a phase shifter, and the two one-dimensional 4×4 Butler matrices are placed symmetrically along the x-axis. The antenna array (300) is connected to the output of two one-dimensional 4×4 Butler matrices; The orthogonal coupler and phase shifter provide a fixed phase difference between adjacent output ports in the y-direction, while the two one-dimensional 4×4 Butler matrices provide a fixed phase difference between adjacent output ports in the x-direction, thus realizing a beamforming network in two dimensions. The antenna array is used to obtain beams with different directions under the excitation of different input ports, thereby realizing beam scanning. An interconnection and transition structure is used to input the received input signal to the eight input ports of the four orthogonal couplers; the interconnection and transition structure includes: a first copper-based micro coaxial line, the output end of which is connected to the input port of the orthogonal coupler; a copper cylinder (111) disposed inside the first copper-based micro coaxial line, the lower part of which is connected to one end of the inner conductor (109) of the first copper-based micro coaxial line; and the top of the copper cylinder (111) extends out to the outer conductor (110) of the first copper-based micro coaxial line. The antenna array (300) includes: multiple air-cavity patch antenna elements, each air-cavity patch antenna element including: a second copper-based microcoaxial line, which includes an inner conductor and an outer conductor nested together; the input end of the inner conductor is connected to the output end of the one-dimensional 4×4 Butler matrix; a radiating patch (311), the bottom of which is connected to the output end of the inner conductor of the second copper-based microcoaxial line; an air cavity (312), used to form an antenna together with the radiating patch, the outside of which is connected to the outer conductor of the second copper-based microcoaxial line; and two dielectric supports are provided at the bottom of the air cavity (312).

2. A two-dimensional multi-beam antenna according to claim 1, characterized in that The one-dimensional 4×4 Butler matrix includes: Two single-stage orthogonal couplers, the input terminals of which are connected to the output terminals of the phase shifter; A first-stage cross junction, whose input is connected to the output of two first-stage quadrature couplers; Two 45° phase shifters are connected at their inputs to the output of the first-stage quadrature coupler. Two secondary orthogonal couplers, whose input terminals are respectively connected to the output terminals of the two 45° phase shifters and to the output terminal of the primary cross junction; Two 0° phase shifters, the input of which is connected to the output of the two secondary orthogonal couplers, and the output of which is connected to the input of the antenna array (300); The input of the second-level cross junction is connected to the output of two second-level orthogonal couplers, and its output is connected to the input of the antenna array (300).

3. A two-dimensional multi-beam antenna according to claim 1, characterized in that The interconnection structure further includes: a pad (112) disposed on the top of the copper cylinder (111), wherein the cross-sectional area of ​​the pad (112) is larger than that of the copper cylinder (111); The outer conductor (110) of the first copper-based micro coaxial line forms a circular coaxial line at its end together with the pad (112) and the copper cylinder.

4. The two-dimensional multi-beam antenna according to claim 1, wherein, Also includes: Multiple release holes (114) are periodically disposed on the outer wall of the outer conductor (110) of the first copper-based micro coaxial line.

5. A two-dimensional multi-beam antenna according to claim 1, characterized in that, The radiation patch (311) has two slits at the top.

6. A two-dimensional multi-beam antenna according to claim 1, wherein, The outer wall of the outer conductor (110) of the first copper-based micro coaxial line is periodically provided with multiple release holes of the same size, the size of which is 0.2mm×0.2mm×0.2mm.

7. A two-dimensional multi-beam antenna according to claim 1, characterized in that, The input and output ports of the orthogonal coupler are 8-layer copper-based micro coaxial cables with an inner conductor width of 0.33 mm; the series arm of the orthogonal coupler is an 8-layer copper-based micro coaxial cable with an inner conductor width of 0.48 mm and an inner conductor length of 1.02 mm; the parallel arm of the orthogonal coupler is an 8-layer copper-based micro coaxial cable with an inner conductor width of 0.33 mm and an inner conductor length of 0.95 mm. The electrical length of the series arm is λ / 4, and its characteristic impedance is 50Ω. The characteristic impedance of the parallel arm is 50Ω.

Images