A fast modeling method for near-field radiation characteristics of an electrically scanned array

Abstract

The application discloses a kind of fast modeling methods of electric scanning array near-field radiation characteristics, comprising the following steps: when the beam scanning of the element of the radiation field having analytical solution is formed into electric scanning array, the analytical formula of the element of the radiation field is used, and the near-field radiation model of electric scanning array is established by superposition principle;When the beam scanning of the element of the radiation field not having analytical solution is formed into electric scanning array, the near-field radiation model of electric scanning array is constructed by superimposing the active element directional diagram of each element.The application establishes the approximate calculation model of electric scanning array near-field radiation characteristics by the analytical formula of the element of the radiation field and the active element directional diagram of typical category element in combination with the excitation phase control required by beam scanning, and the near-field radiation field intensity distribution of electric scanning array under any beam scanning angle can be quickly obtained.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of electronic information, and relates to fast modeling of radiation characteristics of an electrically scanned array, in particular to a fast modeling method of near-field radiation characteristics of an electrically scanned array. BACKGROUND

[0002] The scanning of an array antenna is divided into mechanical scanning and electric scanning: the mechanical scanning is driven by a mechanical device to rotate the antenna, and is often slow in scanning speed; the electric scanning relies on changing the parameters of the array antenna, and is fast in scanning speed, so that the electrically scanned array is widely applied to advanced platforms such as ships and satellites. However, increasingly complex functional requirements cause a large number of devices to be integrated in a high density on a limited platform, thereby causing serious electromagnetic interference between the electrically scanned array and the adjacent devices; the fast modeling of the near-field radiation characteristics of the electrically scanned array has great significance for solving the electromagnetic interference problem between the adjacent devices.

[0003] Taking a full-duplex phased array system with a coplanar layout on a limited platform as an example, the transmit and receive electrically scanned arrays usually do not satisfy the far-field condition, so that the power received by the receiving array at different array element positions needs to consider the influence of the phase difference. Meanwhile, due to the influences of the dynamic beam scanning of the transmit and receive electrically scanned arrays and the high sidelobe level, when the main beam of the transmit array scans to the vicinity of the receiving array, the receiving array can receive a relatively strong irradiation electromagnetic field, and at this time, the electromagnetic interference is particularly serious. In the case of high-power transmission, this influence may further cause the saturation and even damage and failure of the radio frequency front-end devices of the receiving system. Therefore, it is necessary to quickly obtain the near-field radiation characteristics of the electrically scanned array.

[0004] In view of the above problems, the current commonly used method is to select multiple typical scanning angles to obtain the near-field region radiation field intensity of the electrically scanned array through full-wave simulation or actual measurement, so as to further evaluate the interference of the electrically scanned array on the adjacent devices. However, the full-wave simulation and actual measurement method needs to consume a large amount of time and computing resources, and cannot cover any beam scanning angle. SUMMARY

[0005] The purpose of the present application is to overcome the deficiencies of the prior art, and to provide a fast modeling method of near-field radiation characteristics of an electrically scanned array, which can quickly obtain the radiation field intensity level of a phased array antenna in the near-field region at any beam scanning angle, and provides conditions for analyzing the disturbed situation of the adjacent sensitive devices.

[0006] The purpose of the present application is achieved by the following technical scheme: a fast modeling method of near-field radiation characteristics of an electrically scanned array, comprising:

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

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

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

[0010] According to the criteria for field region division, the near-field region of the array satisfies the following range:

[0011]

[0012] where λ is the wavelength and D is the maximum size of the array aperture; for the two-dimensional matrix lattice array, the maximum size D of the array aperture is approximately calculated as follows:

[0013]

[0014] The near-field field point position coordinates (x, y, z) to be calculated are determined according to the range of the near-field region of the array, and specifically, the distance of the field point position coordinates (x, y, z) to the center (0, 0, 0) of the array satisfies the range of the near-field region of the array, and the near-field field point position to be calculated is arbitrarily selected under the condition of satisfying this condition and is converted into spherical coordinates

[0015] S102 Obtain the analytical expression of the element radiation field and make a far-zone approximation;

[0016] The general form of the complex vector of the element radiation field is: where are the unit vectors in the r, θ, directions in the spherical coordinate system, are the complex components of the radiation electric field of the element in the r, θ, directions, and the analytical expressions of the complex components of the electric field are related to the selected element form.

[0017] Generally, the near-field range of the array satisfies the far-field condition of a single element, i.e., the near-field of the array is in the far zone (kr>>1) of each radiation element, and for the region where kr>>1 for each radiation element,

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

[0019] Therefore, the far-field approximation can be made to the array element radiation field analytical expression, only taking the terms related to kr, and ignoring the high-order terms of kr.

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

[0021] Suppose the beam scanning angle is the elevation angle and azimuth angle of the beam pointing The electric scanning array adjusts the phase or time delay of each array element to achieve the purpose of controlling beam scanning, and the corresponding complex excitation of each array element is represented as

[0022] Although the pattern multiplication theorem is not applicable to near-field calculation, the excitation phase that controls the beam pointing still satisfies the conclusion derived from the array factor under the far-field approximation condition, when the beam scanning angle is defined as The phase α mn of the mth array element in the complex excitation should satisfy:

[0023]

[0024] In the formula, x mn , y mn are the position coordinates of the mth array element.

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

[0026]

[0027] S104 calculation of the near-field radiation characteristics of the electric scanning array composed of array elements with analytical solution of the radiation field when the beam is scanned;

[0028] The near-field radiation characteristics are the total radiation electric field of the array, and the field point The electric scanning array composed of array elements with analytical solution of the radiation field, when the beam is scanned, its total radiation electric field is calculated by superimposing the far-field radiation electric field of each array element, 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 , are the distance, elevation angle and azimuth angle of the field point relative to the mth array element, respectively the radiation field component of the mn-th element in r, θ, direction; the near-field radiation model is the near-field total radiation field of the array at any beam scanning angle based on the above general form

[0031] The electrically scanned array composed of elements with no analytical solution of the radiation field, further considers the more practical case that most elements do not have an analytical solution of the radiation field, at this time the near-field radiation model of the electrically scanned array is realized by superimposing the active element pattern of each element, which specifically includes the following steps:

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

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

[0034] The reading of the active element pattern of each element calculated by full-wave simulation includes: when m = 1, 2, …, M; n = 1, 2, …, N, for the mn-th element, an actual array model is established in the full-wave simulation software, and the far-field radiation pattern of the array in the full space is simulated and exported under the condition that only the mn-th element is excited and the other elements are set to matched loads, that is, the corresponding active element pattern data table of the mn-th element at different angles in the full space is obtained;

[0035] At this time, the radiation field of the mn-th element is represented as

[0036]

[0037] In the formula, r mn , θ mn , respectively the distance, the pitch angle and the azimuth angle of the field point relative to the mn-th element, is the complex excitation of the mn-th element, is the active element pattern data of the mn-th element exported by the full-wave simulation software;

[0038] In actual calculation, the pitch and azimuth angles θ mn of the field point to be calculated relative to the mn-th element are obtained by table lookup, and the corresponding active element pattern data is obtained; For the pitch angle and the azimuth angle that cannot be completely matched, the approximate data of the active element pattern at the corresponding angle is obtained by linear interpolation;

[0039] According to the environment where the array element is located, the four elements adjacent to the array element in the up, down, left and right directions are considered to classify the array elements, and the following nine typical categories of array elements are obtained:

[0040] The first category is that the current array element only has adjacent elements in the right and down directions.

[0041] The second category is that the current array element only has adjacent elements in the up, right and down directions.

[0042] The third category is that the current array element only has adjacent elements in the up and right directions.

[0043] The fourth category is that the current array element only has adjacent elements in the left, right and down directions.

[0044] The fifth category is that the current array element has adjacent elements in the left, right, up and down directions.

[0045] The sixth category is that the current array element only has adjacent elements in the left, right and up directions.

[0046] The seventh category is that the current array element only has adjacent elements in the left and down directions.

[0047] The eighth category is that the current array element only has adjacent elements in the up, left and down directions.

[0048] The ninth category is that the current array element only has adjacent elements in the left and up directions.

[0049] For each typical category of array elements, only the active element pattern of an arbitrary array element in the category is selected to replace the patterns of the array elements in the same category, thereby improving the calculation efficiency.

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

[0051] S204 calculates the near-field radiation characteristics of the electrically scanned array formed by the array elements whose radiation fields do not have analytical solutions when the array is beam scanned.

[0052] The near-field radiation characteristics (electric field) of the electrically scanned array formed by the array elements whose radiation fields do not have analytical solutions at the field point when the array is beam scanned can be expressed as follows:

[0053]

[0054] where M and N are the numbers of array elements distributed along the x-axis and y-axis respectively, r mn ,θ mn , are the distance, pitch angle and azimuth angle of the field point relative to the mnth array element, is the value of the active element pattern of the mnth array element in the θ mn , direction.

[0055] The beneficial effects of the present application are: the present application establishes an approximate calculation model of the near-field radiation characteristics of the electric scanning array by combining the element radiation field analytical expression and the active element pattern of the typical category array element with the excitation phase control required by beam scanning, which can quickly obtain the near-field radiation field intensity distribution of the electric scanning array at any beam scanning angle, compared with the prior art, the time and resource consumption required for calculation are saved, and the evaluation efficiency of the adjacent equipment disturbance condition is improved. BRIEF DESCRIPTION OF DRAWINGS

[0056] Figure 1 The method flowchart of the present application is shown in the following table:

[0057] Figure 2 The schematic diagram of the defined near-field region radiation field distribution of the 8*8 electric scanning array composed of electric basic oscillators calculated by the model of the present application in the embodiment when the beam is scanned to (40°, 40°) is shown in the following table:

[0058] Figure 3 The schematic diagram of the near-field region radiation field distribution under the same scenario calculated by the full-wave simulation software Feko is shown in the following table: Figure 2

[0059] Figure 4 The schematic diagram of the Vivaldi array structure whose radiation field does not have an analytical solution according to the present application in the embodiment is shown in the following table:

[0060] Figure 5 The classification schematic diagram of the typical category array element according to the present application in the embodiment is shown in the following table:

[0061] Figure 6 The comparison schematic diagram of the radiation field of the defined semicircular near-field region of the 4*3 electric scanning array composed of Vivaldi array elements calculated by the model of the present application and the calculation result of the full-wave simulation software Feko when the beam is scanned to (10°, 30°) is shown in the following table:

[0062] Figure 7 The comparison schematic diagram of the radiation field of the defined semicircular near-field region of the 4*3 electric scanning array composed of Vivaldi array elements calculated by the model of the present application and the calculation result of the full-wave simulation software Feko when the beam is scanned to (-20°, -50°) is shown in the following table: DETAILED DESCRIPTION

[0063] The technical solutions of the present application are described in further detail below in combination with the drawings, but the protection scope of the present application is not limited to the following description.

[0064] ​The application provides a fast modeling method for near-field radiation characteristics of an electric scanning array, including near-field radiation characteristic models of an electric scanning array formed by two types of array elements with an analytical solution and without an analytical solution during beam scanning, and a specific step flow is shown in the figure Figure 1 .

[0065] For the electric scanning array formed by the array elements with the analytical solution of the radiation field, the near-field radiation characteristics during beam scanning are calculated, and the specific steps include the following steps.

[0066] S101, parameters of the electric scanning array and a position of a near-field point to be calculated are given.

[0067] In the embodiment of the application, the working frequency f of the two-dimensional rectangular grid electric scanning array distributed in the xoy plane and taking 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, the array element spacing d x = d y = λ2=0.015, the position coordinates x mn ,y mn of each array element in the xoy plane (unit: m) are as shown in the following table, and z mn = 0 m.

[0068] 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] [[ 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 region division, the near-field region of the electric scanning array in the embodiment satisfies the following range:

[0071]

[0072] wherein the maximum size of the array aperture is the wavelength λ = 0.03 m.

[0073] According to the range of the near-field region of the array, in the embodiment, the near-field to be calculated is a rectangular region on the xoy plane, and the coordinates of the four vertices of the rectangular region are as shown in the following table:

[0074] x (in m) y (in m) z (in 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, an analytical expression of the radiation field of the array element is obtained and far-field approximation is performed.

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

[0077]

[0078]

[0079]

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

[0081] Further approximating the analytical expression of the radiation field of the electric fundamental oscillator by a far-field approximation, where kr > 100 >> 1 in the far field, and only taking the terms related to kr while ignoring higher-order terms of kr, the complex vector analytical expression 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 elevation angle θ0 of the beam scanning angle is 40°, and the azimuth angle is... The complex excitation of each corresponding basic electric array sub-unit The excitation amplitude of each array element is 1A, and the excitation phase satisfies the following equation:

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

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

[0087] 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] Calculation of near-field radiation characteristics of an electronically scanned array composed of array elements with analytical solutions for the S104 radiation field during beam scanning.

[0089] venue At the specified location, the total near-field radiated electric field of an 8×8 electrically scanned array composed of fundamental electric oscillator elements with analytical solutions to the radiation field during beam scanning can be calculated by superimposing the far-field radiated fields of each element:

[0090]

[0091] In this embodiment, the 8×8 array, composed of electric fundamental oscillators with analytical solutions for the radiation field, is used as array elements. When the beam scans to (40°, 40°) as defined in step S103, the total radiated electric field distribution of the near-field rectangular region determined by the four vertices in step S101 is calculated by the model in step S104. (See [link to relevant documentation]). Figure 2To verify the accuracy of the model, Figure 3 The radiation field distribution results for the same region calculated by the full-wave simulation software Feko are presented for comparison.

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

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

[0094] In the embodiments of this 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 2GHz, the number of array elements distributed along the x-axis and y-axis is M=4, N=3, and the element spacing d is... x =d y =0.082m, the position coordinates of each array element located in the xoy plane. mn ,y mn (Unit: m) are shown in the table below, z mn =0m:

[0095] 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] [[ 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 region of the electro-scanning array described in this embodiment satisfies the following range:

[0098]

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

[0100] Based on the near-field region of the array, in this embodiment, the near-field to be calculated is a semi-circular arc region with a fixed radius centered at the origin above the xoy plane. The coordinates of the near-field points to be calculated in this region are shown in the table below:

[0101]

[0102]

[0103] S202 reads the active element radiation pattern of each array element from the full-wave simulation calculation;

[0104] In this embodiment, a Vivaldi antenna is selected as the array element, and the structure of this array element is as follows: Figure 4As shown, the Active Element Pattern (AEP) of the Vivaldi array element is derived by full-wave simulation software, and the radiation field of the mth array element can be further expressed as

[0105]

[0106] When the array size is large, each array element can be classified according to the environment in which it is located, and only the active element pattern of a typical category of array element is derived instead of the pattern of the same type of array element to substitute into the subsequent calculation formula to improve the calculation efficiency. In the embodiments of the present application, according to the environment in which the array element is located, the four elements adjacent to the upper, lower, left and right of the array element are considered to classify each array element, and the following nine typical category array elements are obtained, as shown (gray for the current array element): Figure 5

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

[0108] The second type, the current array element only has adjacent array elements on the top, right and below;

[0109] The third type, the current array element only has adjacent array elements on the top and right;

[0110] The fourth type, the current array element only has adjacent array elements on the left, right and below;

[0111] The fifth type, the current array element has adjacent array elements on the left, right, top and below;

[0112] The sixth type, the current array element only has adjacent array elements on the left, right and top;

[0113] The seventh type, the current array element only has adjacent array elements on the left and below;

[0114] The eighth type, the current array element only has adjacent array elements on the top, left and below;

[0115] The ninth type, the current array element only has adjacent array elements on the left and top;

[0116] For each typical category of array element, only the active element pattern of an arbitrary array element in the category is selected instead of the pattern of the same type of array element.

[0117] ​In the embodiments of this application, the full-wave simulation software used is Feko. Similar software includes HFSS and CST. Feko software completes the full-wave simulation calculation by implementing the method of moments. Specifically, only the mn-th array element of the array model is excited by a voltage source port, and the remaining ports are filled with 50-ohm matching loads. The far-field radiation pattern of the array at this time is calculated and exported, which is the active element radiation pattern data of this element. It characterizes the radiation characteristics of the array element in the array environment. At this time, the coupling effect of the surrounding elements on the array element is considered.

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

[0119] In this embodiment, compared with step S201 where r = 0.5m, The elevation angle θ0 = 10° and the azimuth angle corresponding to the determined near-field calculation area are... The complex excitation of each corresponding Vivaldi unit The excitation amplitude of each array element is 1A, and the excitation phase satisfies the following equation:

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

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

[0122] 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, compared with step S201 where r = 1.1m, The elevation angle θ0 = -20° and the azimuth angle corresponding to the determined near-field calculation area are... The complex excitation of each corresponding Vivaldi unit The excitation amplitude of each array element is 1A, and the excitation phase satisfies the following equation:

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

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

[0126] 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 The near-field radiation characteristic calculation of the electric scanning array beam scanning of the array element composition of the radiation field without analytical solution;

[0128] Field point At the position, the near-field total radiation characteristic (electric field) of the 4x3 electric scanning array of the Vivaldi array element composition of the radiation field without analytical solution can be expressed as follows when the beam is scanned:

[0129]

[0130] The 4x3 array of the Vivaldi array element composition of the radiation field without analytical solution described in the embodiment, when the beam defined in the step S203 is scanned to (10°, 30°) and (-20°, -50°) respectively, corresponds to the radiation field distribution of the step S201 by r=0.5m, and r=1.1m, The determined near-field region to be calculated, the radiation field distribution of the electric scanning array in the near-field region to be calculated is respectively referred to Figure 6 , Figure 7 In order to verify the accuracy of the model, Figure 6 and Figure 7 The radiation field distribution of the same region calculated by the full-wave simulation software Feko (represented by a solid line) is also given for comparison.

[0131] The above description shows and describes the preferred embodiments of the present application, which is not intended to limit the present application in any form. As mentioned above, it should be understood that the present application is not limited to the form disclosed herein, and should not be considered 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 by the above-mentioned teaching or related art or knowledge.

[0132] Any skilled person in the art can make more possible changes and decorations, or modifications to the technical solutions of the present application without departing from the scope of the present application, which are equivalent embodiments of the present application. Therefore, any equivalent changes within the scope of the present application should be covered by the protection scope of the present application.

Claims

1. A method for fast modeling of near field radiation characteristics of an electrically scanned array, characterized by: The method comprises the following steps: When the element of the electrically scanned array with the analytical solution of the radiation field is scanned, the near-field radiation model of the electrically scanned array is established by using the analytical expression of the element radiation field and the superposition principle, comprising: S101. Given the parameters of the electrically scanned array and the positions of the near-field field points to be calculated; The step S101 comprises: The electric scanning array is a two-dimensional rectangular grid array distributed in the xoy plane with the origin as the geometric center, and the electric scanning array parameters include the array operating frequency f, the number of elements M and N distributed along the x-axis and y-axis, and the element spacing d along the x-axis and y-axis x and d y , the position coordinates (x mn ,y mn ,z mn ) of each element in the xoy plane; According to the criteria for field region division, the near-field region of the array satisfies the following range: Where λ is the wavelength, and D is the maximum size of the array aperture; For the two-dimensional rectangular grid array, the maximum size D of the array aperture is approximately calculated by the following formula: The calculated near-field field point position coordinates (x, y, z) are determined according to the near-field region range of the array, specifically, the distance of the field point position coordinates (x, y, z) to the center (0, 0, 0) of the array The calculated near-field field point position coordinates (x, y, z) are determined according to the near-field region range of the array, specifically, the distance of the field point position coordinates (x, y, z) to the center (0, 0, 0) of the array S102. Obtain the analytical expression of the element radiation field and make a far-field approximation; S103. Define the beam scanning angle and calculate the corresponding complex excitation of each element; S104. Near-field radiation characteristic calculation when the element of the electrically scanned array with the analytical solution of the radiation field is scanned; When the element of the electrically scanned array with the analytical solution of the radiation field is scanned, the near-field radiation model of the electrically scanned array is established by superimposing the active element patterns of each element, comprising: S201. According to step S101, the parameters of the electrically scanned array are given, and the maximum size of the array aperture and the range of the near-field region are calculated, so as to determine the positions of the near-field field points to be calculated; S202. Read the active element patterns of each element calculated by full-wave simulation, classify each element according to the environment of the element, considering the four adjacent elements above, below, left and right of the element, and obtain the following nine typical categories of elements: The first category, the current element only has adjacent elements on the right and below; The second category, the current element only has adjacent elements on the top, right and below; The third category, the current element only has adjacent elements on the top and right; The fourth category, the current element only has adjacent elements on the left, right and below; The fifth category, the current element has adjacent elements on the left, right, top and bottom; The sixth category, the current element only has adjacent elements on the left, right and top; The seventh category, the current element only has adjacent elements on the left and below; The eighth category, the current element only has adjacent elements on the top, left and below; The ninth category, the current element only has adjacent elements on the left and top; For each typical category of elements, only the active element pattern of an arbitrary element in the category is selected to replace the pattern of the same category of elements; S203. According to step S103, define the beam scanning angle and calculate the corresponding complex excitation of each element; S204. Near-field radiation characteristic calculation when the element of the electrically scanned array with the analytical solution of the radiation field is scanned.

2. The method of claim 1, wherein: The step S102 comprises: The general form of the complex vector of the array element radiation field is where are the unit vectors in the r, θ, directions, respectively, are the complex components of the electric field radiated by the array element in the r, θ, directions, respectively. The near-field range of the array satisfies the far-field condition of a single element, that is, the near-field of the array is located in the far field of each radiation element: kr>>1, for the region where kr>>1 for each radiation element, there is: (kr) -1 >>(kr) -2 >>(kr) -3 The far-field approximation is made for the analytical expression of the element radiation field, only the terms related to kr are taken, and the high-order terms of kr are ignored.

3. The method of claim 2, wherein: The step S103 comprises: The beam scanning angle is defined as the elevation angle and the azimuth angle of the beam pointing direction The electric scanning array adjusts the phase or time delay of each array element to achieve the purpose of controlling the beam scanning, and the corresponding complex excitation of each array element is represented as When the beam scanning angle is defined as The phase α of the mnth array element in the complex excitation should satisfy: mn ​ where x mn y mn are the position coordinates of the mth element, respectively. At the same time, the excitation amplitude A of the mnth array element mn =1, the corresponding complex excitation of each array element is 4. The method of claim 3, wherein: The step S104 comprises: The near-field radiation characteristic is the total radiated electric field of the array, Etot(r, θ, φ) An electric scanning array composed of elements whose radiation field at a field point r has an analytical solution, the total radiated electric field of the array when beam scanning is calculated by superimposing the far-zone radiation electric field of each element, at which time the general form of the near-field radiation characteristic is as follows: where M and N are the number of elements distributed along the x and y axes, respectively, r mn , θ mn , are the distance, elevation angle and azimuth angle of the field point relative to the mnth element, respectively, are the radiation electric field components of the mnth element in the r, θ, directions; the near-field radiation model is to calculate the total near-field radiation electric field of the array under any beam scanning angle on the basis of the above general form 5. The method of claim 1, wherein: In the step S202, reading the active element patterns of each element calculated by full-wave simulation comprises: When m = 1, 2, …, M; n = 1, 2, …, N, for the mnth array element, an actual array model is established in the full-wave simulation software, only the unit excitation of the mnth array element and the matched load of other array elements are set under the condition, the far-field radiation pattern of the full space of the array is simulated and derived, that is, the corresponding active unit pattern data table of the mnth array element at different angles in the full space is obtained. angle. At this time, the radiation field of the mth element is represented as: wherein r mn , θ mn , are the distance, the elevation angle and the azimuth angle of the field point relative to the mnth array element, is the complex excitation of the mnth array element, is the active element pattern data of the mnth array element exported by the full-wave simulation software; In actual calculation, the pitch and azimuth angle θ of the calculated point relative to the mnth array element is obtained by looking up the table mn , corresponding to the active unit directional pattern data, and for the pitch angle and azimuth angle that cannot be completely matched, the approximate data of the active unit directional pattern at the corresponding angle is obtained by linear interpolation.

6. The method of claim 1, wherein: The step S204 comprises: The radiation field of the element-constituted electric scanning array without analytical solution, the near-field radiation electric field at the field point is expressed as follows: where M and N are the number of elements distributed along the x and y axes, respectively, r mn , θ mn , are the distance, elevation angle and azimuth angle of the field point relative to the mnth element, is the active element pattern value of the mnth element in the direction of θ mn , ; the near-field radiation model is to calculate the total near-field radiation electric field of the array under any beam scanning angle on the basis of the above general form

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