Method for acquiring and separating scattered field of large-scale array antenna

Abstract

A method for acquiring and separating a scattered field of a large-scale array antenna comprises the following steps: acquiring a radiation field in each unit array of a subarray, and calculating an antenna mode item scattered field in each unit array; solving a mutual coupling correction matrix by using the scattered field of the antenna mode item of each unit calculated by a directional diagram product method and the antenna mode item in the array; correcting a structural mode item scattering field calculated by a directional diagram product method by using a mutual coupling correction matrix; adding scattered fields of the unit antenna mode items and the structure mode items to obtain an in-array scattered field; performing equivalent construction and phase compensation on the sub-arrays to obtain scattered fields of each unit of the large-scale array antenna; obtaining a total scattered field of the large-scale array antenna, a total antenna mode item and a total structure mode item scattered field through field superposition; according to the method, the mutual coupling correction matrix and the subarray theory are introduced, direct matrix operation on the large-scale array antenna is avoided, the calculation speed is increased, and the problem that a large amount of calculation time and resources are consumed when the large-scale array antenna scattering field is obtained in the prior art is solved.

Description

Technical Field

[0001] The present invention belongs to the field of electromagnetic technology, and particularly relates to a method for obtaining and separating the scattering fields of a large-scale array antenna, which can be used to obtain the total scattering field of the large-scale array antenna, as well as the scattering fields of the antenna mode terms and the structure mode terms. Background Art

[0002] In modern warfare, array antennas are an important part of radar systems. To reduce their radar cross-section (RCS), it is of great military significance to study efficient evaluation methods for the scattering characteristics of large-scale array antennas. At present, the research on the scattering characteristics of array antennas mainly relies on numerical algorithms such as the method of moments and the finite element method, or simulation software based on these algorithms. However, for large-scale array antennas, the computational resources and time consumed by using the above methods are extremely large. Studying efficient and high-precision calculation and separation methods for the scattering fields of large-scale array antennas is of important engineering significance for analyzing and revealing the scattering characteristics of array antennas at different frequencies and angles, and then formulating more effective stealth strategies and countermeasures.

[0003] Regarding the analysis of the scattering characteristics of large-scale array antennas, on the one hand, the scattering fields of array antennas are obtained through traditional numerical algorithms or simulation software based on these algorithms. When dealing with the high-precision solution of the scattering fields of ultra-large-scale array antennas, such as phased array radar antennas with tens of thousands of elements, low-frequency algorithms cannot be solved due to limited computer memory expansion, and the accuracy of high-frequency methods cannot meet the requirements. On the other hand, the method of conducting electromagnetic performance verification tests on pre-developed small array antennas is adopted in the hope of providing support for the design of large arrays. However, in actual tests, the test results of small arrays often have limitations in terms of data completeness. Only the total scattering field of the array can be obtained, and the in-array scattering fields of each unit of the array cannot be obtained. There are still many difficulties in accurately deducing the electromagnetic performance of large-scale array antennas through them.

[0004] The patent application with application publication number CN110737873A and titled “A fast analysis method for large-scale array antenna scattering” discloses a fast analysis method for the far-field scattering field of large-scale array antennas. This method performs characteristic mode analysis on the metal dielectric composite unit, copies the characteristic flow of the unit to all units in the array to form a set of bases, and uses this set of bases as the sub-global basis function to expand the equivalent surface current of the array. By using the periodicity and symmetry of the array impedance matrix, a dimensionally reduced impedance matrix based on the characteristic mode current expansion is obtained, and the matrix equation is solved by the direct inversion method to finally obtain the array scattering result. However, this method directly calculates the array matrix. When the array antenna scale increases, the matrix dimension also increases, and the time required for matrix operation continues to increase. This method calculates the scattering field of the entire array and can only obtain the scattering field of the array, and cannot realize the calculation and separation of the scattering field of each unit in the array. In addition, this method is only applicable to simulation calculations and is invalid for test situations. Summary of the invention

[0005] In view of the deficiencies of the above-mentioned prior art, the purpose of the present invention is to propose a method for obtaining and separating the scattered field of a large-scale array antenna, by obtaining the radiation field in each unit array of the subarray, calculating the scattering field of the antenna mode item in each unit array; solving the mutual coupling correction matrix with the scattering field of each unit antenna mode item calculated by the pattern product method and the antenna mode item in the array; correcting the scattering field of the structural mode item calculated by the pattern product method by the mutual coupling correction matrix; adding the scattering field of each unit antenna mode item and the structural mode item to obtain the scattering field in the array; equivalently constructing the subarray and performing phase compensation to obtain the scattering field of each unit of the large-scale array antenna; obtaining the total scattering field of the large-scale array antenna and the scattering field of the total antenna mode item and the total structural mode item by field superposition; the method can reduce the demand for computing resources, shorten the computing time, and improve the evaluation efficiency of large-scale array antennas, and has the advantages of less computing time and resources, high computing accuracy, and the ability to simultaneously realize the calculation and separation of the scattering field.

[0006] In order to achieve the above technical objectives, the present invention adopts the following technical solutions:

[0007] A method for acquiring and separating the scattered field of a large-scale array antenna, the specific steps comprising:

[0008] Step 1: From the large-scale array antenna with M rows and N columns to be solved, select adjacent m rows and n columns as a subarray, and collect the array radiation field of each unit of the subarray. Wherein, M, N, m, n are all integers, and 1≤m≤M, 1≤n≤N, i=1,2,...n,n+1,...,m·n, θ is the pitch angle in the rectangular coordinate system of the measurement space, and φ is the azimuth angle in the rectangular coordinate system of the measurement space;

[0009] Step 2: Use the radiation field of each unit of the subarray in step 1 Calculate the scattering field of the antenna mode item in each unit of the subarray

[0010] Step 3: Obtain the antenna pattern scattering field of a single antenna unit Scattering field with structural mode terms Utilize the antenna mode term scattered field of a single antenna element by pattern product method Calculate the scattering field of each element antenna mode in the subarray The scattered field of the antenna mode item in each unit of the subarray in step 2 The scattering field of each element antenna mode of the subarray calculated by the product method of the directivity pattern Simultaneously solve the overdetermined equations and solve the mutual coupling correction matrix C;

[0011] Step 4: The mutual coupling correction matrix C obtained in step 3 is combined with the scattering field of the structural mode term of a single antenna unit by the directional pattern product method. The calculated scattered field of each unit structure mode of the subarray The matrix composed of the matrix is ​​multiplied to obtain the scattered field of the structural mode item in each unit of the sub-array

[0012] Step 5: Scatter the antenna pattern items of each element of the subarray Scattering field with structural mode terms The scattered field of each unit in the sub-array is obtained by adding them up separately

[0013]

[0014] Step 6: Equivalently construct the subarray of m rows and n columns into a large-scale array antenna of M rows and N columns, and obtain the displacement vector between each unit of the subarray and each unit of the large-scale array antenna:

[0015]

[0016] in, is the row displacement vector of the subarray relative to the I-th row element of the massive array antenna, is the column displacement vector of the subarray relative to the J-th column element of the massive array antenna, is the total displacement vector of the subarray relative to the element in the Ith row and the Jth column of the large-scale array antenna;

[0017] Step 7: According to step 6, calculate the scattered field of the unit in the Ith row and the Jth column of the large-scale array antenna Antenna mode scattered field And the scattered field of the structural mode term

[0018] Step 8. Obtain the total scattered field of the large-scale array antenna according to Step 7 Total antenna mode term scattered field And total structure mode term scattered field

[0019] The antenna mode term scattered field in each unit array of the sub-array calculated in Step 2 Is expressed as follows:

[0020]

[0021] Wherein, Is the matrix composed of the radiation fields in each unit array of the sub-array, mn is the number of antenna elements in the sub-array antenna, [Γ] mn×mn Is the reflection coefficient matrix of each unit load, [I] mn×mn Is the identity matrix, [S] mn×mn Is the S-parameter matrix characterizing mutual coupling, Is the matched receiving vector, and the matched receiving vector b of each unit 4 Is expressed as follows:

[0022]

[0023] Wherein, j is the imaginary symbol, λ is the wavelength, c is the amplitude of the incident wave, Is the amplitude vector of the radiation field generated when the antenna element is excited, Is the propagation direction of the incident plane wave.

[0024] The antenna mode term scattered field of a single antenna element obtained in Step 3 And the structure mode term scattered field Is expressed as follows:

[0025]

[0026] Wherein, s represents the scattered field, a represents the antenna mode term, s represents the structure mode term, Γ l Is the reflection coefficient of the antenna element load, S 11 Is the return loss of the antenna element, Is the scattered field when the antenna element port is connected to an infinite load, Is the scattered field when the antenna element port is connected to a zero load.

[0027] The antenna mode term scattered field of each unit of the sub-array calculated by the pattern multiplication method using the antenna mode term scattered field of a single antenna element in Step 3 Is expressed as follows:

[0028] The antenna mode term scattered field of each unit of the sub-array in the bistatic mode​

[0029]

[0030] Scattering field of antenna mode items of each unit of the subarray in single-station mode

[0031]

[0032] Where j is the imaginary number symbol, is the scattered wave vector, is the incident wave vector, is the displacement of the ith antenna unit, expressed as follows:

[0033]

[0034] in, is the row spacing vector, is the column spacing vector.

[0035] In step 3, the antenna mode item scattering field in each unit array of the subarray is The scattering field of each element antenna mode of the subarray calculated by the product method of the directivity pattern The simultaneous overdetermined equations are expressed as:

[0036]

[0037] Where mn is the number of subarray antenna elements, x is the number of sampling points, and C represents the mutual coupling correction matrix, which is a two-dimensional matrix of mn×mn, as shown below:

[0038]

[0039] in,[] -1 Represents the inverse matrix.

[0040] In step 4, the scattering field of the structural mode item of a single antenna unit is used by the directional pattern product method. The calculated scattered fields of each unit structure mode of the subarray It is expressed as follows:

[0041] Scattering field of each unit structure mode of the subarray in bistatic mode

[0042]

[0043] Scattering field of each unit structure mode of the subarray in single-station mode

[0044]

[0045] where \(j\) is the imaginary symbol, is the scattered wave vector, is the incident wave vector, is the displacement of the \(i\)-th antenna element, expressed as follows:

[0046]

[0047] where is the row pitch vector, is the column pitch vector.

[0048] In step 4, the mutual coupling correction matrix \(C\) is multiplied by the matrix composed of the scattered fields of the structural mode terms of each element of the subarray calculated by the pattern multiplication method using the scattered field of the structural mode terms of a single antenna element, expressed as follows:

[0049]

[0050] where \(mn\) is the number of antenna elements in the subarray, \(x\) is the number of sampling points, and the scattered field of the structural mode terms in each element array is expressed as follows:

[0051]

[0052] where \(C(i,:)\) is the \(i\)-th row of the mutual coupling correction matrix.

[0053] In step 6, the method for obtaining the row displacement vector of the subarray relative to the \(I\)-th row element of the large-scale array antenna is as follows:

[0054] (6a) Equivalent the elements of the first row to the \((m - 1) / 2\)-th row of the subarray to the elements of the first row to the \((m - 1) / 2\)-th row of the \(M\) row \(n\) column array, and the displacement vector of each row of the first row to the \((m - 1) / 2\)-th row of the \(M\) row \(n\) column array is (6a) Equivalent the elements of the first row to the \((m - 1) / 2\)-th row of the subarray to the elements of the first row to the \((m - 1) / 2\)-th row of the \(M\) row \(n\) column array, and the displacement vector of each row of the first row to the \((m - 1) / 2\)-th row of the \(M\) row \(n\) column array is

[0055] (6b) Equivalent the element of the \([(m - 1) / 2]+1\)-th row of the subarray to the elements of the \([(m - 1) / 2]+1\)-th row to the \(M-(m - 1) / 2\)-th row of the \(M\) row \(n\) column array, and the displacement vector of each row of the \([(m - 1) / 2]+1\)-th row to the \(M-(m - 1) / 2\)-th row of the \(M\) row \(n\) column array is where is the row pitch;

[0056] (6c) Equivalent the elements of the \([(m - 1) / 2]+2\)-th row to the \(m\)-th row of the subarray to the elements of the \(M-(m - 1) / 2+1\)-th row to the \(M\)-th row of the \(M\) row \(n\) column array, and the displacement vector of each row of the \(M-(m - 1) / 2+1\)-th row to the \(M\)-th row of the \(M\) row \(n\) column array is

[0057] The column displacement vector of the sub-array relative to the Jth column unit of the large-scale array antenna The acquisition method is as follows:

[0058] (6d) Equivalent the units of the first column to the (n - 1) / 2th column of the M×n array as the units of the first column to the (n - 1) / 2th column of the M×N array, and the column displacement vectors of each column from the first column to the (n - 1) / 2th column of the M×N array are

[0059] (6e) Equivalent the units of the [(n - 1) / 2]+1th column of the M×n array as the units of the [(n - 1) / 2]+1th column to the N-(n - 1) / 2th column of the M×N array, and the column displacement vectors of each column from the [(n - 1) / 2]+1th column to the N-(n - 1) / 2th column of the M×N array are Where is the column pitch;

[0060] (6f) Equivalent the units of the [(n - 1) / 2]+2th column to the nth column of the M×n array as the units of the N-(n - 1) / 2+1th column to the Nth column of the M×N array, and the column displacement vectors of each column from the N-(n - 1) / 2+1th column to the Nth column of the M×N array are

[0061] The specific method of step 7 is:

[0062] The scattered field is calculated in the bistatic mode The scattered field of the antenna mode term And the scattered field of the structure mode term

[0063]

[0064]

[0065] The scattered field is calculated in the monostatic mode The scattered field of the antenna mode term And the scattered field of the structure mode term

[0066]

[0067] Where the superscript s represents the scattered field, j is the imaginary symbol, is the scattered wave vector, is the incident wave vector.

[0068] The specific method of step 8 is:

[0069] The total scattered field is calculated in the bistatic mode Total antenna mode term scattered field Total structural mode scattered field

[0070]

[0071] The total scattered field is calculated in single-station mode Total antenna mode term scattered field Total structural mode scattered field

[0072]

[0073] Compared with the prior art, the present invention has the following advantages:

[0074] First, the present invention uses the reciprocity theorem and the radiation field in each unit array of the subarray to calculate the scattering field of the antenna mode item in each unit array of the subarray, which effectively reduces the difficulty of separating the scattering field of the antenna mode item of the antenna unit in the subarray.

[0075] Second, the present invention introduces a mutual coupling correction matrix, and solves the mutual coupling correction matrix by simultaneously solving the overdetermined equations of the antenna mode item scattering field in each unit array of the subarray and the antenna mode item scattering field of each unit calculated by the pattern product method. The scattering field of the structural mode item of each unit calculated by the pattern product method is corrected to obtain the scattering field of the structural mode item in each unit array, thereby realizing the calculation and separation of the scattering field in each unit array of the array.

[0076] Third, the present invention combines array element similarity with spatial phase compensation theory to simplify the calculation problem of the scattering field of a large-scale array antenna into the calculation problem of the scattering field of a sub-array antenna, establishes the corresponding relationship between the scattering field in each unit array of the sub-array and the scattering field in each unit array of the large-scale array to be solved, completes the equivalent construction of the large-scale array antenna to be solved, and reduces the demand and consumption of computing resources and computing time while ensuring the calculation accuracy.

[0077] In summary, the present invention has the advantages of less computation time and resources, high computation accuracy, and the ability to simultaneously calculate and separate scattered fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0078] Figure 1 It is a flow chart for implementing the present invention.

[0079] Figure 2 Schematic diagram of a large-scale antenna array for acquiring scattered fields in the present invention.

[0080] Figure 3 for Figure 2 Schematic diagram of a sub-array of the antenna array shown.

[0081] Figure 4Schematic diagram of row equivalence and column equivalence for sub - arrays in the present invention; among them, Figure 4 (a) is the schematic diagram of row equivalence, Figure 4 (b) is the schematic diagram of column equivalence.

[0082] Figure 5 Comparison diagram of the calculation results of the present invention with the full - wave simulation results and the calculation results of the pattern multiplication method in the bistatic mode; among them, Figure 5 (a) is the comparison of the scattered field results of the total antenna mode term of the large - scale array antenna in the bistatic mode, Figure 5 (b) is the comparison of the scattered field results of the total structure mode term of the large - scale array antenna in the bistatic mode, Figure 5 (c) is the comparison of the total scattered field results of the large - scale array antenna in the bistatic mode.

[0083] Figure 6 Comparison diagram of the calculation results of the present invention with the full - wave simulation results and the calculation results of the pattern multiplication method in the monostatic mode; among them, Figure 6 (a) is the comparison of the scattered field results of the total antenna mode term of the large - scale array antenna in the monostatic mode, Figure 6 (b) is the comparison of the scattered field results of the total structure mode term of the large - scale array antenna in the monostatic mode, Figure 6 (c) is the comparison of the total scattered field results of the large - scale array antenna in the monostatic mode. Detailed implementation manner

[0084] To more clearly describe the technical solution and effect of the present invention, the following will be described in conjunction with specific embodiments and drawings.

[0085] Refer to Figure 1 , the implementation steps of the present invention are as follows:

[0086] A method for obtaining and separating the scattered field of a large - scale array antenna, the specific steps include:

[0087] Step 1: Construct a large - scale array antenna.

[0088] Refer to Figure 2 , in this embodiment, the Ansys HFSS simulation software is used to model and simulate the large - scale array antenna to be solved. The microstrip patch antenna is used as the antenna element of the array antenna. A planar array with a scale of 10×10 elements is established in the rectangular coordinate xyz coordinate system as the large - scale array antenna to be solved. The antenna elements are evenly arranged. Among them, the arrangement along the positive x - axis is the row, and the row spacing is 0.5λ. The arrangement along the positive y - axis is the column, and the column spacing is 0.7λ. The operating frequency is 2.45 GHz. The incident wave is selected as a plane wave, and the incident angles are set as θ = 0°, φ = 0°.

[0089] Step 2: Obtain the radiation field in each unit array of the sub - array And calculate the scattered field of the antenna mode term in each unit array of the sub - array Where i=1,2,...,49.

[0090] 2.1) According to the array element similarity theory, a 7×7 element array antenna with the same arrangement as the large-scale array antenna is selected as the subarray, such as Figure 3 As shown;

[0091] 2.2) Set the sampling angle range, the pitch angle θ range is 0°~90° with a sampling interval of 1°, the azimuth angle φ range is 0°~360° with a sampling interval of 10°, and obtain the radiation field of each unit array of the subarray

[0092] 2.3) Through the reciprocity theorem, using the radiation field of each unit of the subarray Calculate; get the scattering field of antenna mode items in each element array of the subarray

[0093]

[0094] in, is the matrix composed of the radiation fields of each unit array of the subarray, mn=49, [Γ] mn×mn is the reflection coefficient matrix of each unit load, [I] mn×mn is the identity matrix, [S] mn×mn is the S parameter matrix that characterizes the mutual coupling, To match the received vector, each unit matches the received vector b 4 It is expressed as follows:

[0095]

[0096] Where j is the imaginary number sign, λ is the wavelength, c is the incident wave amplitude, is the amplitude vector of the radiation field generated by the antenna element when it is excited, is the propagation direction of the incident plane wave.

[0097] Step 3: Obtain the antenna pattern scattering field of a single antenna element Scattering field with structural mode terms The scattered field of the antenna mode item in each unit array of the subarray in step 2 The scattered field of the antenna mode term of a single antenna element is obtained by using the pattern product method Calculated scattering field of each element antenna mode in the subarray The overdetermined equations are solved simultaneously to obtain the mutual coupling correction matrix C.

[0098] 3.1) Simulate the scattering field of a single antenna unit, keep the sampling angle range consistent with the radiation field of each unit of the subarray, and obtain the antenna mode item scattering field of the antenna unit Scattering field with structural mode terms

[0099]

[0100] Among them, s represents the scattered field, a represents the antenna pattern term, s represents the structural pattern term, Γ l is the reflection coefficient of the antenna element load, S 11 is the return loss of the antenna element, is the scattered field when the antenna element port is connected to an infinite load, is the scattered field when the antenna element port is connected to a zero load;

[0101] 3.2) Calculate using the pattern multiplication method to obtain the scattered field of the antenna pattern term of each element of the subarray

[0102] Scattered field of the antenna pattern term of each element of the subarray in bistatic mode

[0103]

[0104] Scattered field of the antenna pattern term of each element of the subarray in monostatic mode

[0105]

[0106] Among them, j is the imaginary symbol, is the scattered wave vector, is the incident wave vector, is the displacement of the i-th antenna element, expressed as follows:

[0107]

[0108] Among them, is the row spacing vector, is the column spacing vector;

[0109] 3.3) Combine the scattered field of the antenna pattern term in each element of the subarray with the scattered field of the antenna pattern term of each element of the subarray calculated by the pattern multiplication method to establish an overdetermined equation:

[0110]

[0111] Among them, mn = 49, x = 3367, C represents the mutual coupling correction matrix as a 49×49 two-dimensional matrix, expressed as follows:

[0112]

[0113] Among them, [] -1 represents the inverse matrix.

[0114] Step 4: Multiply the mutual coupling correction matrix by the scattered fields of the structural mode terms of each element of the subarray calculated by the pattern multiplication method using the structural mode term of a single antenna element to obtain the scattered fields of the structural mode terms of each element in the element array Multiply the matrix composed of the scattered fields of the structural mode terms of each element of the subarray calculated by the pattern multiplication method

[0115] 4.1) The scattered fields of the structural mode terms of each element of the subarray calculated by the pattern multiplication method are expressed as follows:

[0116] The scattered fields of the structural mode terms of each element of the subarray in the bistatic mode

[0117]

[0118] The scattered fields of the structural mode terms of each element of the subarray in the monostatic mode

[0119]

[0120] where j is the imaginary symbol, is the scattered wave vector, is the incident wave vector, is the displacement of the i-th antenna element, expressed as follows:

[0121]

[0122] where, is the row spacing vector, is the column spacing vector;

[0123] 4.2) Multiply the mutual coupling correction matrix C by the matrix composed of the scattered fields of the structural mode terms of each element of the subarray calculated by the pattern multiplication method which is expressed as follows:

[0124]

[0125] where mn is the number of antenna elements in the subarray, x is the number of sampling points, and the scattered fields of the structural mode terms of each element in the element array are expressed as follows:

[0126]

[0127] where C(i,:) is the i-th row of the mutual coupling correction matrix.

[0128] Step 5: According to the results of 2.3) and 4.2), the scattered fields of the antenna mode terms of each element in the subarray and the scattered fields of the structural mode terms Add them separately to obtain the scattered fields in each unit array

[0129]

[0130] Step 6: Equivalently construct an m-by-n subarray into an M-by-N large-scale array antenna, and obtain the displacement vectors of each unit of the subarray relative to each unit of the large-scale array antenna

[0131] 6.1) Perform row equivalence on the subarray, and equivalently construct a 7-by-7 subarray into a 10-by-7 array, as shown in Figure 4 a, and obtain the row displacement vectors of the units in the I-th row of the large-scale array antenna

[0132] 6.1.1) Equivalently transform the units in the first to third rows of the subarray into the units in the first to third rows of a 10-by-7 array, and obtain the row displacement vectors of each row from the first to third rows of the 10-by-7 array as

[0133] 6.1.2) Equivalently transform the units in the fourth row of the subarray into the units in the fourth to seventh rows of a 10-by-7 array, and obtain the row displacement vectors of each row from the fourth to seventh rows of the 10-by-7 array as

[0134] 6.1.3) Equivalently transform the units in the fifth to seventh rows of the subarray into the units in the eighth to tenth rows of a 10-by-7 array, and obtain the row displacement vectors of each row from the eighth to tenth rows of the 10-by-7 array as

[0135] 6.2) Perform column equivalence on the 10-by-7 array, and equivalently construct the 10-by-7 array into a 10-by-10 large-scale array antenna, as shown in Figure 4 b, and obtain the column displacement of the units in the J-th column of the large-scale array antenna

[0136] 6.2.1) Equivalently transform the units in the first to third columns of the 10-by-7 array into the units in the first to third columns of the large-scale array antenna, and obtain the column displacement vectors of each column from the first to third columns of the large-scale array antenna as

[0137] 6.2.2) Equivalently transform the units in the fourth column of the 10-by-7 array into the units in the fourth to seventh columns of the large-scale array antenna, and obtain the column displacement vectors of each column from the fourth to seventh columns of the large-scale array antenna as

[0138] 6.2.3) Equivalently transform the units in the fifth to seventh columns of the 10-by-7 array into the units in the eighth to tenth columns of the large-scale array antenna, and obtain the column displacement vectors of each column from the eighth to tenth columns of the large-scale array antenna as

[0139] 6.3) Based on the results of 6.1) and 6.2), obtain the total displacement vector of the unit at the I-th row and J-th column of the large-scale array antenna

[0140]

[0141] Step Seven: Calculate the scattered field, antenna mode term scattered field, and structural mode term scattered field of each unit of the large-scale array antenna through the spatial phase compensation theory.

[0142] 7.1) Based on the results of 2.3) and 6.3), calculate the antenna mode term scattered field of the unit at the I-th row and J-th column of the large-scale array antenna

[0143] Antenna mode term scattered field in bistatic mode

[0144]

[0145] Antenna mode term scattered field in monostatic mode

[0146]

[0147] Among them, the superscript s represents the scattered field, j is the imaginary symbol, is the scattered wave vector, is the incident wave vector;

[0148] 7.2) Based on the results of 4.2) and 6.3), calculate the structural mode term scattered field of the unit at the I-th row and J-th column of the large-scale array antenna

[0149] Structural mode term scattered field in bistatic mode

[0150]

[0151] Structural mode term scattered field in monostatic mode

[0152]

[0153] Among them, the superscript s represents the scattered field, j is the imaginary symbol, is the scattered wave vector, is the incident wave vector;

[0154] 7.3) Based on the results of Step 5 and 6.3), calculate the scattered field of the unit at the I-th row and J-th column of the large-scale array antenna

[0155] Scattered field in bistatic mode

[0156]

[0157] Scattered field in monostatic mode

[0158]

[0159] where the superscript s represents the scattered field and j is the imaginary symbol, is the scattered wave vector, is the incident wave vector.

[0160] Step 8: Obtain the total scattered field of the large-scale array antenna according to the field superposition principle The total antenna mode term scattered field and the total structure mode term scattered field of the antenna

[0161] 8.1) According to the result of 7.1), obtain the total antenna mode term scattered field of the large-scale array antenna through scattered field superposition

[0162] The total antenna mode term scattered field in bistatic mode

[0163]

[0164] The total antenna mode term scattered field in monostatic mode

[0165]

[0166] 8.2) According to the result of 7.2), obtain the total structure mode term scattered field of the large-scale array antenna through scattered field superposition

[0167] The total structure mode term scattered field in bistatic mode

[0168]

[0169] The total structure mode term scattered field in monostatic mode

[0170]

[0171] 8.3) According to the result of 7.3), obtain the total scattered field of the large-scale array antenna through scattered field superposition

[0172] The total scattered field in bistatic mode

[0173]

[0174] Total scattered field in single - station mode

[0175]

[0176] The effects of the present invention can be further illustrated by the following simulation experiments:

[0177] I. Simulation experiment conditions

[0178] Using Ansys HFSS simulation software to model and simulate a large - scale array antenna to be solved. A microstrip patch antenna is used as the antenna element of the array antenna. A planar array with a size of 10×10 elements is established in the rectangular coordinate xyz coordinate system as the large - scale array antenna for which the scattered field is to be obtained. The antenna elements are uniformly arranged. Among them, the arrangement along the positive x - axis is the row, and the row spacing is 0.5λ. The arrangement along the positive y - axis is the column, and the column spacing is 0.7λ. The operating frequency is 2.45 GHz. Sampling parameters are set, and the total scattered field data of the large - scale array antenna is obtained in the range of the spatial elevation angle θ from 0° to 180° and the spatial azimuth angle from 0° to 360°. A 7×7 - element array antenna with the same arrangement as the large - scale array antenna is selected as the sub - array, and the radiation field data of each unit array in the sub - array is obtained. Finally, the scattered field data of a single antenna element is obtained.

[0179] II. Simulation experiment content

[0180] Simulation experiment 1: Under the above experimental conditions, the method of the present invention uses the radiation field data of each unit array in the sub - array and the bistatic scattered field data of the antenna element to compare the scattered field of the large - scale array antenna in the bistatic mode with the results obtained by directly simulating the large - scale array antenna using HFSS and the results calculated by the pattern multiplication method. The results are as Figure 5 shown. Among them:

[0181] Figure 5 (a) is the comparison of the bistatic total antenna mode term scattered field results of the large - scale array antenna, Figure 5 (b) is the comparison of the bistatic total structure mode term scattered field results of the large - scale array antenna, Figure 5 (c) is the comparison of the bistatic total scattered field results of the large - scale array antenna.

[0182] From Figure 5 (a), Figure 5 (b), Figure 5(c) It can be seen that in the bistatic mode, the bistatic scattering field of the large-scale array antenna calculated by the present invention is more consistent with the HFSS simulation results than the pattern multiplication method. Moreover, the scattering field of the antenna mode term calculated by the present invention is basically consistent with the HFSS simulation results, showing good agreement; the main lobe region and the first and second side lobe regions of the scattering field of the structural mode term are basically the same, and only outside the second side lobe region, the error shows a slightly increasing trend with the angular deviation; the main lobe region and the first and second side lobe regions of the total scattering field are basically the same, and only outside the second side lobe region, the error shows a slightly increasing trend with the angular deviation, indicating that the present invention can achieve the acquisition and separation of the scattering field of the large-scale array antenna. Moreover, the present invention only needs to obtain the radiation field data of the subarray and the bistatic antenna mode term scattering field and the structural mode term scattering field of a single antenna element, and the required calculation time and resources are much less than directly simulating the bistatic scattering field of the large-scale array antenna.

[0183] Simulation experiment 2: Under the above experimental conditions, the method of the present invention uses the radiation field data of each unit array in the subarray and the monostatic scattering field data of the antenna element to obtain the monostatic scattering field of the large-scale array antenna in the monostatic mode and compares it with the results obtained by directly simulating the large-scale array antenna using HFSS and the results calculated by the pattern multiplication method. The results are as Figure 6 shown. Among them:

[0184] Figure 6 (a) is the comparison of the monostatic total antenna mode term scattering field results of the large-scale array antenna, Figure 6 (b) is the comparison of the monostatic total structural mode term scattering field results of the large-scale array antenna, Figure 6 (c) is the comparison of the monostatic total scattering field results of the large-scale array antenna.

[0185] From Figure 6 (a), Figure 6 (b), Figure 6 (c) It can be seen that in the monostatic mode, the monostatic scattering field of the large-scale array antenna calculated by the present invention is more consistent with the HFSS simulation results than the pattern multiplication method. Moreover, the scattering field of the antenna mode term calculated by the present invention is basically consistent with the HFSS simulation results, showing good agreement; the scattering field of the structural mode term is basically the same as the HFSS simulation results within the angular range of ±45°, and there are small errors in the remaining angular ranges; the total scattering field is basically the same as the HFSS simulation results within the angular range of ±30°, and there are small errors in the remaining angular ranges, indicating that the present invention can achieve the acquisition and separation of the scattering field of the large-scale array antenna. Moreover, the present invention only needs to obtain the radiation field data of the subarray and the monostatic antenna mode term scattering field and the structural mode term scattering field of a single antenna element, and the required calculation time and resources are much less than directly simulating the monostatic scattering field of the large-scale array antenna.

Claims

1. A method for acquiring and separating the scattered field of a large-scale array antenna, characterized in that: The specific steps include: Step 1: From the large-scale array antenna with M rows and N columns to be solved, select adjacent m rows and n columns as a subarray, and collect the array radiation field of each unit of the subarray. Wherein, M, N, m, n are all integers, and 1≤m≤M, 1≤n≤N, i=1,2,...n,n+1,...,m·n, θ is the pitch angle in the rectangular coordinate system of the measurement space, and φ is the azimuth angle in the rectangular coordinate system of the measurement space; Step 2: Use the radiation field of each unit of the subarray in step 1 Calculate the scattering field of the antenna mode item in each unit of the subarray Step 3: Obtain the antenna pattern scattering field of a single antenna unit Scattering field with structural mode terms Utilize the antenna mode term scattered field of a single antenna element by pattern product method Calculate the scattering field of each element antenna mode in the subarray The scattered field of the antenna mode item in each unit of the subarray in step 2 The scattering field of each element antenna mode of the subarray calculated by the product method of the directivity pattern Simultaneously solve the overdetermined equations and solve the mutual coupling correction matrix C; Step 4: The mutual coupling correction matrix C obtained in step 3 is combined with the scattering field of the structural mode term of a single antenna unit by the directional pattern product method. The calculated scattered field of each unit structure mode of the subarray The matrix composed of the matrix is ​​multiplied to obtain the scattered field of the structural mode item in each unit of the sub-array Step 5: Scatter the antenna pattern items of each element of the subarray Scattering field with structural mode terms The scattered field of each unit in the sub-array is obtained by adding them up separately Step 6: Equivalently construct the subarray of m rows and n columns into a large-scale array antenna of M rows and N columns, and obtain the displacement vector between each unit of the subarray and each unit of the large-scale array antenna: in, is the row displacement vector of the subarray relative to the I-th row element of the massive array antenna, is the column displacement vector of the subarray relative to the J-th column element of the massive array antenna, is the total displacement vector of the subarray relative to the element in the Ith row and the Jth column of the large-scale array antenna; Step 7: According to step 6, calculate the scattered field of the unit in the Ith row and the Jth column of the large-scale array antenna Antenna mode term scattered field And the scattered field of the structural mode term Step 8: According to step 7, obtain the total scattering field of the large-scale array antenna Total antenna mode term scattered field And the total structural mode scattered field 2. The method for obtaining and separating the scattered field of a large-scale array antenna according to claim 1, characterized in that: The scattering field of the antenna mode item in each element array of the subarray calculated in step 2 It is expressed as follows: in, is the matrix composed of the radiation fields of each element array of the subarray, mn is the number of subarray antenna elements, [Γ] mn×mn is the reflection coefficient matrix of each unit load, [I] mn×mn is the identity matrix, [S] mn×mn is the S parameter matrix that characterizes the mutual coupling, To match the receiving vector, each unit matches the receiving vector b4 as follows: Where j is the imaginary sign, λ is the wavelength, c is the incident wave amplitude, is the amplitude vector of the radiation field generated by the antenna element when it is excited, is the propagation direction of the incident plane wave.

3. The method for obtaining and separating the scattered field of a large-scale array antenna according to claim 1, characterized in that: In step 3, the antenna pattern item scattering field of a single antenna unit is obtained Scattering field with structural mode terms It is expressed as follows: Where s represents the scattered field, a represents the antenna mode term, s represents the structural mode term, Γ l is the antenna unit load reflection coefficient, S 11 is the antenna unit return loss, is the scattered field when the antenna unit port is connected to an infinite load, It is the scattered field when the antenna unit port is connected to zero load.

4. The method for obtaining and separating the scattered field of a large-scale array antenna according to claim 1, characterized in that: In step 3, the antenna pattern item scattering field of a single antenna element is used by the pattern product method. The calculated scattering field of each element antenna mode of the subarray It is expressed as follows: Scattering field of antenna mode items of each unit of the subarray in bistatic mode Scattering field of antenna mode items of each unit of the subarray in single-station mode Where j is the imaginary number symbol, is the scattered wave vector, is the incident wave vector, is the displacement of the ith antenna unit, expressed as follows: in, is the row spacing vector, is the column spacing vector.

5. The method for obtaining and separating the scattered field of a large-scale array antenna according to claim 1, characterized in that: In step 3, the antenna mode item scattering field in each element array of the subarray The scattering field of each element antenna mode of the subarray calculated by the product method of the directivity pattern The simultaneous overdetermined equations are expressed as: Where mn is the number of subarray antenna elements, x is the number of sampling points, and C represents the mutual coupling correction matrix, which is a two-dimensional matrix of mn×mn, as shown below: in,[] -1 Represents the inverse matrix.

6. The method for obtaining and separating the scattered field of a large-scale array antenna according to claim 1, characterized in that: In step 4, the scattering field of the structural mode term of a single antenna unit is used by the pattern product method. The calculated scattered fields of each unit structure mode of the subarray It is expressed as follows: Scattering field of each unit structure mode of the subarray in bistatic mode Scattering field of each unit structure mode of the subarray in single-station mode Where j is the imaginary number symbol, is the scattered wave vector, is the incident wave vector, is the displacement of the ith antenna unit, expressed as follows: in, is the row spacing vector, is the column spacing vector.

7. The method for obtaining and separating the scattered field of a large-scale array antenna according to claim 1, characterized in that: The mutual coupling correction matrix C in step 4 is used to scatter the field of the structural mode term of a single antenna unit by the pattern product method The calculated scattered field of each unit structure mode of the subarray The matrix multiplication is expressed as follows: Among them, mn is the number of subarray antenna elements, x is the number of sampling points, and the scattering field of the structural mode term in each element array is It is expressed as follows: Where C(i,:) is the i-th row of the mutual coupling correction matrix.

8. The method for obtaining and separating the scattered field of a large-scale array antenna according to claim 1, characterized in that: The row displacement vector of the subarray in step 6 relative to the Ith row unit of the large-scale array antenna The acquisition method is as follows: (6a) The units from the 1st row to the (m-1) / 2th row of the subarray are equivalent to the units from the 1st row to the (m-1) / 2th row of the M-row n-column array, and the displacement vector of each row from the 1st row to the (m-1) / 2th row of the M-row n-column array is obtained as (6b) The units in the [(m-1) / 2]+1th row of the subarray are equivalent to the units in the [(m-1) / 2]+1th to the M-(m-1) / 2th rows of the M-row n-column array, and the displacement vectors of each row from the [(m-1) / 2]+1th to the M-(m-1) / 2th rows of the M-row n-column array are obtained as follows: in is the line spacing; (6c) The units from the [(m-1) / 2]+2th row to the mth row of the subarray are equivalent to the units from the M-(m-1) / 2+1th row to the Mth row of the M-row n-column array, and the displacement vector of each row from the M-(m-1) / 2+1th row to the Mth row of the M-row n-column array is obtained as follows: The column displacement vector of the subarray relative to the Jth column element of the large-scale array antenna The acquisition method is as follows: (6d) The units from the 1st column to the (n-1) / 2th column of the M-row n-column array are equivalent to the units from the 1st column to the (n-1) / 2th column of the M-row N-column array, and the displacement vector of each column from the 1st column to the (n-1) / 2th column of the M-row N-column array is obtained as (6e) The unit in the [(n-1) / 2]+1th column of the M-row n-column array is equivalent to the unit in the [(n-1) / 2]+1th column to the N-(n-1) / 2th column of the M-row N-column array, and the displacement vector of each column in the [(n-1) / 2]+1th column to the N-(n-1) / 2th column of the M-row N-column array is obtained as follows: in is the column spacing; (6f) The units from [(n-1) / 2]+2 to n in the M-row n-column array are equivalent to the units from N-(n-1) / 2+1 to N in the M-row N-column array, and the displacement vector of each column from N-(n-1) / 2+1 to N in the M-row N-column array is obtained as follows:

9. The method for obtaining and separating the scattered field of a large-scale array antenna according to claim 1, characterized in that: The specific method of step 7 is: The scattered field is calculated in bistatic mode Antenna mode term scattered field And the scattered field of the structural mode term The scattered field is calculated in single-station mode Antenna mode term scattered field And the scattered field of the structural mode term Where, the superscript s represents the scattered field, j is the imaginary number symbol, is the scattered wave vector, is the incident wave vector.

10. The method for obtaining and separating the scattered field of a large-scale array antenna according to claim 1, characterized in that: The specific method of step 8 is: The total scattered field is calculated in bistatic mode Total antenna mode term scattered field Total structural mode scattered field The total scattered field is calculated in single-station mode Total antenna mode term scattered field Total structural mode scattered field

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