Rapid modeling method for near-field radiation characteristics of electric scanning array

Abstract

The invention discloses a rapid modeling method for near-field radiation characteristics of an electric scanning array, and the method comprises the following steps: building a near-field radiation model of the electric scanning array through a superposition principle by using an analytical formula of an array element radiation field during wave beam scanning of the electric scanning array composed of array elements with an analytical solution in the radiation field; and during wave beam scanning of the electric scanning array formed by the array elements without the analytic solutions in the radiation field, constructing a near-field radiation model of the electric scanning array by superposing the active unit directional diagrams of the array elements. According to the method, the approximate calculation model of the near-field radiation characteristics of the electric scanning array is established by combining the array element radiation field analytic expression and the active unit directional diagram of the typical type of array elements with excitation phase regulation required by beam scanning, and the near-field radiation field intensity distribution of the electric scanning array at any beam scanning angle can be quickly obtained.

Description

Technical Field

[0001] The invention belongs to the field of electronic information, and relates to rapid modeling of radiation characteristics of an electronically scanned array, and in particular to a rapid modeling method of near-field radiation characteristics of an electronically scanned array. Background Art

[0002] The scanning of array antennas is divided into mechanical scanning and electronic scanning: mechanical scanning relies on mechanical devices to drive the antenna to rotate, and the scanning speed is often slow; electronic scanning relies on changing the parameters of the array antenna, and the scanning speed is fast. Therefore, electronic scanning arrays have been widely used in advanced platforms such as ships and satellites. However, increasingly complex functional requirements have led to the high-density integration of a large number of devices in a limited platform space, which has caused serious electromagnetic interference problems between electronic scanning arrays and adjacent devices; rapid modeling of near-field radiation characteristics of electronic scanning arrays is of great significance for solving electromagnetic interference problems between adjacent devices.

[0003] Taking the full-duplex phased array system with coplanar layout on a limited platform as an example, the far-field conditions are usually not met between the transmitting and transmitting scanning arrays, which causes the power received at different array element positions of the receiving array to consider the influence of the phase difference. At the same time, due to the dynamic beam scanning and high sidelobe level of the transmitting and transmitting scanning arrays, when the main beam of the transmitting array scans near the receiving array, the receiving array can receive a strong irradiated electromagnetic field, and the electromagnetic interference is particularly serious at this time. In the case of high-power transmission, this influence may further cause saturation or even damage and failure of the RF front-end components of the receiving system. Therefore, it is very necessary to quickly obtain the near-field radiation characteristics of the electronically scanned array.

[0004] To address the above issues, the commonly used method is to use full-wave simulation or actual measurement to select multiple typical scanning angles to obtain the radiation field strength in the near field area of ​​the electronically scanned array, so as to further evaluate the interference of the electronically scanned array to adjacent devices. However, full-wave simulation and actual measurement methods require a lot of time and computing resources, and cannot cover any beam scanning angle. Summary of the invention

[0005] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a rapid modeling method for the near-field radiation characteristics of an electronically scanned array, which can quickly obtain the radiation field strength level of the near-field area of ​​the phased array antenna at any beam scanning angle, thereby providing conditions for analyzing the interference situation of nearby sensitive equipment.

[0006] The object of the present invention is achieved through the following technical scheme: a rapid modeling method for near-field radiation characteristics of an electronically scanned array, comprising:

[0007] When an electronically scanned array composed of array elements with analytical solutions for the radiation field is scanned, the near-field radiation model of the electronically scanned array is established by using the analytical expression of the array element radiation field and the superposition principle, which specifically includes the following steps:

[0008] S101 gives the electronic scanning array parameters and the near-field point position to be calculated;

[0009] Assume that the electronic scanning array is a two-dimensional rectangular grid array distributed in the xoy plane with the origin as the geometric center. The electronic scanning array parameters include the array operating frequency f, the number of array elements M and N distributed along the x-axis and y-axis, and the array element spacing d along the x-axis and y-axis. x and d y , the position coordinates of each array element located in the xoy plane (x mn ,y mn ,z mn );

[0010] According to the criteria for field area division, the near field area of ​​the array meets the following ranges:

[0011]

[0012] Where λ is the wavelength, and D is the maximum size of the array aperture. For the two-dimensional matrix grid array, the maximum size D of the array aperture is approximately calculated using the following formula:

[0013]

[0014] The near-field point position coordinates (x, y, z) to be calculated are determined according to the near-field area of ​​the array. Specifically, the distance from the point position coordinates (x, y, z) to the center of the array (0, 0, 0) is required. Satisfy the array near field range, and arbitrarily select the near field point position to be calculated when this condition is met, and convert it into spherical coordinates

[0015] S102 obtains an analytical expression of the array element radiation field and makes a far-zone approximation;

[0016] The general representation of the complex vector of the array element radiation field is: in are r,θ, The unit vector in the direction, are the array element at r,θ, The analytical expressions of the complex components of the radiated electric field in the direction are related to the selected array element form.

[0017] Usually, the near field range of the array satisfies the far field condition of a single unit, that is, the near field of the array is located in the far area of ​​each radiating unit (kr>>1). For the area of ​​each radiating unit kr>>1,

[0018] (kr) -1 >>(kr) -2 >>(kr)-3

[0019] Therefore, the analytical expression of the element radiation field can be further approximated in the far zone by taking only the terms related to kr and ignoring the high-order terms of kr.

[0020] S103 defines the beam scanning angle and calculates the corresponding complex excitation of each array element;

[0021] Assume that the beam scanning angle is the elevation angle and azimuth angle of the beam pointing The electronic scanning array achieves the purpose of controlling beam scanning by adjusting the phase or time delay of each array element. The corresponding complex excitation of each array element is expressed as

[0022] Although the pattern product theorem is not applicable to near-field calculations, the excitation phase for controlling the beam pointing still satisfies the conclusion derived from the array factor under the far-field approximation. When the beam scanning angle is defined as When the phase α of the mnth array element in the complex excitation is mn Should meet:

[0023]

[0024] Where x mn ,y mn are the position coordinates of the mnth array element respectively.

[0025] At the same time, let the excitation amplitude A of the mnth array element be mn =1, then the corresponding complex excitation of each array element is specifically

[0026]

[0027] S104 Calculation of near-field radiation characteristics of an electronically scanned array beam scanned by array elements with analytical solutions for the radiation field;

[0028] The near-field radiation characteristic is the total radiation electric field of the array, the field point For an electronically scanned array composed of array elements with analytical solutions for the radiation field at the position, its total radiation electric field is calculated by superimposing the far-field radiation electric fields of each array element during beam scanning. At this time, the general form of the near-field radiation characteristics is as follows:

[0029]

[0030] Where M and N are the number of array elements distributed along the x-axis and y-axis respectively, r mn ,θ mn , Field points The distance, elevation and azimuth relative to the mnth array element, are the mnth array elements at r,θ, The near-field radiation model calculates the total near-field radiation electric field of the array at any beam scanning angle based on the above general form.

[0031] When the electronically scanned array composed of array elements whose radiation field does not have an analytical solution is scanned, a more practical situation is further considered, that is, most array elements do not have an analytical solution for the radiation field. At this time, the near-field radiation model of the electronically scanned array is realized by superimposing the active unit radiation pattern of each array element, which specifically includes the following steps:

[0032] S201. According to step S101, the electronic scanning array parameters are given, and the maximum size of the array aperture and the range of the near field area are calculated, so as to determine the position of the near field point to be calculated;

[0033] S202 reads the active unit pattern of each array element calculated by full-wave simulation;

[0034] The reading of the active unit pattern of each array element calculated by full-wave simulation includes: when m=1, 2, ..., M; n=1, 2, ..., N, for the mnth array element, establishing an actual array model in the full-wave simulation software, only unit excitation of the mnth array element, and setting matching loads for other array elements, simulating and deriving the far-field radiation pattern of the entire array space, that is, obtaining the mnth array element in different positions in the entire space. The data table of active unit directivity diagram corresponding to the angle;

[0035] At this time, the radiation field of the mnth array element is expressed as

[0036]

[0037] Where r mn ,θ mn , Field points The distance, elevation and azimuth relative to the mnth array element, is the complex excitation of the mnth array element, The active unit pattern data of the mnth array element exported by the full-wave simulation software;

[0038] In actual calculation, the pitch and azimuth angles θ of the proposed calculation point relative to the mnth array element are obtained by looking up the table. mn , The corresponding active unit pattern data, for the elevation angle and azimuth angle that cannot be completely matched, obtain the approximate data of the active unit pattern at the corresponding angle through linear interpolation;

[0039] According to the environment where the array element is located, the four adjacent units above, below, left and right of the array element are considered to classify each array element, and the following nine typical categories of array elements are obtained:

[0040] The first type: the current array element has adjacent array elements only to the right and below;

[0041] The second type is that the current array element has adjacent array elements only above, to the right, and below;

[0042] The third type is that the current array element has adjacent array elements only above and to the right;

[0043] The fourth category: the current array element has adjacent array elements only to the left, right and bottom;

[0044] The fifth category: the current array element has adjacent array elements on the left, right, above and below;

[0045] The sixth category: the current array element has adjacent array elements only to the left, right and above;

[0046] The seventh category: the current array element has adjacent array elements only to the left and below;

[0047] The eighth category: the current array element has adjacent array elements only above, to the left and below;

[0048] The ninth category: the current array element has adjacent array elements only to the left and above;

[0049] For each typical type of array element, only the active unit directional pattern of any array element in the category is selected to replace the directional pattern of the same type of array element, so as to improve the calculation efficiency.

[0050] S203 defines the beam scanning angle according to step S103 and calculates the corresponding complex excitation of each array element;

[0051] S204 Calculation of near-field radiation characteristics of an electronically scanned array beam scanned by array elements whose radiation field does not have an analytical solution;

[0052] The radiation field does not have an electronically scanned array composed of array elements with an analytical solution. When the beam is scanned, the field point The near-field radiation characteristics (electric field) at the position can be expressed as follows:

[0053]

[0054] Where M and N are the number of array elements distributed along the x-axis and y-axis respectively, r mn ,θ mn , Field points The distance, elevation and azimuth relative to the mnth array element, is the mnth array element at θ mn , The active unit directional pattern value in the direction.

[0055] The beneficial effects of the present invention are as follows: the present invention establishes an approximate calculation model for the near-field radiation characteristics of an electronically scanned array through the analytical expression of the array element radiation field and the active unit radiation pattern of a typical category of array elements combined with the excitation phase control required for beam scanning, and can quickly obtain the near-field radiation field strength distribution of the electronically scanned array at any beam scanning angle. Compared with the prior art, the present invention saves the time and resource consumption required for calculation and improves the efficiency of evaluating the interference situation of nearby equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 is a flow chart of the method of the present invention;

[0057] Figure 2 It is a schematic diagram of the radiation field distribution in the near field region defined when the beam of the 8×8 electric scanning array composed of electric basic oscillators calculated by the model of the present invention in the embodiment is scanned to (40°, 40°);

[0058] Figure 3 To calculate using the full-wave simulation software Feko Figure 2 Schematic diagram of the radiation field distribution in the near field area under the same scenario;

[0059] Figure 4 A schematic diagram of a Vivaldi array element structure in which the radiation field of the present invention does not have an analytical solution in an embodiment;

[0060] Figure 5 A schematic diagram of the classification of typical types of array elements described in the present invention in an embodiment;

[0061] Figure 6 It is a schematic diagram comparing the radiation field of the semicircular near field area defined by the 4×3 electronically scanned array composed of Vivaldi array elements calculated by the model of the present invention in the embodiment when the beam is scanned to (10°, 30°) and the calculation result of the full-wave simulation software Feko;

[0062] Figure 7 It is a schematic diagram comparing the radiation field of the semicircular near field area defined by the 4×3 electronically scanned array composed of Vivaldi array elements calculated by the model of the present invention in the embodiment when the beam is scanned to (-20°, -50°) and the calculation result of the full-wave simulation software Feko; DETAILED DESCRIPTION

[0063] The technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings, but the protection scope of the present invention is not limited to the following.

[0064] The present invention proposes a rapid modeling method for the near-field radiation characteristics of an electronically scanned array, including a near-field radiation characteristic model of an electronically scanned array beam scanned by two types of array elements, one with an analytical solution and the other without an analytical solution. The specific steps are as follows: Figure 1 shown.

[0065] For an electronically scanned array composed of array elements having an analytical solution for the radiation field, the near-field radiation characteristics calculation during beam scanning specifically includes the following steps:

[0066] S101 gives the electronic scanning array parameters and the near-field point position to be calculated;

[0067] In the embodiment of the present application, the operating frequency f of the two-dimensional rectangular grid electronic scanning array distributed in the xoy plane with the origin as the geometric center is 10 GHz, the number of array elements distributed along the x-axis and the y-axis is M=N=8, and the array element spacing d x =d y =λ2=0.015, m is the position coordinate x of each element in the xoy plane mn ,y mn (Unit: m) are shown in the following table, z mn =0m:

[0068] <![CDATA[x mn ]]> m＝1 m＝2 m＝3 m＝4 m＝5 m＝6 m＝7 m＝8 n＝1 -0.0525 -0.0375 -0.0225 -0.0075 0.0075 0.0225 0.0375 0.0525 n＝2 -0.0525 -0.0375 -0.0225 -0.0075 0.0075 0.0225 0.0375 0.0525 n＝3 -0.0525 -0.0375 -0.0225 -0.0075 0.0075 0.0225 0.0375 0.0525 n＝4 -0.0525 -0.0375 -0.0225 -0.0075 0.0075 0.0225 0.0375 0.0525 n＝5 -0.0525 -0.0375 -0.0225 -0.0075 0.0075 0.0225 0.0375 0.0525 n＝6 -0.0525 -0.0375 -0.0225 -0.0075 0.0075 0.0225 0.0375 0.0525 n＝7 -0.0525 -0.0375 -0.0225 -0.0075 0.0075 0.0225 0.0375 0.0525 n＝8 -0.0525 -0.0375 -0.0225 -0.0075 0.0075 0.0225 0.0375 0.0525

[0069] <![CDATA[y mn ]]> m＝1 m＝2 m＝3 m＝4 m＝5 m＝6 m＝7 m＝8 n＝1 -0.0525 -0.0525 -0.0525 -0.0525 -0.0525 -0.0525 -0.0525 -0.0525 n＝2 -0.0375 -0.0375 -0.0375 -0.0375 -0.0375 -0.0375 -0.0375 -0.0375 n＝3 -0.0225 -0.0225 -0.0225 -0.0225 -0.0225 -0.0225 -0.0225 -0.0225 n＝4 -0.0075 -0.0075 -0.0075 -0.0075 -0.0075 -0.0075 -0.0075 -0.0075 n＝5 0.0075 0.0075 0.0075 0.0075 0.0075 0.0075 0.0075 0.0075 n＝6 0.0225 0.0225 0.0225 0.0225 0.0225 0.0225 0.0225 0.0225 n＝7 0.0375 0.0375 0.0375 0.0375 0.0375 0.0375 0.0375 0.0375 n＝8 0.0525 0.0525 0.0525 0.0525 0.0525 0.0525 0.0525 0.0525

[0070] According to the criteria for field area division, the near field area of ​​the electronic scanning array described in this embodiment meets the following range:

[0071]

[0072] The maximum size of the array aperture Wavelength λ=0.03m.

[0073] In this embodiment, the near field to be calculated is determined according to the range of the near field area of ​​the array as a rectangular area on the xoy plane. The coordinates of the four vertices of the rectangular area are shown in the following table:

[0074] x(unit: m) y(unit: m) z(unit:m) Vertex 1 0.5525 0.0525 0 Vertex 2 0.6575 0.0525 0 Vertex 3 0.6575 -0.0525 0 Vertex 4 0.5525 -0.0525 0

[0075] S102 obtains an analytical expression of the array element radiation field and makes a far-zone approximation;

[0076] In this embodiment, the electric basic oscillator is selected as the array element, and the analytical expression of the complex vector of the radiation field is as follows:

[0077]

[0078]

[0079]

[0080] The length of the electric basic oscillator ds is 0.003m. is the complex excitation current of the array element (for specific values, see step S103 in this embodiment), the wave number k is 2π / λ, and the free space wave impedance η is 120π.

[0081] Further, the analytical expression of the radiation field of the electric basic oscillator is approximated in the far zone. At this time, in the far zone, kr>100>>1, and only the terms related to kr are taken in the formula, and the high-order terms of kr are ignored. The analytical expression of the complex vector of the radiation field can be simplified to:

[0082]

[0083] S103 defines the beam scanning angle and calculates the corresponding complex excitation of each array element;

[0084] In this embodiment, the beam scanning angle has an elevation angle θ0=40° and an azimuth angle The corresponding complex excitation of each electric basic array unit The excitation amplitude of each array element is 1A, and the excitation phase satisfies the following formula

[0085] α mn =-k(x mn sin40°cos40°+y mn sin40°sin40°)

[0086] The excitation phase of each array element α mn (Unit: °) The values ​​are shown in the following table:

[0087] <![CDATA[α mn ]]> m＝1 m＝2 m＝3 m＝4 m＝5 m＝6 m＝7 m＝8 n＝1 570.52 481.88 393.25 304.62 215.98 127.35 38.72 -49.91 n＝2 496.14 407.51 318.88 230.25 141.61 52.98 -35.65 -124.29 n＝3 421.77 333.14 244.51 155.87 67.24 -21.39 -110.02 -198.66 n＝4 347.40 258.77 170.13 81.50 -7.13 -95.76 -184.40 -273.03 n＝5 273.03 184.40 95.76 7.13 -81.50 -170.13 -258.77 -347.40 n＝6 198.66 110.02 21.39 -67.24 -155.87 -244.51 -333.14 -421.77 n＝7 124.29 35.65 -52.98 -141.61 -230.25 -318.88 -407.51 -496.14 n＝8 49.91 -38.72 -127.35 -215.98 -304.62 -393.25 -481.88 -570.52

[0088] S104 Calculation of near-field radiation characteristics of an electronically scanned array beam scanned by array elements with analytical solutions for the radiation field;

[0089] Site At the position, the radiation field has an 8×8 electronically scanned array composed of electric basic oscillator array elements with analytical solutions. Its near-field total radiation electric field during beam scanning can be calculated by superimposing the far-field radiation fields of each array element:

[0090]

[0091] The radiation field of this embodiment has an 8×8 array composed of electric basic oscillators with analytical solutions as array elements. When the beam defined in step S103 is scanned to (40°, 40°), the total radiation electric field distribution result of the near-field rectangular area determined by the four vertices in step S101 is calculated by the model in step S104. Figure 2In order to verify the accuracy of the model, Figure 3 The radiation field distribution results of the same area calculated by the full-wave simulation software Feko are given for comparison.

[0092] For an electronically scanned array composed of array elements whose radiation field does not have an analytical solution, the near-field radiation characteristics calculation during beam scanning specifically includes the following steps:

[0093] S201 gives the electronic scanning array parameters and the near-field point position to be calculated;

[0094] In the embodiment of the present application, the operating frequency f of the two-dimensional rectangular grid electronic scanning array distributed in the xoy plane with the origin as the geometric center is 2 GHz, the number of array elements distributed along the x-axis and y-axis is M=4, N=3, and the array element spacing d x =d y =0.082m, the position coordinates of each array element in the xoy plane are x mn ,y mn (Unit: m) are shown in the following table, z mn =0m:

[0095] <![CDATA[x mn ]]> m＝1 m＝2 m＝3 m＝4 n＝1 -0.1230 -0.0410 0.0410 0.1230 n＝2 -0.1230 -0.0410 0.0410 0.1230 n＝3 -0.1230 -0.0410 0.0410 0.1230

[0096] <![CDATA[y mn ]]> m＝1 m＝2 m＝3 m＝4 n＝1 -0.0820 -0.0820 -0.0820 -0.0820 n＝2 0.0000 0.0000 0.0000 0.0000 n＝3 0.0820 0.0820 0.0820 0.0820

[0097] According to the criteria for field area division, the near field area of ​​the electronic scanning array described in this embodiment meets the following range:

[0098]

[0099] The maximum size of the array aperture Wavelength λ≈0.15m.

[0100] In this embodiment, the near field to be calculated is determined according to the near field area range of the array. The near field to be calculated is a semicircular arc area with a fixed radius centered at the origin above the xoy plane. The position coordinates of the near field points to be calculated in the area are shown in the following table:

[0101]

[0102]

[0103] S202 reads the active unit pattern of each array element calculated by full-wave simulation;

[0104] In this embodiment, a Vivaldi antenna is selected as an array element. The array element structure is as follows: Figure 4As shown, the active element pattern (AEP) of the Vivaldi array element is derived from the full-wave simulation software, and the radiation field of the mn-th array element can be further expressed as

[0105]

[0106] When the array scale is large, each array element can be classified according to the environment in which the array element is located, and only the active unit directional pattern of the typical type of array element is derived to replace the directional pattern of the same type of array element in the subsequent calculation formula to improve the calculation efficiency. In the embodiment of the present application, according to the environment in which the array element is located, the four units adjacent to the upper, lower, left and right of the array element are considered to classify each array element, and the following nine typical types of array elements are obtained, such as Figure 5 As shown (gray is the current array element):

[0107] The first type: the current array element has adjacent array elements only to the right and below;

[0108] The second type is that the current array element has adjacent array elements only above, to the right, and below;

[0109] The third type is that the current array element has adjacent array elements only above and to the right;

[0110] The fourth category: the current array element has adjacent array elements only to the left, right and bottom;

[0111] The fifth category: the current array element has adjacent array elements on the left, right, above and below;

[0112] The sixth category: the current array element has adjacent array elements only to the left, right and above;

[0113] The seventh category: the current array element has adjacent array elements only to the left and below;

[0114] The eighth category: the current array element has adjacent array elements only above, to the left and below;

[0115] The ninth category: the current array element has adjacent array elements only to the left and above;

[0116] For each typical type of array element, only the active unit directional pattern of any array element in the category is selected to replace the directional pattern of the same type of array element.

[0117] In the embodiment of the present application, the full-wave simulation software uses Feko, and similar software includes HFSS, CST, etc. The Feko software completes the full-wave simulation calculation by implementing the moment method. Specifically, the voltage source port excitation is added only to the mnth array element of the array model, and a 50-ohm matching load is added to the remaining ports. The far-field radiation pattern of the array at this time is calculated and derived, that is, the active unit pattern data of the unit here, which characterizes the radiation characteristics of the array element in the array environment, and the coupling effect of the surrounding units on the array element is considered at this time.

[0118] S203 defines the beam scanning angle and calculates the corresponding complex excitation of each array element;

[0119] In this embodiment, as in step S201, r=0.5m, The beam scanning angle corresponding to the determined near-field calculation area is the elevation angle θ0=10° and the azimuth angle The corresponding complex excitation of each Vivaldi unit The excitation amplitude of each array element is 1A, and the excitation phase satisfies the following formula

[0120] α mn =-k(x mn sin10°cos30°+y mn sin10°sin30°)

[0121] The excitation phase of each array element α mn (Unit: °) The values ​​are shown in the following table:

[0122] <![CDATA[α mn ]]> m＝1 m＝2 m＝3 m＝4 n＝1 61.52 31.91 2.29 -27.33 n＝2 44.42 14.81 -14.81 -44.42 n＝3 27.33 -2.29 -31.91 -61.52

[0123] In this embodiment, as in step S201, r=1.1m, The beam scanning angle corresponding to the determined near-field calculation area is the elevation angle θ0=-20° and the azimuth angle The corresponding complex excitation of each Vivaldi unit The excitation amplitude of each array element is 1A, and the excitation phase satisfies the following formula

[0124] α mn =-k(x mn sin-20°cos-50°+y mn sin-20°sin-50°)

[0125] The excitation phase of each array element α mn (Unit: °) The values ​​are shown in the following table:

[0126] <![CDATA[α mn ]]> m＝1 m＝2 m＝3 m＝4 n＝1 -13.35 29.95 73.25 116.54 n＝2 -64.94 -21.65 21.65 64.94 n＝3 -116.54 -73.25 -29.95 13.35

[0127] S204 Calculation of near-field radiation characteristics of an electronically scanned array beam scanned by array elements whose radiation field does not have an analytical solution;

[0128] Site At the position, the radiation field does not have an analytical solution for the 4×3 electronically scanned array composed of Vivaldi array elements. Its near-field total radiation characteristics (electric field) during beam scanning can be expressed as follows:

[0129]

[0130] The radiation field of this embodiment does not have a 4×3 array of Vivaldi array elements with an analytical solution. The beams defined in step S203 are scanned to (10°, 30°) and (-20°, -50°), which correspond to r=0.5m in step S201, respectively. and r = 1.1m, The radiation field distribution results of the electronically scanned array in the near field region to be calculated are respectively shown in Figure 6 , Figure 7 In order to verify the accuracy of the model, Figure 6 and Figure 7 The radiation field distribution results of the same area calculated by the full-wave simulation software Feko are also given (represented by the solid line) for comparison.

[0131] The above description shows and describes a number of preferred embodiments of the present invention and does not limit the present invention in any form. However, as mentioned above, it should be understood that the present invention is not limited to the form disclosed herein and should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be modified within the scope of the inventive concept described herein through the above teachings or the technology or knowledge of the relevant field.

[0132] Any technician familiar with the art, without departing from the scope of the technical solution of the present invention, can make more possible changes and modifications to the technical solution of the present invention using the technical content disclosed above, or the modifications are all equivalent embodiments of the present invention. Therefore, all equivalent and equivalent changes made according to the ideas of the present invention without departing from the content of the technical solution of the present invention should be included in the protection scope of the present invention.

Claims

1. A rapid modeling method for near-field radiation characteristics of an electronically scanned array, characterized by: The following steps are involved: When the electronically scanned array composed of array elements with analytical solutions for radiation fields is scanned, the near-field radiation model of the electronically scanned array is established by using the analytical expression of the radiation field of the array elements and the superposition principle; When an electronically scanned array composed of array elements whose radiation field does not have an analytical solution is scanned, a near-field radiation model of the electronically scanned array is constructed by superimposing the active unit radiation patterns of each array element.

2. The rapid modeling method for near-field radiation characteristics of an electronically scanned array according to claim 1, characterized in that: When the radiation field is scanned by an electronically scanned array beam composed of array elements having an analytical solution, the process of establishing the near-field radiation characteristic model includes: S101. Given the electronic scanning array parameters and the near-field point position to be calculated; S102. Obtain an analytical expression of the array element radiation field and make a far-zone approximation; S103. Define the beam scanning angle and calculate the corresponding complex excitation of each array element; S104. Calculation of near-field radiation characteristics of an electronically scanned array composed of array elements with analytical solutions for the radiation field during beam scanning.

3. The rapid modeling method for near-field radiation characteristics of an electronically scanned array according to claim 2, characterized in that: The step S101 includes: Assume that the electronic scanning array is a two-dimensional rectangular grid array distributed in the xoy plane with the origin as the geometric center. The electronic scanning array parameters include the array operating frequency f, the number of array elements M and N distributed along the x-axis and y-axis, and the array element spacing d along the x-axis and y-axis. x and d y , the position coordinates of each array element located in the xoy plane (x mn ,y mn ,z mn ); According to the criteria for field area division, the near field area of ​​the array meets the following ranges: Where λ is the wavelength, and D is the maximum size of the array aperture. For the two-dimensional matrix grid array, the maximum size D of the array aperture is approximately calculated using the following formula: The near-field point position coordinates (x, y, z) to be calculated are determined according to the near-field area of ​​the array. Specifically, the distance from the point position coordinates (x, y, z) to the center of the array (0, 0, 0) is required. Satisfy the array near field range, and arbitrarily select the near field point position to be calculated under this condition, and convert it into spherical coordinates 4. The rapid modeling method for near-field radiation characteristics of an electronically scanned array according to claim 2, characterized in that: The step S102 includes: The general representation of the complex vector of the array element radiation field is: in In the spherical coordinate system The unit vector in the direction, are respectively The complex component of the radiated electric field in the direction; The near field range of the array meets the far field condition of a single unit, that is, the near field of the array is located in the far zone of each radiating unit: kr>>1. For the area of ​​each radiating unit kr>>1, we have: (kr) -1 >>(kr) -2 >>(kr) -3 The far-field approximation is made for the analytical expression of the radiation field of the array element, and only the terms related to kr are taken, and the high-order terms of kr are ignored.

5. The rapid modeling method for near-field radiation characteristics of an electronically scanned array according to claim 2, characterized in that: The step S103 includes: Assume that the beam scanning angle is the elevation angle and azimuth angle of the beam pointing The electronic scanning array achieves the purpose of controlling beam scanning by adjusting the phase or time delay of each array element. The corresponding complex excitation of each array element is expressed as When the beam scanning angle is defined as When the phase α of the mnth array element in the complex excitation is mn Should meet: Where x mn ,y mn are the position coordinates of the mnth array element respectively. At the same time, let the excitation amplitude A of the mnth array element be mn =1, then the corresponding complex excitation of each array element is specifically 6. The rapid modeling method for near-field radiation characteristics of an electronically scanned array according to claim 2, characterized in that: The step S104 includes: The near-field radiation characteristic is the total radiation electric field of the array, the field point For an electronically scanned array composed of array elements with analytical solutions for the radiation field at the position, its total radiation electric field is calculated by superimposing the far-field radiation electric fields of each array element during beam scanning. At this time, the general form of the near-field radiation characteristics is as follows: Where M and N are the number of array elements distributed along the x-axis and y-axis respectively. Field points The distance, elevation and azimuth relative to the mnth array element, The mnth array element is The near-field radiation model calculates the total near-field radiation electric field of the array at any beam scanning angle based on the above general form.

7. The rapid modeling method for near-field radiation characteristics of an electronically scanned array according to claim 3, characterized in that: When the electronically scanned array beam is scanned by array elements whose radiation field does not have an analytical solution, the process of establishing the near-field radiation characteristic model includes: S201. According to step S101, the electronic scanning array parameters are given, and the maximum size of the array aperture and the range of the near field area are calculated, so as to determine the position of the near field point to be calculated; S202. Read the active unit pattern of each array element calculated by full-wave simulation; S203. Define the beam scanning angle according to step S103 and calculate the corresponding complex excitation of each array element; S204. Calculation of near-field radiation characteristics of an electronically scanned array composed of array elements whose radiation field does not have an analytical solution during beam scanning.

8. The method for rapid modeling of near-field radiation characteristics of an electronically scanned array according to claim 7, characterized in that: The step S202 includes: The reading of the active unit pattern of each array element calculated by full-wave simulation includes: when m=1, 2, ..., M; n=1, 2, ..., N, for the mnth array element, establishing an actual array model in the full-wave simulation software, only unit excitation of the mnth array element, and setting matching loads for other array elements, simulating and deriving the far-field radiation pattern of the entire array space, that is, obtaining the mnth array element in different positions in the entire space. The data table of active unit directivity diagram corresponding to the angle; At this time, the radiation field of the mnth array element is expressed as In the formula Field points The distance, elevation and azimuth relative to the mnth array element, is the complex excitation of the mnth array element, The active unit pattern data of the mnth array element exported by the full-wave simulation software; In actual calculation, the pitch and azimuth angles of the proposed calculation point relative to the mnth array element are obtained by looking up the table. The corresponding active unit pattern data, for the elevation angle and azimuth angle that cannot be completely matched, obtain the approximate data of the active unit pattern at the corresponding angle through linear interpolation; According to the environment where the array element is located, the four adjacent units above, below, left and right of the array element are considered to classify each array element, and the following nine typical categories of array elements are obtained: The first type: the current array element has adjacent array elements only to the right and below; The second type is that the current array element has adjacent array elements only above, to the right, and below; The third type is that the current array element has adjacent array elements only above and to the right; The fourth category: the current array element has adjacent array elements only to the left, right and bottom; The fifth category: the current array element has adjacent array elements on the left, right, above and below; The sixth category: the current array element has adjacent array elements only to the left, right and above; The seventh category: the current array element has adjacent array elements only to the left and below; The eighth category: the current array element has adjacent array elements only above, to the left and below; The ninth category: the current array element has adjacent array elements only to the left and above; For each typical type of array element, only the active unit directional pattern of any array element in the category is selected to replace the directional pattern of the same type of array element.

9. The method for rapid modeling of near-field radiation characteristics of an electronically scanned array according to claim 7, characterized in that: The step S204 includes: The radiation field does not have an electronically scanned array composed of array elements with an analytical solution. When the beam is scanned, the field point The near-field radiated electric field at position is expressed as follows: Where M and N are the number of array elements distributed along the x-axis and y-axis respectively. Field points The distance, elevation and azimuth relative to the mnth array element, For the mnth array element The near-field radiation model calculates the total near-field radiation electric field of the array at any beam scanning angle based on the above general form.

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