Method for rapidly evaluating response of array antenna to high-power microwave coupling

Abstract

The invention discloses a method for rapidly evaluating the coupling response of an array antenna to a high-power microwave, and belongs to the technical field of ship electromagnetic design, and the method comprises the steps: building a small-scale array antenna through employing the same array elements in the same arrangement mode according to the array element structure and the array element arrangement mode of an original array antenna; through a full-wave simulation method, a three-dimensional achievable gain directional diagram of each array element in a small-scale array antenna is obtained through calculation; and response voltages of all array elements in the original array antenna are obtained through the response voltages of the array elements of the target-scale array antenna to the high-power microwaves. By utilizing the method, the response voltage of the array element in the array antenna to the electromagnetic pulse with certain intensity in each incoming wave direction can be quickly evaluated, and guidance is provided for the electromagnetic protection design of the array antenna.

Description

Technical Field

[0001] The present invention belongs to the technical field of ship electromagnetic design, and more specifically, relates to a method for rapidly evaluating the response of an array antenna to high-power microwave coupling. Background Art

[0002] Active phased array radars are widely used in various tactical radars such as guidance and reconnaissance due to their obvious advantages. Active phased array radars contain a large number of identical radiating units, each of which is independently controlled in phase and amplitude. In the current complex battlefield electromagnetic environment, the array antenna in the radar is an open device for front-door coupling. After being interfered by strong electromagnetic pulses, it will seriously affect the normal function of the radar and even cause damage to the system. Therefore, it is necessary to pre-evaluate the electromagnetic coupling response value of each array element channel in the array antenna to high-power microwaves of several typical waveforms. According to the evaluation results, corresponding electromagnetic protection measures can be taken in advance in the design.

[0003] There are two main methods for evaluating the response of array antennas to high-power microwave coupling. One is to conduct a high-power microwave irradiation experiment, and the other is to conduct a full-wave simulation experiment on the entire array. The high-power microwave irradiation experiment requires that after the array antenna is processed, it must be combined with several types of high-power microwave sources to conduct multi-angle irradiation experiments. The experiment is very costly and time-consuming. The full-wave simulation experiment of the entire array antenna, due to the large scale of the array antenna, generally contains thousands of array elements. The simulation experiment has high requirements for computer hardware and algorithms. It takes several days to dozens of days to run a single angle irradiation experiment. The required technical threshold is high and the simulation cycle is long. Summary of the invention

[0004] In view of the above defects or improvement needs of the prior art, the present invention proposes a method for quickly evaluating the response of an active phased array antenna to high-power microwave coupling, which can quickly evaluate the response voltage of an array element in the array antenna to an electromagnetic pulse of a certain intensity in each incoming wave direction, thereby providing guidance for the electromagnetic protection design of the array antenna.

[0005] To achieve the above object, the present invention provides a method for quickly evaluating the response of an array antenna to high-power microwave coupling, comprising:

[0006] According to the array element structure and array element arrangement of the original array antenna, a target scale array antenna is established by using the same array elements in the same arrangement, wherein the scale of the target scale array antenna is smaller than the scale of the original array antenna;

[0007] Through full-wave simulation method, the three-dimensional achievable gain pattern of each array element in the target scale array antenna is calculated;

[0008] Based on the three-dimensional achievable gain pattern of each array element in the target scale array antenna, the response voltage of the array element of the target scale array antenna to high-power microwave is calculated;

[0009] The response voltages of all array elements in the original array antenna are obtained according to the response voltages of the array elements of the target scale array antenna to the high power microwave.

[0010] In some optional implementation schemes, the difference between the achievable gain pattern characteristics of the target scale array antenna center unit and the achievable gain pattern characteristics of the original array antenna center unit is within a preset range.

[0011] In some optional implementation schemes, the step of calculating the response voltage of the array element of the target scale array antenna to the high-power microwave based on the three-dimensional achievable gain pattern of each array element in the target scale array antenna comprises:

[0012] The corresponding plane wave power density is obtained from the known high-power microwave field intensity threat value;

[0013] For the array elements in the array, the received power is obtained from the plane wave power density;

[0014] For array antennas, the relationship between aperture and gain is obtained from the received power;

[0015] The response voltage of the array elements of the target-scale array antenna to high-power microwaves is calculated from the relationship between aperture and gain.

[0016] In some optional embodiments, The corresponding plane wave power density S is obtained, where E is the plane wave field intensity peak of high-power microwave at a certain frequency, and η is the free space wave impedance.

[0017] In some optional embodiments, The received power is obtained, where Ae is the antenna equivalent aperture, U and I are the response voltage peak and response current peak of the array element port, and R is the characteristic impedance of the array element port.

[0018] In some optional embodiments, The relationship between aperture and gain is obtained, where G is the achievable gain of the antenna in the incident direction and λ is the wavelength.

[0019] In some optional embodiments, The response voltage of the array elements of the target scale array antenna to high power microwaves is obtained.

[0020] In general, the above technical solutions conceived by the present invention can achieve the following beneficial effects compared with the prior art:

[0021] The calculation method is to estimate the response voltage of the array element port at the frequency according to the achievable gain of the array element and the incident wave field strength. Based on the known three-dimensional gain radiation pattern of a typical array element, the response voltage of the array element to the electromagnetic pulse of each incoming wave direction can be quickly evaluated, which greatly reduces the test cost and shortens the simulation cycle. It can be applied to the electromagnetic protection design of active phased array radar. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic flow chart of a method for rapidly evaluating the response of an array antenna to high-power microwave coupling provided by an embodiment of the present invention;

[0023] Figure 2 is a schematic structural diagram of a printed dipole array element provided by an embodiment of the present invention;

[0024] Figure 3 It is a relatively small-scale dipole array arrangement diagram and array element port numbering provided by an embodiment of the present invention;

[0025] Figure 4 is a gain of each array element at 3 GHz provided by an embodiment of the present invention (unit: dBi);

[0026] Figure 5 It is a three-dimensional achievable gain pattern provided by an embodiment of the present invention, wherein (a) is the three-dimensional achievable gain pattern of array element No. 37 at 3 GHz, (b) is the three-dimensional achievable gain pattern of array element No. 37 at 8.5 GHz, (c) is the three-dimensional achievable gain pattern of array element No. 37 at 15.9 GHz, and (d) is the three-dimensional achievable gain pattern of array element No. 37 at 18.5 GHz. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0028] like Figure 1 As shown, the method provided by the present invention for quickly evaluating the response of an array antenna to high-power microwave coupling specifically includes:

[0029] (1) Based on the array element structure and array element arrangement of the original array antenna, a smaller-scale array antenna (i.e., target-scale array antenna) is established using the same array elements in the same arrangement. The principle for determining the scale of the smaller-scale array antenna is that the achievable gain pattern characteristics of the central unit of the smaller-scale array antenna are almost consistent with the achievable gain pattern characteristics of the central unit of the original array antenna; based on the electromagnetic distribution characteristics and the array element (i.e., typical array element) characteristics of the smaller-scale array antenna, the characteristics of all the array elements in the original array antenna can be obtained;

[0030] (2) Using full-wave simulation methods, the three-dimensional achievable gain pattern of each element in a smaller-scale array antenna is calculated;

[0031] (3) The response voltage of a typical array element to high-power microwaves is calculated using an evaluation formula. Based on the response voltage of the typical array element, the response voltages of all array elements in the original array antenna can be obtained.

[0032] The calculation results of the method proposed in the present invention are compared with the full-wave simulation results. The results show that the method proposed in the present invention can more accurately calculate the port response voltage value of the array element under high-power microwave irradiation. In the case of obtaining the three-dimensional gain pattern of a typical array element by pre-simulation or measurement, the calculation method can be used to quickly evaluate the response voltage of the array element to a certain intensity electromagnetic pulse in each incoming wave direction, providing guidance for electromagnetic protection.

[0033] A C-band large-scale planar phased array antenna using printed dipoles as array elements and arranged in a triangular grid is selected as an example for description.

[0034] The operating frequency range of the phased array antenna is 2.7 GHz to 3.3 GHz, and the port reflection coefficient is less than -10 dB. The high-power microwave source shown in Table 1 is used to irradiate the phased array antenna, and the irradiation direction is perpendicular to the array surface.

[0035] Table 1 Resonant frequency and peak field intensity of HPM wave source

[0036] HPM resonant frequency (GHz) HPM field strength peak (kV / m) 2 18 3 20 8.5 69 15.9 12 18.5 12

[0037] The structure of a single printed dipole array element is as follows Figure 2 As shown in Figure 2, the array element is printed on a dielectric substrate with a thickness of 0.762 mm, and the array element radiation arm and J-shaped coupling feeding structure are printed on the front and back sides respectively. The board material of the dielectric substrate is Rogers 4350B, which has a relative dielectric constant of 3.66 and a loss tangent value of 0.0037. The size of the dielectric substrate is 50 mm × 30 mm. The structural parameters of the printed dipole array element are shown in Table 2.

[0038] Table 2 Structural parameters of printed dipoles

[0039] <![CDATA[W1]]> <![CDATA[W2]]> <![CDATA[W3]]> <![CDATA[W4]]> <![CDATA[W5]]> <![CDATA[L1]]> <![CDATA[L2]]> <![CDATA[L3]]> <![CDATA[L4]]> 50mm 13mm 1mm 8mm 1.7mm 32mm 17mm 13mm 4mm

[0040] First, a corresponding smaller-scale array is established. The small-scale array antenna has 7 columns along the x-axis direction, 7 array elements in odd-numbered columns along the y-axis direction, and 6 array elements in even-numbered columns. The normal direction of the array surface is along the z-axis direction. The spacing between the elements in each column is 0.6 times the working wavelength, which is 60mm based on the antenna working frequency center of 3GHz. The spacing between columns is also 60mm. The layout diagram and array element port number of the smaller-scale dipole array are shown in the figure. Figure 3 As shown. In this smaller-scale array, there are antenna units with various positional characteristics. In the edge units, due to the triangular grid arrangement, the outermost antennas between columns are arranged in an alternating manner with protruding and concave positions; in the same column of antenna units, the positions of the antennas at the center and edge of the column are also different; for antenna units in different columns, the arrangement of multiple columns of antennas also differs between the edge and the center. Except for unit No. 37 in the center of the array, the achievable gain patterns of the other units in the array will be different when the array is working due to their different positions in the array. The achievable gain pattern of unit No. 37 in the center of the array is almost consistent with the achievable gain pattern characteristics of the units in the central area of ​​the original large-scale array.

[0041] like Figure 4 The figure shows the gain distribution of each element of the array antenna at 3 GHz, where the gain value is the gain dB value of the achievable gain pattern of the antenna unit at theta = 0°, phi = 0°. The achievable gain distribution results of each element show that due to the influence of the distribution position of the antenna unit in the array, there are obvious differences in achievable gain between the antenna elements. Only at the angle of theta = 0°, phi = 0° at 3 GHz, the achievable gain difference between the elements can reach up to 2.6 dB.

[0042] In addition to the differences and distribution patterns of the radiation patterns of each array element within the working frequency band, there are also multiple resonant frequency bands in the high-frequency part outside the working frequency band. Within the frequency range of less than 20 GHz, the radiation patterns of the array center unit No. 37 antenna at different frequencies are as follows: Figure 5 As shown in the figure, (a) is the three-dimensional achievable gain pattern of the 37th element at 3 GHz, (b) is the three-dimensional achievable gain pattern of the 37th element at 8.5 GHz, (c) is the three-dimensional achievable gain pattern of the 37th element at 15.9 GHz, and (d) is the three-dimensional achievable gain pattern of the 37th element at 18.5 GHz. It can be seen that the achievable gain patterns at different frequency points are very different.

[0043] For the known high-power microwave field intensity threat value E, the corresponding plane wave power density is:

[0044]

[0045] For an element in the array, its received power can be expressed as:

[0046]

[0047] For an array antenna, the relationship between its aperture Ae and gain is:

[0048]

[0049] In the above formula, S is the plane wave power density, E is the plane wave field intensity peak of high-power microwave at a certain frequency, η is the free space wave impedance (about 377Ω), Ae is the antenna equivalent aperture, G is the achievable gain of the antenna in the incident direction, U and I are the response voltage peak and response current peak of the array element port, and R is the characteristic impedance of the array element port, which is set to 50Ω here.

[0050] Therefore, when the external high-power microwave field strength and the achievable gain of the antenna itself are known, the response voltage of the antenna port can be calculated as:

[0051]

[0052] When the three-dimensional gain pattern of a typical array element is obtained by pre-simulation or measurement, the estimation formula can be used to quickly evaluate the response voltage of the array element to an electromagnetic pulse of a certain intensity in each incoming wave direction, providing guidance for electromagnetic protection.

[0053] As can be seen from Table 3, the comparison between the response voltage value calculated by the estimation formula and the response voltage value obtained by full-wave simulation based on the model shows that, in most frequency ranges, the antenna port response voltage value calculated by the estimation formula can more accurately estimate the front-door coupling voltage result of high-power microwave to the array antenna port. When the frequency is much higher than the working frequency band of the array antenna, the response voltage values ​​obtained by the two methods have a large deviation, but because the antenna directional pattern is severely split in this state, the gain that can be achieved is very small, and the coupling voltage value of high-power microwave is very low, which has little impact on the system protection design.

[0054] Table 3 Port response voltage values ​​obtained using different methods

[0055]

[0056]

[0057] In summary, the method for evaluating the response of an array antenna to high-power microwave front-door coupling proposed in the present invention has the characteristics of low cost and short cycle, and can quickly evaluate the response of an array antenna to high-power microwave coupling.

[0058] It should be pointed out that, according to the needs of implementation, the various steps / components described in this application can be split into more steps / components, and two or more steps / components or partial operations of steps / components can be combined into new steps / components to achieve the purpose of the present invention.

[0059] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for rapidly evaluating the response of an array antenna to high-power microwave coupling, characterized in that: include: According to the array element structure and array element arrangement of the original array antenna, a target scale array antenna is established by using the same array elements in the same arrangement, wherein the scale of the target scale array antenna is smaller than the scale of the original array antenna; Through full-wave simulation method, the three-dimensional achievable gain pattern of each array element in the target scale array antenna is calculated; Based on the three-dimensional achievable gain pattern of each array element in the target scale array antenna, the response voltage of the array element of the target scale array antenna to high-power microwave is calculated; The response voltages of all array elements in the original array antenna are obtained according to the response voltages of the array elements of the target scale array antenna to the high power microwave.

2. The method according to claim 1, characterized in that The difference between the achievable gain pattern characteristics of the target scale array antenna center unit and the achievable gain pattern characteristics of the original array antenna center unit is within a preset range.

3. The method according to claim 1 or 2, characterized in that: The step of calculating the response voltage of the array element of the target scale array antenna to the high-power microwave based on the three-dimensional achievable gain pattern of each array element in the target scale array antenna comprises: The corresponding plane wave power density is obtained from the known high-power microwave field intensity threat value; For the array elements in the array, the received power is obtained from the plane wave power density; For array antennas, the relationship between aperture and gain is obtained from the received power; The response voltage of the array elements of the target-scale array antenna to high-power microwaves is calculated from the relationship between aperture and gain.

4. The method according to claim 3, characterized in that Depend on The corresponding plane wave power density S is obtained, where E is the plane wave field intensity peak of high-power microwave at a certain frequency, and η is the free space wave impedance.

5. The method according to claim 4, characterized in that Depend on The received power is obtained, where Ae is the antenna equivalent aperture, U and I are the response voltage peak and response current peak of the array element port, and R is the characteristic impedance of the array element port.

6. The method according to claim 5, characterized in that Depend on The relationship between aperture and gain is obtained, where G is the achievable gain of the antenna in the incident direction and λ is the wavelength.

7. The method according to claim 6, characterized in that Depend on The response voltage of the array elements of the target scale array antenna to high power microwaves is obtained.

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