A method for measuring near-field environment of a high-power electromagnetic pulse antenna

Abstract

This invention discloses a method for measuring the near-field environment of a strong electromagnetic pulse antenna, comprising the following steps: selecting a suitable area and placing the strong electromagnetic pulse radiation source and the radiating antenna at the center of the area; adjusting the measuring antenna so that the aperture of the measuring antenna is opposite to the aperture of the radiating antenna and the center of the aperture of the measuring antenna is at the same height as the center of the aperture of the radiating antenna; keeping the position of the measuring antenna unchanged, adjusting the attitude of the radiating antenna, including the azimuth and elevation angles, and recording the corresponding vertical and horizontal polarization field strengths; after all attitude measurements of the radiating antenna at this location are completed, changing the position of the measuring antenna, i.e., changing the distance between the measuring antenna and the radiating antenna, and repeating the measurement at the previous position; finally, obtaining the azimuth, elevation, vertical polarization field strength, horizontal polarization field strength, and combined field strength at each distance and attitude. This invention can solve the problem of measuring the near-field of strong electromagnetic pulse radiation waves.

Description

Technical Field

[0001] This invention belongs to the field of complex electromagnetic environment effect testing technology, specifically relating to a method for measuring the near-field environment of a strong electromagnetic pulse antenna. Background Technology

[0002] With the development of high electromagnetic pulse (HEP) weapon technology, the electronic information equipment and systems of the attacked party face the threat of HEP weapons. In order to study the radiation characteristics of HEP sources and the protective effect of their own platforms under HEP radiation, accurate measurements of the near field of HEP radiation are required in related experiments to provide electromagnetic environment input for the protection of related equipment and systems.

[0003] High electromagnetic pulse sources employing relativistic backwave tubes typically use multiple reflections to reflect the signal from the waveguide port through a parabolic antenna. Each change in elevation or azimuth of the radiating antenna causes a corresponding change in the transmission channel structure. Because the radiated wave is linearly polarized, the polarization of the emitted electromagnetic wave changes along with the transmission channel structure. For example, a 0.2-degree change in antenna azimuth can result in a significant change in the polarization of the emitted electromagnetic wave compared to before the change.

[0004] Currently, the focus of attention on strong electromagnetic pulse radiation waves is on their far field, while the measurement of the near field of strong electromagnetic pulse radiation waves is not given much attention. Based on the characteristics of its own platform, this invention does not require measurements to be carried out in a professional shielded anechoic chamber, but can carry out near field measurements in the field. Summary of the Invention

[0005] The purpose of this invention is to provide a method for measuring the near-field environment of a strong electromagnetic pulse antenna, thereby solving the problem of near-field measurement of strong electromagnetic pulse radiation.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows:

[0007] A method for measuring the near-field environment of a strong electromagnetic pulse antenna includes the following steps:

[0008] Choose a suitable area and place the strong electromagnetic pulse radiation source and the radiating antenna in the center of that area;

[0009] Adjust the measuring antenna so that the aperture of the measuring antenna is opposite to the aperture of the radiating antenna and the center of the aperture of the measuring antenna is at the same height as the center of the aperture of the radiating antenna.

[0010] Connect the strong electromagnetic pulse radiation source to the radiating antenna. The strong electromagnetic pulse radiation source emits a strong electromagnetic pulse signal through the radiating antenna. The measuring antenna measures the vertical polarization field strength and horizontal polarization field strength at its location and deduces the radiation power of the strong electromagnetic pulse radiation source. When the difference between the deduce radiation power of the strong electromagnetic pulse radiation source and the actual value is within a certain range, it is considered that the measurement conditions are met.

[0011] With the measuring antenna position unchanged, adjust the attitude of the radiating antenna, including the azimuth and elevation angles, and record the corresponding vertical and horizontal polarization field strengths. After all the attitude measurements of the radiating antenna at this position are completed, change the position of the measuring antenna, i.e., change the distance between the measuring antenna and the radiating antenna, and repeat the measurement at the previous position.

[0012] Based on the vertical and horizontal polarization field strengths at various distances and attitudes, the combined field strength is calculated, and finally the azimuth, pitch, vertical polarization field strength, horizontal polarization field strength, and combined field strength are obtained at various distances and attitudes.

[0013] Furthermore, a suitable area is an open and flat area.

[0014] Furthermore, there are two measurement antennas, one for measuring the vertical polarization field strength and the other for measuring the horizontal polarization field strength. The two measurement antennas are connected to the attenuator via RF cables and finally to the oscilloscope.

[0015] Furthermore, both the attenuator and the oscilloscope are located inside the shielded vehicle.

[0016] Furthermore, the reverse reasoning includes:

[0017] Let the signal measured by the oscilloscope be S, the attenuator be X1, the RF cable attenuation be X2, and the antenna factor be X3. Then the field strength at the antenna is:

[0018] electric field strength = S * 10 (X1+X2+X3) / 20

[0019] Let the vertical polarization field strength and the horizontal polarization field strength be respectively the field strength 垂直 With field strength 水平 The combined field strength is:

[0020]

[0021]

[0022] In the formula, the unit of electric field strength (combined) is V / m, and the unit of power density (combined) is mW / cm². 2 .

[0023] Furthermore, the range is ±3dB.

[0024] Furthermore, a precision servo mechanism is used to adjust the orientation of the radiating antenna.

[0025] Further adjustments to the orientation of the radiating antenna include:

[0026] Assume that the azimuth and elevation angles when the aperture of the radiating antenna is opposite to the aperture of the measuring antenna are 0 degrees.

[0027] The azimuth angle is increased by the first angle, and the elevation angle is increased by the second angle in turn until it reaches 90 degrees. When the elevation angle reaches 90 degrees, the azimuth angle is increased by the first angle again, and the elevation angle is decreased by the second angle in turn until it reaches 0 degrees, or the elevation angle is increased from 0 degrees to the second angle in turn until it reaches 90 degrees.

[0028] Repeat this process until the azimuth angle increases to 180 degrees; based on symmetry, obtain the vertical polarization field strength and horizontal polarization field strength corresponding to the attitude.

[0029] Furthermore, the first angle is 1 degree and the second angle is 10 degrees.

[0030] Furthermore, the distance ranges from 5m to 100m.

[0031] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0032] 1) The azimuth and elevation of the radiation source are adjusted by a precise servo mechanism, which ensures good repeatability of the measurement. Since there is a large amount of data in the entire measurement process, if the error in the relative relationship between the radiating antenna and the measuring antenna is too large, it may lead to large differences in the data, affecting the judgment of the near-field distribution law of strong electromagnetic pulses.

[0033] 2) By adjusting the azimuth and elevation of the radiation source while keeping the measuring antenna stationary, measurement efficiency can be greatly improved.

[0034] 3) By utilizing the principle of symmetry, the measurement of the 360-degree horizontal azimuth is simplified to measuring only the 180-degree horizontal azimuth. Since the beam in the elevation direction is wider, the elevation azimuth is simplified to 9 azimuths, which greatly reduces the workload and improves the measurement efficiency.

[0035] 4) One of the core aspects of this method is that the center of the radiating antenna aperture is at the same height as the center of the measuring antenna aperture, and the measuring antenna aperture is aligned with the center of the radiating antenna aperture. Since the signal characteristics of some strong electromagnetic pulses are that the main beam is extremely narrow, if this is not done, either no signal can be detected, or the measured signal is several orders of magnitude worse.

[0036] 5) This method does not require measurements to be conducted in a conventional shielded semi-dark room; measurements can also be conducted in open areas in the field, without being limited by experimental conditions. Attached Figure Description

[0037] Figure 1Side view of a near-field environment measurement scenario for a strong electromagnetic pulse antenna;

[0038] Figure 2 Top view of a near-field environment measurement scenario using a high-power electromagnetic pulse antenna;

[0039] Figure 3 A schematic diagram showing the connection between the vertical and horizontal polarization field strengths for measuring the oscilloscope. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0041] This invention provides a method for conducting near-field environment measurements using a strong electromagnetic pulse antenna, which falls under the category of complex electromagnetic environment effect testing technology and relates to near-field environment measurement technology and methods under strong electromagnetic pulse radiation.

[0042] When equipment on the platform is in a near-field environment with electromagnetic pulse radiation fields reaching tens of kV / m in amplitude, pulse widths of only tens of ns, and carrier frequencies covering hundreds of megahertz to several gigahertz, interference or burnout may occur. To conduct relevant experiments, preliminary tests need to be performed on the equipment before installation on the platform. Measurements are needed to understand the near-field distribution patterns and provide electromagnetic environment inputs for the locations of the interfered equipment in the experiments. The technical problem this invention aims to solve is to provide a measurement method that offers both accurate measurement capabilities and rapid understanding of the near-field distribution patterns.

[0043] The method of the present invention for conducting near-field environment measurements using a strong electromagnetic pulse antenna, such as... Figure 1 and Figure 2 As shown, it includes:

[0044] 1) Select an open, flat area and place the strong electromagnetic pulse radiation source and radiation antenna at the center of the area.

[0045] 2) Adjust the center of the aperture of the measuring antenna to be at the same height as the center of the aperture of the strong electromagnetic pulse radiation antenna, so that the aperture of the measuring antenna is opposite to the aperture of the strong electromagnetic pulse radiation antenna.

[0046] 3) A strong electromagnetic pulse source is emitted, and the corresponding signal and amplitude are measured in the shielded vehicle. Based on the calculations of parameters such as distance, antenna coefficient, and cable loss, the radiated power of the strong electromagnetic pulse source is inferred. When the inferred radiated power of the strong electromagnetic pulse source differs from the actual value within a certain range (generally less than ±3dB), the measurement conditions are considered met; otherwise, the attitudes of the measuring antenna and the radiating antenna are adjusted until the measurement conditions are met.

[0047] The reverse reasoning method is as follows:

[0048] like Figure 1 and Figure 3 As shown, let the signal measured at the oscilloscope be S(V), the attenuator be X1(dB), the cable attenuation be X2(dB), and the antenna coefficient be X3(dB). Then the field strength at the antenna port is:

[0049] electric field strength = S * 10 (X1+X2+X3) / 20 (V / m)

[0050] When measuring, two antennas are often used, one horizontally polarized and the other vertically polarized. The combined field strength is then:

[0051]

[0052]

[0053] 4) Keep the measuring antenna stationary in its initial position, adjust the attitude (azimuth and elevation) of the high electromagnetic pulse radiation antenna and transmit. Measure and confirm the validity of the data in the shielded vehicle. Record the parameters of the high-power radiation source, the parameters of the measuring antenna, and the measurement data of vertical polarization and horizontal polarization. After measuring one position, move the measuring antenna to the next position (change the distance between the radiation source and the measuring antenna) and repeat the measurement at the previous position.

[0054] 5) Combine the vertical and horizontal polarization data measured under each attitude to calculate the overall field strength. Under each set of determined test conditions, record the data for distance, azimuth, pitch, vertical polarization field strength, horizontal polarization field strength, and overall field strength.

[0055] The near-field environment measurement method of a high-power electromagnetic pulse antenna according to an embodiment of the present invention includes:

[0056] 1) Select an open, flat area with no obstacles protruding from the ground within a radius of 200m from the center of the area.

[0057] 2) The strong electromagnetic pulse radiation source and radiating antenna are placed at the center of the area, with the radiating antenna aligned with the designated 0-degree position. The shielded measurement vehicle is placed at a suitable position between 181 degrees and 359 degrees of the strong electromagnetic pulse antenna, such as... Figure 1 and Figure 2 As shown.

[0058] 3) The elevation of the strong electromagnetic pulse antenna is 0 degrees; the center of the aperture of the two measuring antennas (one horizontally polarized and one vertically polarized) is at the same height as the center of the aperture of the microwave antenna, with an elevation of 0 degrees. The measuring antenna is placed on the extension line of the strong electromagnetic pulse antenna at 0 degrees, with the antenna aperture facing the center of the aperture of the strong electromagnetic pulse antenna, and the distance from the center of the circle is 5m.

[0059] 4) A strong electromagnetic pulse source is emitted, and the corresponding signal and amplitude are measured in the shielded vehicle. Based on the calculation of parameters such as distance, antenna coefficient, and cable loss, the radiation power of the strong electromagnetic pulse source is inversely estimated. When the difference between the inversely estimated radiation power of the strong electromagnetic pulse source and the actual value is within a certain range (generally less than ±3dB), the next measurement is carried out. If the requirements are not met, the attitude of the measuring antenna is adjusted until the requirements are met.

[0060] 5) Rotate the high-power electromagnetic pulse antenna to a horizontal 0-degree azimuth position; the high-power electromagnetic pulse source emits at a frequency of 1Hz / s-10Hz / s. After measuring and confirming the valid data in the shielded vehicle, record the parameters of the high-power radiation source, the parameters of the measuring antenna, and the measurement data of vertical polarization and horizontal polarization. The high-power electromagnetic pulse source stops emitting; the measuring antenna position remains unchanged, and the high-power electromagnetic pulse antenna rotates to a horizontal 1-degree azimuth position; measure sequentially until the high-power electromagnetic pulse antenna rotates to a horizontal 180-degree azimuth position and valid data is measured.

[0061] 6) With the strong electromagnetic pulse antenna in an azimuth range of 0 to 90 degrees, repeat step 4 every 10 degrees.

[0062] By utilizing the principle of symmetry, the measurement of the 360-degree horizontal azimuth is simplified to measuring only the 180-degree horizontal azimuth. Due to the wider beam in the elevation direction, the elevation azimuth is simplified to 9 azimuths, which greatly reduces the workload and improves the measurement efficiency.

[0063] 7) Place the measuring antenna on the 0-degree extension line of the strong electromagnetic pulse antenna, at a distance of 5m-100m from the center of the circle, and repeat steps 5 and 6.

[0064] 8) Combine the data of vertical polarization and horizontal polarization measured at each distance and at each attitude to calculate the overall field strength. Under each set of determined test conditions, record the data of distance, azimuth, pitch, vertical polarization field strength, horizontal polarization field strength, and overall field strength.

[0065] It should be noted that, depending on the implementation needs, the various steps / components described in this application can be broken down into more steps / components, or two or more steps / components or parts of the operation of steps / components can be combined into new steps / components to achieve the purpose of this invention.

[0066] Those skilled in the art will readily understand that the above are merely preferred embodiments of the present invention and are 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 within the scope of protection of the present invention.

Claims

1. A method for measuring the near-field environment of a strong electromagnetic pulse antenna, characterized in that, Includes the following steps: Choose a suitable area and place the strong electromagnetic pulse radiation source and the radiating antenna in the center of that area; Adjust the measuring antenna so that the aperture of the measuring antenna is opposite to the aperture of the radiating antenna and the center of the aperture of the measuring antenna is at the same height as the center of the aperture of the radiating antenna. Connect the strong electromagnetic pulse radiation source to the radiating antenna. The strong electromagnetic pulse radiation source emits a strong electromagnetic pulse signal through the radiating antenna. The measuring antenna measures the vertical polarization field strength and horizontal polarization field strength at its location and deduces the radiation power of the strong electromagnetic pulse radiation source. When the difference between the deduce radiation power of the strong electromagnetic pulse radiation source and the actual value is within a certain range, it is considered that the measurement conditions are met. With the measuring antenna position unchanged, adjust the attitude of the radiating antenna, including the azimuth and elevation angles, and record the corresponding vertical and horizontal polarization field strengths. After all the attitude measurements of the radiating antenna at this position are completed, change the position of the measuring antenna, i.e., change the distance between the measuring antenna and the radiating antenna, and repeat the measurement at the previous position. Based on the vertical and horizontal polarization field strengths at various distances and attitudes, the combined field strength is calculated, and finally the azimuth, pitch, vertical polarization field strength, horizontal polarization field strength, and combined field strength are obtained at various distances and attitudes.

2. The near-field environment measurement method of a high-intensity electromagnetic pulse antenna according to claim 1, characterized in that, The ideal area is an open and flat area.

3. The near-field environment measurement method of a high-intensity electromagnetic pulse antenna according to claim 1, characterized in that, There are two measuring antennas, one for measuring the vertical polarization field strength and the other for measuring the horizontal polarization field strength. The two measuring antennas are connected to the attenuator via RF cables and then to the oscilloscope.

4. The near-field environment measurement method of a high-intensity electromagnetic pulse antenna according to claim 3, characterized in that, Both the attenuator and the oscilloscope are located inside the shielded vehicle.

5. The near-field environment measurement method for a strong electromagnetic pulse antenna according to claim 3, characterized in that, The reverse reasoning includes: Let the signal measured by the oscilloscope be S, the attenuator be X1, the RF cable attenuation be X2, and the antenna factor be X3. Then the field strength at the antenna is: electric field strength = S * 10 (X1+X2+X3) / 20 Let the vertical polarization field strength and the horizontal polarization field strength be respectively the field strength 垂直 With field strength 水平 The combined field strength is: In the formula, the unit of electric field strength (combined) is V / m, and the unit of power density (combined) is mW / cm². 2 .

6. The method for measuring the near-field environment of a strong electromagnetic pulse antenna according to claim 1, 3, 4 or 5, characterized in that, The range is ±3dB.

7. The near-field environment measurement method of a high-intensity electromagnetic pulse antenna according to claim 1, characterized in that, The attitude of the radiating antenna is adjusted using a precision servo mechanism.

8. The method for measuring the near-field environment of a strong electromagnetic pulse antenna according to claim 1 or 7, characterized in that, Adjusting the attitude of the radiating antenna includes: Assume that the azimuth and elevation angles when the aperture of the radiating antenna is opposite the aperture of the measuring antenna are 0 degrees. The azimuth angle is increased by the first angle, and the elevation angle is increased by the second angle in turn until it reaches 90 degrees. When the elevation angle reaches 90 degrees, the azimuth angle is increased by the first angle again, and the elevation angle is decreased by the second angle in turn until it reaches 0 degrees, or the elevation angle is increased from 0 degrees to the second angle in turn until it reaches 90 degrees. Repeat this process until the azimuth angle increases to 180 degrees; based on symmetry, obtain the vertical polarization field strength and horizontal polarization field strength corresponding to the attitude.

9. The near-field environment measurement method for a strong electromagnetic pulse antenna according to claim 8, characterized in that, The first angle is 1 degree, and the second angle is 10 degrees.

10. The near-field environment measurement method of a high-intensity electromagnetic pulse antenna according to claim 1, characterized in that, The distance ranges from 5m to 100m.

Images