Antenna radiation characteristic acquisition method based on skeletonization and MoM-PO algorithm

Abstract

The invention provides an antenna radiation characteristic obtaining method based on skeletonization and a MoM-PO algorithm. The method comprises the steps that an electrically-large-size platform and an antenna on the electrically-large-size platform are subdivided; defining an RWG primary function of the triangular patch pair; constructing matrix equations of the MoM region and the PO region based on the RWG primary functions of the MoM region and the PO region; the near-field matrix and the far-field matrix are filled based on an MoM-PO method and a skeletonization algorithm; and obtaining radiation characteristics of the antenna. According to the method, a skeletonization algorithm is adopted, far-field matrixes of coupling matrixes of the MoM and PO regions are filled through each group of impedance sub-matrixes of the coupling matrixes calculated through each group of interpolation matrixes of the MoM and PO regions and the coupling matrixes between the corresponding skeleton basis functions, the number of the skeleton basis functions is smaller than that of basis functions of the MoM and PO regions, and calculation is faster; the antenna radiation characteristic obtaining efficiency is effectively improved, and the computer memory requirement is reduced.

Description

Technical Field

[0001] The present invention belongs to the field of electromagnetic simulation technology, and further relates to a method for obtaining antenna radiation characteristics, specifically to a method for obtaining antenna radiation characteristics based on a skeletonization algorithm and a MoM-PO hybrid algorithm. Background Art

[0002] Antenna radiation parameters include its radiation pattern and gain. The radiation pattern is a graphical representation of the spatial distribution of electromagnetic energy radiated or received by an antenna. It reflects the antenna's radiation intensity or sensitivity in different directions. Gain measures the antenna's ability to effectively radiate or receive input power in a specific direction, comprehensively reflecting the antenna's directivity and efficiency.

[0003] The hybrid method of moments and physical optics (MoM-PO) is a highly efficient numerical computational approach that accurately solves electromagnetic radiation and scattering problems. This method combines the method of moments with the Poisson equation, allowing for both high-frequency electromagnetic waves in radiation problems and complex boundary conditions and dielectric properties in scattering problems. When analyzing antennas near a conductive platform, this method treats the antenna and the conductive platform as separate regions, significantly simplifying the computation.

[0004] However, when the number of MoM regions in the moment method is too large, the memory requirements and computational complexity of the self-impedance matrix of the MoM region and the coupling matrix of the MoM and physical optics PO regions increase dramatically, and a lot of computing time will be wasted when solving. In order to overcome this defect, for example, the patent document of Xidian University "Antenna Radiation Characteristics Acquisition Method Based on ACA and MOM-PO Algorithm" (application date: August 23, 2023, application number 202311066672.8, application publication number: (CN117150195A) proposes an antenna radiation characteristics acquisition method based on ACA and MoM-PO algorithm. The method calculates the excitation vector of each sub-region; The size platform and the array antennas near it are divided into regions; the regions are divided using the triangulation method; the RWG basis functions of each region are defined and the electric field integral equation is converted into a matrix equation using the Galerkin method; the MoM self-impedance matrix in the matrix equation is divided into near-field blocks and far-field blocks; the MoM self-impedance matrix far-field blocks and the MoM-PO mutual impedance matrix are compressed using ACA; the excitation vector and PO correction coefficient matrix are filled; the matrix equation is solved using the BICG method to solve the surface current coefficient and obtain the radiation characteristics of the antenna array. This invention has a small amount of calculation, a fast speed in solving the matrix equation, and a small demand for computer memory. However, its direct calculation of the PO correction coefficient matrix results in a long matrix filling time and a high demand for computer memory, which affects the further improvement of calculation efficiency. Summary of the Invention

[0005] The purpose of the present invention is to overcome the defects of the above-mentioned prior art and propose an antenna radiation characteristics acquisition method based on the skeletonization algorithm and the MoM-PO hybrid algorithm to solve the technical problems of low acquisition efficiency and high computer memory requirements in the prior art.

[0006] To achieve the above object, the technical solution adopted by the present invention includes the following steps:

[0007] (1) Dissect the electrically large platform and nearby antennas:

[0008] The electrically large platform and the nearby antennas are segmented to obtain the MoM area triangle patch pairs and PO area triangle patch pairs;

[0009] (2) Define the RWG basis function of the triangle patch pair:

[0010] Define the first The RWG basis function of a triangle patch pair is and PO area The RWG basis function of a triangle patch pair is ,in, , , represents the position vector of the field point;

[0011] (3) Construct the matrix equation of the MoM region based on the RWG basis functions of the MoM region and the PO region:

[0012] based on and Constructing the self-impedance matrix including the MoM region And the mutual impedance matrix of MoM area and PO area The matrix equation of the MoM region is:

[0013] ;

[0014] ;

[0015] in, The near-field matrix representing the self-impedance matrix of the MoM region, The far-field matrix representing the self-impedance matrix of the MoM region, The near-field matrix representing the mutual impedance matrix of the MoM and PO regions, The far-field matrix representing the mutual impedance matrix of the MoM and PO regions;

[0016] (4) Construct the matrix equation of the PO region based on the RWG basis function of the PO region:

[0017] based on Construct a coupling matrix containing MoM and PO regions The matrix equation of the PO region is:

[0018] ;

[0019] in, The near-field matrix representing the coupling matrix between the MoM and PO regions, The far-field matrix representing the coupling matrix between the MoM and PO regions;

[0020] (5) Fill the near-field matrix and far-field matrix based on the MoM-PO method and the skeletonization algorithm respectively: Based on the MoM-PO method, the near-field matrix elements are calculated by the RWG basis functions of the MoM region and the PO region, and the near-field matrices in steps (3) and (4) are filled respectively by the matrix elements to obtain the filled near-field matrix 、 、 At the same time, based on the skeletonization algorithm, the far-field impedance sub-matrix is ​​calculated through the skeleton basis function and interpolation matrix of each group, and the far-field matrices in steps (3) and (4) are filled respectively by the impedance sub-matrix to obtain the far-field matrix after accelerated filling 、 、 ;

[0021] (6) Obtain the radiation characteristics of the antenna:

[0022] pass and 、 and Calculated filled MoM region self-impedance matrix , MoM area and PO area mutual impedance matrix , while passing and Calculated coupling matrix between MoM and PO regions and through 、 and Calculation of surface current coefficients in MoM and PO regions 、 , then by and Calculate the antenna's pattern and gain.

[0023] Compared with the prior art, the present invention has the following advantages:

[0024] The present invention adopts a skeletonization algorithm, and calculates each group of impedance sub-matrices of the coupling matrix of the MoM area and the PO area through the coupling matrix between each group of interpolation matrices in the MoM area and the PO area and their corresponding skeleton basis functions, and then fills the far-field matrix of the coupling matrix of the MoM and PO areas. The skeleton basis functions are smaller in number and faster in calculation than the basis functions of the MoM and PO areas, avoiding the defect of the prior art of long array filling time caused by directly calculating the PO correction coefficient matrix, effectively improving the efficiency of obtaining antenna radiation characteristics, and reducing computer memory requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a flow chart for implementing the present invention.

[0026] Figure 2 The radiation patterns of the XOY planar antenna of the present invention and the prior art are shown.

[0027] Figure 3 The radiation patterns of the XOZ planar antennas of the present invention and the prior art are shown. DETAILED DESCRIPTION

[0028] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0029] Reference Figure 1 , the present invention comprises the following steps:

[0030] Step 1) Segment the electrically large platform and nearby antennas:

[0031] The electrically large platform and the nearby antennas are segmented to obtain the MoM area triangle patch pairs and PO area triangle patch pairs;

[0032] The steps for segmenting the electrically large platform and the antenna nearby are as follows: the antenna and the electrically large platform nearby are divided into the MoM region and the physical optics PO region respectively, and the two regions are segmented into triangular patches respectively, and the triangular patches with common edges are used to form a patch pair to obtain the MoM region. triangle patch pairs and PO area triangle patch pairs.

[0033] In this example, the electrically large platform is an aircraft model with a length of 2.3 meters, a height of 1.293 meters, a wingspan of 3.484 meters, and a tail width of 1.522 meters. The bowtie antenna array consists of two elements separated by 0.2 meters. In each element, the bowtie antenna is mounted on a circular plane. The length of the bowtie is 0.05 meters and the width is 0.04 meters. The bowtie antenna and platform are divided into the MoM region, and the aircraft is divided into the PO region. The MoM region has 19,327 triangle patch pairs, and the PO region has 237,638 triangle patch pairs.

[0034] Step 2) Define the RWG basis function of the triangle patch pair:

[0035] Define the first The RWG basis function of a triangle patch pair is and PO area The RWG basis function of a triangle patch pair is ,in, , , Represents the field point position vector.

[0036] MoM area RWG basis functions for triangle patch pairs and PO area RWG basis functions for triangle patch pairs , whose expressions are:

[0037] ;

[0038] ;

[0039] in, Indicates the composition Two triangle patches of a triangle patch pair and The length of the common side, and Respectively and The area, express Vertices not on a common edge point to the position vector The vector of express of The vector pointing to the vertex that is not on the common edge, Indicates the composition Two triangle patches of a triangle patch pair and The length of the common side, and Respectively and The area, express Vertices not on a common edge point to The vector of express of Vectors pointing to vertices that are not on a common edge.

[0040] Step 3) Construct the matrix equation of the MoM region based on the RWG basis functions of the MoM region and the PO region:

[0041] based on and Constructing the self-impedance matrix including the MoM region And the mutual impedance matrix of MoM area and PO area The matrix equation of the MoM region is:

[0042] ;

[0043] ;

[0044] in, The near-field matrix representing the self-impedance matrix of the MoM region, The far-field matrix representing the self-impedance matrix of the MoM region, The near-field matrix representing the mutual impedance matrix of the MoM and PO regions, The far-field matrix representing the mutual impedance matrix of the MoM and PO regions;

[0045] 3a) Based on RWG basis function 、 The surface current density of the MoM region and the PO region is expanded respectively to obtain the target surface current density of the MoM region and the PO region after expansion. 、 :

[0046] ;

[0047] ;

[0048] in, 、 Indicates the current coefficient of the MoM region and the PO region;

[0049] 3b) Target surface current density through the expanded MoM region and PO region 、 Construct the electric field integral equation:

[0050] ;

[0051] ;

[0052] ;

[0053] in, represents the electric field of the incident wave, represents the integral operator, represents the tangent direction of the vector, , represents the imaginary unit, represents pi, represents the wave number, represents the radiation frequency of the antenna, represents the vacuum permeability, represents the dielectric constant of vacuum, represents the free space wave impedance, , represents the surface integral, Represents the area of ​​the surface where the source point is located, represents the Green's function, and Represent the field point position vector and the source point position vector respectively;

[0054] 3c) Existing methods for transforming the electric field integral equation include the point selection method and the Galerkin method. This example uses, but is not limited to, the Galerkin method, which uses the same function as the basis function for verification. This method has the advantage of a small number of unknowns. Its implementation steps are as follows:

[0055] ;

[0056] in, represents the test function in the Galerkin method, , represents the RWG basis function at the source point of the PO region, Represents the RWG basis function at the MoM region point.

[0057] The above linear equation is simplified by row transformation, column transformation and inverse matrix to obtain the matrix equation of the MoM region:

[0058] ;

[0059] in, represents the MoM region self-impedance matrix, represents the unknown current coefficient in the MoM region, represents the MoM-PO region mutual impedance matrix, represents the MoM region excitation vector matrix, The near-field matrix representing the self-impedance matrix of the MoM region, The far-field matrix representing the self-impedance matrix of the MoM region, The near-field matrix representing the mutual impedance matrix of the MoM-PO region, The far-field matrix representing the mutual impedance matrix of the MoM region and the PO region;

[0060] 3d) The existing methods for data grouping include quadtree algorithm, octree algorithm, binary space partitioning BSP algorithm, kd number algorithm. This example uses but is not limited to the octree algorithm. The octree method is used to group 、 It is divided into far-field matrix and near-field matrix, and the implementation steps are:

[0061] Based on the octree algorithm, the As a starting point, The cube with the same side length is divided into eight equal parts, and each cube after division is divided into eight equal parts again, and so on, until the side length of each cube after division is less than , and then select all cubes obtained from the last segmentation that contain RWG basis functions cubes, and then group the RWG basis functions in each cube into a group to obtain the RWG basis function group .in The calculation formula is:

[0062] ;

[0063] in, Indicates the antenna radiation frequency The corresponding wavelength, , 、 , 、 , Respectively The maximum and minimum values ​​of the x, y, and z axis components of the triangle patch vertex coordinates in the triangle patch pair, Indicates the maximum value operation. Indicates the modulo operation. The same method can be used to obtain the RWG basis function group of the PO area. .

[0064] After the RWG basis functions are grouped, the center distance between two cubes of the same layer in the MoM regional basis function group is greater than The impedance matrix formed by the RWG basis function is divided into a far-field impedance matrix, otherwise it is a near-field impedance matrix. The center distance between the two cubes of the same layer of the basis function group in the MoM area and the PO area is greater than The impedance matrix formed by the RWG basis function is divided into a far-field impedance matrix, otherwise it is a near-field impedance matrix, where is the side length of the thinnest cube.

[0065] Step 4) Construct the matrix equation of the PO region based on the RWG basis function of the PO region:

[0066] based on Construct a coupling matrix containing MoM and PO regions The matrix equation of the PO region is:

[0067] ;

[0068] in, The near-field matrix representing the coupling matrix between the MoM and PO regions, The far-field matrix representing the coupling matrix between the MoM and PO regions;

[0069] 4a) Surface current density in the PO region represented by incident field excitation and coupled excitation between the MoM and PO regions :

[0070] ;

[0071] in, Indicates the The incident field excitation on the triangular patch pair is represents the coupled excitation between the MoM and PO regions;

[0072] 4b) Use the same method as in (3c) to Transform the expression to obtain the matrix equation of the PO region:

[0073] ;

[0074] in, Indicates the unknown current coefficient in the PO region, represents the coupling matrix between MoM and PO regions, represents the unknown current coefficient in the MoM region, represents the excitation vector of the PO region. And the same method as (3d) is used to convert It is divided into far-field impedance matrix and near-field impedance matrix.

[0075] Step 5) Fill the near-field matrix and far-field matrix based on the MoM-PO method and skeletonization algorithm respectively:

[0076] Based on the MoM-PO method, the near-field matrix elements are calculated by the RWG basis functions in the MoM region and the PO region to obtain the filled near-field matrix 、 、 ; At the same time, the far field matrix is ​​filled based on the skeleton algorithm to obtain the far field matrix after accelerated filling 、 、 .

[0077] 5a) For near-field matrix filling, the matrix element calculation formula is:

[0078] ;

[0079] ;

[0080] ;

[0081] in, 、 and express 、 and The elements in represents the test function in the Galerkin method, , represents the RWG basis function at the source point of the MoM region, represents the RWG basis function at the source point of the PO region, represents the occlusion coefficient, is the unit vector at the midpoint of the common edge of the RWG basis function.

[0082] 5b) Construct the matrix to be decomposed for the PO region, MoM region, and the coupling matrix between the MoM region and the PO region:

[0083] ;

[0084] ;

[0085] ;

[0086] The proxy surface is a spherical surface that completely wraps the cube and completely isolates non-adjacent cubes. Indicates the MoM area The matrix to be decomposed of the group, Indicates the MoM area the number of basis functions in the group, Indicates the the number of basis functions on the group's proxy surface, Indicates the MoM area The RWG basis function group of the group, Indicates the source point of the MoM region The RWG basis function group of the group, Indicates the The RWG basis function group on the group's proxy, Indicates the The RWG basis function group at the source point on the group's proxy, the matrix to be decomposed in the PO region Construction method and The construction method is the same.

[0087] The formula for constructing the matrix to be decomposed of the coupling matrix between the MoM region and the PO region is:

[0088] ;

[0089] ;

[0090] ;

[0091] in, Indicates the PO area the number of basis functions in the group, Indicates the the number of basis functions on the group's proxy surface, and is the unit vector at the midpoint of the common edge of the RWG basis function, is the outward direction vector of the PO region, Indicates the source point of the PO area The RWG basis function group of the group, Indicates the The RWG basis function group at the source point on the proxy surface of the group.

[0092] 5c) Perform interpolation decomposition on the matrix to be decomposed to obtain the first Group interpolation matrix , and skeleton basis functions, the first Group interpolation matrix , and skeleton basis functions, the coupling matrix Group interpolation matrix , And the skeleton basis function, the coupling matrix between the skeleton basis functions is expressed as follows:

[0093] ;

[0094] ;

[0095] ;

[0096] in, represents the occlusion coefficient, is the outward direction vector of the PO region, Indicates the MoM area Group and The coupling matrix between the skeleton basis functions of the group, Indicates the MoM area Group and PO Area No. The coupling matrix between the group skeleton basis functions, Indicates PO area Group and MoM Region No. The coupling matrix between the skeleton basis functions of the group coupling matrix, , Indicates MoM , No. Group skeleton basis functions, , Indicates PO area Group skeleton basis functions, , , Indicates the MoM area , No. Skeleton basis function at the group source point, Indicates PO area Skeleton basis functions at group source points;

[0097] 5d) Use the coupling matrix between the interpolation matrix and the skeleton basis function to calculate the far-field matrix after filling 、 、 , among which the MoM region Group and Group, PO area Group and Group, coupling matrix between MoM region and PO region Group and Impedance submatrix of the group , , , the calculation formula is as follows:

[0098] ;

[0099] ;

[0100] ;

[0101] in, Indicates the MoM area The interpolation matrix of the group, ,The coupling matrix between the interpolation matrix and the skeleton basis function is used to calculate the far field matrix after filling. The skeleton basis function is used instead of all the basis functions in the MoM area and PO area during the calculation process. The number of basis functions used is smaller, which can reduce memory usage and speed up calculation efficiency.

[0102] Step 6) Obtain the radiation characteristics of the antenna:

[0103] pass and 、 and Calculated filled MoM region self-impedance matrix , MoM area and PO area mutual impedance matrix , while passing and Calculated coupling matrix between MoM and PO regions , calculate the surface current coefficient of MoM region and PO region respectively 、 and through and Calculate antenna package radiation pattern and directivity.

[0104] 6a) Electric field of incident wave Calculate the MoM region excitation vector matrix and through , and using the double conjugate gradient BICG method, by And the filled MoM area self-impedance matrix , MoM area and PO area mutual impedance matrix and the coupling matrix between MoM and PO regions , the matrix equations of the MoM region and the PO region are solved respectively to obtain the surface current coefficients of the MoM region and the PO region 、 ,in:

[0105] ;

[0106] in, represents the electric field of the incident wave, express The elements in represents the trial function in the Galerkin method, ;

[0107] 6b) Surface current coefficient through MoM region and PO region 、 Calculate the surface current coefficient of an electrically large platform and its antenna ,pass Calculate the far-field electric field vector of the antenna and through Calculating antenna radiation patterns and gain :

[0108] ;

[0109] ;

[0110] ;

[0111] in, represents the imaginary unit, represents the wave number, Indicates the antenna radiation frequency The corresponding angular frequency, represents magnetic permeability, exp represents exponential operation, represents the source position vector, Represents the field point position vector The unit vector of surface The surface current density vector at Indicates the modulo value, express The maximum value of represents the solid angle of the spherical element, Indicates the radiation efficiency of the antenna.

[0112] The technical effects of the present invention are further illustrated below in conjunction with simulation experiments.

[0113] 1. Simulation conditions and content:

[0114] The simulation software platform is an Intel(R) Core(TM) i9-13900k CPU with a 3GHz clock speed and 128.0GB of memory. The software platform is Windows 10 operating system, Intel Visual Fortran 2013, and Altair Feko 2021.

[0115] The peak memory usage and calculation time used to calculate the antenna radiation pattern of the present invention and the prior art, as well as the antenna radiation pattern of the XOY plane and the XOZ plane are compared and simulated. The results are shown in Table 1 and Figure 2 and Figure 3 shown.

[0116] 2. Analysis of simulation results:

[0117] Refer to Table 1

[0118] Table 1.

[0119] method Peak memory (GB) Computation time (s) Existing technology 75.3 24006 The present invention 13.6 2377

[0120] From Table 1, it can be seen that the peak memory usage of the present invention is reduced by 82% and the impedance matrix filling time is shortened by 90% compared with the prior art, which shows that the present invention effectively improves the efficiency of obtaining antenna radiation characteristics.

[0121] Reference Figure 2 , in the XOY plane antenna radiation pattern of the present invention and the prior art, the present invention can accurately obtain the XOY plane radiation characteristics of the array antenna.

[0122] Reference Figure 3 , in the XOZ planar antenna radiation pattern of the present invention and the prior art, the present invention can accurately obtain the XOZ planar radiation characteristics of the array antenna.

Claims

1. A method for obtaining antenna radiation characteristics based on skeletonization and MoM-PO algorithm, characterized in that The steps include: (1) Dissect the electrically large platform and the antenna on it: The electrically large platform and the antenna on it are segmented to obtain the MoM area triangle patch pairs and PO area triangle patch pairs; (2) Define the RWG basis function of the triangle patch pair: Define the first The RWG basis function of a triangle patch pair is and PO area The RWG basis function of a triangle patch pair is ,in, , , represents the position vector of the field point; (3) The matrix equation of the MoM region is constructed based on the RWG basis functions of the MoM region and the PO region: based on and Constructing the self-impedance matrix including the MoM region And the mutual impedance matrix of MoM area and PO area The matrix equation of the MoM region is: ； ； in, 、 Respectively The near-field matrix and far-field matrix of 、 Respectively Near-field matrix and far-field matrix; (4) Construct the matrix equation of the PO region based on the RWG basis function of the PO region: based on Construct a coupling matrix containing MoM and PO regions The matrix equation of the PO region is: ； in, 、 Respectively Near-field matrix and far-field matrix; (5) Fill the near-field matrix and far-field matrix based on the MoM-PO method and the skeletonization algorithm respectively: Based on the MoM-PO method, the near-field matrix elements are calculated by the RWG basis functions of the MoM area and the PO area, and the near-field matrices in steps (3) and (4) are filled respectively by the matrix elements to obtain the filled near-field matrix 、 、 At the same time, based on the skeletonization algorithm, the far-field impedance sub-matrix is ​​calculated through the skeleton basis function and interpolation matrix of each group, and the far-field matrices in steps (3) and (4) are filled respectively by the impedance sub-matrix to obtain the far-field matrix after accelerated filling 、 、 ; (6) Obtain the radiation characteristics of the antenna: pass and 、 and Calculated filled MoM region self-impedance matrix , MoM area and PO area mutual impedance matrix , while passing and Calculated coupling matrix between MoM and PO regions and through 、 and Calculation of surface current coefficients in MoM and PO regions 、 , then by and Calculate the antenna's pattern and gain.

2. The method according to claim 1, characterized in that The steps for segmenting the electrically large platform and the nearby antennas as described in step (1) are as follows: The antenna and the electrically large platform near the electrically large platform are divided into the MoM method region and the physical optics PO region, and the two regions are triangularly divided and the triangles with common edges are used to form a patch pair to obtain the MoM region. triangle patch pairs and PO area triangle patch pairs.

3. The method according to claim 1, characterized in that In the MoM region described in step (2) RWG basis functions for triangle patch pairs and PO area RWG basis functions for triangle patch pairs , whose expressions are: ； ； in, Indicates the composition Two triangle patches of a triangle patch pair and The length of the common side, and Respectively and The area, express Vertices not on a common edge point to the position vector The vector of express of The vector pointing to the vertex that is not on the common edge, Indicates the composition Two triangle patches of a triangle patch pair and The length of the common side, and Respectively and The area, express Vertices not on a common edge point to The vector of express of Vectors pointing to vertices that are not on a common edge.

4. The method according to claim 1, wherein The matrix equations constructed based on the RWG basis functions of the triangle face pairs described in step (3) are implemented as follows: (3a) Based on RWG basis function 、 The surface current density of the MoM region and the PO region is expanded respectively to obtain the target surface current density of the MoM region and the PO region after expansion. 、 : ； ； in, 、 Indicates the current coefficient of the MoM region and the PO region; (3b) Target surface current density through the expanded MoM region and PO region 、 Construct the electric field integral equation: ； ； ； in, represents the electric field of the incident wave, represents the integral operator, represents the tangential component of the vector, , represents the imaginary unit, represents pi, represents the wave number, represents the radiation frequency of the antenna, represents the vacuum permeability, represents the dielectric constant of vacuum, represents the free space wave impedance, , represents the surface integral, Represents the area element of the surface where the source point is located, represents the Green's function, Represents the source point position vector; (3c) The Galerkin method is used to transform the electric field integral equation to obtain the matrix equation of the MoM region: ； in, represents the MoM region self-impedance matrix, represents the unknown current coefficient in the MoM region, represents the mutual impedance matrix of the MoM region and the PO region, represents the MoM region excitation vector matrix, The near-field matrix representing the self-impedance matrix of the MoM region, The far-field matrix representing the self-impedance matrix of the MoM region, The near-field matrix representing the mutual impedance matrix of the MoM region and the PO region, The far-field matrix representing the mutual impedance matrix of the MoM region and the PO region.

5. The method according to claim 4, characterized in that The matrix equation for constructing the PO region described in step (4) is implemented as follows: (4a) Surface current density in the PO region expressed by incident field excitation and coupled excitation between the MoM and PO regions : ； in, Indicates the The incident field excitation on the triangular patch pair is represents the coupled excitation between the MoM and PO regions; (4b) Use the Galerkin method to calculate the Transform the expression to obtain the matrix equation of the PO region: ； in, Indicates the unknown current coefficient in the PO region, represents the coupling matrix between MoM and PO regions, represents the unknown current coefficient in the MoM region, Represents the excitation vector of the PO region.

6. The method according to claim 4, characterized in that The calculation of the far-field impedance sub-matrix described in step (5) is implemented as follows: Based on the skeletonization algorithm, the proxy surface method is used to construct the coupling between the basis functions within the group and the proxy surface. The matrix to be decomposed in the MoM region, The matrix to be decomposed of the PO region and the coupling matrix of the MoM region and the PO region are decomposed, and each group of matrices to be decomposed is interpolated and decomposed, and then each group of interpolation matrices of the MoM region after interpolation decomposition is obtained. and The coupling matrix between its corresponding skeleton basis functions and each set of interpolation matrices in the PO region and And the coupling matrix between the corresponding skeleton basis functions, each set of interpolation matrices in the MoM region and the PO region and and the coupling matrix between its corresponding skeleton basis functions, calculate the MoM region Group and Impedance submatrix of the group , PO area Group and Group impedance submatrix , the coupling matrix between MoM region and PO region Group and Group impedance submatrix : ； ； ； in, Indicates the MoM area Group and The coupling matrix between the skeleton basis functions of the group, , Indicates the MoM area The interpolation matrix of the group, Indicates the MoM area Group and PO Area No. The coupling matrix between the group skeleton basis functions, Indicates PO area Group and MoM Region No. The group coupling matrix is ​​the coupling matrix between the skeleton basis functions.

7. The method according to claim 4, characterized in that The steps for obtaining the radiation characteristics of the antenna described in step (6) are as follows: (6a) Electric field of incident wave Calculate the MoM region excitation vector matrix , and using the double conjugate gradient BICG method, by And the filled MoM area self-impedance matrix , MoM area and PO area mutual impedance matrix and the coupling matrix between MoM and PO regions , the matrix equations of the MoM region and the PO region are solved respectively to obtain the surface current coefficients of the MoM region and the PO region 、 ,in: ； in, represents the electric field of the incident wave, express The elements in represents the trial function in the Galerkin method, ; (6b) Surface current coefficient through the MoM region and PO region 、 Calculate the surface current coefficient of an electrically large platform and its antenna ,pass Calculate the far-field electric field vector of the antenna and through Calculating antenna radiation patterns and gain : ； ； ； in, represents the imaginary unit, represents the wave number, Indicates the antenna radiation frequency The corresponding angular frequency, represents magnetic permeability, exp represents exponential operation, represents the source position vector, Represents the field point position vector The unit vector of surface The surface current density vector at Indicates the modulo value, express The maximum value of represents the solid angle of the spherical element, Indicates the radiation efficiency of the antenna.

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