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CN-122021518-A - Broadband scattering simulation method based on grid self-adaptive encryption

CN122021518ACN 122021518 ACN122021518 ACN 122021518ACN-122021518-A

Abstract

The invention discloses a broadband scattering simulation method based on grid self-adaptive encryption, and belongs to the technical field of electromagnetic simulation. The method only carries out independent self-adaptive grid encryption at the lowest frequency point of the frequency band. For the rest frequency points in the frequency band, the optimization grid is not generated independently, and error information at adjacent frequencies is used for guiding optimization. And then, adopting a cauchy method, and reconstructing response data between adjacent sampling points based on frequency sampling points obtained by solving on an optimized grid, thereby efficiently and accurately obtaining broadband electromagnetic response. The method can efficiently optimize the grids at each frequency point without independent self-adaptive optimization at each selected frequency point as the traditional self-adaptive encryption method, simultaneously maintains the advantage that the self-adaptive encryption realizes higher precision with less unknown quantity, and can efficiently and accurately reconstruct complex frequency band response by using the Cauchy method.

Inventors

  • HU JUN
  • CAO HAOJIE
  • ZHAO RAN
  • JIANG MING
  • YANG XIONG
  • ZONG XIANZHENG

Assignees

  • 电子科技大学

Dates

Publication Date
20260512
Application Date
20260414

Claims (6)

  1. 1. A broadband scattering simulation method based on grid adaptive encryption is characterized by comprising the following steps: Step 1, setting an initial grid size, namely using a triangular grid discrete target model surface with the initial grid size, wherein the initial grid size is more than one tenth of the maximum wavelength of a frequency band to be simulated, setting the encryption iteration number as 1, and solving the response of a target surface current and a radar scattering cross section RCS at a lowest frequency point f 0 of the frequency band to be simulated based on a current grid, setting the encryption iteration number as +1, and encrypting the current grid; Step 2, solving target surface current and RCS response at a lowest frequency point f 0 of a frequency band to be simulated; step 3, judging whether RCS response change between two adjacent encryption iterations is smaller than a set threshold value; If not, evaluating the current discontinuity error of each grid based on the distribution of the target surface current, selecting partial grids with the largest current discontinuity error for encryption, and returning to the step 2; If yes, outputting the current grid M 0 and the corresponding target surface current I 0 , and executing the step 4; step4, initializing a frequency point index i=0; Step 5, calculating the current discontinuity error of each grid in the grids M i at the frequency point f i , setting the encryption proportion beta of the unit, determining the next frequency point f i+1 , selecting the grid with the largest current discontinuity error to encrypt, and obtaining an optimized grid M i+1 ; Step 6, let i=i+1, at frequency point f i , solving the target surface current I i based on grid M i ; step 7, judging whether the frequency point f i reaches the highest frequency point of the frequency band to be simulated; if not, returning to the execution step 5; if yes, output grid { , , ..., And the corresponding target surface current { thereof , , ..., }; Step 8, setting an initial frequency sampling point sequence in a frequency band to be simulated, wherein the initial frequency sampling point sequence is composed of a plurality of frequency sampling points with equal step sizes; Step 9, solving each frequency sampling point by using a grid closest to the frequency sampling point to obtain a target surface current and RCS response corresponding to the current frequency sampling point; Step 10, checking extreme points and frequency points with curvature exceeding a set threshold value in the full-band RCS response curve obtained by interpolation, and judging whether the error between the interpolation result and the simulation result based on the closest grid meets the precision requirement; If not, judging that the verification fails, adding the frequency points with the failed verification into the frequency sampling point sequence, and returning to the step 9; if yes, outputting the interpolation result as a final broadband RCS response.
  2. 2. The wideband scattering simulation method based on grid adaptive encryption according to claim 1, wherein in step 1 and step 2, the target surface current and RCS response are solved using a multi-layer fast multipole method.
  3. 3. The broadband scattering simulation method based on grid adaptive encryption according to claim 1, wherein in the step 3, partial grids with the largest current discontinuity error of 30% -50% are selected for encryption.
  4. 4. The wideband scattering simulation method based on grid adaptive encryption according to claim 1, wherein in step 5, the relationship between the adaptive encryption scale β and the frequency point selection is expressed as: 。
  5. 5. The broadband scattering simulation method based on the grid adaptive encryption according to claim 1, wherein in the step 1, the step 3 and the step 5, the specific process of encrypting the grid is that the midpoints of three sides of the triangle of the grid are interconnected, and the grid is equally divided into four triangle grids.
  6. 6. The wideband scattering simulation method based on grid adaptive encryption as claimed in claim 1, wherein the cauchy method of step 9 is specifically implemented as follows: the RCS response is modeled as the ratio of two polynomials, expressed as: ; Wherein f represents the frequency, Represents the RCS response at frequency f, P is the order of the molecular polynomial, P is more than or equal to 0 and less than or equal to P-1, Is a p-order coefficient; Is the order of denominator polynomials, Q is more than or equal to 0 and less than or equal to Q-1, Is a q-order coefficient; and (3) rewriting the formula into an equation set form, and solving to obtain a coefficient value, thereby further obtaining the RCS response.

Description

Broadband scattering simulation method based on grid self-adaptive encryption Technical Field The invention belongs to the technical field of electromagnetic simulation, and particularly relates to a broadband scattering simulation method based on grid self-adaptive encryption. Background Broadband Radar Cross Section (RCS) analysis plays an important role in engineering applications including target recognition, radar design, and the like. One method of obtaining broadband scattering responses is to use a frequency domain method, first calculate the response of the finite frequency samples, and then reconstruct the remaining frequency points using a data reconstruction technique. Common techniques often require solving a series of sampling frequencies under a fixed grid in preparation for reconstructing the required information. However, the grid required to achieve efficient and accurate solutions varies with frequency. If a single grid is used in a wide frequency band range, the grid suitable for the high frequency introduces unnecessary calculation load at the low frequency, and the grid suitable for the low frequency may not be solved at the high frequency to obtain enough calculation accuracy. The cauchy method does not limit the grid, models the amplitude-frequency response of the system as the ratio of two polynomials, allows non-uniform frequency sampling, and can generate accurate frequency response with relatively low calculation cost, but the prior art does not apply the method to solving the grid to improve flexibility. In addition, the effectiveness of adaptive trellis encryption techniques has been demonstrated in single frequency analysis, which can achieve good solution accuracy with less unknowns. However, in the integral equation broadband electromagnetic scattering analysis, the adaptive encryption technology has not been applied yet. Disclosure of Invention The invention aims to overcome the defects of the prior art and provides a broadband scattering simulation method based on grid adaptive encryption. The technical problems proposed by the invention are solved as follows: a broadband scattering simulation method based on grid adaptive encryption comprises the following steps: Step 1, setting an initial grid size, namely using a triangular grid discrete target model surface with the initial grid size, wherein the initial grid size is more than one tenth of the maximum wavelength of a frequency band to be simulated, setting the encryption iteration number as 1, and solving the response of a target surface current and a radar scattering cross section RCS at a lowest frequency point f 0 of the frequency band to be simulated based on a current grid, setting the encryption iteration number as +1, and encrypting the current grid; Step 2, solving target surface current and RCS response at a lowest frequency point f 0 of a frequency band to be simulated; step 3, judging whether RCS response change between two adjacent encryption iterations is smaller than a set threshold value; If not, evaluating the current discontinuity error of each grid based on the distribution of the target surface current, selecting partial grids with the largest current discontinuity error for encryption, and returning to the step 2; If yes, outputting the current grid M 0 and the corresponding target surface current I 0, and executing the step 4; step4, initializing a frequency point index i=0; Step 5, calculating the current discontinuity error of each grid in the grids M i at the frequency point f i, setting the encryption proportion beta of the unit, determining the next frequency point f i+1, selecting the grid with the largest current discontinuity error to encrypt, and obtaining an optimized grid M i+1; Step 6, let i=i+1, at frequency point f i, solving the target surface current I i based on grid M i; step 7, judging whether the frequency point f i reaches the highest frequency point of the frequency band to be simulated; if not, returning to the execution step 5; if yes, output grid { , , ..., And the corresponding target surface current { thereof, , ..., }; Step 8, setting an initial frequency sampling point sequence in a frequency band to be simulated, wherein the initial frequency sampling point sequence is composed of a plurality of frequency sampling points with equal step sizes; Step 9, solving each frequency sampling point by using a grid closest to the frequency sampling point to obtain a target surface current and RCS response corresponding to the current frequency sampling point; Step 10, checking extreme points and frequency points with curvature exceeding a set threshold value in the full-band RCS response curve obtained by interpolation, and judging whether the error between the interpolation result and the simulation result based on the closest grid meets the precision requirement; If not, judging that the verification fails, adding the frequency points with the failed verification into the frequ