CN113970670B - Foil strip air-mixed dielectric constant measuring method, system, equipment, medium and terminal - Google Patents

Abstract

The invention belongs to the technical field of microwave measurement and analysis of material dielectric constant, and discloses a foil strip air-mixed dielectric constant measuring method, wherein the foil strip air-mixed dielectric constant measuring system comprises: the device comprises a device connecting module, a device calibrating module, a target measuring module, a data acquisition module and an image processing module. The invention measures the material dielectric constant according to the measuring equipment of the rectangular waveguide method, choose different filling rates to measure the mixed dielectric constant of the foil strip air; deducing the dielectric constant of a sample to be tested by using a scattering equation of an NRW transmission/reflection method, filling different foil strip numbers in a rectangular waveguide to control the filling rate, and measuring the mixed dielectric constant of foil strip air, so that the calibration problem in the experiment is solved, and the blank of the experiment process is filled; the method has the advantages that the specific data of the air mixing dielectric constant of the foil strips are obtained, the most real and effective data are provided for the subsequent research on the propagation characteristics of the foil strip interferent, and a data basis is laid for the subsequent research on novel materials.

Description

Method, system, equipment, medium and terminal for measuring the dielectric constant of chaff-air mixture

technical field

The invention belongs to the technical field of microwave measurement and analysis of the dielectric constant of materials, and in particular relates to a method for measuring the dielectric constant of a foil-air mixture.

Background technique

At present, chaff is widely used in modern maritime electronic warfare due to its low price, simple manufacturing process and excellent radar jamming performance. As a light air-reflecting target cloud, it can be generated by alternating electromagnetic fields in a certain space. The alternating current is induced to radiate electromagnetic waves twice, which plays a passive role in the target radar. There is no need to analyze and understand radar information during the use of chaff jammers, but the research on radar equipment is expanding to the microwave stage, and the anti-jamming performance is gradually strengthened. chaff material. The chaff currently used in the market is mainly made of glass fiber as the base and coated with metal foil, or directly using metal wire and metal-coated medium. From the three aspects of characteristics and radio wave propagation characteristics, there are few studies on the statistical relative permittivity of chaff. If it is regarded as a dielectric material to study its electrical properties, it can provide reference data for the research and application of chaff materials.

The study of electrical properties of dielectric materials has broad application prospects and significant academic value in both materials science and electromagnetics. In the field of materials science, chaff is the longest-used and most widely used passive interferer. Most of today's chaff materials use glass fiber to maintain rigidity, and a uniform thin metal layer is plated on a very fine glass fiber carrier. It has good electrical properties on the basis of light weight, good dispersibility, low cost and easy processing. Therefore, measuring the dielectric constant of the chaff is of great significance for the research and development of new chaff materials. Through these studies, we can understand the characteristics and laws of the microstructure of the medium, which is convenient for in-depth research on some laws and characteristics of its molecular structure or material structure; at the same time, through the study of its characteristics, it is possible for us to obtain new types that meet technical requirements. some dielectric materials. In the field of electromagnetism, through the measurement of the dielectric constant, we can understand the interaction between electromagnetic waves and the medium and the field change, and by connecting the macroscopic phenomenon of medium polarization with the microscopic structure of the medium. The research on the measurement of the dielectric constant of the air-mixed medium of chaff is currently blank, and the experimental measurement steps of the air-mixed dielectric constant of the chaff are rarely introduced. The research on the passive interference performance of the strip is of great significance. Therefore, it is of great practical significance to study the measurement method of the dielectric constant of chaff to achieve efficient and accurate measurement for the subsequent application and research of chaff materials.

There are two methods to study the dielectric constant of materials: modeling and measurement. Modeling can better grasp the properties of the dielectric constant and facilitate the learning of formulas. Measurement can obtain measured data, and the results are more real and accurate. The research focus of the present invention lies in the experimental measurement, which is the most direct and effective method for the study of the electrical properties of the medium, and the data of the dielectric constant obtained by the experimental method has higher practical value. The measurement of dielectric constant is mainly concentrated in the microwave stage, and the measurement methods include free space method, probe method, resonant cavity method, transmission line method, and waveguide transmission/reflection method. The free space method is used for large-area open measurement. There are mainly two types of reflection method and transmission method. However, in the measurement process, the reflection method cannot cover the metal plate due to the small number of chaff samples, resulting in scattering or secondary reflection, and it is impossible to accurately measure a single sheet. The value of sub-reflection, the measurement accuracy is not high; the transmission method has difficulties in the calibration of the position of the chaff, and due to the small size of the chaff, diffraction and other phenomena will occur during the measurement process. Although the measurement results of the probe method are stable and have high precision, the measurement results can only be within a certain range. The sample preparation of the resonant cavity method is difficult, the cost is high, the design is complicated, and it is not suitable for the measurement of the dielectric constant of the chaff. The transmission line method will cause changes in the intrinsic properties of the sample processing, which will make the measurement results deviate from the actual results. Compared with the previous methods, the waveguide transmission/reflection method has higher measurement accuracy and is easier to calculate. The error caused by sample placement can be solved by calibration. Therefore, this measurement adopts the waveguide method, specifically the rectangular waveguide method.

The essence of the dielectric constant measurement by the waveguide method is to use the sample to be tested as a two-port network, measure the S parameters of the two ports, namely S ₁₁ , S ₁₂ , S ₂₁ , S ₂₂ , and use the scattering equation of the NRW transmission/reflection method to derive The dielectric constant of the sample to be tested. However, at this stage, the specific experimental scheme for the measurement experiment of the air mixed dielectric constant of the chaff is scarce, and there are many errors and difficulties in the actual measurement process. How to design the experiment and the actual operation is the top priority of the present invention. The S value tested in the experimental measurement process is not the scattering parameter of the end face of the sample to be tested, which requires the addition of the hardware calibration process of the coaxial waveguide converter; the cutting, placement and packaging of the chaff during the experimental process are also technical difficulties.

Through the above analysis, the existing problems and defects in the prior art are: the design scheme of the specific experiment and the detailed experimental process for measuring the air-mixed dielectric constant of the chaff by using the rectangular waveguide method are blank at this stage. The theoretical analysis of constants is less.

The difficulty of solving the above problems and defects is as follows:

(1) The specific experimental design of the rectangular waveguide method to measure the dielectric constant of the chaff-air mixture.

(2) The specific steps of the experiment and the detailed flow description of the operation.

(3) Theoretical analysis of measuring scattering constant and inversion of dielectric constant by rectangular waveguide method.

The significance of solving the above problems and defects is: to fill the gap of experimental design for the measurement of the relative permittivity of chaff clouds, to propose an analysis method, to lay a certain theoretical foundation for subsequent experimental measurements, and to promote the development of electromagnetic measurement experiments. The experimental measurement provides practical and reliable measured data for the research and development of chaff materials, which is of great significance to the research of materials science.

SUMMARY OF THE INVENTION

Aiming at the problems existing in the prior art, the present invention provides a method for measuring the air-mixed dielectric constant of chaff, in particular to the design and measurement system of an experimental scheme for measuring the air-mixed dielectric constant of chaff by a rectangular waveguide method.

The present invention is realized in this way, a method for measuring the air-mixed dielectric constant of a chaff strip, which comprises the following steps:

Step 1: Select the experimental site, prepare the experimental instruments and materials to be tested, connect the computer and the vector network analyzer, turn on the power supply to supply power to the equipment, and check whether the connection of the lines is correct. Prepare the experimental equipment and check the connection of the circuit in advance, which provides convenience for the measurement of subsequent experiments and eliminates possible safety hazards;

Step 2: Connect the coaxial cable to the port of the vector network analyzer, open the computer measurement software to set parameters, and connect the coaxial cable and the coaxial waveguide converter to the port of the vector network analyzer. A whole, which simplifies the subsequent calibration process;

Step 3, start the calibration, calibrate the two-port scattering parameters of the vector network analyzer to the two end faces of the measurement waveguide, and eliminate the errors caused by the loss of the experimental components during the experiment. This calibration procedure is simpler, and simplifies the process of calibrating the vector network analyzer, coaxial line, coaxial line to measuring the end face of the waveguide, and is suitable for the calibration process of the measurement experiment using the rectangular waveguide method;

Step 4: The essence of using the waveguide method to measure the dielectric constant is to use the sample to be tested as a two-port network, and the data tested by the vector network analyzer are the scattering parameters of the medium, that is, the S parameters S ₁₁ , S ₁₂ , S ₂₁ of the two ports, S ₂₂ , using the scattering equation of the NRW transmission/reflection method to deduce the dielectric constant of the sample to be tested, the theoretical research on the inversion derivation is very mature, and provides a strong theoretical basis for the invention;

Step 5, stick the polypropylene film material on the surface of the rectangular waveguide, encapsulate the air in the rectangular waveguide, measure the dielectric constant under this condition, record and save the data, compare the dielectric constant data of the unencapsulated air, and verify the poly The propylene film material has no effect on the method of measuring the dielectric constant of the medium by the rectangular waveguide method. This verification process is the focus of this experiment. The experimental data proves that the polypropylene film material has little influence on the experimental measurement process. The polypropylene film material is used to encapsulate the medium. The experiment of the material was carried out, and the error caused by the packaging process was ruled out;

Step 6: Use polypropylene membrane material to encapsulate the soil, measure the soil-air mixing permittivity, record and save the data, query the existing empirical model, verify the accuracy of the soil permittivity data, and prove the feasibility of the experiment. The measurement of the dielectric constant of the mixed medium with the existing empirical model provides an idea for the measurement of the chaff-air mixed medium, and verifies the feasibility of the rectangular waveguide method to measure the dielectric constant of the mixed medium;

Step 7: Cut the chaff material, control the number of chaff strips to control the filling rate, use polypropylene film material for packaging, measure the air-mixing dielectric constant of the chaff strip, record and save the data, this process is controlled by the variable method To change the foil to be tested, observe and study the data of the dielectric constant of the mixed medium under different conditions, find the dielectric constant law of the chaff-air mixed medium, and provide data support for the follow-up study of its scattering characteristics;

Step 8: Analyze the experimental data graph, conduct experimental error analysis, and make experimental data analysis graphs and data comparison graphs. The experimental results are more intuitive and clear, which is convenient for studying the existing laws and analyzing the errors in the experimental process, and provides follow-up improvement. ideas.

Further, in step 1, select the experimental site, prepare experimental instruments and materials to be tested, connect the computer and the vector network analyzer, turn on the power supply to supply power to the equipment, and check whether the connection of the lines is correct, including:

(1) Select an open area for experimental measurement to avoid interference to the measurement system caused by other instruments;

(2) The measurement system includes a vector network analyzer, a computer, a twisted pair cable, two coaxial cables, a set of calibration parts, a set of rectangular waveguide parts, a roll of polypropylene film material, a soil Several pieces, several chaff strips, a pair of scissors, a ruler, and tweezers; use a twisted pair cable to connect the RJ45 interface of the computer with the LAN port of the vector network analyzer;

(3) Pay attention to the protection of the vector network analyzer before connecting the power supply, pay attention to the maximum withstand power, beware of high power damage to the port, turn on the power supply, turn on the vector network analyzer and the computer, and use the measurement software on the computer to check whether the line is connected , the experimental measurement can be carried out after the connection is completed.

Further, in step 2, the coaxial line is connected to the port of the vector network analyzer, and the computer measurement software is opened to set parameters, including:

Connect the coaxial cable to the port of the vector network analyzer, open the computer testing software to set the parameters, select the frequency band, set the start frequency, stop frequency, and the number of measurement points, and confirm that the set parameters are consistent on the vector network analyzer.

Further, in step 3, the calibration is started, and the two-port scattering parameters of the vector network analyzer are calibrated to the two end faces of the measurement waveguide, so as to eliminate the errors caused by the loss of the experimental components during the experiment, including:

(1) Select the calibration button on the vector network analyzer, select the calibration type as non-guided calibration, use mechanical calibration parts for response calibration, single-port calibration, dual-port calibration, select full dual-port TRL in non-guided calibration, ignoring isolation Two buttons to go to the next step;

(2) Straight-through, port 1 reflection, port 2 reflection, line/match calibration in sequence according to the instructions;

(3) Connect the coaxial waveguide converters to the two ends of the coaxial cable respectively, and use the pins to connect the coaxial waveguide converters together. When connecting, the pins are inserted into the holes diagonally opposite each other; after the connection is completed, click the through button and click THRU Press the button, the instrument starts to calibrate, and after completion, press the OK button to proceed to the next calibration;

(4) Connect the shorting pieces at both ends of the coaxial waveguide converter, use pins to connect the devices, click the port 1 reflection button, click the THRU button, and press the OK button after the calibration is completed to proceed to the next calibration;

(5) The reflection step of port 2 is the same as (4), and the next step is calibrated after completion;

(6) Connect the rectangular waveguide sheet to both ends of the coaxial waveguide converter, pay attention to the position of the corresponding rectangle when connecting, press the line/match calibration button, click the BJ-220, that is, the λ/4LINE button, and press the OK button after the calibration is completed. The calibration step is completed;

(7) When exiting the guide, the calibration set will be saved to channel 1 for long-term use.

Further, in step 4, the essence of using the waveguide method to measure the dielectric constant is to use the sample to be tested as a two-port network, and the data tested by the vector network analyzer are the scattering parameters of the medium, that is, the S parameters S ₁₁ , S of the two ports. ₁₂ , S ₂₁ , S ₂₂ , use the scattering equation of the NRW transmission/reflection method to deduce the dielectric constant of the sample to be tested, including:

When the electromagnetic wave propagates in the waveguide transmission line, its transmission characteristics have nothing to do with the position, and only reflection and transmission occur at the boundary surface of the medium. VI represents the incident voltage, _{VR represents} the reflected voltage, and VT represents the total transmission voltage _. The following relationship is established, which is also the definition of scattering parameters, namely:

VR = _{S 11} ·V _I ;

V _T =S ₂₁ · _VI ;

If the incident voltage is set to 1, the scattering parameters are expressed as the total incident voltage _VR and the total transmission voltage _VT , namely:

_{S 11} =VR ;

S ₂₁ =V _T ;

The single reflection coefficient of the interface between the air and the medium is Γ, and the transmission coefficient of the two surfaces of the measured medium is T. The size of the scattering parameter can be deduced, namely:

set up:

V ₁ =S ₂₁ +S ₁₁ ;

V ₂ =S ₂₁ -S ₁₁ ;

Derive:

The relationship between the relative complex permeability μ _r and relative complex permittivity ε _r of known materials and the propagation constant γ is:

where μ _r is the relative complex permeability of the material, ε _r is the relative complex permittivity, is the propagation constant of the measured sample segment, λ ₀ is the operating wavelength in air, λ _c is the cut-off wavelength of the waveguide transmission line, j is an imaginary unit.

d is the thickness of the sample to be tested, and the relationship between the transmission coefficient of the sample to be tested and the propagation constant is:

T=e- ^γd ;

Derive from the above formula:

Among them, Z ₀ represents the characteristic impedance of the air region in the transmission line, and Z represents the characteristic impedance of the sample section of the measured medium.

The reflection coefficient Γ is expressed as:

The relative complex permeability μ _r and relative complex permittivity ε _r of the measured medium are obtained as:

In the formula,

and there is:

Among them, λ _g is the waveguide wavelength of the sample to be measured. For the measurement system of the coaxial transmission line, the cut-off wavelength λ _c =∞, and for the measurement system based on the rectangular waveguide, the cut-off wavelength λ _c =2a.

Based on the principle of NRW transmission/reflection algorithm, open the computer test software and set the parameter to be dielectric constant measurement, bidirectional test, the distance to port A and port B are set to 0.000mm, the sample thickness is set to 4.500mm, click to measure, observe In the data graph that appears on the panel, the test result is that the real part of the dielectric constant of air is 1 and the imaginary part is 0, indicating that the calibration is successful, and the real and imaginary data of the air dielectric constant measured at this time are saved.

Further, in step 5, the polypropylene film material is attached to the surface of the rectangular waveguide, the air in the rectangular waveguide is encapsulated, the dielectric constant under this condition is measured, the data is recorded and saved, and the dielectric of the air without encapsulation is compared. Constant data to verify that the polypropylene film material has no effect on the method of measuring the dielectric constant of the dielectric by the rectangular waveguide method, including:

(1) Measure the size of the rectangular waveguide, cut the polypropylene film material into two rectangles of different sizes, and stick to each other to ensure that the rectangular aperture is completed with polypropylene material and can be adhered to the surface of the rectangular waveguide to avoid subsequent chaff air During the experimental measurement of the dielectric constant of the mixed medium, the chaff material adheres to the surface of the polypropylene material;

(2) Encapsulate both ends of the rectangular waveguide sheet with polypropylene film material, connect the rectangular waveguide sheet to the coaxial waveguide converter, and use the test software in the computer to measure the dielectric constant of the packaged polypropylene film material. Measure, record the data, compare the real and imaginary parts of the measured air permittivity, and exclude the polypropylene film material has no effect on the method of measuring the dielectric permittivity of the medium by the rectangular waveguide method.

In step 6, the soil is encapsulated by the polypropylene film material, the soil-air mixed dielectric constant is measured, the data is recorded and saved, the existing empirical model is inquired, the accuracy of the soil dielectric constant data is verified, and the experimental effect on the mixed medium dielectric constant is proved. Feasibility of electric constant measurement, including:

Open the packaged rectangular waveguide, and fill the soil to be tested into the rectangular waveguide. During the filling process, the soil needs to be spread into the waveguide, and the waveguide should be filled as much as possible. Due to the elasticity of the polypropylene film material, care should be taken that the filled soil does not exceed In the encapsulation area of polypropylene film material, the encapsulated rectangular waveguide sheet is connected to the coaxial waveguide converter to measure the dielectric constant of soil-air mixture, record the data, and compare the tested data with the data in the soil empirical model to verify Experimental feasibility of hybrid permittivity measurements.

Further, in step 7, the chaff material is cut, the number of chaff strips is controlled to control the filling rate, the polypropylene film material is used for packaging, the measurement of the air-mixed dielectric constant of the chaff strip is performed, and the data is recorded and saved, including :

(1) Take out the tested soil sample, clean the surrounding of the rectangular waveguide, and restore it to the state before the soil test;

(2) Preparation of dielectric samples: process as carefully as possible to keep the flatness of the dielectric samples, cut the foil strips into long strips, place them along the length of the rectangular waveguide, and fill 2, 4, 6, and 8 respectively. , 10, 12, 14, 16 chaff strips to test, record the experimental data, and observe the data law.

In the eighth step, the analysis of the experimental data graph and the reflection on the possibility of causing experimental errors in the experimental process include:

Process the experimental data, draw a graph of the relationship between frequency and dielectric permittivity, compare the effects of different filling rates on the permittivity of the chaff-air mixture, and analyze the influence of possible errors in the experimental process on the experimental data.

Another object of the present invention is to provide a chaff-air-mixed dielectric constant measurement system using the method for measuring the chaff-air-mixed dielectric constant. The chaff-air-mixed dielectric constant measurement system includes:

The equipment connection module is used for the dielectric constant system of the whole rectangular waveguide method to test the medium. Use the twisted pair cable to connect the computer to the vector network analyzer, use the power cable to connect the power supply to the vector network analyzer, and connect the coaxial cable to the vector network analyzer. Two ports of the vector network analyzer, and connect two coaxial waveguide converters at the ports, place the medium in the rectangular waveguide, connect the coaxial waveguide converters, and connect the devices into a channel;

The equipment calibration module is used to calibrate the measurement error existing in the system after the test system is built;

The target measurement module is used to measure the scattering parameters of the medium loaded in the rectangular waveguide, and set the starting frequency, ending frequency, and the number of test points;

The data acquisition module is used to test the scattering constant of different dielectric materials, obtain the dielectric constant data through the test software, and perform the test by changing the filling rate of the dielectric material, and save the data for subsequent image analysis;

The graphics processing module is used for image processing of the collected data, and intuitively analyzes the influence of different conditions on the dielectric constant data of the medium.

Another object of the present invention is to provide a computer device, the computer device includes a memory and a processor, the memory stores a computer program, and when the computer program is executed by the processor, the processor executes the following step:

Select the experimental site, prepare the experimental instruments and materials to be tested, connect the computer and the vector network analyzer, turn on the power supply to supply power to the equipment, and check whether the connection of the line is correct; connect the coaxial cable to the port of the vector network analyzer, open the The computer measurement software sets the parameters; starts the calibration, calibrates the two-port scattering parameters of the vector network analyzer to the two end faces of the measurement waveguide, and eliminates the error caused by the loss of the experimental components during the experiment; the essence of using the waveguide method to measure the dielectric constant is to The sample to be tested is used as a two-port network, and the data measured by the vector network analyzer are the scattering parameters of the medium, that is, the S-parameters S ₁₁ , S ₁₂ , S ₂₁ , S ₂₂ of the two ports, which are derived using the scattering equation of the NRW transmission/reflection method. Get the dielectric constant of the sample to be tested;

Paste the polypropylene film material on the surface of the rectangular waveguide, encapsulate the air in the rectangular waveguide, measure the dielectric constant under this condition, record and save the data, compare the dielectric constant data of the unencapsulated air, and verify the polypropylene film material It has no effect on the method of measuring the dielectric constant of the medium by the rectangular waveguide method; the soil is encapsulated with a polypropylene film material, the dielectric constant of the soil-air mixture is measured, the data is recorded and saved, the existing empirical model is inquired, and the accuracy of the soil dielectric constant data is verified. To prove the feasibility of the experiment; cut the chaff material, control the number of chaff strips to control the filling rate, use polypropylene film material for packaging, measure the dielectric constant of the air mixture of the chaff strip, record and save the data; analysis; Experimental data graphs, and experimental error analysis.

Another object of the present invention is to provide a computer-readable storage medium, which stores a computer program, and when the computer program is executed by a processor, causes the processor to perform the following steps:

Select the experimental site, prepare the experimental instruments and materials to be tested, connect the computer and the vector network analyzer, turn on the power supply to supply power to the equipment, and check whether the connection of the line is correct; connect the coaxial cable to the port of the vector network analyzer, open the The computer measurement software sets the parameters; starts the calibration, calibrates the two-port scattering parameters of the vector network analyzer to the two end faces of the measurement waveguide, and eliminates the error caused by the loss of the experimental components during the experiment; the essence of using the waveguide method to measure the dielectric constant is to The sample to be tested is used as a two-port network, and the data measured by the vector network analyzer are the scattering parameters of the medium, that is, the S-parameters S ₁₁ , S ₁₂ , S ₂₁ , S ₂₂ of the two ports, which are derived using the scattering equation of the NRW transmission/reflection method. Get the dielectric constant of the sample to be tested;

Paste the polypropylene film material on the surface of the rectangular waveguide, encapsulate the air in the rectangular waveguide, measure the dielectric constant under this condition, record and save the data, compare the dielectric constant data of the unencapsulated air, and verify the polypropylene film material It has no effect on the method of measuring the dielectric constant of the medium by the rectangular waveguide method; the soil is encapsulated with a polypropylene film material, the dielectric constant of the soil-air mixture is measured, the data is recorded and saved, the existing empirical model is inquired, and the accuracy of the soil dielectric constant data is verified. To prove the feasibility of the experiment; cut the chaff material, control the number of chaff strips to control the filling rate, use polypropylene film material for packaging, measure the dielectric constant of the air mixture of the chaff strip, record and save the data; analysis; Experimental data graphs, and experimental error analysis.

Another object of the present invention is to provide an information data processing terminal, the information data processing terminal is used for realizing the above-mentioned system for measuring the dielectric constant of the chaff-air mixture.

In combination with all the above technical solutions, the advantages and positive effects of the present invention are: the system for measuring the air-mixed dielectric constant of the chaff provided by the present invention relates to a method for measuring the parameters of dielectric materials by the waveguide method, and specifically relates to the rectangular waveguide method for measuring the chaff The design of the experimental plan of the air-mixed dielectric constant and the analysis method of inverting the dielectric constant from the S-parameter can provide the data of the air-mixed dielectric constant of the chaff, which provides the most realistic and effective research on the propagation characteristics of the chaff interferers. The data laid a data foundation for the follow-up research on new materials, and found the law about the dielectric constant of the mixed medium from the measured data, providing data proof for the research of the mixed medium.

The invention uses the scattering equation of the NRW transmission/reflection method to deduce the dielectric constant of the sample to be tested, fills the rectangular waveguide with different numbers of foil strips to control the filling rate, measures the mixed dielectric constant of the foil strip air, and simultaneously The calibration problem in the experiment is solved, the calibration steps are simplified, a new idea is provided for the experimental measurement, and the blank of the experimental process is filled. The invention obtains the specific data of the air-mixing dielectric constant of the chaff, provides the most real and effective data for the subsequent research on the propagation characteristics of the chaff interferer, and lays a data foundation for the subsequent research on the new material.

The invention is based on the measuring device for measuring the dielectric constant of the substance by the rectangular waveguide method, adopts the control variable method, and measures the mixed dielectric constant of the air of the chaff by selecting different filling rates, and provides the method for measuring the dielectric constant of the substance by the rectangular waveguide method. The specific experimental design and experimental steps also solve the calibration problem in the experiment and make up for the blank of the experimental process. The invention uses the scattering equation of the NRW transmission/reflection method to deduce the dielectric constant of the sample to be tested, and obtains the specific data of the dielectric constant of the chaff-air mixture.

Description of drawings

In order to illustrate the technical solutions of the embodiments of the present invention more clearly, the following will briefly introduce the accompanying drawings that need to be used in the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can also be obtained from these drawings without creative effort.

FIG. 1 is a flowchart of a method for measuring the dielectric constant of a chaff-air mixture provided by an embodiment of the present invention.

2 is a structural block diagram of a system for measuring the dielectric constant of a chaff-air mixture provided by an embodiment of the present invention;

In the figure: 1. Equipment connection module; 2. Equipment calibration module; 3. Target measurement module; 4. Data acquisition module; 5. Graphics processing module.

FIG. 3 is a structural diagram of a waveguide method measurement system provided by an embodiment of the present invention.

FIG. 4 is a schematic diagram of setting parameters of test software bands provided by an embodiment of the present invention.

FIG. 5 is a schematic diagram of setting the frequency and the number of measurement points of the test software provided by the embodiment of the present invention.

FIG. 6 is a flowchart of calibration of a rectangular waveguide provided by an embodiment of the present invention.

FIG. 7 is a graph showing the variation of the real part of the measured air dielectric constant with frequency according to an embodiment of the present invention.

FIG. 8 is a graph showing the variation of the imaginary part of the measured air dielectric constant with frequency according to an embodiment of the present invention.

FIG. 9 is a schematic diagram of a waveguide sheet packaged with a polypropylene material according to an embodiment of the present invention.

FIG. 10 is an actual measurement diagram of the dielectric constant measured by the rectangular waveguide method provided by the embodiment of the present invention.

FIG. 11 is a comparison diagram of real part data of air dielectric constant before and after packaging according to an embodiment of the present invention.

FIG. 12 is a comparison diagram of imaginary part data of air dielectric constants before and after packaging according to an embodiment of the present invention.

FIG. 13 is a graph showing the variation of the real part of the dielectric constant of soil-air mixture with frequency according to an embodiment of the present invention.

FIG. 14 is a graph showing the variation of the imaginary part of the dielectric constant of soil-air mixture with frequency according to an embodiment of the present invention.

FIG. 15 is a graph showing the variation of the real part of the air-mixed dielectric constant of the chaff with frequency when two chaffs are filled according to an embodiment of the present invention.

FIG. 16 is a graph showing the variation of the imaginary part of the air-mixed dielectric constant of the chaff with frequency when two chaffs are filled according to an embodiment of the present invention.

FIG. 17 is a graph showing the variation of the real part of the air-mixed dielectric constant of the chaff with frequency when four chaffs are filled according to an embodiment of the present invention.

FIG. 18 is a graph showing the variation of the imaginary part of the air-mixed dielectric constant of the chaff with frequency when four chaffs are filled according to an embodiment of the present invention.

FIG. 19 is a graph showing the variation of the real part of the air-mixed dielectric constant of the chaff with frequency when 6 chaffs are filled according to an embodiment of the present invention.

FIG. 20 is a graph showing the variation of the imaginary part of the air-mixed dielectric constant of the chaff with frequency when 6 chaffs are filled according to an embodiment of the present invention.

FIG. 21 is a graph showing the variation of the real part of the air-mixed dielectric constant of the chaff with frequency when 8 chaffs are filled according to an embodiment of the present invention.

FIG. 22 is a graph showing the variation of the imaginary part of the air-mixed dielectric constant of the chaff with frequency when eight chaffs are filled according to an embodiment of the present invention.

FIG. 23 is a graph showing the variation of the real part of the air-mixed dielectric constant of the chaff with frequency when 10 chaffs are filled according to an embodiment of the present invention.

FIG. 24 is a graph showing the variation of the imaginary part of the air-mixed dielectric constant of the chaff with frequency when 10 chaffs are filled according to an embodiment of the present invention.

FIG. 25 is a graph showing the variation of the real part of the air-mixed dielectric constant of the chaff with frequency when 12 chaffs are filled according to an embodiment of the present invention.

FIG. 26 is a graph showing the variation of the imaginary part of the air-mixed dielectric constant of the chaff with frequency when 12 chaffs are filled according to an embodiment of the present invention.

FIG. 27 is a graph showing the variation of the real part of the air-mixed dielectric constant of the chaff with frequency when 14 chaffs are filled according to an embodiment of the present invention.

FIG. 28 is a graph showing the variation of the imaginary part of the air-mixed dielectric constant of the chaff with frequency when 14 chaffs are filled according to an embodiment of the present invention.

FIG. 29 is a graph showing the variation of the real part of the air-mixed dielectric constant of the chaff with frequency when 16 chaffs are filled according to an embodiment of the present invention.

FIG. 30 is a graph showing the variation of the imaginary part of the air-mixed dielectric constant of the chaff with frequency when 16 chaffs are filled according to an embodiment of the present invention.

Detailed ways

In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, but not to limit the present invention.

In view of the problems existing in the prior art, the present invention provides a method for measuring the dielectric constant of the air mixture of foil strips. The present invention will be described in detail below with reference to the accompanying drawings.

As shown in FIG. 1 , the method for measuring the air-mixed dielectric constant of a foil strip provided by an embodiment of the present invention includes the following steps:

S101, select the experimental site, prepare the experimental instruments and materials to be tested, connect the computer and the vector network analyzer, turn on the power supply to supply power to the equipment, and check whether the connection of the lines is correct;

S102, connect the coaxial cable to the port of the vector network analyzer, and open the computer measurement software to set parameters;

S103, start the calibration, calibrate the two-port scattering parameters of the vector network analyzer to the two end faces of the measurement waveguide, and eliminate the errors caused by the loss of the experimental components during the experiment;

S104, the essence of using the waveguide method to measure the dielectric constant is to use the sample to be tested as a two-port network, and the data tested by the vector network analyzer are the scattering parameters of the medium, that is, the S parameters S ₁₁ , S ₁₂ , S ₂₁ , S of the two ports _22. Use the scattering equation of the NRW transmission/reflection method to derive the dielectric constant of the sample to be tested;

S105, stick the polypropylene film material on the surface of the rectangular waveguide, encapsulate the air in the rectangular waveguide, measure the dielectric constant under this condition, record and save the data, compare the dielectric constant data of the air without encapsulation, and verify the polypropylene The film material has no effect on the method of measuring the dielectric constant of the medium by the rectangular waveguide method;

S106, use polypropylene membrane material to encapsulate the soil, measure the soil-air mixed dielectric constant, record and save the data, query the existing empirical model, verify the accuracy of the soil dielectric constant data, and prove the feasibility of the experiment;

S107, cutting the chaff material, controlling the number of chaff strips to control the filling rate, using polypropylene film material for packaging, measuring the dielectric constant of the chaff-air mixture, and recording and saving the data;

S108, analyze the experimental data graph, and perform experimental error analysis.

As shown in FIG. 2 , the system for measuring the dielectric constant of the chaff-air mixture provided by the embodiment of the present invention includes:

Equipment connection module 1, used for the entire dielectric constant system of the test medium by the rectangular waveguide method, use a twisted pair cable to connect the computer with the vector network analyzer, use the power cable to connect the power supply to the vector network analyzer, and connect the coaxial cable to the vector network analyzer. To the two ports of the vector network analyzer, and connect two coaxial waveguide converters at the ports, place the medium in the rectangular waveguide, connect the coaxial waveguide converters, and connect the devices into a channel;

The equipment calibration module 2 is used to calibrate the measurement error existing in the system after the test system is built;

The target measurement module 3 is used to measure the scattering parameters of the medium loaded in the rectangular waveguide, and to set the starting frequency, the ending frequency, and the number of test points;

The data acquisition module 4 is used to test the scattering constant of different dielectric materials, obtain the dielectric constant data through the test software, and perform the test by changing the filling rate of the dielectric material, and save the data for subsequent image analysis;

The graphics processing module 5 is used for image processing of the collected data, and intuitively analyzes the influence of different conditions on the dielectric constant data of the medium.

The technical solutions of the present invention will be further described below with reference to specific embodiments.

The present invention is realized in this way, a specific experimental scheme for measuring the air-mixed dielectric constant of the chaff, the specific measurement experimental scheme for the air-mixed dielectric constant of the chaff, including:

Step 1: Select the experimental site, prepare the experimental instruments and materials to be tested, connect the computer and the vector network analyzer, turn on the power supply to supply power to the equipment, and check whether the connection of the lines is correct;

Step 2, connect the coaxial cable to the port of the vector network analyzer, and open the computer measurement software to set the parameters;

Step 3, start the calibration, calibrate the two-port scattering parameters of the vector network analyzer to the two end faces of the measurement waveguide, and eliminate the errors caused by the loss of the experimental components during the experiment;

Step 4: The essence of using the waveguide method to measure the dielectric constant is to use the sample to be tested as a two-port network, and the data tested by the vector network analyzer are the scattering parameters of the medium, that is, the S parameters S ₁₁ , S ₁₂ , S ₂₁ of the two ports, S ₂₂ , using the scattering equation of the NRW transmission/reflection method to derive the dielectric constant of the sample to be tested;

Step 5, stick the polypropylene film material on the surface of the rectangular waveguide, encapsulate the air in the rectangular waveguide, measure the dielectric constant under this condition, record and save the data, compare the dielectric constant data of the unencapsulated air, and verify the poly The acrylic film material has no effect on the method of measuring the dielectric constant of the medium by the rectangular waveguide method;

Step 6: Use polypropylene membrane material to encapsulate the soil, measure the soil-air mixing permittivity, record and save the data, query the existing empirical model, verify the accuracy of the soil permittivity data, and prove the feasibility of the experiment;

Step 7: Cut the chaff material, control the number of chaff strips to control the filling rate, use polypropylene film material for packaging, measure the air-mixed dielectric constant of the chaff strips, and record and save the data;

The eighth step is to analyze the experimental data graph and carry out the experimental error analysis.

In step 1 provided by the embodiment of the present invention, an experimental site is selected, experimental instruments and materials to be tested are prepared, a computer and a vector network analyzer are connected, the power supply is turned on to supply power to the equipment, and it is checked whether the connection of the lines is correct, specifically:

(1) An open area should be selected for this experimental measurement to avoid interference to the measurement system by other instruments.

(2) The experimental instruments and materials to be tested include a vector network analyzer, a computer, a twisted pair cable, two coaxial cables, a set of calibration components, a set of rectangular waveguide components, and a polypropylene film material. Rolls, some soil, some chaff, a pair of scissors, a ruler, and tweezers.

(3) Use twisted pair cable to connect the RJ45 interface of the computer to the LAN port of the vector network analyzer; before connecting the power supply, pay attention to the protection of the vector network analyzer, pay attention to the maximum withstand power, beware of high power damage to the port, turn on the power supply, Turn on the vector network analyzer and the computer, and use the measurement software on the computer to check whether the line is connected. After the connection is completed, the experimental measurement can be carried out. The structure of the waveguide method measurement system is shown in Figure 3.

In step 2 provided by the embodiment of the present invention, the coaxial cable is connected to the port of the vector network analyzer, and the computer measurement software is opened to set parameters, specifically:

(1) Connect the coaxial cable to the port of the vector network analyzer, open the computer test software to set the parameters, and select the band, as shown in Figure 4.

(2) Set the starting frequency, ending frequency, and the number of measurement points, as shown in Figure 5, and confirm that the set parameters are consistent on the vector network analyzer.

In step 3 provided by the embodiment of the present invention, calibration is started, and the two-port scattering parameters of the vector network analyzer are calibrated to the two end faces of the measurement waveguide. The calibration flow chart of the rectangular waveguide is shown in FIG. The resulting errors are as follows:

(1) Select the calibration button on the vector network analyzer, select the calibration type as non-guided calibration (response calibration using mechanical calibration parts, single-port calibration, dual-port calibration), select full dual-port TRL in non-guided calibration, ignore Isolate the two keys and proceed to the next step.

(2) Thru-through, port 1 reflection, port 2 reflection, line/match calibration are performed in sequence as indicated.

(3) Connect the coaxial waveguide converters to the two ends of the coaxial cable respectively, and use the pins to connect the coaxial waveguide converters together. Note that the pins are inserted into the holes diagonally opposite each other when connecting, so that the connection will reduce the failure of the device connection. If the error is caused by tightness, click the pass-through button after the connection is completed, click the THRU button, and the instrument starts to calibrate. After completion, press the OK button to proceed to the next step of calibration.

(4) Connect the shorting pieces at both ends of the coaxial waveguide converter, use pins to connect the devices, click the port 1 reflection button, click the THRU button, and press the OK button after the calibration is completed to proceed to the next calibration;

(5) The reflection steps of port 2 are the same as (4), and the next step of calibration is performed after completion.

(6) Connect the rectangular waveguide sheet to both ends of the coaxial waveguide converter, pay attention to the position of the corresponding rectangle when connecting, press the line/match calibration button, click the BJ-220 (λ/4LINE) button, and press the OK button after the calibration is completed. The calibration procedure is complete.

(7) When exiting the guide, the calibration set will be saved to channel 1, which can be used for a long time.

In step 4 provided by the embodiment of the present invention, the essence of using the waveguide method to measure the dielectric constant is to use the sample to be tested as a two-port network, and the data tested by the vector network analyzer is the scattering parameter of the medium, that is, the S parameter _S11 of the two ports. , S ₁₂ , S ₂₁ , S ₂₂ , using the scattering equation of the NRW transmission/reflection method to deduce the dielectric constant of the sample to be tested, specifically:

When the electromagnetic wave propagates in the waveguide transmission line, its transmission characteristics have nothing to do with the position, and only reflection and transmission occur at the boundary surface of the medium. VI represents the incident voltage, _{VR represents} the reflected voltage, and VT represents the total transmission voltage _. The following relationship is established, which is also the definition of scattering parameters, namely:

VR = _{S 11} ·V _I

V _T =S ₂₁ ·V _I

If the incident voltage is set to 1, the scattering parameters are expressed as the total incident voltage _VR and the total transmission voltage _VT , namely:

_{S 11} =VR

S ₂₁ =V _T

The single reflection coefficient of the interface between the air and the medium is Γ, and the transmission coefficient of the two surfaces of the measured medium is T. The size of the scattering parameter can be deduced, namely:

For simplicity of operation, set:

V ₁ =S ₂₁ +S ₁₁

V ₂ =S ₂₁ -S ₁₁

It can be deduced that:

The relationship between the relative complex permeability μ _r and relative complex permittivity ε _r of known materials and the propagation constant γ is:

where μ _r is the relative complex permeability of the material, ε _r is the relative complex permittivity, is the propagation constant of the measured sample segment, λ ₀ is the operating wavelength in air, λ _c is the cut-off wavelength of the waveguide transmission line, j is an imaginary unit.

d is the thickness of the sample to be tested, and the relationship between the transmission coefficient of the sample to be tested and the propagation constant is:

T=e- ^γd

Derive from the above formula:

Among them, Z ₀ represents the characteristic impedance of the air region in the transmission line, and Z represents the characteristic impedance of the sample section of the measured medium.

The reflection coefficient Γ can be expressed as:

The relative complex permeability μ _r and relative complex permittivity ε _r of the measured medium are obtained as:

In the formula,

and there is:

Among them, λ _g is the waveguide wavelength of the sample to be measured. For the measurement system of the coaxial transmission line, the cut-off wavelength λ _c =∞, and for the measurement system based on the rectangular waveguide, the cut-off wavelength λ _c =2a.

To sum up, the above is the principle of NRW transmission/reflection algorithm. Open the computer test software and set the parameter as dielectric constant measurement, bidirectional test, the distance to port A and port B are set to 0.000mm, and the sample thickness is set to 4.500mm , click Measure, observe the data graph that appears on the panel, save the data of the real and imaginary parts of the air dielectric constant measured at this time, the theoretical value of the real part of the air dielectric constant is 1, the theoretical value of the imaginary part is 0. The relationship between the real part of the dielectric constant and the frequency change is shown in Figure 7. The relationship between the real part of the dielectric constant and the frequency change of the measured air is shown in Figure 8. The average value of the real part of the measured air dielectric constant is 1.0014, and the average value of the imaginary part is -0.0002 , which is less different from the theoretical value of the air dielectric constant, indicating that the calibration is successful.

In step 5 provided by the embodiment of the present invention, the polypropylene film material is attached to the surface of the rectangular waveguide, the air in the rectangular waveguide is encapsulated, the dielectric constant under this condition is measured, the data is recorded and saved, and the air without encapsulation is compared. Dielectric constant data, verifying that polypropylene film material has no effect on the method of measuring dielectric permittivity by rectangular waveguide method, specifically:

(1) Measure the size of the rectangular waveguide, cut the polypropylene film material into two rectangles of different sizes, and stick to each other to ensure that the rectangular aperture is completed with polypropylene material and can be adhered to the surface of the rectangular waveguide to avoid subsequent chaff air The experimental measurement of the dielectric constant of the mixed medium shows that the chaff material adheres to the surface of the polypropylene material.

(2) Encapsulate both ends of the rectangular waveguide sheet with polypropylene film material, as shown in Figure 9, connect the rectangular waveguide sheet to the coaxial waveguide converter, as shown in Figure 10, use the test software in the computer Measure the dielectric constant of the polypropylene film material after encapsulation, record the data, and compare the real and imaginary parts of the air dielectric constant measured without encapsulation.

The relationship between the real part of the dielectric constant and the frequency change is shown in Figure 11, and the relationship between the imaginary part of the dielectric constant and the frequency change is shown in Figure 12. The average value of the real part of the dielectric constant of the encapsulated air is 1.0189, and the average value of the imaginary part is -0.0002 , which is less different from the air dielectric constant value of the unpackaged test, so that the influence of the polypropylene film material on the method of measuring the dielectric constant of the dielectric by the rectangular waveguide method is excluded.

In the sixth step provided by the embodiment of the present invention, the soil is encapsulated with a polypropylene film material, the soil-air mixing permittivity is measured, the data is recorded and saved, the existing empirical model is inquired, the accuracy of the soil permittivity data is verified, and the experiment is proved. The feasibility of measuring the dielectric constant of mixed media, specifically:

Open the packaged rectangular waveguide, and fill the soil to be tested into the rectangular waveguide. During the filling process, the soil needs to be spread into the waveguide, and the waveguide should be filled as much as possible. Due to the elasticity of the polypropylene film material, care should be taken that the filled soil does not exceed In the encapsulation area of polypropylene film material, the encapsulated rectangular waveguide sheet is connected to the coaxial waveguide converter to measure the dielectric constant of soil-air mixture, record the data, and compare the tested data with the data in the soil empirical model.

The data comparison of the real part of the permittivity is shown in Figure 13, and the data comparison of the imaginary part of the permittivity is shown in Figure 14. The empirical value of the real part of the permittivity of dry soil is 4, and the empirical value of the real part of the permittivity of air is 1. The average value of the real part of the dielectric constant of the soil-air mixed dielectric material measured this time is 2.0729, and the data is within the range of empirical values; the imaginary part of the dielectric constant of dry soil is generally less than 0.05, and the imaginary part of the air dielectric constant is 0 , the mean value of the imaginary part of the dielectric constant of the soil-air mixed dielectric material measured this time is 0.4671, and the data is within the empirical value range. The soil-air mixing data verifies the feasibility of the experiment to measure the mixed dielectric constant.

In step 7 provided by the embodiment of the present invention, the chaff material is cut, the number of chaff strips is controlled, the filling rate is controlled, the polypropylene film material is used for packaging, the air-mixed dielectric constant of the chaff strip is measured, and the data is recorded and stored, Specifically:

Take out the tested soil sample, clean the surrounding of the rectangular waveguide, restore it to the state before the soil test, and proceed to the preparation of the dielectric sample: process as carefully as possible, keep the flatness of the dielectric sample, and cut the chaff to length 2, 4, 6, 8, 10, 12, 14, and 16 chaff strips are respectively filled to test, record the experimental data, and observe the data law. Figures 15-30 show the relationship between the real and imaginary parts of the air-mixed dielectric constant of the chaff as a function of frequency. Table 1 is the mean value of the real and imaginary parts of the fill rate chaff air-mixed dielectric constant.

Table 1 The mean value of the real and imaginary parts of the air-mixed dielectric constant of the chaff in the filling rate

Number of filling chaff Mean real part of mixed permittivity The mean value of the imaginary part of the mixed permittivity 2 0.96490 0.00369 4 0.97231 0.04012 6 1.16830 0.65645 8 0.99643 0.19336 10 1.05572 0.66778 12 2.40473 0.24253 14 2.41952 0.30911 16 2.34906 0.43057

According to the experimental data, when the number of chaff is increased within a certain range, the real and imaginary parts of the air-mixed dielectric constant of the chaff will increase; the real and imaginary parts of the dielectric constant show regular changes under different filling rates. ; and during the test, it was found that the imaginary part of the mixed dielectric constant had a negative value, which provided important data for the study of new materials.

In step 8 provided by the embodiment of the present invention, an experimental error analysis is performed, which is specifically:

Process the experimental data, draw a graph of the relationship between frequency and dielectric permittivity, compare the effects of different filling rates on the permittivity of the chaff-air mixture, and analyze the influence of possible errors in the experimental process on the experimental data.

During the experiment, because the chaff is very small, the chaff can only be stretched as flat as possible during the placement process, which may cause errors in the experimental data.

In the above-mentioned embodiments, it may be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented in whole or in part in the form of a computer program product, the computer program product includes one or more computer instructions. When the computer program instructions are loaded or executed on a computer, all or part of the processes or functions described in the embodiments of the present invention are generated. The computer may be a general purpose computer, special purpose computer, computer network, or other programmable device. The computer instructions may be stored in or transmitted from one computer readable storage medium to another computer readable storage medium, for example, the computer instructions may be downloaded from a website site, computer, server or data center Transmission to another website site, computer, server, or data center by wire (eg, coaxial cable, fiber optic, digital subscriber line (DSL), or wireless (eg, infrared, wireless, microwave, etc.)). The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device such as a server, a data center, or the like that includes an integration of one or more available media. The usable media may be magnetic media (eg, floppy disks, hard disks, magnetic tapes), optical media (eg, DVD), or semiconductor media (eg, Solid State Disk (SSD)), and the like.

The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited to this. Any person skilled in the art is within the technical scope disclosed by the present invention, and all within the spirit and principle of the present invention Any modifications, equivalent replacements and improvements made within the scope of the present invention should be included within the protection scope of the present invention.

Claims (9)

1. A method for measuring the air-mixed dielectric constant of a foil strip, wherein the method for measuring the air-mixed dielectric constant of the foil strip comprises the following steps: Step 1: Select the experimental site, prepare the experimental instruments and materials to be tested, connect the computer and the vector network analyzer, turn on the power supply to supply power to the equipment, and check whether the connection of the lines is correct; Step 2, connect the coaxial cable to the port of the vector network analyzer, and open the computer measurement software to set the parameters; Step 3, start the calibration, calibrate the two-port scattering parameters of the vector network analyzer to the two end faces of the measurement waveguide, and eliminate the errors caused by the loss of the experimental components during the experiment; Step 4: The essence of using the waveguide method to measure the dielectric constant is to use the sample to be tested as a two-port network, and the data tested by the vector network analyzer are the scattering parameters of the medium, that is, the S parameters S ₁₁ , S ₁₂ , S ₂₁ of the two ports, S ₂₂ , using the scattering equation of the NRW transmission/reflection method to derive the dielectric constant of the sample to be tested; Step 5, stick the polypropylene film material on the surface of the rectangular waveguide, encapsulate the air in the rectangular waveguide, measure the dielectric constant under this condition, record and save the data, compare the dielectric constant data of the unencapsulated air, and verify the poly The acrylic film material has no effect on the method of measuring the dielectric constant of the medium by the rectangular waveguide method; Step 6: Use polypropylene membrane material to encapsulate the soil, measure the soil-air mixing permittivity, record and save the data, query the existing empirical model, verify the accuracy of the soil permittivity data, and prove the feasibility of the experiment; Step 7: Cut the chaff material, control the number of chaff strips to control the filling rate, use polypropylene film material for packaging, measure the air-mixed dielectric constant of the chaff strips, and record and save the data; Step 8, analyze the experimental data graph, and carry out the experimental error analysis; In step 7, the chaff material is cut, the number of chaff strips is controlled to control the filling rate, the polypropylene film material is used for packaging, the air-mixed dielectric constant of the chaff strip is measured, and the data is recorded and saved, including: (1) Take out the tested soil sample, clean the surrounding of the rectangular waveguide, and restore it to the state before the soil test; (2) Preparation of dielectric samples: process as carefully as possible to keep the flatness of the dielectric samples, cut the foil strips into long strips, place them along the length of the rectangular waveguide, and fill 2, 4, 6, and 8 respectively. , 10, 12, 14, 16 chaff strips to test, record the experimental data, and observe the data law; In the eighth step, the analysis of the experimental data graph and the reflection on the possibility of causing experimental errors in the experimental process include: Process the experimental data, draw a graph of the relationship between frequency and dielectric permittivity, compare the effects of different filling rates on the permittivity of the chaff-air mixture, and analyze the influence of possible errors in the experimental process on the experimental data. 2. The method for measuring the air-mixed dielectric constant of chaff as claimed in claim 1, characterized in that, in step 1, the selected experimental site, the experimental instrument and the material to be tested are prepared, and a computer and a vector network analyzer are connected, Turn on the power supply to supply power to the device, and check that the wiring is properly connected, including: (1) Select an open area for experimental measurement to avoid the interference of other instruments on the measurement system; (2) The measurement system includes a vector network analyzer, a computer, a twisted pair cable, two coaxial cables, a set of calibration parts, a set of rectangular waveguide parts, a roll of polypropylene film material, a soil Several pieces, several chaff strips, a pair of scissors, a ruler, and tweezers; use a twisted pair cable to connect the RJ45 interface of the computer with the LAN port of the vector network analyzer; (3) Pay attention to the protection of the vector network analyzer before connecting the power supply, pay attention to the maximum withstand power, beware of high power damage to the port, turn on the power supply, turn on the vector network analyzer and the computer, and use the measurement software on the computer to check whether the line is connected , the experimental measurement can be carried out after the connection is completed; In step 2, the coaxial line is connected to the port of the vector network analyzer, and the computer measurement software is opened to set parameters, including: Connect the coaxial cable to the port of the vector network analyzer, open the computer testing software to set the parameters, select the frequency band, set the start frequency, stop frequency, and the number of measurement points, and confirm that the set parameters are consistent on the vector network analyzer. 3. The method for measuring the air-mixed dielectric constant of chaff as claimed in claim 1, wherein in step 3, the calibration is started, and the two-port scattering parameters of the vector network analyzer are calibrated to the two end faces of the measurement waveguide, Eliminate the errors caused by the loss of experimental components during the experiment, including: (1) Select the calibration button on the vector network analyzer, select the calibration type as non-guided calibration, use mechanical calibration parts for response calibration, single-port calibration, dual-port calibration, select full dual-port TRL in non-guided calibration, ignoring isolation Two buttons to go to the next step; (2) Straight-through, port 1 reflection, port 2 reflection, line/match calibration in sequence according to the instructions; (3) Connect the coaxial waveguide converters to the two ends of the coaxial cable respectively, and use the pins to connect the coaxial waveguide converters together. When connecting, the pins are inserted into the holes diagonally opposite each other; after the connection is completed, click the through button and click THRU Press the button, the instrument starts to calibrate, and after completion, press the OK button to proceed to the next calibration; (4) Connect the shorting pieces at both ends of the coaxial waveguide converter, use pins to connect the devices, click the port 1 reflection button, click the THRU button, and press the OK button after the calibration is completed to proceed to the next calibration; (5) The reflection step of port 2 is the same as (4), and the next step is calibrated after completion; (6) Connect the rectangular waveguide sheet to both ends of the coaxial waveguide converter, pay attention to the position of the corresponding rectangle when connecting, press the line/match calibration button, click the BJ-220, that is, the λ/4LINE button, and press the OK button after the calibration is completed. The calibration step is completed; (7) When exiting the guide, the calibration set will be saved to channel 1 for long-term use. 4. The method for measuring the dielectric constant of chaff-air mixture as claimed in claim 1, wherein in step 4, the essence of using the waveguide method to measure the dielectric constant is to use the sample to be tested as a two-port network, a vector network The data tested by the analyzer are the scattering parameters of the medium, namely the S parameters S ₁₁ , S ₁₂ , S ₂₁ , and S ₂₂ of the two ports. The scattering equation of the NRW transmission/reflection method is used to deduce the dielectric constant of the sample to be tested, including : When the electromagnetic wave propagates in the waveguide transmission line, its transmission characteristics have nothing to do with the position, and only reflection and transmission occur at the boundary surface of the medium. VI represents the incident voltage, _{VR represents} the reflected voltage, and VT represents the total transmission voltage _. The following relationship is established, which is also the definition of scattering parameters, namely: VR = _{S 11} ·V _I ; V _T =S ₂₁ · _VI ; If the incident voltage is set to 1, the scattering parameters are expressed as the total incident voltage _VR and the total transmission voltage _VT , namely: _{S 11} =VR ; S ₂₁ =V _T ; The single reflection coefficient of the interface between the air and the medium is Γ, and the transmission coefficient of the two surfaces of the measured medium is T. The size of the scattering parameter can be deduced, namely:

set up: V ₁ =S ₂₁ +S ₁₁ ; V ₂ =S ₂₁ -S ₁₁ ;

Derive:

The relationship between the relative complex permeability μ _r and relative complex permittivity ε _r of known materials and the propagation constant γ is:

where μ _r is the relative complex permeability of the material, ε _r is the relative complex permittivity, is the propagation constant of the measured sample segment, λ ₀ is the operating wavelength in air, λ _c is the cut-off wavelength of the waveguide transmission line, j is an imaginary unit; d is the thickness of the sample to be tested, and the relationship between the transmission coefficient of the sample to be tested and the propagation constant is: T=e- ^γd ; Deduced:

Among them, Z ₀ represents the characteristic impedance of the air region in the transmission line, and Z represents the characteristic impedance of the measured medium sample segment; The reflection coefficient Γ is expressed as:

The relative complex permeability μ _r and relative complex permittivity ε _r of the measured medium are obtained as:

In the formula,

and there is:

Among them, λ _g is the waveguide wavelength of the sample to be measured, for the measurement system of the coaxial transmission line, the cut-off wavelength λ _c =∞, and for the measurement system based on the rectangular waveguide, the cut-off wavelength λ _c =2a; Based on the principle of NRW transmission/reflection algorithm, open the computer test software and set the parameter to be dielectric constant measurement, bidirectional test, the distance to port A and port B are set to 0.000mm, the sample thickness is set to 4.500mm, click to measure, observe In the data graph that appears on the panel, the test result is that the real part of the dielectric constant of air is 1 and the imaginary part is 0, indicating that the calibration is successful, and the real and imaginary data of the air dielectric constant measured at this time are saved. 5 . The method for measuring the air-mixed dielectric constant of a chaff strip according to claim 1 , wherein in step 5, the polypropylene film material is attached to the surface of the rectangular waveguide, the air in the rectangular waveguide is encapsulated, and the measurement is performed. 6 . The dielectric constant under this condition, record and save the data, compare the dielectric constant data of unencapsulated air, and verify that the polypropylene film material has no effect on the method of measuring the dielectric constant of the dielectric by the rectangular waveguide method, including: (1) Measure the size of the rectangular waveguide, cut the polypropylene film material into two rectangles of different sizes, and stick to each other to ensure that the rectangular aperture is completed with polypropylene material and can be adhered to the surface of the rectangular waveguide to avoid subsequent chaff air During the experimental measurement of the dielectric constant of the mixed medium, the chaff material adheres to the surface of the polypropylene material; (2) Encapsulate both ends of the rectangular waveguide sheet with polypropylene film material, connect the rectangular waveguide sheet to the coaxial waveguide converter, and use the test software in the computer to measure the dielectric constant of the packaged polypropylene film material. Measure, record the data, compare the real and imaginary parts of the measured air dielectric constant, and exclude the polypropylene film material has no effect on the method of measuring the dielectric constant of the dielectric constant by the rectangular waveguide method; In step 6, the soil is encapsulated by the polypropylene film material, the soil-air mixed dielectric constant is measured, the data is recorded and saved, the existing empirical model is inquired, the accuracy of the soil dielectric constant data is verified, and the experimental effect on the mixed medium dielectric constant is proved. Feasibility of electric constant measurement, including: Open the packaged rectangular waveguide and fill the rectangular waveguide with the soil to be tested. During the filling process, the soil needs to be spread into the waveguide, and the waveguide should be filled as much as possible. Due to the elasticity of the polypropylene film material, care should be taken that the filled soil does not exceed In the encapsulation area of polypropylene film material, the encapsulated rectangular waveguide sheet is connected to the coaxial waveguide converter to measure the dielectric constant of soil-air mixture, record the data, and compare the tested data with the data in the soil empirical model to verify Experimental feasibility of hybrid permittivity measurements. 6 . A system for measuring the air-mixed dielectric constant of a foil strip using the method for measuring the air-mixed dielectric constant of a foil strip according to any one of claims 1 to 5 , wherein the air-mixed dielectric constant of the foil strip is The measurement system includes: The equipment connection module is used for the dielectric constant system of the whole rectangular waveguide method to test the medium. Use the twisted pair cable to connect the computer to the vector network analyzer, use the power cable to connect the power supply to the vector network analyzer, and connect the coaxial cable to the vector network analyzer. Two ports of the vector network analyzer, and connect two coaxial waveguide converters at the ports, place the medium in the rectangular waveguide, connect the coaxial waveguide converters, and connect the devices into a channel; The equipment calibration module is used to calibrate the measurement error existing in the system after the test system is built; The target measurement module is used to measure the scattering parameters of the medium loaded in the rectangular waveguide, and set the starting frequency, ending frequency, and the number of test points; The data acquisition module is used to test the scattering constant of different dielectric materials, obtain the dielectric constant data through the test software, and perform the test by changing the filling rate of the dielectric material, and save the data for subsequent image analysis; The graphics processing module is used for image processing of the collected data, and intuitively analyzes the influence of different conditions on the dielectric constant data of the medium. 7. A computer device, characterized in that the computer device comprises a memory and a processor, the memory stores a computer program, and when the computer program is executed by the processor, the processor is made to execute claim 1 The method for measuring the air-mixed dielectric constant of the chaff according to any one of ~5. 8. A computer-readable storage medium storing a computer program, which, when executed by a processor, causes the processor to perform the measurement of the dielectric constant of the chaff-air mixture according to any one of claims 1 to 5 method. 9 . An information data processing terminal, characterized in that, the information data processing terminal is used to implement the system for measuring the dielectric constant of a chaff-air mixture according to claim 6 . 10 .

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