CN-122021257-A - RCS prediction and arrangement optimization method for liquid crystal electric control adjustable super-surface array

CN122021257ACN 122021257 ACN122021257 ACN 122021257ACN-122021257-A

Abstract

The invention relates to the technical field of liquid crystal electric control adjustable super-surface arrays, in particular to an RCS prediction and arrangement optimization method of a liquid crystal electric control adjustable super-surface array, which comprises the steps of obtaining the geometric structure and the dimensional parameters of a liquid crystal electric control adjustable super-surface unit and an array thereof; the method comprises the steps of establishing and processing a frequency point-state parameter set index table, calculating RCS values of a super-surface array in an observation direction, constructing an adaptability function which takes a short-cut quantity between a simulated RCS curve and an ideal reduction curve in a target frequency band as a main term, introducing a diversity regular term, carrying out iterative search by adopting a genetic algorithm, and outputting an optimal unit state arrangement scheme capable of realizing a better RCS reduction effect.

Inventors

JIANG DI
ZHANG YI
ZHAO JIAHAO
Cui Diexuan
XIAO CHENGYUAN
YUAN YONGBO
ZHAO JIACHENG
YOU CHANGJIANG
SU WEIFENG
HU WEI
HU DACHENG
DONG LINGFENG

Assignees

电子科技大学

Dates

Publication Date: 20260512
Application Date: 20251229

Claims (7)

1. The RCS prediction and arrangement optimization method for the liquid crystal electrically-controlled adjustable super-surface array is characterized by comprising the following steps of: Acquiring the geometric structure and the dimensional parameters of an array of the liquid crystal electrically-controlled adjustable super-surface unit; obtaining reflection data of the liquid crystal super-surface unit in each electric control state through simulation, wherein the reflection data comprises frequency, amplitude and phase, performing phase unwrapping treatment on the reflection phase, and interpolating complex reflection coefficients of all states to a uniform frequency axis to form a frequency point-state parameter set index table; Calculating unit direction factors according to incidence and scattering directions for each frequency point, constructing separable phase distribution vectors along an x axis and a y axis, substituting a unit complex reflection coefficient matrix of the corresponding frequency point into a fast accumulation formula to solve a scattered field, calculating RCS values of the hypersurface array in the observation direction based on the scattered field, wherein RCS is a radar scattering cross section; Constructing an adaptability function taking the short-cut between the simulated RCS curve and the ideal reduction curve in the target frequency band as a main term, introducing a diversity regular term, performing iterative search by adopting a genetic algorithm, and outputting an optimal unit state arrangement scheme capable of realizing a better RCS reduction effect.
2. The method for predicting and optimizing the RCS of an electrically controlled tunable subsurface array for liquid crystals as claimed in claim 1, wherein in the step of obtaining the geometric structure and dimensional parameters of the electrically controlled tunable subsurface unit for liquid crystals and the array thereof, The liquid crystal electric control adjustable super surface is composed of periodically arranged super surface units, each super surface unit is of a three-layer composite structure, the three-layer composite structure comprises a top layer, a middle layer and a bottom layer, the top layer and the bottom layer are metal layers, the top layer and the bottom layer are made of copper, the middle layer is a dielectric layer, and the middle layer is made of a phase-phase liquid crystal material.
3. The RCS predicting and arranging optimizing method of a liquid crystal electronically-controlled adjustable super-surface array according to claim 2, wherein the specific steps of obtaining reflection data of the liquid crystal super-surface unit in each electronically-controlled state through simulation, the reflection data including frequency, amplitude and phase, performing phase unwrapping processing on the reflection phase, and interpolating complex reflection coefficients of all states to a uniform frequency axis, and forming a frequency point-state parameter set index table include: Simulating the structure of the liquid crystal super-surface unit, and sampling the frequency in a preset working frequency range in a certain step length to respectively obtain the reflection amplitude and the reflection phase of the liquid crystal super-surface unit under different frequencies in each electric control state; performing phase unwrapping processing on the reflection phases in each electric control state, converting the original phases into continuous curves, and then calculating complex reflection coefficients in each state; the complex reflection coefficients of each state are uniformly interpolated to the same frequency axis through segmented three Hermite interpolation, and the frequency axis covers the reduced working frequency band of the target RCS.
4. The RCS prediction and arrangement optimization method of an electrically controlled adjustable super-surface array for liquid crystal according to claim 1, wherein in the step of performing a phase unwrapping process on the reflection phases in each electrically controlled state, converting the original phases into a continuous curve, and then calculating complex reflection coefficients in each state, The complex reflection coefficient has the following calculation formula: wherein For the amplitude of the reflection, For the reflected phase after the phase unwrapping process, f represents the frequency.
5. The RCS prediction and placement optimization method for an electrically controlled tunable subsurface array for liquid crystals as described in claim 4, wherein in the step of calculating cell direction factors based on the incident and scattering directions, The unit direction factor is positioned as follows: Wherein d is the side length of the super surface unit, And The direction factors of the cell in the x and y directions of the local coordinate system respectively, Is the weighting factor of the cosine of the direction of incidence and scattering.
6. The method for predicting and optimizing the RCS of an electrically controlled tunable subsurface array for liquid crystals as recited in claim 5, wherein separable phase distribution vectors along the x-axis and the y-axis are constructed, the matrix of complex reflection coefficients of units corresponding to the frequency points is substituted into the fast accumulation formula to solve for the fringe field, The fast accumulation formula is: , wherein, 、 Separable phase distribution vectors respectively constructed along the x-axis and the y-axis, The global propagation phase factor introduced for the array reference point, For the scattered field, f represents frequency.
7. The RCS prediction and placement optimization method for an electrically controlled tunable subsurface array for liquid crystals as described in claim 6, wherein in the step of calculating the RCS value of the subsurface array in the observation direction based on the fringe field, The calculation formula of the RCS value of the hypersurface array in the observation direction is as follows: ; ; ; where k represents wavenumber, j is an imaginary unit, satisfying j 2 = -1, η is free space wave impedance, The integrated factor is used for representing the influence of actual engineering factors such as mutual coupling among units, a liquid crystal feed structure and the like on the scattering amplitude, and f represents frequency.

Description

RCS prediction and arrangement optimization method for liquid crystal electric control adjustable super-surface array Technical Field The invention relates to the technical field of liquid crystal electric control adjustable super-surface arrays, in particular to an RCS prediction and arrangement optimization method of a liquid crystal electric control adjustable super-surface array. Background The radar scattering cross section (RCS) is a key index for evaluating the electromagnetic detectability of a target, and the phase and the amplitude of a reflected wave are actively regulated and controlled by utilizing an adjustable super-surface, so that the redirection of the scattered wave and the effective reduction of the RCS can be realized on the premise of keeping the appearance of the target basically unchanged. The liquid crystal adjustable super surface is taken as a typical implementation mode, the unit reflection characteristic of the liquid crystal adjustable super surface can be continuously or discretely adjusted through an external bias electric field, and the liquid crystal adjustable super surface has the characteristic of multi-state adjustability. Under oblique incidence conditions, the "arrangement-performance" mapping of the supersurface exhibits a high degree of nonlinearity due to the large array scale, multiple state combinations, complex incidence angles. In addition, when the electromagnetic wave is obliquely incident, the coherent superposition of each unit in the array is obviously changed along with the frequency and the incident angle, if the RCS evaluation is carried out by adopting a frequency point-by-frequency point and unit-by-unit fine solving mode, the calculation cost is linearly increased along with the number of frequency points and the scale of the array, so that the RCS evaluation and the intelligent optimization algorithm cannot be effectively cooperated, and a multi-state array arrangement scheme for effectively reducing the RCS in a target frequency band cannot be designed under the controllable calculation precision. For the above reasons, there is a need for a fast prediction and arrangement optimization method of an oblique incidence single-station RCS for a liquid crystal electronically controlled adjustable super-surface array, which is suitable for fast computing the RCS in a scattering scene under oblique incidence conditions, and is used for reducing the computation complexity in the optimization process under controllable computation precision, and designing a multi-state array arrangement scheme for effectively reducing the RCS in a target frequency band. Disclosure of Invention The invention aims to provide an RCS prediction and arrangement optimization method for a liquid crystal electronic control adjustable super-surface array, which can reduce the calculation complexity in the optimization process under the controllable calculation precision and design a multi-state array arrangement scheme for effectively reducing RCS in a target frequency band. In order to achieve the above purpose, the invention provides an RCS prediction and arrangement optimization method of a liquid crystal electrically-controlled adjustable super-surface array, comprising the following steps: Acquiring the geometric structure and the dimensional parameters of an array of the liquid crystal electrically-controlled adjustable super-surface unit; obtaining reflection data of the liquid crystal super-surface unit in each electric control state through simulation, wherein the reflection data comprises frequency, amplitude and phase, performing phase unwrapping treatment on the reflection phase, and interpolating complex reflection coefficients of all states to a uniform frequency axis to form a frequency point-state parameter set index table; Calculating unit direction factors according to incidence and scattering directions for each frequency point, constructing separable phase distribution vectors along an x axis and a y axis, substituting a unit complex reflection coefficient matrix of the corresponding frequency point into a fast accumulation formula to solve a scattered field, calculating RCS values of the hypersurface array in the observation direction based on the scattered field, wherein RCS is a radar scattering cross section; Constructing an adaptability function taking the short-cut between the simulated RCS curve and the ideal reduction curve in the target frequency band as a main term, introducing a diversity regular term, performing iterative search by adopting a genetic algorithm, and outputting an optimal unit state arrangement scheme capable of realizing a better RCS reduction effect. Wherein, in the step of obtaining the geometric structure and the dimensional parameters of the liquid crystal electric control adjustable super-surface unit and the array thereof, The liquid crystal electric control adjustable super surface is composed of periodically arranged super surf