System and method for measuring electromagnetic parameters of materials in a strong microwave electric field environment based on parallel strip lines

Abstract

The present invention provides a system and method for measuring the electromagnetic parameters of materials in a strong microwave electric field environment based on parallel strips, belonging to the field of microwave testing technology. The present invention innovatively designs a double-sided parallel strip with a slotted structure, and constructs a measurement system under strong microwave electric field loading based on the double-sided parallel strip. The test sample is tested by separating the test frequency from the strong microwave electric field frequency, and the reflection coefficient and transmission coefficient of the test sample are obtained, thereby calculating the electromagnetic parameters of the material to be tested under the microwave strong field loading environment. The measurement system of the present invention realizes the decoupling of the test frequency and the strong microwave electric field frequency, that is, the test frequency is no longer determined by the setting of the microwave electric field frequency, thereby meeting the testing requirements at different frequencies.

Description

Technical Field

[0001] The present invention belongs to the technical field of microwave testing, and in particular relates to a system and method for measuring electromagnetic parameters of materials in a strong microwave electric field environment based on parallel strip lines. Background Art

[0002] Typical semiconductor materials, piezoelectric ceramics, and other functional ceramic materials have unique electrical properties and are widely used in sensors, acoustic wave devices, and other fields. The electromagnetic parameters of these materials will change in a strong microwave electric field, which will have a certain impact on the characteristics of the device. Conversely, this characteristic can also be used to design devices that meet the requirements. Therefore, measuring the electromagnetic parameters of such materials in a strong microwave field environment is particularly critical, and the complex dielectric constant ε r and complex magnetic permeability μ r They are two important parameters that characterize the electromagnetic properties of materials.

[0003] At present, some research has been conducted on the testing of microwave materials in strong microwave electric field environments. In "Experimental Study on the Effect of High-Power Microwave Pulse Width" (Fang Jinyong, Liu Guozhi, Li Ping et al. High-Power Laser and Particle Beams, 1999(05):639-642), the phenomenon of electronic systems being disturbed by high-power microwaves was explored, and a simulation method for strong microwave electric fields was proposed. In the patent "System and Method for Studying and Testing Microwave Dielectric Properties of Materials in Strong Electromagnetic Field Environments" with publication number CN107202922A, instead of directly using a high-power source, a compressed rectangular resonant cavity under a certain power excitation is used to provide a strong electromagnetic field environment at the compression point. By introducing a band-stop filter, the test power signal and the excitation power signal are separated, reducing the test error to a certain extent, and then using the resonance method to test the material. However, the aforementioned testing methods currently only test the electromagnetic parameters of materials under strong microwave field loading frequencies. Since microwave devices operate under the interference of complex environments with strong microwave electric fields, and the operating frequency of microwave devices and the interference frequency of strong microwave electric fields are often not in the same frequency band, such as in strong electromagnetic radiation locations such as radio communication base stations and radar stations, it is important to test the material electromagnetic parameter test frequency separately from the strong microwave electric field frequency. Currently, testing methods that separate the test frequency from the strong microwave electric field frequency have not been described. Summary of the Invention

[0004] In response to the problems existing in the background technology, the purpose of the present invention is to provide a system and method for measuring the electromagnetic parameters of materials in a strong microwave electric field environment based on parallel strip lines. The present invention innovatively designs a double-sided parallel strip line with a slotted structure, and constructs a measurement system under strong microwave electric field loading based on the double-sided parallel strip line. By separating the test frequency from the strong microwave electric field frequency, the test sample is tested, and the reflection coefficient and transmission coefficient of the test sample are obtained, thereby calculating the electromagnetic parameters of the material under the microwave strong field loading environment.

[0005] To achieve the above object, the technical solution of the present invention is as follows:

[0006] A strong microwave electric field environment material electromagnetic parameter measurement system based on parallel strip lines, including a strong microwave electric field environment loading device, a strong microwave electric field generating device and an electromagnetic parameter measuring device;

[0007] The strong microwave electric field generating device includes a first vector network analyzer, a first isolator, a second isolator, a power amplifier, a power meter, a first attenuator, a second attenuator and a directional coupler; the first port of the first vector network analyzer, the first isolator, the power amplifier, the second isolator and the input end of the directional coupler are connected in sequence, the second port of the first vector network analyzer, the second attenuator and the reflection end of the directional coupler are connected in sequence, the coupling end of the directional coupler is connected in sequence to the first attenuator and the power meter, and the output end of the directional coupler is connected to the strong microwave electric field environment loading device;

[0008] The electromagnetic parameter measuring device includes a second vector network analyzer, a transmitting antenna, a receiving antenna, and a metal reflective surface; the first port of the second vector network analyzer is connected to the transmitting antenna, and the second port is connected to the receiving antenna; the metal reflective surface includes two reflective surface units, and the two reflective surfaces are flush with each other for focusing the antenna beam; the transmitting antenna and the receiving antenna are arranged on both sides of the sample to be measured, and the centers of the transmitting antenna and the receiving antenna are flush with the centers of the reflective surface units; a strong microwave electric field environment loading device is arranged at the center of the transmitting antenna and the receiving antenna beam, and the E-plane direction of the transmitting antenna and the receiving antenna is perpendicular to the short side direction of the gap of the metal parallel strip line in the strong microwave electric field environment loading device;

[0009] The strong microwave electric field environment loading device includes a metal bracket, a terminal short-circuit plate, an N-type connector and a microstrip line; wherein the metal bracket is a rectangular metal frame with a hollow center, an N-type connector is arranged at the center of one short side of the metal bracket, and a terminal short-circuit plate is arranged at the center of the other short side; a microstrip line is arranged inside the metal bracket, and the microstrip line includes an impedance matching area and a slit parallel strip line;

[0010] The slit parallel strips include a first metal parallel strip and a second metal parallel strip of identical structure and size; the metal parallel strip is a metal plate with two symmetrical rectangular slits, and the two rectangular slits are symmetrical about a line connecting the center points of the two short sides of the metal bracket;

[0011] The impedance matching region is rectangular and fixedly disposed on the inner side of the metal bracket near the N-type connector, and does not contact the inner short side of the metal bracket to prevent short circuit of the microstrip line; the impedance matching region is symmetrical about the line connecting the center points of the two short sides of the metal bracket, and includes a rectangular dielectric plate and metal layers disposed on the upper and lower surfaces of the rectangular dielectric plate;

[0012] The metal layer on the upper surface includes a rectangular area and a gradient area. The probe of the N-type connector contacts the center of a short side of the rectangular area. The gradient area connects the rectangular area and one end of the first metal parallel strip line. The other end of the first metal parallel strip line is fixedly connected to the terminal short-circuit plate.

[0013] The metal layer on the lower surface is shaped like a rectangle and a trapezoid, wherein one long side of the rectangle is flush with the edge of the dielectric plate, the lower base of the trapezoid coincides with the other long side of the rectangle, the upper base is connected to one end of the second metal parallel strip line, and the other end of the second metal parallel strip line is fixedly connected to the terminal short-circuit plate;

[0014] The center of the long side of the metal bracket is slotted, and the sample to be tested or the metal short-circuit board is placed between the upper and lower layers of parallel metal strips through the slot of the long side of the metal bracket.

[0015] Furthermore, the transmitting antenna and the receiving antenna are linearly polarized pyramidal horn antennas.

[0016] Furthermore, when placing the metal short-circuit plate and the sample material to be tested in the double-sided parallel strip line strong microwave electric field environment loading device, the electromagnetic wave beam should be incident vertically on both surfaces, and during the placement process, ensure that the surface facing the transmitting antenna side is in the same position.

[0017] Furthermore, the size of the sample to be tested should completely cover the gap area of ​​the metal parallel strip lines.

[0018] Furthermore, the distance between the two rectangular gaps is 1-2 mm, the width of the rectangular gap is 2.5-2.5 mm, and the thickness of the metal parallel strip lines is 20-100 μm.

[0019] The present invention also provides a method for performing electromagnetic parameter testing based on the above-mentioned measurement system, comprising the following steps:

[0020] Step 1: Connect the measurement system and adjust the antenna so that the electromagnetic wave transmission path of the measurement system is directly connected and the received signal is maximized;

[0021] Step 2: Set the basic parameters of the second vector network analyzer and then perform TRL calibration on the measurement system.

[0022] Step 3: Place the sample to be tested at the center of the double-sided parallel strip line strong microwave electric field environment loading device, and move the receiving antenna away from the transmitting antenna in parallel. The moving distance is the thickness of the sample to be tested.

[0023] Step 4: Turn on the first vector network analyzer and adjust the power amplifier to create a strong microwave electric field loading environment at the sample to be tested, with the electric field intensity peak value E max The relationship between it and the input power P is:

[0024]

[0025] Where Z c is the characteristic impedance of the double-sided parallel strip line, d0 is the spacing between the double-sided parallel strip lines;

[0026] Step 4: Use the second vector network analyzer to measure the S of the sample under strong microwave electric field loading environment. 11材 、S 21材 Parameters, the reflection coefficient Γ and transmission coefficient T of the sample to be tested under vertical incidence are calculated as follows:

[0027]

[0028] in:

[0029]

[0030] Step 5: Based on the thickness d of the sample material to be tested, the reflection coefficient Γ and transmission coefficient T of the sample material to be tested under normal incidence, calculate the complex dielectric constant ε of the sample material to be tested r and complex magnetic permeability μ r , the specific formula is:

[0031]

[0032] in:

[0033] M=jlnT / (dk0) (7)

[0034] Where k0 is the wave number of the electromagnetic wave in free space.

[0035] Furthermore, the specific process of step 1 is: placing the metal short-circuit plate in a double-sided parallel strip line strong microwave electric field environment loading device, and adjusting the position of the transmitting and receiving antennas so that the S 11 、S 22 The curve should be as stable as possible and have the maximum value in the test frequency band, then take out the metal calibration plate, and adjust the position of the transmitting and receiving antennas so that the S21 The curve should be as smooth as possible and have the maximum value in the test frequency band.

[0036] Furthermore, the basic parameters in step 2 include test frequency, intermediate frequency bandwidth, etc.

[0037] Furthermore, in step 4, the measured S 11材 、S 21材 The parameters need to be time-gated.

[0038] The mechanism of the present invention is as follows: the present invention utilizes the electric field distribution characteristics of double-sided parallel strip lines, and enhances the field strength between the two parallel strip lines by using double-sided parallel strip lines and adopting terminal short-circuiting. At the same time, air is used as the medium of the ultra-thin parallel strip lines, and the parallel strip lines with slit structures are designed to ensure the transmittance of electromagnetic wave propagation, and finally realize the construction of a strong microwave electric field loading device; the present invention realizes the loading of a strong microwave electric field by designing an ultra-thin parallel strip line structure, and at the same time does not affect the extraction of material electromagnetic parameters by a material electromagnetic parameter testing device in free space. In addition, by designing parallel strip line structures with different operating frequencies, testing can be achieved under the separation of the test frequency and the strong microwave electric field frequency.

[0039] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0040] The present invention innovatively designs a double-sided parallel strip line based on the terminal short-circuit method as a strong microwave electric field loading device. The measurement system built based on the loading device realizes the decoupling of the test frequency and the strong microwave electric field frequency, that is, the test frequency is no longer determined by the microwave electric field frequency, thereby meeting the test requirements at different frequencies; the present invention uses the reflection coefficient and transmission coefficient obtained by measurement to calculate the electromagnetic parameters of the material to be tested under the strong microwave electric field loading environment, effectively solving the problem that the electromagnetic parameters of the material are difficult to test when the test frequency and the strong microwave electric field frequency are separated, and provides a reliable data testing method for the changes in the electromagnetic parameters of the material under the interference of strong microwave electric fields at different frequencies. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 This is a structural diagram of the electromagnetic parameter measurement system for materials in a strong microwave electric field environment of the present invention.

[0042] Figure 2 This is a schematic structural diagram of a strong microwave electric field environment loading device in the measurement system of the present invention;

[0043] Among them, (a) is a top view of the device, (b) is a bottom view of the device without 18 metal bracket structures, and (c) is a side view of the device without 18 metal bracket structures.

[0044] Figure 3This is a test curve of the complex dielectric constant of the absorbing material sample of Example 1 of the present invention.

[0045] Figure 1: 1 is a first vector network analyzer, 2 is a first isolator, 3 is a power amplifier, 4 is a second isolator, 5 is a power meter, 6 is a first attenuator, 7 is a second attenuator, 8 is a directional coupler, 9 is a second vector network analyzer, 10 is a transmitting antenna, 11 is a receiving antenna, 12 is a strong microwave electric field environment loading device, 13 is a metal reflecting surface, 14 is an N-type connector, 15 is a rectangular dielectric block, 16 is a slit parallel strip line, 17 is a terminal short-circuit plate, and 18 is a metal bracket. DETAILED DESCRIPTION

[0046] In order to make the objectives, technical solutions and advantages of the present invention more clear, the present invention is further described in detail below in conjunction with the implementation methods and drawings.

[0047] The electromagnetic parameter measurement system of materials in a strong microwave electric field environment based on parallel strip lines is shown in the diagram of the system structure. Figure 1 As shown, it includes a strong microwave electric field environment loading device, a strong microwave electric field generating device and an electromagnetic parameter measuring device;

[0048] A strong microwave electric field environment material electromagnetic parameter measurement system based on parallel strip lines, including a strong microwave electric field environment loading device, a strong microwave electric field generating device and an electromagnetic parameter measuring device;

[0049] The strong microwave electric field generating device includes a first vector network analyzer 1, a first isolator 2, a second isolator 4, a power amplifier 3, a power meter 5, a first attenuator 6, a second attenuator 7 and a directional coupler 8; the first port of the first vector network analyzer 1, the first isolator 2, the power amplifier 3, the second isolator 4 and the input end (IN) of the directional coupler 8 are connected in sequence, the second port of the first vector network analyzer 1, the second attenuator 7 and the reflection end of the directional coupler 8 are connected in sequence, the coupling end of the directional coupler 8 is connected in sequence to the first attenuator 6 and the power meter 5, and the output end (OUT) of the directional coupler 8 is connected to the strong microwave electric field environment loading device;

[0050] The electromagnetic parameter measuring device includes a second vector network analyzer 9, a transmitting antenna 10, a receiving antenna 11 and a metal reflective surface 13; the first port of the second vector network analyzer 9 is connected to the transmitting antenna 10, and the second port is connected to the receiving antenna 11; the metal reflective surface 13 includes two reflective surface units, and the two reflective surfaces are flush with each other for focusing the antenna beam; the transmitting antenna and the receiving antenna are arranged on both sides of the sample to be measured, and the centers of the transmitting antenna and the receiving antenna are flush with the centers of the reflective surface units; the strong microwave electric field environment loading device 12 is arranged at the center position of the beam of the transmitting antenna 10 and the receiving antenna 11, and the E-plane direction of the transmitting antenna 10 and the receiving antenna 11 is perpendicular to the short side direction of the gap of the metal parallel strip line in the strong microwave electric field environment loading device 12;

[0051] The structural diagram of the strong microwave electric field environment loading device 12 is as follows Figure 2 As shown, it includes a metal bracket 18, a terminal short-circuit plate 17, an N-type connector 14 and a microstrip line; wherein (a) is a top view of the device, (b) is a bottom view of the device without the metal bracket structure 18, and (c) is a side view of the device without the metal bracket structure 18; the metal bracket 18 is a rectangular metal frame with a hollow center, an N-type connector 14 is set at the center of the outer side of one short side of the metal bracket, and a terminal short-circuit plate 17 is set at the center of the other short side; a microstrip line is set inside the metal bracket 18, and the microstrip line includes an impedance matching area and a slit parallel strip line;

[0052] The slit parallel strips include a first metal parallel strip 16 and a second metal parallel strip 16 having the same structure and size. The metal parallel strips 16 are metal plates with two symmetrical rectangular slits, and the two rectangular slits are symmetrical about the line connecting the center points of the two short sides of the metal bracket.

[0053] The impedance matching region is rectangular and fixedly disposed on the inner side of the metal bracket near the N-type connector, and does not contact the inner short side of the metal bracket to prevent short circuit of the microstrip line; the impedance matching region is symmetrical about the line connecting the center points of the two short sides of the metal bracket, and includes a rectangular dielectric plate and metal layers disposed on the upper and lower surfaces of the rectangular dielectric plate;

[0054] The metal layer on the upper surface includes a rectangular area and a gradient area. The probe of the N-type connector contacts the center of a short side of the rectangular area. The gradient area connects the rectangular area and one end of the first metal parallel strip line. The other end of the first metal parallel strip line is fixedly connected to the terminal short-circuit plate.

[0055] The metal layer on the lower surface is shaped like a rectangle and a trapezoid, wherein one long side of the rectangle is flush with the edge of the dielectric plate, the lower base of the trapezoid coincides with the other long side of the rectangle, the upper base is connected to one end of the second metal parallel strip line, and the other end of the second metal parallel strip line is fixedly connected to the terminal short-circuit plate;

[0056] The impedance matching area is fixed by: a metal block and a set of metal strips are fixed at different heights inside the metal bracket; the metal strips and the metal block are symmetrical about the line connecting the center points of the two short sides of the metal bracket; the impedance matching area is set between the metal strip and the metal block and fixed by screws; and an arc-shaped notch is provided in the center of the metal block to facilitate the connection of the second metal parallel strip line to the metal layer on the lower surface;

[0057] The center of the long side of the metal bracket is slotted, and the sample to be tested or the metal short-circuit board is placed between the upper and lower layers of parallel metal strips through the slot of the long side of the metal bracket.

[0058] Example 1

[0059] This example uses a square absorbing material with a thickness of 1 mm and dimensions of 60 × 70 mm as the test sample. Its electromagnetic parameters are measured at normal incidence within the frequency range of 110–170 GHz. Linearly polarized horn antennas operating in the 110–170 GHz band are used as the transmitting and receiving antennas, and the parallel stripline high-field loading device operates at a frequency of 2.45 GHz.

[0060] The distance between the two rectangular gaps is 1.6 mm, the width of the rectangular gap is 1.8 mm, the length of the rectangular gap is 60 mm, the thickness of the metal parallel strip is 50 μm, the spacing between the two double-sided parallel strips is 1 mm, and the size of the metal bracket is 115×70 mm.

[0061] Place the square absorbing material between the upper and lower layers of parallel metal strips. The electromagnetic parameter test steps of the absorbing material under vertical incidence are as follows:

[0062] Step 1: Install the first vector network analyzer 1, the second vector network analyzer 9, the first isolator 2, the second isolator 4, the power amplifier 3, the power meter 5, the first attenuator 6, the second attenuator 7, the directional coupler 8, the transmitting antenna 10, the receiving antenna 11, the metal reflective surface 13 and the double-sided parallel strip line strong microwave electric field environment loading device 12 based on the terminal short-circuit method in sequence. The double-sided parallel strip line strong microwave electric field environment loading device 12 is set at the center position of the transmitting and receiving antenna beam, so that the E-plane direction of the transmitting and receiving antennas 10 and 11 is perpendicular to the arrangement direction of the double-sided parallel strip line 16. Place the metal short-circuit plate in the double-sided parallel strip line strong microwave electric field environment loading device 12, and adjust the positions of the transmitting and receiving antennas 10 and 11 so that the S 11 、S 22 The curve should be as stable as possible and have the maximum value in the test frequency band. Then take out the metal calibration plate and adjust the position of the transmitting and receiving antennas 10 and 11 so that the S 21 The curve should be as smooth as possible and have the maximum value in the test frequency band;

[0063] Step 2: Set basic parameters such as test frequency and intermediate frequency bandwidth on the second vector network analyzer 9, and then perform TRL calibration on the entire measurement system;

[0064] Step 3: Place and fix the sample material to be tested at the center of the double-sided parallel strip line strong microwave electric field environment loading device 12, move the receiving antenna 11 outward by the thickness of the sample material to be tested through the displacement platform, turn on the first vector network analyzer 1 and adjust the power amplifier 3, and detect the amplified power through the power meter 5. The double-sided parallel strip line strong microwave electric field loading device 12 can generate electric field intensities of different intensities under different power excitations, and can achieve strong field loading when the power output is relatively large, thereby meeting the electromagnetic parameter test of the sample material to be tested under strong microwave electric field loading, and the electric field intensity peak E that can be generated max The relationship between it and the input power P is:

[0065]

[0066] Where Z c is the characteristic impedance of the double-sided parallel strip line, d0 is the spacing between the double-sided parallel strip lines;

[0067] Step 4: Measure the S of the flat plate sample under the strong microwave electric field loading environment by the second vector network analyzer 9. 11材 、S 21材 Parameters, based on the measured S of the sample material under strong microwave electric field loading 11材 、S 21材 Parameters, the reflection coefficient Γ and transmission coefficient T of the sample material under vertical incidence can be calculated as follows:

[0068]

[0069] in:

[0070]

[0071] Step 5: Based on the thickness d of the sample material to be tested, the reflection coefficient Γ and transmission coefficient T of the sample material to be tested under normal incidence, calculate the complex dielectric constant ε of the sample material to be tested r and complex magnetic permeability μ r , the specific formula is:

[0072]

[0073] in:

[0074] M=jlnT / (dk0) (7)

[0075] Where k0 is the wave number of the electromagnetic wave in free space.

[0076] Figure 3 This is a test curve of the complex dielectric constant of the absorbing material sample of Example 1 of the present invention in the initial state without strong field loading in the 110-170 GHz frequency band and under 48 dBm continuous wave strong field loading at 2.45 GHz; wherein, Figure 3 (a) is the relative dielectric constant of the absorbing material in the 110-170 GHz frequency band, Figure 3 (b) is the loss tangent value of the absorbing material in the 110-170 GHz frequency band. Figure 3 In (a), in the initial state without strong field loading, the relative dielectric constant of the circular absorbing material is stable at around 1.10 in the 110-170 GHz frequency band. Under continuous wave strong field loading, the relative dielectric constant decreases and reaches a minimum value of around 1.00 at about 140 GHz. Figure 3 In (b), in the initial state without strong field loading, the loss tangent value of the circular absorbing material in the 110-170GHz band fluctuates between 0.010 and 0.015. Under continuous wave strong field loading, the loss tangent value changes slightly. Except for the 115GHz to 125GHz band, the loss tangent value is slightly smaller than the initial state without strong field loading. Figure 3 It can be seen from the test results that the test device can realize the test of the electromagnetic parameters of the material under the separation of the test frequency and the strong microwave electric field frequency, and the complex dielectric constant of the material under the enhanced microwave electric field at 2.45GHz has obvious changes compared with the initial state without strong field loading, indicating that the test device of the present invention can realize the test of special materials that affect the electromagnetic properties of the material under the strong microwave electric field environment.

[0077] The above description is only a specific embodiment of the present invention. Any feature disclosed in this specification, unless otherwise stated, can be replaced by other equivalent or alternative features with similar purposes; all disclosed features, or all steps in the methods or processes, except for mutually exclusive features and / or steps, can be combined in any way.

Claims

1. A system for measuring electromagnetic parameters of materials in a strong microwave electric field environment based on parallel strip lines, characterized by: It includes a strong microwave electric field environment loading device, a strong microwave electric field generating device and an electromagnetic parameter measuring device; The strong microwave electric field generating device includes a first vector network analyzer, a first isolator, a second isolator, a power amplifier, a power meter, a first attenuator, a second attenuator and a directional coupler; the first port of the first vector network analyzer, the first isolator, the power amplifier, the second isolator and the input end of the directional coupler are connected in sequence, the second port of the first vector network analyzer, the second attenuator and the reflection end of the directional coupler are connected in sequence, the coupling end of the directional coupler is connected in sequence to the first attenuator and the power meter, and the output end of the directional coupler is connected to the strong microwave electric field environment loading device; The electromagnetic parameter measuring device includes a second vector network analyzer, a transmitting antenna, a receiving antenna and a metal reflective surface; The first port of the second vector network analyzer is connected to the transmitting antenna, and the second port is connected to the receiving antenna; the metal reflective surface includes two reflective surface units, and the two reflective surfaces are flush with each other to focus the antenna beam; the transmitting antenna and the receiving antenna are arranged on both sides of the sample to be tested, and the centers of the transmitting antenna and the receiving antenna are flush with the centers of the reflective surface units; the strong microwave electric field environment loading device is arranged at the center of the transmitting antenna and the receiving antenna beam, and the E-plane direction of the transmitting antenna and the receiving antenna is perpendicular to the short side direction of the gap of the metal parallel strip line in the strong microwave electric field environment loading device; The strong microwave electric field environment loading device includes a metal bracket, a terminal short-circuit plate, an N-type connector and a microstrip line; wherein the metal bracket is a rectangular metal frame with a hollow center, an N-type connector is arranged at the center of one short side of the metal bracket, and a terminal short-circuit plate is arranged at the center of the other short side; a microstrip line is arranged inside the metal bracket, and the microstrip line includes an impedance matching area and a slit parallel strip line; The slit parallel strips include a first metal parallel strip and a second metal parallel strip of identical structure and size; the metal parallel strip is a metal plate with two symmetrical rectangular slits, and the two rectangular slits are symmetrical about a line connecting the center points of the two short sides of the metal bracket; The impedance matching region is rectangular and fixedly disposed on the inner side of the metal bracket near the N-type connector, and does not contact the inner short side of the metal bracket to prevent short circuit of the microstrip line; the impedance matching region is symmetrical about the line connecting the center points of the two short sides of the metal bracket, and includes a rectangular dielectric plate and metal layers disposed on the upper and lower surfaces of the rectangular dielectric plate; The metal layer on the upper surface includes a rectangular area and a gradient area. The probe of the N-type connector contacts the center of a short side of the rectangular area. The gradient area connects the rectangular area and one end of the first metal parallel strip line. The other end of the first metal parallel strip line is fixedly connected to the terminal short-circuit plate. The metal layer on the lower surface is shaped like a rectangle and a trapezoid, wherein one long side of the rectangle is flush with the edge of the dielectric plate, the lower base of the trapezoid coincides with the other long side of the rectangle, the upper base is connected to one end of the second metal parallel strip line, and the other end of the second metal parallel strip line is fixedly connected to the terminal short-circuit plate; The center of the long side of the metal bracket is slotted, and the sample to be tested or the metal short-circuit board is placed between the upper and lower layers of parallel metal strips through the slot of the long side of the metal bracket.

2. The electromagnetic parameter measurement system for materials in a strong microwave electric field environment as claimed in claim 1, characterized in that: The transmitting antenna and the receiving antenna are linearly polarized pyramidal horn antennas.

3. The strong microwave electric field environment material electromagnetic parameter measurement system according to claim 1, characterized in that: When placing the metal short-circuit plate and the sample material to be tested in the double-sided parallel strip line strong microwave electric field environment loading device, the electromagnetic wave beam should be incident vertically on both surfaces, and during the placement process, ensure that the surface facing the transmitting antenna side is in the same position.

4. The strong microwave electric field environment material electromagnetic parameter measurement system according to claim 1, characterized in that: The size of the sample to be tested should completely cover the gap area of ​​the metal parallel strip lines.

5. The strong microwave electric field environment material electromagnetic parameter measurement system according to claim 1, characterized in that: The distance between the two rectangular gaps is 1-2 mm, the width of the rectangular gap is 2.5-2.5 mm, and the thickness of the metal parallel strip line is 20-100 μm.

6. A method for testing electromagnetic parameters based on the electromagnetic parameter measurement system for materials in a strong microwave electric field environment according to any one of claims 1 to 5, characterized in that: The following steps are involved: Step 1: Connect the measurement system and adjust the antenna so that the electromagnetic wave transmission path of the measurement system is directly connected and the received signal is maximized; Step 2: Set the basic parameters of the second vector network analyzer and then perform TRL calibration on the measurement system. Step 3: Place the sample to be tested at the center of the double-sided parallel strip line strong microwave electric field environment loading device, and move the receiving antenna away from the transmitting antenna in parallel. The moving distance is the thickness of the sample to be tested. Step 4: Turn on the first vector network analyzer and adjust the power amplifier to create a strong microwave electric field loading environment at the sample to be tested, with the electric field intensity peak value E max The relationship between it and the input power P is: Where Z c is the characteristic impedance of the double-sided parallel strip line, d0 is the spacing between the double-sided parallel strip lines; Step 4: Use the second vector network analyzer to measure the S of the sample under strong microwave electric field loading environment. 11材 、S 21材 Parameters, the reflection coefficient Γ and transmission coefficient T of the sample to be tested under vertical incidence are calculated as follows: in: Step 5: Based on the thickness d of the sample material to be tested, the reflection coefficient Γ and transmission coefficient T of the sample material to be tested under normal incidence, calculate the complex dielectric constant ε of the sample material to be tested r and complex magnetic permeability μ r , the specific formula is: in: M=jlnT / (dk0) (7) Where k0 is the wave number of the electromagnetic wave in free space.

7. The method for electromagnetic parameter testing according to claim 6, wherein: The specific process of step 1 is: place the metal short-circuit plate in the double-sided parallel strip line strong microwave electric field environment loading device, and adjust the position of the transmitting and receiving antennas so that the S 11 、S 22 The curve should be as stable as possible and have the maximum value in the test frequency band, then take out the metal calibration plate, and adjust the position of the transmitting and receiving antennas so that the S 21 The curve should be as smooth as possible and have the maximum value in the test frequency band.

8. The method for electromagnetic parameter testing according to claim 6, wherein: The basic parameters in step 2 include the test frequency and IF bandwidth.

9. The method for electromagnetic parameter testing according to claim 6, wherein: In step 4, the measured S 11材 、S 21材 The parameters need to be time-gated.

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