A beam pointing and width joint regulation encoding method based on 1-bit metasurface

Abstract

The application discloses a kind of based on 1-bit hypersurface beam pointing and width joint regulation and control coding method. Including the following steps: step one: establish beam control model, including target pointing and width parameter, coding array calculation, calculate theoretical gain as verification benchmark. Step two: beam scanning and zooming joint coding method includes (1) based on the scale transformation of Fourier transform constructs secondary zooming phase, adopts orthogonal decoupling strategy to control beam shape;(2) according to generalized shell calculation scanning pointing phase;(3) introduce the dynamic angle compensation factor based on aperture projection effect is modified to obtain the equivalent zooming phase of scanning state. Step three: using the principle of phase superposition, the equivalent zooming bit, scanning pointing phase and feed compensation phase are linearly superimposed, and the coding matrix is generated after 1-bit quantization. The application can realize the precise control of beam width under the specified scanning direction, and is suitable for wireless communication coverage and radar search and other fields.

Description

Technical Field

[0001] This invention belongs to the field of electromagnetic metasurfaces and wireless communication technology, specifically relating to a 1-bit metasurface coding method that can simultaneously achieve flexible control of beam pointing deflection and beamwidth. Background Technology

[0002] In recent years, with the rapid development of wireless communication and radar detection technologies, people have placed higher demands on the coverage flexibility and response speed of communication systems. To meet the diverse needs of modern communication in different scenarios, antenna technology with adjustable beamwidth has emerged. Compared to antennas with fixed beamwidth, antenna systems that can flexibly adjust beam pointing and width have better channel adaptability and higher energy efficiency. However, most common beamwidth control methods currently rely on changes in hardware structure, such as using mechanical zoom structures to move the feed, complex feed networks for amplitude weighting, or switching between different antenna apertures. These methods face a series of problems, including large system size, high hardware cost, slow response speed, and complex feed network design, making it difficult to meet the integration and real-time requirements of modern systems. Furthermore, existing pure phase modulation methods often struggle to achieve joint control of beam pointing and shape under 1-bit quantization conditions, and are prone to beam distortion during large-angle scanning. The beam pointing and width joint control coding method based on 1-bit encoded metasurface of the present invention replaces the complex hardware zoom structure with a fully digital phase coding strategy, providing a new technical path to solve the above problems. Summary of the Invention

[0003] This invention aims to address the problems of existing beamwidth control methods, which mainly rely on hardware structures such as mechanical zoom or complex feed networks, resulting in large system size, high cost, and slow response speed. It also solves the technical problems of existing 1-bit metasurface coding methods during large-angle beam scanning, where the aperture projection effect causes natural beam broadening, gain reduction, and a lack of dynamic compensation mechanisms. This invention achieves rapid pointing deflection and active beam shape control in the two-dimensional angular domain through a fully digital phase coding strategy.

[0004] The objective of this invention is achieved through the following technical solution:

[0005] The beam pointing and width joint modulation coding method for 1-bit metasurfaces includes the following steps:

[0006] Step 1: Establish a beam control model, including input target pointing and target beamwidth parameters, perform coding array calculation, and calculate the theoretical gain of the target pointing based on the principle of energy conservation as a verification benchmark;

[0007] Step 2: Perform beam scanning and zoom joint encoding. First, based on the scaling property of Fourier transform, construct a secondary zoom phase model and calculate the basic zoom coefficient. Then, based on the generalized Snell's law, calculate the scanning pointing phase. Next, based on the aperture projection effect caused by beam scanning, introduce a dynamic compensation factor to correct the basic zoom coefficient to obtain an equivalent zoom phase suitable for the scanning state.

[0008] Step 3: Apply the joint coding model to generate the target beam. Utilize the phase superposition principle to linearly superimpose the equivalent zoom phase, scanning pointing phase, and feed compensation phase obtained in Step 2. After 1-bit quantization, generate the final coding matrix, thereby achieving controllable beamwidth in a specified scanning direction on the metasurface array.

[0009] Furthermore, in step one, the input parameters also include the operating frequency of the metasurface array, the cell spacing, and the array aperture size; at the same time, based on the principle of energy conservation, the theoretical gain in this direction is calculated to evaluate the beamforming quality.

[0010] Furthermore, in step two, the beam scanning and zoom joint encoding method includes three parts:

[0011] (1) Based on the scaling property of Fourier transform, a quadratic zoom phase model is constructed; considering the nonlinear characteristics of the 1-bit quantization system, an inverse mapping model between beamwidth and zoom coefficient is established; by presetting the phase quantization threshold and the phase change rate limit, the effective control range of the zoom coefficient is defined; within the range, an orthogonal decoupling strategy is adopted, and the first-dimensional control coefficient A and the second-dimensional control coefficient B are set respectively to construct an asymmetric quadratic zoom phase model to achieve independent control of beamwidth in different dimensions. The effective range threshold calculation formula and the symmetric quadratic zoom phase distribution function are also described. They are shown below;

[0012]

[0013]

[0014]

[0015] in, This is the lower threshold of the effective range of the zoom factor. This is the upper threshold of the effective range of the zoom factor. The array aperture radius, For unit spacing, These are correction coefficients set based on quantization noise and array mutual coupling effects; Let these be the coordinates of the array elements on the aperture plane. and These are the physical aperture radii of the array in the first and second dimensions, respectively;

[0016] (2). Construct a linear scanning phase based on the generalized Snell's law. The formula for calculating the scanning phase is as follows:

[0017]

[0018] in, and The angle pointing to the target. The wavelength of the incident wave;

[0019] (3). To address the aperture projection effect caused by beam scanning, a dynamic angle compensation factor is introduced. Independent control coefficients in step 2.1 Make corrections to obtain an equivalent zoom phase suitable for the scanning state. The formulas for calculating the equivalent zoom phase and compensation factor are as follows:

[0020]

[0021]

[0022] in, As a dynamic angle compensation factor, To scan the pitch angle, This is the aperture projection correction factor, with a value range of [value range missing]. .

[0023] Furthermore, in step three, based on the convolution theorem of Fourier transform, and utilizing the physical property that the product of the aperture domain complex amplitude distribution corresponds to the far-field pattern convolution, beam scanning is considered as phase modulation of the zoom beam; according to the complex exponential operation rule, the product of the aperture field complex amplitudes is transformed into a linear superposition of phases; and the equivalent zoom phase is... Linear scanning phase With feed compensation phase Linear superposition is performed to generate the final phase distribution. The encoding matrix is ​​generated by 1-bit quantization. The phase superposition, feed source compensation phase, and 1-bit discretization formulas are as follows:

[0024]

[0025]

[0026]

[0027] in, For feed source phase compensation, Focal length The encoded value for the array cell.

[0028] The beneficial effects of this invention are as follows:

[0029] This invention presents a beam pointing and width joint control coding method based on a 1-bit coded metasurface. Through a fully digital phase coding strategy, it eliminates the reliance on mechanical zoom structures or complex feed networks, significantly reducing system cost and size. In particular, by introducing a scanning correction coefficient based on the aperture projection effect, it effectively overcomes the problems of severe beam distortion and gain reduction in large-angle scanning using traditional methods, making it suitable for scenarios requiring flexible beamforming, such as radar search and satellite communication. Attached Figure Description

[0030] Figure 1 Flowchart of a method for joint beam pointing and width modulation encoding of a 1-bit metasurface;

[0031] Figure 2 This is a simulation diagram of normal beamwidth adjustment;

[0032] Figure 3 This is a simulation diagram of scanning beamwidth adjustment. Detailed Implementation

[0033] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. The following embodiments are only a part of the embodiments of the present invention and are used to more clearly illustrate the technical solutions of the present invention. It should be understood that the specific embodiments described are only used to explain the present invention, but the implementation of the present invention is not limited thereto.

[0034] An embodiment of the present invention provides a beam pointing and width joint control coding method based on a 1-bit coded metasurface, the specific implementation steps of which are as follows:

[0035] Step 1: Establish a beam control model, including input target pointing and target beamwidth parameters, perform coding array calculation, and calculate the theoretical gain of the target pointing based on the principle of energy conservation as a verification benchmark;

[0036] Step 2: Beam scanning and zoom joint coding method, such as... Figure 1 As shown, firstly, based on the scaling property of Fourier transform, a secondary zoom phase model containing independent control coefficients is constructed. Then, the scanning pointing phase is calculated according to the generalized Snell's law. Finally, considering the aperture projection effect caused by beam scanning, the dynamic angle compensation factor is calculated and the zoom coefficient is corrected to obtain the equivalent zoom phase suitable for the scanning state.

[0037] Step 3: The 1-bit joint encoding method is applied to the array model; based on the convolution theorem, the above phases are linearly superimposed and then quantized by 1-bit to generate the final encoding matrix;

[0038] Furthermore, in step one, the entire beam control model includes the user-inputted target pointing angle. and beamwidth System parameter frequency Array size Array element spacing Initialization; based on the principle of energy conservation, calculate the theoretical gain under ideal full-aperture radiation. This serves as a benchmark for evaluating beamwidth.

[0039] Furthermore, in step 2, the beam scanning and zoom joint encoding method includes three parts:

[0040] (1) Based on the scaling property of Fourier transform, a quadratic zoom phase model is constructed; considering the nonlinear characteristics of the 1-bit quantization system, an inverse mapping model between beamwidth and zoom coefficient is established; by presetting the phase quantization threshold and the phase change rate limit, the effective control range of the zoom coefficient is defined; within the range, an orthogonal decoupling strategy is adopted, and the first-dimensional control coefficient A and the second-dimensional control coefficient B are set respectively to construct an asymmetric quadratic zoom phase model to achieve independent control of beamwidth in different dimensions. The effective range threshold calculation formula and the symmetric quadratic zoom phase distribution function are also described. They are shown below;

[0041]

[0042]

[0043]

[0044] in, This is the lower threshold of the effective range of the zoom factor. This is the upper threshold of the effective range of the zoom factor. The array aperture radius, For unit spacing, These are correction coefficients set based on quantization noise and array mutual coupling effects; Let these be the coordinates of the array elements on the aperture plane. and These are the physical aperture radii of the array in the first and second dimensions, respectively;

[0045] (2). Construct a linear scanning phase based on the generalized Snell's law. The formula for calculating the scanning phase is as follows:

[0046]

[0047] in, and The angle pointing to the target. The wavelength of the incident wave;

[0048] (3). To address the aperture projection effect caused by beam scanning, a dynamic angle compensation factor is introduced. Independent control coefficients in step 2.1 Make corrections to obtain an equivalent zoom phase suitable for the scanning state. The formulas for calculating the equivalent zoom phase and compensation factor are as follows:

[0049]

[0050]

[0051] in, As a dynamic angle compensation factor, To scan the pitch angle, This is the aperture projection correction factor, with a value range of [value range missing]. .

[0052] Furthermore, in step 3, the equivalent zoom phase, scan pointing phase, and feed sourcing compensation phase obtained in step 2 are linearly superimposed based on the convolution theorem; then, a 1-bit quantization operation is performed to generate the final 1-bit array encoding matrix. The phase superposition, feed sourcing compensation phase, and 1-bit discretization formulas are as follows:

[0053]

[0054]

[0055]

[0056] in, For feed source phase compensation, Focal length The encoded value for the array cell.

[0057] Depend on Figure 2 The simulation diagram shown is for normal beamwidth adjustment. Figure 2 (a) Figure 2 (b) is a phase distribution diagram of a metasurface element array with different widths. Figure 2 (c) Figure 2 (d) are the corresponding far-field 3D radiation patterns. Figure 2 (e) Figure 2 (f) is the corresponding polar coordinate diagram. When the input beam points to the normal direction, the beamwidths are 7.5° and 16.6° respectively. The simulation results show that the main lobe of the beam points to the normal direction, and the beamwidths are 7.5° and 16.6° respectively, which are basically consistent with the input. This verifies that the present invention has accurate active zoom capability in the normal direction.

[0058] Depend on Figure 3 The simulation diagram of scanning beamwidth adjustment shown is as follows, in which Figure 3 (a) Phase distribution diagram of the metasurface unit array before the introduction of correction coefficients. Figure 3 (b) is the phase distribution diagram of the metasurface unit array after introducing the correction coefficient. Figure 3 (c) Figure 3 (d) are the corresponding far-field 3D radiation patterns. Figure 3 (e) Figure 3 (f) shows the corresponding polar coordinates, with the input pointing at an azimuth angle of 90°, an elevation angle of 15°, and a beamwidth of 16.5°. Figure 3 As can be seen, the beam pointing is 90° azimuth and 15° elevation. However, before introducing the correction coefficient, due to the aperture projection effect, the beamwidth passively widens to 19.7°, significantly deviating from the target value. After introducing the dynamic correction coefficient, the beamwidth is corrected to 16.4°, which is basically consistent with the input target. It can be seen that the coded metasurface array calculated by the method in this paper can effectively overcome the aperture effect distortion caused by scanning and achieve precise and controllable beamwidth under a specified scanning direction.

Claims

1. A beam pointing and width joint control coding method based on a 1-bit metasurface, characterized in that, Includes the following steps: Step 1: Establish a beam control model, including input target pointing and target beamwidth parameters, perform coding array calculation, and calculate the theoretical gain of the target pointing based on the principle of energy conservation as a verification benchmark; Step 2: Perform beam scanning and zoom joint encoding. First, based on the scaling property of Fourier transform, construct a secondary zoom phase model and calculate the basic zoom coefficient. Then, based on the generalized Snell's law, calculate the scanning pointing phase. Next, based on the aperture projection effect caused by beam scanning, introduce a dynamic compensation factor to correct the basic zoom coefficient to obtain an equivalent zoom phase suitable for the scanning state. Step 3: Apply the joint coding model to generate the target beam. Utilize the phase superposition principle to linearly superimpose the equivalent zoom phase, scanning pointing phase, and feed compensation phase obtained in Step 2. After 1-bit quantization, generate the final coding matrix, thereby achieving controllable beamwidth in a specified scanning direction on the metasurface array.

2. The beam pointing and width joint control coding method for a 1-bit metasurface according to claim 1, characterized in that, In step two, the beam scanning and zoom joint encoding method is specifically as follows: Step 2.1: Based on the scaling property of Fourier transform, construct a quadratic zoom phase model; for the nonlinear characteristics of the 1-bit quantization system, establish an inverse mapping model between beamwidth and zoom coefficient; define the effective control range of zoom coefficient by preset phase quantization threshold and phase change rate limit; within the range, adopt an orthogonal decoupling strategy, set the first dimension control coefficient A and the second dimension control coefficient B respectively, and construct an asymmetric quadratic zoom phase model to achieve independent control of beamwidth in different dimensions. The effective range threshold calculation formula and the symmetric quadratic zoom phase distribution function are also described. They are shown below; ; ; ; in, This is the lower threshold of the effective range of the zoom factor. This is the upper threshold of the effective range of the zoom factor. The array aperture radius, unit spacing These are correction coefficients set based on quantization noise and array mutual coupling effects; Let these be the coordinates of the array elements on the aperture plane. and These are the physical aperture radii of the array in the first and second dimensions, respectively; Step 2.2: Construct a linear scanning phase according to the generalized Snell's law. The formula for calculating the scanning phase is as follows: ; in, and The angle pointing to the target. The wavelength of the incident wave; Step 2.3: To address the aperture projection effect caused by beam scanning, a dynamic angle compensation factor is introduced. Independent control coefficients in step 2.1 Make corrections to obtain an equivalent zoom phase suitable for the scanning state. The formulas for calculating the equivalent zoom phase and compensation factor are as follows: ; ; in, For dynamic angle compensation factor, To scan the pitch angle, This is the aperture projection correction factor, with a value range of [value range missing]. .

3. The beam pointing and width joint control coding method for a 1-bit metasurface according to claim 1 or 2, characterized in that, The specific implementation of step three is as follows: Based on the convolution theorem of Fourier transform, and utilizing the physical property that the product of the aperture domain complex amplitude distribution corresponds to the convolution of the far-field radiation pattern, beam scanning is considered as phase modulation of the zoom beam; according to the complex exponential operation rule, the product of the aperture field complex amplitudes is transformed into a linear superposition of phases; the equivalent zoom phase is then... Linear scanning phase With feed compensation phase Linear superposition is performed to generate the final phase distribution. The phase synthesis formula is as follows: The phase synthesis is then quantized using 1-bit to generate an encoding matrix. ; ; in, For feed source phase compensation, It is the focal length.

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