A lossless multi-beam feed network design method

Abstract

The application discloses a lossless multi-beam feed network design method, which comprises the following steps: S1, determining target input port number and output port number of the lossless multi-beam feed network and comprehensive beamforming indexes according to application scene requirements; S2, obtaining a transmission matrix of the lossless multi-beam network according to the target input port number and output port number and the comprehensive beamforming indexes; S3, decomposing the transmission matrix of the multi-beam network by using a matrix decomposition method to obtain a decomposition formula of the transmission matrix of the multi-beam network; and S4, obtaining a lossless multi-beam network design result according to the decomposition formula of the transmission matrix of the multi-beam network. The application can comprehensively synthesize multi-beam networks with any port number, and simultaneously consider the comprehensive effect of the network's directional diagram.

Description

Technical Field

[0001] This invention relates to the field of network design technology, and specifically to a method for designing a lossless multi-beam fed network. Background Technology

[0002] With the increasing complexity and diversity of wireless communication scenarios, multi-beam antenna arrays have become a key technology for various applications, including diverse beam coverage and beam inter-interference suppression. Multi-beam antenna arrays can be implemented using lens technology or beamforming networks. Lens technologies such as Rotman lenses or Luneburg lenses offer advantages such as simple structure and wide bandwidth. However, high manufacturing precision and high cost limit their application. Beamforming networks offer advantages such as flexible design and low manufacturing cost. Therefore, designing a beamforming network that can meet complex and varied beam coverage requirements is crucial.

[0003] Among the many types of beamforming networks, the Butler matrix is ​​the most widely used passive orthogonal beamforming network, based on the Fast Fourier Transform (FFT). Therefore, its input and output (I / O) port numbers are limited to 2^M, where M is an arbitrary integer. Many efforts have been made to overcome the limitations of the Butler matrix. For example, expanding the number of ports in the Butler matrix, providing flexible phase outputs, and two-dimensional scanning Butler matrices, etc. Besides the Butler matrix, other matrix beamforming networks include the Blass matrix and the Nolen matrix. The Blass matrix is ​​based on Gram-Schmidt orthogonalization and consists of couplers, phase shifters, and load terminals. However, due to structural limitations, its overall efficiency is low, limiting its application scenarios. The Nolen matrix, based on the principles of the Blass matrix, overcomes its high loss problem.

[0004] Based on the above analysis, it can be concluded that each beamforming network employs a unique matrix decomposition theory. Essentially, beamforming network synthesis is equivalent to decomposing the beamforming network matrix into a cascade of matrices that characterize the devices. Therefore, the problem of synthesizing beamforming networks is equivalent to mathematically decomposing orthogonal networks. Current synthesized beamforming networks suffer from drawbacks such as a fixed number of ports, losses, and the inability to simultaneously achieve amplitude and phase modulation. Furthermore, there is still no effective design method for multi-beam networks that simultaneously meet the requirements of both the number of network ports and beamforming. Summary of the Invention

[0005] The purpose of this invention is to provide a design method for a lossless multi-beam feeder network, which can integrate multi-beam networks with any number of ports while taking into account the overall effect of the network's radiation pattern.

[0006] The technical solution of the present invention to solve the above-mentioned technical problems is as follows:

[0007] This invention provides a method for designing a lossless multibeam feed network, the method comprising:

[0008] S1: Determine the target number of input ports and output ports of the lossless multi-beam feeder network, as well as the comprehensive beamforming index, based on the application scenario requirements.

[0009] S2: Based on the target number of input ports and output ports and the integrated beamforming index, obtain the transmission matrix of the lossless multi-beam network;

[0010] S3: The transmission matrix of the multi-beam network is decomposed using the matrix decomposition method to obtain the decomposition formula of the transmission matrix of the multi-beam network.

[0011] S4: Based on the decomposition formula of the transmission matrix of the multi-beam network, the design result of the lossless multi-beam network is obtained.

[0012] Alternatively, in step S3, the transmission matrix of the multi-beam network is decomposed into a concatenation of several Givens matrices, and the decomposition formula is as follows: for:

[0013]

[0014] Among them, G i Let H represent the i-th Givens matrix, H represent the conjugate, R represent a matrix with all elements except the diagonal elements being 0, and M and N represent the number of input ports and the number of output ports, respectively.

[0015] Alternatively, the integrated beamforming parameters include amplitude and phase, and the Givens matrix is:

[0016]

[0017] Where c and s represent amplitude, θ and Indicates phase, e ±j This represents a complex number, and m and n represent the position information of the elements.

[0018] Alternatively, step S4 may include:

[0019] S41: Obtain the transmission matrix decomposition formula of the lossless multibeam network, wherein the transmission matrix decomposition formula of the lossless multibeam network is a cascade of several Givens matrices.

[0020] S42: Obtain parameter information from the target Givens matrix, the parameter information being obtained through the integrated beamforming index and including amplitude and phase;

[0021] S43: Based on the parameter information in the Givens matrix, determine the representation device of the target matrix and the port cascade position information of the device;

[0022] S44: Based on the characterization device of the target matrix and the port cascade position information of the device, the design result of the lossless multibeam network is obtained.

[0023] Alternatively, step S43 may include:

[0024] If the Givens matrix expression is equivalent to the transmission matrix expression of the directional coupler, then the representation device of the target matrix is ​​determined to be the directional coupler, and the parameter position information of the Givens matrix is ​​determined to be the cascade position of the directional coupler in the multi-beam network.

[0025] If the Givens matrix expression differs from the transmission matrix expression of the directional coupler, the Givens matrix is ​​decomposed into two sub-matrices, one of which is determined to be the same as the transmission matrix expression of the directional coupler, and the other represents the port shift term. Therefore, the Givens matrix represents the cascade of the directional coupler and the phase shifter.

[0026] Alternatively, the transfer matrix expression T of the directional coupler coupler for:

[0027]

[0028] Where α represents the pass-through coefficient, β represents the coupling coefficient, φ represents the phase difference between the output ports, and e ±j It represents a complex number.

[0029] Optionally, the decomposition result includes the transfer matrix expressions for the directional coupler and the phase shifter as follows:

[0030]

[0031] in, Indicates phase shifter, This represents a directional coupler, where c and s represent amplitudes, and θ and Indicates phase, e ±j This represents a complex number, and m and n represent the position information of the elements.

[0032] The present invention has the following beneficial effects:

[0033] 1. The multi-beam network synthesis problem is transformed into a matrix factorization problem, realizing the synthesis of multi-beam networks with orthogonal lossless characteristics with arbitrary number of ports;

[0034] 2. By combining the multi-beam network synthesis problem with optimization algorithms, a multi-beam network with orthogonal lossless characteristics that comprehensively meets special radiation requirements can be realized.

[0035] 3. The specific components of the integrated multi-beam network are only directional couplers and phase shifters, and the network form is simple;

[0036] 4. Since the multi-beam feed network generated by this invention has no lossy components, it is suitable for lossless multi-beam feed networks. Attached Figure Description

[0037] Figure 1 This is a flowchart of the lossless multi-beam feeder network design method of the present invention;

[0038] Figure 2 This is a topology diagram of a 2×6 multibeam feeder network implemented based on matrix decomposition formula;

[0039] Figure 3 This is a diagram showing the correspondence between the Givens matrix and the physical properties of the device.

[0040] Figure 4 Based on Figure 2 Physical diagram of a multi-beam feeder network;

[0041] Figure 5 The array antenna configuration provided in the embodiments of the present invention;

[0042] Figure 6 This is the beam radiation pattern. Detailed Implementation

[0043] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0044] Example

[0045] The technical solution of the present invention to solve the above-mentioned technical problems is as follows:

[0046] This invention provides a design method for a lossless multi-beam feeder network, with reference to... Figure 1 As shown, the multi-beam feed network design method includes:

[0047] S1: Determine the target number of input ports and output ports of the lossless multi-beam feeder network, as well as the comprehensive beamforming index, based on the application scenario requirements.

[0048] In this invention, the target number of input ports and output ports of the multi-beam feeder network are determined according to the requirements of the application scenario. Those skilled in the art can set these numbers according to the requirements of the application scenario, and this invention does not impose any specific limitations.

[0049] As one embodiment, this invention uses a multi-beam feed network with 2 input ports and 6 output ports for subsequent description. Regarding the overall beam characteristics, with the increasing complexity of the electromagnetic environment, rectangular beams with flat-top characteristics can effectively reduce mutual interference from different electromagnetic wave radiations, and are therefore widely used. The integrated beam of this invention consists of two symmetrical rectangular beams with a beam pointing of ±25° and a beamwidth of 20°.

[0050] Based on this, when the multi-beam feed network is connected to a 1×6 array antenna, two fixed beams can be achieved.

[0051] S2: Based on the target number of input ports and output ports and the integrated beamforming index, with the target beam as the target, under the constraint of lossless operation, the transmission matrix of the lossless multi-beam network is obtained by adjusting the amplitude and phase values ​​of the internal parameters of the transmission matrix.

[0052] S3: The transmission matrix of the multi-beam network is decomposed using the matrix decomposition method to obtain the decomposition formula of the transmission matrix of the multi-beam network.

[0053] The transmission matrix of the multi-beam network is decomposed into a concatenation of several Givens matrices, and the decomposition formula is as follows: for:

[0054]

[0055] Among them, G i Let H represent the i-th Givens matrix, H represent the conjugate, R represent a matrix with all elements except the diagonal elements being 0, and M and N represent the number of input ports and the number of output ports, respectively.

[0056] Specifically, when the number of input ports in a multi-beam feeder network is 2 and the number of output ports is 6, considering the symmetry of the input and output ports of the entire network and the symmetry of the network's synthesized beams, the synthesis result of the multi-beam feeder network should also be symmetric. Its transmission matrix decomposition formula can be represented as:

[0057]

[0058] Its comprehensive form is as follows Figure 2 As shown.

[0059] In this invention, the integrated beamforming parameters include amplitude and phase, and the Givens matrix is:

[0060]

[0061] Where c and s represent amplitude, θ and Indicates phase, e ±j To represent a complex number, c and s satisfy the relation c 2 +s 2 =1, m, n refer to the element positions.

[0062] Alternatively, step S4 may include:

[0063] S41: Obtain the transmission matrix decomposition formula of the lossless multibeam network, wherein the transmission matrix decomposition formula of the lossless multibeam network is a cascade of several Givens matrices.

[0064] S42: Obtain parameter information from the target Givens matrix, the parameter information being obtained through the integrated beamforming index and including amplitude and phase;

[0065] S43: Based on the parameter information in the Givens matrix, determine the representation device of the target matrix and the port cascade position information of the device;

[0066] Alternatively, step S43 may include:

[0067] If the Givens matrix expression is equivalent to the transmission matrix expression of the directional coupler, then the representation device of the target matrix is ​​determined to be the directional coupler, and the parameter position information of the Givens matrix is ​​determined to be the cascade position of the directional coupler in the multi-beam network.

[0068] If the Givens matrix expression differs from the transmission matrix expression of the directional coupler, the Givens matrix is ​​decomposed into two sub-matrices, one of which is determined to be the same as the transmission matrix expression of the directional coupler, and the other represents the port shift term. Therefore, the Givens matrix represents the cascade of the directional coupler and the phase shifter.

[0069] Specifically, the correspondence between the Givens matrix and the device physics is shown in the diagram below. Figure 3 As shown.

[0070] In this invention, the phase parameter values ​​in the Givens matrix are determined. If the phase parameter value in the Givens matrix is ​​0, then the Givens matrix is ​​equivalent to the transmission matrix expression of the directional coupler, that is, the Givens matrix represents a directional coupler, and the parameter position information of the Givens matrix is ​​the cascade position of the directional coupler in the multi-beam network;

[0071] If the phase parameter in the Givens matrix is ​​not 0, then the Givens matrix is ​​decomposed to obtain the transmission matrix expression for the directional coupler and the transmission matrix expression for the phase shifter.

[0072] S44: Based on the characterization device of the target matrix and the port cascade position information of the device, the design result of the lossless multibeam network is obtained.

[0073] Wherein, the transfer matrix expression T of the directional coupler coupler for:

[0074]

[0075] Where α represents the pass-through coefficient, β represents the coupling coefficient, φ represents the phase difference between the output ports, and e ±j It represents a complex number.

[0076] It is easy to see that when the phase parameter θ in the Givens matrix is ​​0, the transfer matrix form of the directional coupler is consistent with the Givens matrix form. This is because, in physical implementation, the Givens matrix can characterize a directional coupler. Furthermore, the positional information m and n of the Givens matrix parameters can indicate the cascaded position of the device in a multi-beam network.

[0077] Optionally, the decomposition result includes the transfer matrix expressions for the directional coupler and the phase shifter as follows:

[0078]

[0079] in, Indicates phase shifter, This represents a directional coupler, where c and s represent amplitudes, and θ and Indicates phase, e ±j This represents a complex number, and m and n represent the position information of the elements.

[0080] As can be seen, the two Givens matrices after decomposition It is a unitary matrix, and its corresponding specific device is a phase shifter, with connection ports m and n respectively. The transfer matrix expression is consistent with that of the directional coupler and can be implemented by referring to the above analysis.

[0081] A physical diagram of the 2×6 multibeam feed network of this invention is shown below. Figure 4 As shown.

[0082] S4: Based on the device, the port cascade location information of the device, and the preset array antenna model, the design result of the multi-beam feed network is obtained.

[0083] As one embodiment, in a 2×6 multi-beam feed network, the array antenna model uses a microstrip patch antenna, and the array antenna is as follows: Figure 5As shown, it consists of 6 identical microstrip antennas operating at 3.5 GHz, with an adjacent antenna spacing of 59 mm, approximately 0.7λ. The total antenna dimensions are 392 mm in length and 97 mm in width, and the isolation between elements is above 20 dB.

[0084] By cascading a 2×6 multibeamforming network with a given 1×6 microstrip patch array antenna, the resulting multibeam array antenna exhibits flat-top characteristics in both output patterns. The maximum pointing angle of the main beam is ±25°, the rectangular beamwidth fluctuates within 1dB at 20°±5°, and the sidelobe level is less than -4.5dB. Figure 6 As shown.

[0085] The present invention has the following beneficial effects:

[0086] 1. The multi-beam network synthesis problem is transformed into a matrix factorization problem, realizing the synthesis of multi-beam networks with orthogonal lossless characteristics with arbitrary number of ports;

[0087] 2. By combining the multi-beam network synthesis problem with optimization algorithms, a multi-beam network with orthogonal lossless characteristics that comprehensively meets special radiation requirements can be realized.

[0088] 3. The specific components of the integrated multi-beam network are only directional couplers, and the network form is simple.

[0089] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A design method for a lossless multi-beam feeder network, characterized in that, The multi-beam feeder network design method includes: S1: Determine the target number of input ports and output ports of the lossless multi-beam feeder network, as well as the comprehensive beamforming index, based on the application scenario requirements. S2: Based on the target number of input ports and output ports and the integrated beamforming index, obtain the complex transmission matrix of the lossless multibeam network; S3: Based on the symmetry constraint of the integrated beam index, the complex transmission matrix of the multi-beam network is decomposed in a specific order using the matrix decomposition method to obtain the decomposition formula of the complex transmission matrix of the multi-beam network. S4: Based on the decomposition formula of the complex transmission matrix of the multi-beam network, the complex transmission matrix is ​​mapped to a cascade of directional couplers and phase shifters to obtain the design result of the lossless multi-beam network. In step S3, the complex transmission matrix of the multi-beam network is decomposed into several... Givens Matrix concatenation, its decomposition formula for: in, Indicates the first i indivual Givens matrix, H Indicates conjugate. R Represented as a matrix where all elements except the diagonal elements are 0. M, N These represent the number of input ports and the number of output ports, respectively. Step S4 includes: S41: Obtain the complex transmission matrix decomposition formula of the lossless multibeam network, wherein the complex transmission matrix decomposition formula of the lossless multibeam network is several... Givens Matrix cascading; S42: Obtain the target Givens The parameter information in the matrix, which is obtained through the integrated beamforming index and includes amplitude and phase; S43: According to the above Givens The parameter information in the matrix is ​​used to determine the representation device of the target matrix and the port cascade position information of the device; S44: Based on the characterization device of the target matrix and the port cascade position information of the device, the design result of the lossless multibeam network is obtained; Step S43 includes: If the above Givens If the matrix expression is equivalent to the transmission matrix expression of a directional coupler, then the device representing the target matrix is ​​determined to be a directional coupler, and thus the target matrix is ​​determined to be... Givens The parameter position information of the matrix is ​​the cascade position of the directional coupler in the multi-beam network; If the above Givens If the matrix expression differs from the transfer matrix expression of the directional coupler, then... Givens The matrix is ​​decomposed into two sub-matrices, one of which is determined to be the same as the transmission matrix expression of the directional coupler, and the other represents the port shift term. Therefore, the Givens matrix represents the cascade of the directional coupler and the phase shifter. The integrated beamforming parameters include amplitude and phase. Givens The matrix is: in, c and s Indicates amplitude, θ and φ Indicates phase, To represent a complex number, m and n Indicates the position information of the element; The transfer matrix expression of the directional coupler for: in, Indicates the pass-through coefficient. Represents the coupling coefficient. This indicates the phase difference between the output ports. To represent a complex number; The decomposition results include the transfer matrix expressions for the directional coupler and the phase shifter, as follows: in, Indicates phase shifter, Indicates a directional coupler. c and s Indicates amplitude, θ and φ Indicates phase, To represent a complex number, m and n Indicates the position information of the element.

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