Two-dimensional multi-beam antenna based on vertical plane folded Butler matrix
By folding the Butler matrix design vertically, the topology is simplified, the cross-coupler is removed, and the input and output ports are centralized, which solves the shortcomings of the Butler matrix in miniaturization and low loss, and achieves low insertion loss and high reliability, suitable for millimeter wave communication.
Patent Information
- Application Number
- CN202510903781.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-01
- Publication Date
- 2025-09-02
AI Technical Summary
The existing Butler matrix has shortcomings in miniaturization and low loss, especially in millimeter wave band and two-dimensional design, large-size and high insertion losses are difficult to meet practical application needs.
The Butler matrix design adopts a vertical plane folding, connects the bottom and top portions through a multi-layer interconnect structure, removes the cross coupler, and concentrates the input and output ports at the center of the network matrix, simplifying the topology and shortening the signal transmission path.
The Butler matrix miniaturization and low insertion loss are achieved, reducing the risk of manufacturing defects, improving the reliability and operating bandwidth of the millimeter wave band, and simplifying integration with active circuits.
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Figure CN120581850A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of microwave and millimeter wave antennas, in particular to a two-dimensional multi-beam antenna based on a vertical plane folded Butler matrix. Background Art
[0002] Beamforming array technology has garnered significant attention in recent years, particularly in applications such as 5G / 6G millimeter-wave communications, radar imaging, and detection. Methods for implementing beamforming arrays can be broadly categorized into three types: analog beamforming, digital beamforming, and hybrid beamforming. Analog beamforming arrays include passive beamforming arrays and active beamforming arrays. The Butler matrix is a typical implementation of passive beamforming.
[0003] Due to its excellent beam orthogonality, good port isolation and simple structure, domestic and foreign scholars have conducted a lot of related research on the Butler matrix. However, the Butler matrix reported so far has shortcomings in miniaturization and low loss, especially in the millimeter wave frequency band and the design of the two-dimensional Butler matrix. The large size and high insertion loss of the Butler matrix are difficult to meet the application requirements of actual scenarios. In order to reduce the size of the Butler matrix and reduce the loss of the network, it is necessary to simplify the network topology while reducing the distance of signal transmission. The current solutions to achieve miniaturization of the Butler matrix all use different transmission lines to fold the network, without considering reducing the distance of signal transmission, which makes the loss of the Butler matrix difficult to control. Summary of the Invention
[0004] Purpose of the invention: The purpose of the present invention is to address the problems existing in the above-mentioned prior art and provide a two-dimensional multi-beam antenna based on a vertical plane folded Butler matrix. It includes N N×M Butler matrices of the first order, M N×M Butler matrices of the second order, and an M×M antenna array. The present invention adopts a vertical plane folding solution. Compared with the traditional Butler matrix, it simplifies the components of the Butler matrix, realizes the removal of the cross-coupler, and avoids the crossing of the traces. The structure of the present invention is centrally symmetrical, and the unique layout makes the overall traces shorter, which is beneficial to reducing the insertion loss of the Butler matrix. The input and output ports of the Butler matrix are deployed in the center of the network matrix instead of around it, which is beneficial to the cascading between matrices and the planarization of the multi-beam antenna. The two-dimensional multi-beam antenna has N×N signal input ports, which can generate N×N independent beams within a certain spatial range.
[0005] Technical solution: To achieve this purpose, the present invention adopts the following technical solution:
[0006] A two-dimensional multi-beam antenna based on a vertical folded Butler matrix comprises, from bottom to top, N first-order N×M Butler matrices, M second-order N×M Butler matrices, and an M×M antenna array.
[0007] Furthermore, the first-order N×M Butler matrix and the second-order N×M Butler matrix have the same structure and the same size.
[0008] Furthermore, the N first-order N×M Butler matrices are arranged along the Y-axis, and the M second-order N×M Butler matrices are arranged along the X-axis.
[0009] Furthermore, the output ports of the N first-order N×M Butler matrices are connected to the input ports of the M second-order N×M Butler matrices, and the output ports of the M second-order N×M Butler matrices are connected to the input ports of the M×M antenna array.
[0010] Furthermore, when N=M=4, the first-order N×M Butler matrix consists of a bottom part and a top part.
[0011] Furthermore, the bottom layer of the Butler matrix includes a first signal input port, a second signal input port, a third signal input port, a fourth signal input port, a first directional coupler, a second directional coupler, a first 45-degree phase shifter, a second 45-degree phase shifter, a first multi-layer interconnection structure, a second multi-layer interconnection structure, a third multi-layer interconnection structure, and a fourth multi-layer interconnection structure.
[0012] Furthermore, the top layer of the Butler matrix includes a first signal output port, a second signal output port, a third signal output port, a fourth signal output port, a third directional coupler, a fourth directional coupler, a first 0-degree phase shifter, a second 0-degree phase shifter, a fifth multi-layer interconnection structure, a sixth multi-layer interconnection structure, a seventh multi-layer interconnection structure, and an eighth multi-layer interconnection structure.
[0013] Furthermore, the bottom part and the top part include 4 signal input ports and 4 signal output ports. The input signal ports and the output signal ports are deployed in the center of the network matrix. When the 4 signal input ports are independently input, the 4 output ports output signals with different phase differences; wherein, when the first signal input port is input, the four output ports output signals with the same amplitude and a phase difference of -45 degrees; when the second signal input port is input, the four output ports output signals with the same amplitude and a phase difference of 135 degrees; when the third signal input port is input, the four output ports output signals with the same amplitude and a phase difference of -135 degrees; when the fourth signal input port is input, the four output ports output signals with the same amplitude and a phase difference of 45 degrees.
[0014] Furthermore, the first directional coupler and the second directional coupler are centrally symmetrically distributed; the two input ports of the first directional coupler are connected to the first signal input port and the second signal input port, and the two output ports are connected to the first 45-degree phase shifter and the second multi-layer interconnection structure. When a signal is input from the input port to the first directional coupler, the output signals of the two output ports have the same amplitude, and one output port lags the other output port by 90 degrees in phase; the two input ports of the second directional coupler are connected to the third signal input port and the fourth signal input port, and the two output ports are connected to the second 45-degree phase shifter and the third multi-layer interconnection structure. When a signal is input from the input port to the second directional coupler, the output signals of the two output ports have the same amplitude, and one output port lags the other output port by 90 degrees in phase.
[0015] Furthermore, the third and fourth directional couplers are centrally symmetrically distributed; the two input ports of the third directional coupler are connected to the fifth and seventh multi-layer interconnect structures, and the two output ports are connected to the first 0-degree phase shifter and the third signal output port. When a signal is input from the input port to the third directional coupler, the output signals of the two output ports have the same amplitude, and one output port lags the other output port by 90 degrees in phase; the two input ports of the fourth directional coupler are connected to the sixth and eighth multi-layer interconnect structures, and the two output ports are connected to the second 0-degree phase shifter and the second signal output port. When a signal is input from the input port to the fourth directional coupler, the output signals of the two output ports have the same amplitude, and one output port lags the other output port by 90 degrees in phase.
[0016] Furthermore, the first multi-layer interconnection structure and the fifth multi-layer interconnection structure are a group and are connected to each other; the second multi-layer interconnection structure and the sixth multi-layer interconnection structure are a group and are connected to each other; the third multi-layer interconnection structure and the seventh multi-layer interconnection structure are a group and are connected to each other; and the fourth multi-layer interconnection structure and the eighth multi-layer interconnection structure are a group and are connected to each other.
[0017] Compared with the prior art, the present invention has the following significant advantages:
[0018] The present invention adopts a vertically folded design, with the upper and lower layers connected via a multi-layer interconnect structure. Cross-couplers are eliminated from the topology, and cross-wires are eliminated, simplifying the network topology. Devices on the bottom and top layers are centrally symmetrically distributed, with input and output ports positioned at the center of the network. This structure reduces signal transmission distance, which helps reduce insertion loss in the Butler matrix.
[0019] Specifically, the innovative features and corresponding beneficial effects of the present invention are:
[0020] 1. The present invention adopts a double-layer architecture with a bottom layer and a top layer, connected vertically through a multi-layer interconnect structure, replacing traditional planar wiring. It can remove cross-couplers and avoid crossing of traces, simplifying network complexity; shortening the signal transmission path, and reducing the measured insertion loss to 0.4dB; achieving three-dimensional spatial folding, significantly reducing the physical size.
[0021] 2. All directional couplers and phase shifters in the present invention are centrally distributed and the input / output ports are centrally deployed at the center of the network matrix. This optimizes signal transmission balance and reduces phase error. Direct connection between the first-order and second-order matrices reduces winding and improves system integration. The symmetrical design offsets process deviations and improves reliability in the millimeter-wave frequency band.
[0022] 3. The present invention completely removes the cross coupler and only realizes phase control through the combination of directional coupler + phase shifter; it can avoid the parasitic coupling problem caused by cross lines in the high-frequency band; the multi-layer interconnect structure replaces the planar cross, reducing the risk of manufacturing defects; and extending the operating bandwidth.
[0023] 4. The first-order N×M matrix and the second-order N×M matrix of the present invention are isomorphic and of the same size and are regularly arranged along the X / Y axis; N×N beams can be realized by cascading the same modules; the output port is centered to simplify the connection with the antenna array. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] Figure 1 Schematic diagram of the topological structure of a two-dimensional multi-beam antenna of a vertically folded Butler matrix in a specific embodiment of the present invention;
[0025] Figure 2 Schematic diagram of a 4×4 Butler matrix network topology structure with vertical folding in a specific embodiment of the present invention;
[0026] Figure 3 This is a schematic diagram of the underlying network topology structure in a specific embodiment of the present invention;
[0027] Figure 4 This is a schematic diagram of the top-level network topology structure in a specific embodiment of the present invention;
[0028] Figure 5 Schematic diagram of a 4×4 Butler matrix network simulation model with vertical folding in a specific embodiment of the present invention;
[0029] Figure 6 This is a schematic diagram of the underlying network simulation model in a specific embodiment of the present invention;
[0030] Figure 7 This is a schematic diagram of a top-level network simulation model in a specific embodiment of the present invention;
[0031] Figure 8This is the return loss simulation result of the 4×4 Butler matrix network;
[0032] Figure 9 The simulation results of the input port isolation of the 4×4 Butler matrix network are shown below.
[0033] Figure 10 The simulation results of the transmission coefficient of the 4×4 Butler matrix network;
[0034] Figure 11 This is the simulation result of the phase distribution of the 4×4 Butler matrix network;
[0035] Figure 12 Schematic diagram of the simulation model of a two-dimensional multi-beam antenna with a vertically folded Butler matrix;
[0036] Figure 13 Return loss simulation results of a two-dimensional multi-beam antenna with a vertically folded Butler matrix;
[0037] Figure 14 Simulation results of the two-dimensional multi-beam radiation pattern of the vertically folded Butler matrix. DETAILED DESCRIPTION
[0038] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.
[0039] In one embodiment, the present invention proposes a two-dimensional multi-beam antenna based on a vertical plane folded Butler matrix, wherein the two-dimensional multi-beam antenna (topology structure as shown in FIG. Figure 1 As shown) includes, from bottom to top, N first-order N×M Butler matrices 1, M second-order N×M Butler matrices 2, and an M×M antenna array 3.
[0040] Furthermore, in some embodiments, Figure 1 The first-order N×M Butler matrix 1 and the second-order N×M Butler matrix 2 have the same structure and the same size.
[0041] Furthermore, in some embodiments, Figure 1 The N first-order N×M Butler matrices 1 are arranged along the Y-axis, and the M second-order N×M Butler matrices 2 are arranged along the X-axis.
[0042] Furthermore, in some embodiments, Figure 1 The output ports of the N first-order N×M Butler matrices 1 are connected to the input ports of the M second-order N×M Butler matrices 2, and the output ports of the M second-order N×M Butler matrices 2 are connected to the input ports of the M×M antenna array 3.
[0043] Furthermore, in some embodiments, Figure 2 When N=M=4, the 4×4 Butler matrix consists of a bottom part 11 and a top part 12.
[0044] Furthermore, in some embodiments, Figure 3 The Butler matrix bottom layer 11 includes a first signal input port 101, a second signal input port 102, a third signal input port 103, a fourth signal input port 104, a first directional coupler 111, a second directional coupler 112, a first 45-degree phase shifter 121, a second 45-degree phase shifter 122, a first multi-layer interconnection structure 131, a second multi-layer interconnection structure 132, a third multi-layer interconnection structure 133, and a fourth multi-layer interconnection structure 134;
[0045] Combine Figure 4 The top layer portion 12 of the Butler matrix includes a first signal output port 201, a second signal output port 202, a third signal output port 203, a fourth signal output port 204, a third directional coupler 211, a fourth directional coupler 212, a first 0-degree phase shifter 221, a second 0-degree phase shifter 222, a fifth multi-layer interconnection structure 231, a sixth multi-layer interconnection structure 232, a seventh multi-layer interconnection structure 233, and an eighth multi-layer interconnection structure 234.
[0046] Furthermore, in some embodiments, Figure 3 and Figure 4 The bottom part 11 and the top part 12 include 4 signal input ports and 4 signal output ports. The input signal ports and the output signal ports are deployed in the center of the network matrix. When the 4 signal input ports are independently input, the 4 output ports output signals with different phase differences; among them, when the first signal input port 101 is input, the output signals of the four output ports have the same amplitude and a phase difference of -45 degrees; when the second signal input port 102 is input, the output signals of the four output ports have the same amplitude and a phase difference of 135 degrees; when the third signal input port 103 is input, the output signals of the four output ports have the same amplitude and a phase difference of -135 degrees; when the fourth signal input port 104 is input, the output signals of the four output ports have the same amplitude and a phase difference of 45 degrees.
[0047] Furthermore, in some embodiments, Figure 3 and Figure 4 The first directional coupler 111, the second directional coupler 112, the third directional coupler 211, and the fourth directional coupler 212 have the same structure and the same size.
[0048] Furthermore, in some embodiments, Figure 3 The first directional coupler 111 and the second directional coupler 112 are centrally symmetrically distributed; the two input ports of the first directional coupler 111 are connected to the first signal input port 101 and the second signal input port 102, and the two output ports are connected to the first 45-degree phase shifter 121 and the second multi-layer interconnection structure 132. When a signal is input from the input port to the first directional coupler 111, the output signals of the two output ports have the same amplitude, and one output port lags the phase of the other output port by 90 degrees; the two input ports of the second directional coupler 112 are connected to the third signal input port 103 and the fourth signal input port 104, and the two output ports are connected to the second 45-degree phase shifter 122 and the third multi-layer interconnection structure 133. When a signal is input from the input port to the second directional coupler 112, the output signals of the two output ports have the same amplitude, and one output port lags the phase of the other output port by 90 degrees.
[0049] Furthermore, in some embodiments, Figure 4 The third directional coupler 211 and the fourth directional coupler 212 are centrally symmetrically distributed. The two input ports of the third directional coupler 211 are connected to the fifth multi-layer interconnect structure 231 and the seventh multi-layer interconnect structure 233, and the two output ports are connected to the first 0-degree phase shifter 221 and the third signal output port 203. When a signal is input from the input port to the third directional coupler 211, the output signals of the two output ports have the same amplitude, and one output port lags the other output port by 90 degrees. The two input ports of the fourth directional coupler 212 are connected to the sixth multi-layer interconnect structure 232 and the eighth multi-layer interconnect structure 234, and the two output ports are connected to the second 0-degree phase shifter 222 and the second signal output port 202. When a signal is input from the input port to the fourth directional coupler 212, the output signals of the two output ports have the same amplitude, and one output port lags the other output port by 90 degrees.
[0050] Furthermore, in some embodiments, Figure 3 and Figure 4 The first multi-layer interconnection structure 131 and the fifth multi-layer interconnection structure 231 are a group and are connected to each other; the second multi-layer interconnection structure 132 and the sixth multi-layer interconnection structure 232 are a group and are connected to each other; the third multi-layer interconnection structure 133 and the seventh multi-layer interconnection structure 233 are a group and are connected to each other; the fourth multi-layer interconnection structure 134 and the eighth multi-layer interconnection structure 234 are a group and are connected to each other.
[0051] In order to verify the authenticity and reliability of the proposed two-dimensional multi-beam antenna based on the vertical folded Butler matrix, a full-wave simulation model of the 4×4 Butler matrix was first established and an optimized simulation design was performed. The full-wave simulation model connects the directional coupler, phase shifter, and multi-layer interconnect structure according to the proposed topology (see Figure 5-Figure 7 shown). Figures 8-11 The return loss, isolation, transmission coefficient, and phase distribution of a vertically folded 4×4 Butler matrix are demonstrated. The proposed Butler matrix performs well in the 24.25-29.5 GHz range, verifying the correctness and reliability of the matrix network. The proposed Butler matrix has a compact size and profile, and the simulated average insertion loss is approximately 0.4 dB.
[0052] Furthermore, four 4×4 Butler matrices are used as the first-order Butler matrix, and four identical 4×4 Butler matrices are used as the second-order Butler matrix. The output port of the first-order Butler matrix is connected to the input port of the second-order Butler matrix. 16 magnetoelectric dipole antennas are used as the antenna array, and the output port of the second-order Butler matrix is connected to the input port of the antenna array. The specific full-wave simulation model is as follows: Figure 12 As shown, Figure 13 is the S parameter of the multi-beam antenna, Figure 14 The 16 input ports of the multi-beam antenna generate 16 independent beams.
[0053] In summary, the present invention proposes a two-dimensional multi-beam antenna based on a vertical folded Butler matrix. The multi-beam antenna has a simple topology and a short transmission path, which realizes the miniaturization and low insertion loss of the matrix network. The overall profile is low, which is conducive to integration with front-end active circuits. It is an excellent choice for millimeter wave 5G / B6G wireless communications.
[0054] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention, and such changes and modifications fall within the scope of the invention as claimed.
Claims
1. A two-dimensional multi-beam antenna based on a vertical folded Butler matrix, characterized in that: The two-dimensional multi-beam antenna comprises, from bottom to top, N first-order N×M Butler matrices (1), M second-order N×M Butler matrices (2), and an M×M antenna array (3); wherein the output port of the first-order Butler matrix (1) is connected to the input port of the second-order Butler matrix (2), and the output port of the second-order Butler matrix (2) is connected to the input port of the antenna array (3).
2. A two-dimensional multi-beam antenna based on a vertical folded Butler matrix according to claim 1, characterized in that: The first-order N×M Butler matrix (1) and the second-order N×M Butler matrix (2) have the same structure and the same size.
3. The two-dimensional multi-beam antenna based on a vertical folded Butler matrix according to claim 1, characterized in that: The N first-order N×M Butler matrices (1) are arranged along the Y axis, and the M second-order N×M Butler matrices (2) are arranged along the X axis.
4. The two-dimensional multi-beam antenna based on a vertical folded Butler matrix according to claim 1, characterized in that: When N=M=4, the first-order N×M Butler matrix (1) is composed of a bottom portion (11) and a top portion (12) through a vertical interconnection structure.
5. The two-dimensional multi-beam antenna based on a vertical folded Butler matrix according to claim 4, characterized in that: The bottom layer (11) includes a first signal input port (101), a second signal input port (102), a third signal input port (103), a fourth signal input port (104), a first directional coupler (111), a second directional coupler (112), a first 45-degree phase shifter (121), a second 45-degree phase shifter (122), a first multi-layer interconnection structure (131), a second multi-layer interconnection structure (132), a third multi-layer interconnection structure (133), and a fourth multi-layer interconnection structure (134); The input port of the first directional coupler (111) is connected to the first and second signal input ports (101, 102), and the output port is connected to the first 45° phase shifter (121) and the second multi-layer interconnection structure (132) respectively; the input port of the second directional coupler (112) is connected to the third and fourth signal input ports (103, 104), and the output port is connected to the second 45° phase shifter (122) and the third multi-layer interconnection structure (133) respectively; The top layer portion (12) includes a first signal output port (201), a second signal output port (202), a third signal output port (203), a fourth signal output port (204), a third directional coupler (211), a fourth directional coupler (212), a first 0-degree phase shifter (221), a second 0-degree phase shifter (222), a fifth multi-layer interconnection structure (231), a sixth multi-layer interconnection structure (232), a seventh multi-layer interconnection structure (233), and an eighth multi-layer interconnection structure (234); The input port of the third directional coupler (211) is connected to the fifth and seventh interconnection structures (231, 233), and the output port is connected to the first 0° phase shifter (221) and the third signal output port (203) respectively; the input port of the fourth directional coupler (212) is connected to the sixth and eighth interconnection structures (232, 234), and the output port is connected to the second 0° phase shifter (222) and the second signal output port (202) respectively.
6. The two-dimensional multi-beam antenna based on a vertical folded Butler matrix according to claim 5, characterized in that: The bottom part (11) and the top part (12) include four signal input ports and four signal output ports. The input signal ports and the output signal ports are all deployed at the center of the network matrix. When the four signal input ports are independently input, the four output ports output signals with different phase differences. When the first signal input port (101) is input, the four output ports output signals with the same amplitude and a phase difference of -45 degrees; when the second signal input port (102) is input, the four output ports output signals with the same amplitude and a phase difference of 135 degrees; when the third signal input port (103) is input, the four output ports output signals with the same amplitude and a phase difference of -135 degrees; when the fourth signal input port (104) is input, the four output ports output signals with the same amplitude and a phase difference of 45 degrees.
7. The two-dimensional multi-beam antenna based on a vertical folded Butler matrix according to claim 5, characterized in that: The first directional coupler (111), the second directional coupler (112), the third directional coupler (211), and the fourth directional coupler (212) have the same structure and the same size.
8. The two-dimensional multi-beam antenna based on a vertical folded Butler matrix according to claim 5, characterized in that: All signal input ports (101-104) and output ports (201-204) are deployed in the central area of the network matrix.
9. The two-dimensional multi-beam antenna based on a vertical folded Butler matrix according to claim 5, characterized in that: The first directional coupler (111) and the second directional coupler (112) are distributed in a centrally symmetrical manner, and the third directional coupler (211) and the fourth directional coupler (212) are distributed in a centrally symmetrical manner.
10. The two-dimensional multi-beam antenna based on a vertical folded Butler matrix according to claim 5, characterized in that: The first multi-layer interconnection structure (131) and the fifth multi-layer interconnection structure (231) are a group and are connected to each other; the second multi-layer interconnection structure (132) and the sixth multi-layer interconnection structure (232) are a group and are connected to each other; the third multi-layer interconnection structure (133) and the seventh multi-layer interconnection structure (233) are a group and are connected to each other; the fourth multi-layer interconnection structure (134) and the eighth multi-layer interconnection structure (234) are a group and are connected to each other.