CN113970670A

CN113970670A - Foil strip air-mixed dielectric constant measuring method

Info

Publication number: CN113970670A
Application number: CN202111156211.0A
Authority: CN
Inventors: 卢雅雯; 彭傲; 左炎春; 郭立新; 刘伟; 余乐; 方争光; 李金本; 佘俊杰
Original assignee: Xidian University
Current assignee: Xidian University
Priority date: 2021-09-29
Filing date: 2021-09-29
Publication date: 2022-01-25
Anticipated expiration: 2041-09-29
Also published as: CN113970670B

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

Foil strip air-mixed dielectric constant measuring method

Technical Field

The invention belongs to the technical field of microwave measurement and analysis of dielectric constant of materials, and particularly relates to a foil strip air-mixed dielectric constant measuring method.

Background

At present, foil strips are widely applied in modern maritime electronic wars due to low price, simple manufacturing process and excellent radar interference performance, and can be used as light aerial reflection target clouds to generate induction alternating current under the action of an alternating electromagnetic field in a certain space range so as to secondarily radiate electromagnetic waves and play a role in passive interference on target radars. The use process of the foil strip interferent does not need to analyze and know radar information, but the research on radar equipment is expanding towards the microwave stage, the anti-interference performance is gradually enhanced, the research on the foil strip interferent is further advanced, and a novel foil strip material is developed on the basis. At present, the foil strips used in the market are mainly made of glass fibers serving as a matrix and coated with metal foils, or metal wires and metal-coated media are directly used, the research on the interference performance of the foil strips at the present stage is mainly started from three aspects of motion diffusion characteristics, electromagnetic scattering characteristics and electric wave propagation characteristics, the research on the statistical relative dielectric constant of the foil strips is less, and if the electrical performance characteristics of the foil strips are researched by taking the foil strips as dielectric materials, reference data can be provided for the research and application of the foil strip materials.

The research on the electrical characteristic parameters of the dielectric material has wide application prospect and obvious academic value in the fields of materials science and electromagnetism. In the field of materials science, the foil strip is the most widely used passive interferent with the longest service time, most of the current foil strip materials use glass fiber to keep rigidity, and a uniform metal thin layer is plated on a superfine glass fiber carrier, so that the foil strip has good electrical property on the basis of light weight, good dispersibility, low cost and convenience in processing, and therefore, the measurement of the dielectric constant of the foil strip has important significance for the research and development of novel foil strip materials. Through the research, the characteristics and the rules of the microstructure of the medium can be known, and the deep research on certain rule characteristics of the molecular structure or the material structure of the medium is facilitated; meanwhile, through the research on the characteristics of the dielectric material, the dielectric material can be obtained, which is novel and meets the technical requirements. In the field of electromagnetism, the action relationship and field change between electromagnetic waves and a medium can be known through the measurement of dielectric constant, and the macroscopic phenomenon of medium polarization is related to the microstructure of the medium through the action relationship and field change. The research on the dielectric constant measurement of the foil strip air-mixed medium is blank at present, specific introduction is provided for experimental measurement steps of the foil strip air-mixed dielectric constant, and the understanding of the measurement of the foil strip air-mixed dielectric constant is of great significance for the research on the passive interference performance of the foil strip. Therefore, the method for researching the dielectric constant of the foil strip realizes efficient and accurate measurement, and has very important practical significance for the application and research of subsequent foil strip materials.

The research on the dielectric constant of the material has two methods of modeling and measuring, the modeling can better grasp the property of the dielectric constant, the study of formulation is convenient, the measurement can obtain the measured data, and the result is more real and accurate. The research of the invention focuses on experimental measurement, which is the most direct and effective method for the electrical property research of the medium, and the data of the dielectric constant obtained by the experimental method has higher practical value. The measurement of the dielectric constant is mainly focused on the microwave stage, and the measurement methods include a free space method, a probe method, a resonant cavity method, a transmission line method and a waveguide transmission/reflection method. The free space method is used for large-area open measurement, and mainly comprises a reflection method and a transmission method, but the reflection method causes scattering or secondary reflection because a foil strip sample is less and a metal plate cannot be fully paved in the measurement process, the value of single reflection cannot be accurately measured, and the measurement precision is not high; the transmission method has difficulty in calibrating the position of the foil strip, and diffraction and other phenomena can be generated in the measuring process due to the small volume of the foil strip. Although the measurement result of the probe method is stable and has high precision, the measurement result can only be within a certain range. The sample preparation of the resonant cavity method is difficult, the manufacturing cost is high, the design is complex, and the method is not suitable for measuring the dielectric constant of the foil strip. The transmission line method causes a change in the intrinsic properties of the sample during the processing, which may cause the measurement result to deviate from the actual result. Compared with the former methods, the waveguide transmission/reflection method has high measurement result precision and is easy to calculate, and errors generated by sample placement can be solved through calibration, so that the measurement is carried out by adopting a waveguide method, specifically a rectangular waveguide method.

The essence of the waveguide method for measuring the dielectric constant is that a sample to be measured is used as a two-port network, and S parameters, namely S, of two ports are measured₁₁，S₁₂，S₂₁，S₂₂And deducing the dielectric constant of the sample to be measured by using a scattering equation of the NRW transmission/reflection method. However, at present, a specific experimental scheme for a measurement experiment of the air-mixed dielectric constant of the foil strip is scarce, a lot of errors and difficulties occur in the actual measurement process, and how to design the experiment and actually operate the experiment is the focus of the 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, so that the hardware calibration process of the coaxial waveguide converter needs to be added; the cutting, placing and packaging of the foil strips in the experimental process are also technical difficulties.

Through the above analysis, the problems and defects of the prior art are as follows: the design scheme of a specific experiment for measuring the foil strip air-mixed dielectric constant by using a rectangular waveguide method and the current stage of a detailed experimental process are blank, and the theoretical analysis on the foil strip air-mixed dielectric constant is less.

The difficulty in solving the above problems and defects is:

(1) the specific experimental design for measuring the air-mixed dielectric constant of the foil strip by the rectangular waveguide method.

(2) The detailed procedures and operation of the experiment are described.

(3) The rectangular waveguide method measures the scattering constant and inverts the theoretical analysis of the dielectric constant.

The significance of solving the problems and the defects is as follows: the method fills the blank of experimental design of foil strip cloud relative dielectric constant measurement, provides an analysis method, lays a certain theoretical foundation for subsequent experimental measurement, and promotes the development of electromagnetic measurement experiments. The experimental measurement provides practical and reliable measured data for the research and development of the foil strip material, and has important significance for the research of materials science.

Disclosure of Invention

Aiming at the problems in the prior art, the invention provides a foil strip air-mixed dielectric constant measuring method, and particularly relates to a design and measuring system of an experimental scheme for measuring foil strip air-mixed dielectric constant by a rectangular waveguide method.

The invention is realized in such a way that a method for measuring the air-mixed dielectric constant of a foil strip comprises the following steps:

selecting an experimental site, preparing an experimental instrument and a material to be tested, connecting a computer and a vector network analyzer, switching on a power supply to supply power to equipment, and checking whether the connection of a circuit is correct. The connection of the experimental equipment and the inspection line is prepared in advance, so that convenience is provided for measurement of subsequent experiments, and potential safety hazards are eliminated;

connecting the coaxial line to the port of the vector network analyzer, opening the computer measurement software to set parameters, and connecting the coaxial line and the coaxial waveguide converter to the port of the vector network analyzer, wherein the steps are to regard the coaxial line and the coaxial waveguide converter as a whole, and simplify the subsequent calibration process;

and step three, starting calibration, calibrating the scattering parameters of the two ports of the vector network analyzer to the two end faces of the measurement waveguide, and eliminating errors caused by the loss of experimental elements in the experimental process. The calibration step is simpler and more convenient, simplifies the process of calibrating a vector network analyzer, a coaxial line and a coaxial line to the end surface of the measuring waveguide, and is suitable for the calibration process of a measuring experiment by adopting a rectangular waveguide method;

step four, the essence of measuring the dielectric constant by using the waveguide method is that the sample to be measured is used as a two-port network, the data measured by the vector network analyzer is the scattering parameter of the medium, namely two portsS parameter S of₁₁，S₁₂，S₂₁，S₂₂The dielectric constant of the sample to be measured is deduced by using a scattering equation of an NRW transmission/reflection method, the inversion deduction theory is very mature, and a powerful theoretical basis is provided for the method;

attaching a polypropylene film material to the surface of the rectangular waveguide, packaging air in the rectangular waveguide, measuring the dielectric constant under the condition, recording and storing data, comparing the dielectric constant data of air without packaging, verifying that the polypropylene film material has no influence on the method for measuring the dielectric constant of the medium by the rectangular waveguide method, wherein the verification process is the key point of the experiment, the experiment data proves that the polypropylene film material has little influence on the experimental measurement process, the experiment for packaging the medium material by using the polypropylene film material is only carried out, and the error caused by the packaging process is eliminated;

and step six, packaging the soil by using a polypropylene film material, measuring the air mixed dielectric constant of the soil, recording and storing data, inquiring the existing empirical model, verifying the accuracy of the dielectric constant data of the soil, and proving the feasibility of the experiment. The method has the advantages that the method provides an idea for measuring the foil strip air mixed medium by measuring the dielectric constant of the mixed medium of the existing empirical model, and verifies the feasibility of measuring the dielectric constant of the mixed medium by using a rectangular waveguide method;

cutting the foil material, controlling the number of the foil strips to control the filling rate, packaging by using a polypropylene film material, measuring the air-mixed dielectric constant of the foil strips, recording and storing data, changing a medium to be measured of the foil by controlling a variable method in the process, observing and researching the data of the dielectric constant of the mixed medium under different conditions, searching the dielectric constant rule of the air-mixed medium of the foil strips from the data, and providing data support for the subsequent research of the scattering characteristic of the air-mixed medium of the foil strips;

and step eight, analyzing the experiment data graph, analyzing experiment errors, and making an experiment data analysis graph and a data comparison graph, so that the experiment result is more visual and clear, the existing rule of the experiment result and the errors in the experiment process are conveniently researched, and a thought is provided for subsequent improvement.

Further, in the first step, the selecting an experimental site, preparing an experimental instrument and a material to be tested, connecting the computer and the vector network analyzer, switching on a power supply to supply power to the equipment, and checking whether the connection of the circuit is correct includes:

(1) an open area is selected for experimental measurement, and interference of other instruments to the measurement system is avoided;

(2) the measuring system comprises a vector network analyzer, a computer, a twisted pair cable, coaxial lines, a calibration piece, a rectangular waveguide piece, a roll of polypropylene membrane material, a plurality of soil, a plurality of foil strips, a pair of scissors, a pair of rulers and tweezers; connecting a computer RJ45 interface with a LAN interface of a vector network analyzer by using a twisted pair cable;

(3) before connecting the power supply, paying attention to the protection of the vector network analyzer, paying attention to the maximum bearing power, protecting the high-power damaged port, switching on the power supply, turning on the vector network analyzer and the computer, checking whether the circuit is switched on by using measurement software on the computer, and carrying out experimental measurement after the switching-on is finished.

Further, in step two, the connecting the coaxial line to the port of the vector network analyzer and opening the computer measurement software to set parameters includes:

connecting the coaxial line to a port of a vector network analyzer, opening computer test software to set parameters, selecting wave bands, setting starting frequency, terminating frequency and measuring point number, and confirming that the set parameters are consistent on the vector network analyzer.

Further, in the third step, the starting calibration, calibrating the scattering parameters of the two ports of the vector network analyzer to the two end faces of the measurement waveguide, and eliminating errors caused by loss of experimental elements in the experimental process, includes:

(1) selecting a calibration key on the vector network analyzer, selecting the calibration type as non-guide calibration, using a mechanical calibration piece to perform response calibration, single-port calibration and double-port calibration, selecting a full double-port TRL in the non-guide calibration, neglecting two isolated keys, and performing the next step;

(2) according to the instruction, the straight-through, port 1 reflection, port 2 reflection and line/matching calibration are carried out in sequence;

(3) connecting coaxial waveguide converters at two ends of the coaxial line respectively, connecting the coaxial waveguide converters together by using pins, and inserting the pins into the holes diagonally and oppositely during connection; clicking the direct key after connection is completed, clicking the THRU key, starting calibration of the instrument, pressing the determined key after connection is completed, and carrying out next calibration;

(4) connecting short-circuit pieces at two ends of the coaxial waveguide converter, connecting the devices by using pins, clicking a port 1 reflection key, clicking a THRU key, pressing a determined key after the calibration is finished, and carrying out the next calibration;

(5) the port 2 reflection step is the same as the step (4), and the next calibration is carried out after the port 2 reflection step is completed;

(6) connecting rectangular waveguide pieces at two ends of the coaxial waveguide converter, paying attention to the position of a corresponding rectangle during connection, pressing a LINE/matching calibration key, clicking BJ-220 (namely a lambda/4 LINE key), pressing a determined key after calibration is finished, and finishing the calibration step;

(7) when the guide is withdrawn, the calibration set is stored in the channel 1 and can be used for a long time.

Further, in the fourth step, the essence of the measurement of the dielectric constant by using the waveguide method is that the sample to be measured is used as a two-port network, and the data measured by the vector network analyzer is the scattering parameter of the medium, i.e. the S parameter S of the two ports₁₁，S₁₂，S₂₁，S₂₂The method for deriving the dielectric constant of the sample to be measured by using the scattering equation of the NRW transmission/reflection method comprises the following steps:

when electromagnetic wave propagates in waveguide transmission line, its transmission characteristics are independent of position, and only reflection and transmission occur at medium boundary surface, V_IRepresenting the incident voltage, V_RRepresenting reflected voltage, V_TRepresenting the total transmission voltage, the following relationship holds, also a definition of the scattering parameter, namely:

V_R＝S₁₁·V_I；

V_T＝S₂₁·V_I；

if the incident voltage is set to be 1,the scattering parameter is expressed as the total incident voltage V_RAnd a total transmission voltage V_TNamely:

S₁₁＝V_R；

S₂₁＝V_T；

the single reflection coefficient of the interface between air and the medium is gamma, the transmission coefficients of the two surfaces of the measured medium are T, and the size of a scattering parameter can be deduced, namely:

setting:

V₁＝S₂₁+S₁₁；

V₂＝S₂₁-S₁₁；

the derivation yields:

known material relative complex permeability mu_rAnd a relative complex dielectric constant ε_rThe relationship to the propagation constant γ is:

wherein, mu_rIs the relative complex permeability, epsilon, of the material_rIs the relative complex dielectric constant, is the propagation constant of the sample section under test, λ₀Is the operating wavelength in air, λ_cIs the cutoff wavelength of the waveguide transmission line, and j is the imaginary unit.

d is the thickness of the measured sample, and the relation between the transmission coefficient and the propagation constant of the measured sample is as follows:

T＝e^-γd；

deducing by the following formula:

wherein Z is₀Representing the characteristic impedance of the air region in the transmission line and Z representing the characteristic impedance of the measured dielectric sample segment.

The reflection coefficient Γ is expressed as:

obtaining the relative complex permeability mu of the measured medium_rAnd a relative complex dielectric constant ε_rComprises the following steps:

in the formula (I), the compound is shown in the specification,

and has:

wherein λ is_gFor the waveguide wavelength of the sample to be measured, the cut-off wavelength lambda is used for the measurement system of the coaxial transmission line_cInfinity, cut-off wavelength λ for a rectangular waveguide based measurement system_c＝2a。

Based on the NRW transmission/reflection algorithm principle, opening computer test software to set parameters as the measurement of dielectric constant, performing bidirectional test, setting the distance from the port A to the port B to be 0.000mm, setting the thickness of a sample to be 4.500mm, performing click measurement, observing a data graph appearing on a panel, wherein the test result is that the real part of the dielectric constant of air is 1, the imaginary part is 0, indicating that the calibration is successful, and storing the measured real part and imaginary part data of the dielectric constant of air at the moment.

Further, in the fifth step, attaching the polypropylene film material to the surface of the rectangular waveguide, encapsulating the air in the rectangular waveguide, measuring the dielectric constant under the condition, recording and storing data, comparing the dielectric constant data of the air without encapsulation, and verifying that the polypropylene film material has no influence on the method for measuring the dielectric constant of the medium by the rectangular waveguide method, including:

(1) measuring the size of the rectangular waveguide, cutting the polypropylene film material into two rectangles with different sizes, and adhering the rectangles to each other, so that the rectangular aperture can be adhered to the surface of the rectangular waveguide while the polypropylene material is used, and the foil material is prevented from adhering to the surface of the polypropylene material when the experimental measurement of the dielectric constant of the foil air mixed medium is carried out subsequently;

(2) the method comprises the steps of packaging two ends of a rectangular waveguide sheet by using a polypropylene film material, connecting the rectangular waveguide sheet to a coaxial waveguide converter, measuring the dielectric constant of the polypropylene film material packaged by using test software in a computer, recording data, comparing the real part and the imaginary part of the measured air dielectric constant, and eliminating the influence of the polypropylene film material on the method for measuring the dielectric constant of the medium by using a rectangular waveguide method.

In the sixth step, the step of encapsulating the soil by using the polypropylene film material, measuring the air mixed dielectric constant of the soil, recording and storing data, inquiring the existing empirical model, verifying the accuracy of the dielectric constant data of the soil, and proving the feasibility of the experiment on the measurement of the dielectric constant of the mixed medium comprises the following steps:

the method comprises the steps of opening a packaged rectangular waveguide, filling soil to be tested into the rectangular waveguide, paving the soil into the waveguide in a filling process, filling the waveguide as full as possible, paying attention to the fact that the filled soil does not exceed a packaging area of a polypropylene film material due to the fact that the polypropylene film material has elasticity, connecting a packaged rectangular waveguide sheet to a coaxial waveguide converter, measuring the mixed dielectric constant of the soil and the air, recording data, comparing the measured data with data in a soil experience model, and verifying feasibility of experiments on mixed dielectric constant measurement.

Further, in the seventh step, the cutting of the foil material, the control of the number of the foil to control the filling rate, the encapsulation with the polypropylene film material, the measurement of the air-mixed dielectric constant of the foil, and the recording and storing of data include:

(1) taking out the tested soil sample, cleaning the periphery of the rectangular waveguide sheet, and recovering the sample to be tested;

(2) preparation of the medium sample: processing as carefully as possible, keeping the flatness of the medium sample, cutting the foil strips into strips, placing the strips along the length direction of the rectangular waveguide, filling 2, 4, 6, 8, 10, 12, 14 and 16 foil strips respectively for testing, recording experimental data and observing data rules.

In the eighth step, the analyzing the experimental data graph, the possibility of causing experimental error in the process of the backstepping experiment, includes:

and processing experimental data, drawing a relation graph of frequency and dielectric constant, comparing the influence of different filling rates on the air mixing dielectric constant of the foil strip, and analyzing the influence of errors possibly existing in the experimental process on the experimental data.

Another object of the present invention is to provide a foil air-mix dielectric constant measuring system using the foil air-mix dielectric constant measuring method, the foil air-mix dielectric constant measuring system including:

the device connection module is used for testing a dielectric constant system of a medium by using the whole rectangular waveguide method, a computer is connected with a vector network analyzer by using a twisted pair cable, a power line is connected with a power supply to supply power to the vector network analyzer, a coaxial line is connected to two ports of the vector network analyzer, two coaxial waveguide converters are connected at the ports, the medium is placed in the rectangular waveguide, the coaxial waveguide converters are connected, and the device is connected into a passage;

the equipment calibration module is used for calibrating the measurement error in the system after the test system is built;

the target measurement module is used for measuring scattering parameters of a medium loaded in the rectangular waveguide, and setting an initial frequency, a termination frequency and a test point number;

the data acquisition module is used for testing the scattering constants of different dielectric materials, obtaining dielectric constant data through test software, testing by changing the filling rate of the dielectric materials, and storing the data for subsequent image analysis;

and the graphic processing module is used for carrying out imaging processing on the acquired data and visually analyzing the influence of different conditions on the dielectric constant data of the medium.

It is a further object of the invention to provide a computer device comprising a memory and a processor, the memory storing a computer program which, when executed by the processor, causes the processor to perform the steps of:

selecting an experimental site, preparing an experimental instrument and a material to be tested, connecting a computer and a vector network analyzer, and switching on a power supply to supply power to equipmentChecking whether the connection of the line is correct; connecting the coaxial line to a port of a vector network analyzer, and opening computer measurement software to set parameters; starting calibration, calibrating scattering parameters of two ports of the vector network analyzer to two end faces of the measurement waveguide, and eliminating errors caused by loss of experimental elements in the experimental process; the essence of measuring the dielectric constant by using the waveguide method is that a sample to be measured is used as a two-port network, data measured by a vector network analyzer is scattering parameters of a medium, namely S parameters S of two ports₁₁，S₁₂，S₂₁，S₂₂Deducing the dielectric constant of the sample to be measured by using a scattering equation of an NRW transmission/reflection method;

attaching a polypropylene film material to the surface of the rectangular waveguide, packaging air in the rectangular waveguide, measuring the dielectric constant under the condition, recording and storing data, comparing the dielectric constant data of the air without packaging, and verifying that the polypropylene film material has no influence on the method for measuring the dielectric constant of the medium by the rectangular waveguide method; packaging soil by using a polypropylene film material, measuring the air-mixed dielectric constant of the soil, recording and storing data, inquiring the existing experience model, verifying the accuracy of the dielectric constant data of the soil, and proving the feasibility of the experiment; cutting the foil material, controlling the number of the foil to control the filling rate, packaging by using a polypropylene film material, measuring the air-mixed dielectric constant of the foil, and recording and storing data; and analyzing the experimental data graph and performing experimental error analysis.

It is another object of the present invention to provide a computer-readable storage medium storing a computer program which, when executed by a processor, causes the processor to perform the steps of:

selecting an experimental site, preparing an experimental instrument and a material to be tested, connecting the experimental instrument and the material to be tested with a computer and a vector network analyzer, switching on a power supply to supply power to equipment, and checking whether the connection of a circuit is correct; connecting the coaxial line to a port of a vector network analyzer, and opening computer measurement software to set parameters; starting calibration, calibrating the scattering parameters of the two ports of the vector network analyzer to the two end faces of the measurement waveguide, and eliminating the loss of experimental elements in the experimental processA resultant error; the essence of measuring the dielectric constant by using the waveguide method is that a sample to be measured is used as a two-port network, data measured by a vector network analyzer is scattering parameters of a medium, namely S parameters S of two ports₁₁，S₁₂，S₂₁，S₂₂Deducing the dielectric constant of the sample to be measured by using a scattering equation of an NRW transmission/reflection method;

Another object of the present invention is to provide an information data processing terminal for implementing the foil strip air-mix permittivity measurement system.

By combining all the technical schemes, the invention has the advantages and positive effects that: the invention provides a foil strip air-mixed dielectric constant measuring system, relates to a method for measuring dielectric material parameters by a waveguide method, in particular to a design of an experimental scheme for measuring foil strip air-mixed dielectric constant by a rectangular waveguide method and an analysis method for inverting the dielectric constant by S parameters.

The method uses the scattering equation of the NRW transmission/reflection method to deduce the dielectric constant of the sample to be tested, fills different foil strips in the rectangular waveguide to control the filling rate, measures the mixed dielectric constant of the foil strips and air, solves the calibration problem in the experiment, simplifies the calibration steps, provides a new idea for experimental measurement, and fills the blank of the experimental process. The method obtains the specific data of the air-mixed dielectric constant of the foil strip, provides the truest and effective data for the subsequent research on the propagation characteristics of the foil strip interferent, and lays a data foundation for the subsequent research on novel materials.

According to the measuring equipment for measuring the dielectric constant of the substance by the rectangular waveguide method, the variable control method is adopted, the mixed dielectric constant of the foil strip air is measured by selecting different filling rates, the specific experimental design and the experimental steps for measuring the dielectric constant of the substance by the rectangular waveguide method are provided, the calibration problem in the experiment is solved, and the blank of the experimental process is made up. The dielectric constant of the sample to be measured is deduced by using a scattering equation of an NRW transmission/reflection method, and specific data of the foil strip air mixing dielectric constant are obtained.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments of the present invention will be briefly described below, and it is obvious that the drawings described below are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without creative efforts.

Fig. 1 is a flowchart of a method for measuring an air-mixed dielectric constant of a foil strip according to an embodiment of the present invention.

FIG. 2 is a block diagram of a system for measuring air-mixed dielectric constant of a foil strip according to an embodiment of the present invention;

in the figure: 1. a device connection module; 2. a device calibration module; 3. a target measurement module; 4. a data acquisition module; 5. and a graphics processing module.

Fig. 3 is a structural diagram of a waveguide measurement system according to an embodiment of the present invention.

Fig. 4 is a schematic diagram of setting parameters of a test software band according to an embodiment of the present invention.

Fig. 5 is a schematic diagram of setting the test software frequency and the number of measurement points according to the embodiment of the present invention.

Fig. 6 is a flowchart of a rectangular waveguide calibration method according to an embodiment of the present invention.

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

FIG. 8 is a graph of the imaginary part of the measured air dielectric constant as a function of frequency provided by an embodiment of the present invention.

Fig. 9 is a schematic view of a waveguide sheet encapsulated by a polypropylene material according to an embodiment of the present invention.

FIG. 10 is a diagram of a rectangular waveguide method for measuring dielectric constant according to an embodiment of the present invention.

FIG. 11 is a comparison graph of real part of dielectric constant of air before and after packaging provided by the embodiment of the invention.

Fig. 12 is a comparison graph of imaginary data of air dielectric constant before and after packaging according to an embodiment of the present invention.

FIG. 13 is a graph of real part of the dielectric constant of soil air mixture as a function of frequency provided by an embodiment of the present invention.

FIG. 14 is a graph of imaginary part of the soil-air mixture permittivity as a function of frequency provided by an embodiment of the present invention.

FIG. 15 is a graph of the real part of the air mix permittivity of the foil strip as a function of frequency when 2 foil strips are filled according to an embodiment of the present invention.

FIG. 16 is a graph of the imaginary part of the air mix dielectric constant of the foil strip as a function of frequency for a 2 foil strip fill provided by an embodiment of the present invention.

FIG. 17 is a graph of the real part of the air mix permittivity of the foil strip as a function of frequency when 4 foil strips are filled according to an embodiment of the present invention.

FIG. 18 is a graph of the imaginary part of the air mix dielectric constant of the foil strip as a function of frequency when filling 4 foil strips according to an embodiment of the present invention.

FIG. 19 is a graph of the real part of the air mix permittivity of the foil strip as a function of frequency when 6 foil strips are filled according to an embodiment of the present invention.

FIG. 20 is a graph of imaginary part of the foil strip air mix permittivity as a function of frequency for 6 foil strips filled in accordance with an embodiment of the present invention.

FIG. 21 is a graph of the real part of the air mix permittivity of the foil strip as a function of frequency when 8 foil strips are filled according to an embodiment of the present invention.

FIG. 22 is a graph of the imaginary part of the air mix dielectric constant of the foil strip as a function of frequency when 8 foil strips are filled according to an embodiment of the present invention.

FIG. 23 is a graph of the real part of the air mix permittivity of the foil strip as a function of frequency when 10 foil strips are filled according to an embodiment of the present invention.

FIG. 24 is a graph of the imaginary part of the air mix dielectric constant of the foil strip as a function of frequency for 10 foil strips filled in accordance with an embodiment of the present invention.

FIG. 25 is a graph of the real part of the air mix permittivity of the foil strip as a function of frequency when 12 foil strips are filled according to an embodiment of the present invention.

FIG. 26 is a graph of the imaginary part of the air mix dielectric constant of the foil strip as a function of frequency when filling 12 foil strips according to an embodiment of the present invention.

FIG. 27 is a graph of the real part of the air mix permittivity of 14 foil strips as a function of frequency when filled with the foil strips according to an embodiment of the present invention.

FIG. 28 is a graph of the imaginary part of the air mix dielectric constant of the foil strip as a function of frequency when filling 14 foil strips according to an embodiment of the present invention.

FIG. 29 is a graph of the real part of the air mix permittivity of the foil strip as a function of frequency when 16 foil strips are filled according to an embodiment of the present invention.

FIG. 30 is a graph of the imaginary part of the air mix dielectric constant of the foil strip as a function of frequency when filling 16 foil strips according to an embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Aiming at the problems in the prior art, the invention provides a method for measuring the air-mixed dielectric constant of a foil strip, and the invention is described in detail with reference to the accompanying drawings.

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

s101, selecting an experiment site, preparing an experiment instrument and a material to be tested, connecting a computer and a vector network analyzer, switching on a power supply to supply power to equipment, and checking whether the connection of a circuit is correct;

s102, connecting the coaxial line to a port of a vector network analyzer, and opening computer measurement software to set parameters;

s103, starting calibration, calibrating the scattering parameters of the two ports of the vector network analyzer to the two end faces of the measurement waveguide, and eliminating errors caused by loss of experimental elements in the experimental process;

s104, the essence of measuring the dielectric constant by using the waveguide method is that a sample to be measured is used as a two-port network, data measured by a vector network analyzer is scattering parameters of a medium, namely S parameters S of two ports₁₁，S₁₂，S₂₁，S₂₂Deducing the dielectric constant of the sample to be measured by using a scattering equation of an NRW transmission/reflection method;

s105, attaching a polypropylene film material to the surface of the rectangular waveguide, packaging air in the rectangular waveguide, measuring the dielectric constant under the condition, recording and storing data, comparing the dielectric constant data of the air without packaging, and verifying that the polypropylene film material has no influence on the method for measuring the dielectric constant of the medium by the rectangular waveguide method;

s106, packaging soil by using a polypropylene film material, measuring the air mixed dielectric constant of the soil, recording and storing data, inquiring the existing empirical model, verifying the accuracy of the dielectric constant data of the soil, and proving the feasibility of the experiment;

s107, cutting the foil material, controlling the number of the foil to control the filling rate, packaging by using a polypropylene film material, measuring the air-mixed dielectric constant of the foil, and recording and storing data;

and S108, analyzing the experimental data graph and carrying out experimental error analysis.

As shown in fig. 2, the foil strip air-mix dielectric constant measurement system provided by the embodiment of the present invention includes:

the device connection module 1 is used for testing a dielectric constant system of a medium by using the whole rectangular waveguide method, a computer is connected with a vector network analyzer by using a twisted pair cable, a power supply is connected with a power supply to supply power to the vector network analyzer, a coaxial line is connected to two ports of the vector network analyzer, two coaxial waveguide converters are connected to the ports, the medium is placed in a rectangular waveguide, the coaxial waveguide converters are connected, and the device is connected into a passage;

the equipment calibration module 2 is used for calibrating the measurement error existing in the system after the test system is built;

the target measurement module 3 is used for measuring scattering parameters of a medium loaded in the rectangular waveguide, and setting the starting frequency, the terminating frequency and the number of test points;

the data acquisition module 4 is used for testing the scattering constants of different dielectric materials, obtaining dielectric constant data through test software, testing by changing the filling rate of the dielectric materials, and storing the data for subsequent image analysis;

and the graphic processing module 5 is used for performing imaging processing on the acquired data and visually analyzing the influence of different conditions on the dielectric constant data.

The technical solution of the present invention is further described below with reference to specific examples.

The invention is realized in such a way that a specific experimental scheme for measuring the air-mixed dielectric constant of a foil strip comprises the following steps:

selecting an experimental site, preparing an experimental instrument and a material to be tested, connecting a computer and a vector network analyzer, switching on a power supply to supply power to equipment, and checking whether the connection of a circuit is correct;

connecting the coaxial line to a port of a vector network analyzer, and opening computer measurement software to set parameters;

step three, starting calibration, calibrating the scattering parameters of the two ports of the vector network analyzer to the two end faces of the measurement waveguide, and eliminating errors caused by the loss of experimental elements in the experimental process;

step four, the essence of measuring the dielectric constant by using the waveguide method is that the sample to be measured is taken as a two-port network, the data measured by the vector network analyzer is the scattering parameter of the medium, namely the S parameter S of the two ports₁₁，S₁₂，S₂₁，S₂₂Deducing the dielectric constant of the sample to be measured by using a scattering equation of an NRW transmission/reflection method;

attaching a polypropylene film material to the surface of the rectangular waveguide, packaging air in the rectangular waveguide, measuring the dielectric constant under the condition, recording and storing data, comparing the dielectric constant data of the air without packaging, and verifying that the polypropylene film material has no influence on the method for measuring the dielectric constant of the medium by the rectangular waveguide method;

step six, packaging the soil by using a polypropylene film material, measuring the air mixed dielectric constant of the soil, recording and storing data, inquiring the existing empirical model, verifying the accuracy of the dielectric constant data of the soil, and proving the feasibility of the experiment;

cutting the foil material, controlling the number of the foil strips to control the filling rate, packaging by using a polypropylene film material, measuring the air-mixed dielectric constant of the foil strips, and recording and storing data;

and step eight, analyzing the experimental data graph and carrying out experimental error analysis.

In the first step provided by the embodiment of the invention, an experimental site is selected, an experimental instrument and a material to be tested are prepared, a computer and a vector network analyzer are connected, a power supply is switched on to supply power to equipment, and whether the connection of a circuit is correct or not is specifically as follows:

(1) the experiment measurement should select an open area to avoid interference of other instruments to the measurement system.

(2) The experimental instrument and the material to be tested comprise a vector network analyzer, a computer, a twisted-pair cable, a coaxial cable, a calibration piece, a rectangular waveguide piece, a roll of polypropylene membrane material, a plurality of soil, a plurality of foil strips, a pair of scissors, a pair of ruler and tweezers.

(3) Connecting a computer RJ45 interface with a LAN interface of a vector network analyzer by using a twisted pair cable; before connecting with a power supply, paying attention to the protection of the vector network analyzer, paying attention to the maximum bearing power, protecting a high-power damaged port, switching on the power supply, opening the vector network analyzer and a computer, checking whether a circuit is switched on by using measurement software on the computer, and carrying out experimental measurement after the circuit is switched on, wherein the structure of the waveguide method measurement system is shown in figure 3.

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

(1) connecting the coaxial line to the port of the vector network analyzer, opening the computer test software to set parameters, and selecting the wave band, as shown in fig. 4.

(2) The start frequency, the end frequency, the number of measurement points are set as shown in fig. 5, and it is confirmed on the vector network analyzer that the set parameters are consistent.

In the third step provided by the embodiment of the present invention, calibration is started, and two port scattering parameters of the vector network analyzer are calibrated to two end faces of the measurement waveguide, and a rectangular waveguide calibration flowchart is shown in fig. 6, so as to eliminate errors caused by loss of experimental elements in the experimental process, specifically:

(1) selecting a calibration key on the vector network analyzer, selecting the calibration type to be non-guide calibration (using a mechanical calibration piece to carry out response calibration, single-port calibration and double-port calibration), selecting a full double-port TRL in the non-guide calibration, neglecting two isolated keys, and carrying out the next step.

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

(3) The coaxial waveguide converters are connected to two ends of the coaxial line respectively, the coaxial waveguide converters are connected together through pins, the oblique opposite angles of the pins are inserted into the holes oppositely when the coaxial waveguide converters are connected, errors caused by untight connection of devices can be reduced due to connection, the through key is clicked after connection is completed, the THRU key is clicked, the instrument starts to be calibrated, the confirming key is pressed after the instrument is completed, and next calibration is carried out.

(5) and (4) performing the same reflection step of the port 2 as the step (4), and performing the next calibration after the reflection step is completed.

(6) Connecting rectangular waveguide pieces at two ends of the coaxial waveguide converter, paying attention to the position of a corresponding rectangle during connection, pressing a LINE/matching calibration key, clicking a BJ-220 (lambda/4 LINE) key, pressing a determined key after calibration is finished, and finishing the calibration step.

(7) When the guide is withdrawn, the calibration set is saved in the channel 1 and can be used for a long time.

In the fourth step provided by the embodiment of the invention, the essence of measuring the dielectric constant by using the waveguide method is that the sample to be measured is taken as a two-port network, the data measured by the vector network analyzer is the scattering parameter of the medium, namely the S parameter S of the two ports₁₁，S₁₂，S₂₁，S₂₂The dielectric constant of the sample to be measured is deduced by using a scattering equation of an NRW transmission/reflection method, which specifically comprises the following steps:

V_R＝S₁₁·V_I

V_T＝S₂₁·V_I

if the incident voltage is 1, the scattering parameter is expressed as the total incident voltage V_RAnd a total transmission voltage V_TNamely:

S₁₁＝V_R

S₂₁＝V_T

for simple calculation, setting:

V₁＝S₂₁+S₁₁

V₂＝S₂₁-S₁₁

it can be deduced that:

wherein, mu_rIs the relative complex permeability of the material,ε_ris the relative complex dielectric constant, is the propagation constant of the sample section under test, λ₀Is the operating wavelength in air, λ_cIs the cutoff wavelength of the waveguide transmission line, and j is the imaginary unit.

T＝e^-γd

deducing by the following formula:

The reflection coefficient Γ may be expressed as:

in the formula (I), the compound is shown in the specification,

and has:

In conclusion, the principle of the NRW transmission/reflection algorithm is described, a computer test software is opened to set parameters for dielectric constant measurement, bidirectional test is performed, the distance from the port a to the port B is set to be 0.000mm, the thickness of a sample is set to be 4.500mm, click measurement is performed, a data graph appearing on a panel is observed, real part and imaginary part data of the air dielectric constant measured at the moment are stored, the theoretical value of the real part of the dielectric constant of air is 1, the theoretical value of the imaginary part of the dielectric constant is 0, the relationship between the real part of the dielectric constant of actually measured air and the frequency is shown in fig. 7, the relationship between the imaginary part of the dielectric constant of actually measured air and the frequency is shown in fig. 8, the mean value of the real part of the dielectric constant of actually measured air is 1.0014, the mean value of the imaginary part is-0.0002, and the difference between the real part of the dielectric constant and the theoretical value of the air is small, and the calibration is successful.

In the fifth step provided by the embodiment of the invention, a polypropylene film material is attached to the surface of the rectangular waveguide, air in the rectangular waveguide is encapsulated, the dielectric constant under the condition is measured, stored data is recorded, and compared with the dielectric constant data of air without encapsulation, the polypropylene film material is verified to have no influence on the method for measuring the dielectric constant of the medium by the rectangular waveguide method, and the method specifically comprises the following steps:

(1) the size of the rectangular waveguide is measured, the polypropylene film material is cut into two rectangles with different sizes, the rectangles are mutually adhered, the rectangular aperture is guaranteed to be completed by the polypropylene material, and the rectangles can be adhered to the surface of the rectangular waveguide, so that the foil material is prevented from being adhered to the surface of the polypropylene material during subsequent experimental measurement of the dielectric constant of the foil air mixed medium.

(2) Both ends of the rectangular waveguide sheet are packaged by using a polypropylene film material, as shown in fig. 9, the rectangular waveguide sheet is connected to the coaxial waveguide converter, as shown in fig. 10, the dielectric constant of the polypropylene film material after packaging is measured by using test software in a computer, data is recorded, and the real part and the imaginary part of the air dielectric constant measured without packaging are compared.

The relation between the real part of the dielectric constant and the frequency is shown in FIG. 11, the relation between the imaginary part of the dielectric constant and the frequency is shown in FIG. 12, the mean value of the real part of the dielectric constant of the packaged air is 1.0189, the mean value of the imaginary part is-0.0002, and the difference between the mean value of the real part of the dielectric constant and the mean value of the imaginary part of the dielectric constant of the packaged air is less than that of the air with no packaging test, so that the influence of polypropylene film materials on the method for measuring the dielectric constant of the medium by a rectangular waveguide method is eliminated.

In the sixth step provided by the embodiment of the invention, the soil is encapsulated by using a polypropylene film material, the air mixed dielectric constant of the soil is measured, the stored data is recorded, the existing empirical model is inquired, the accuracy of the dielectric constant data of the soil is verified, and the feasibility of the experiment on the dielectric constant measurement of the mixed medium is proved, specifically:

opening the packaged rectangular waveguide, filling soil to be tested into the rectangular waveguide, paving the soil into the waveguide in the filling process, filling the waveguide as full as possible, paying attention to the fact that the filled soil does not exceed a packaging area of the polypropylene film material due to elasticity of the polypropylene film material, connecting the packaged rectangular waveguide sheet to a coaxial waveguide converter, measuring the air-soil mixed dielectric constant, recording data, and comparing the tested data with data in a soil empirical model.

The real part of dielectric constant data pair is shown in FIG. 13, the imaginary part of dielectric constant data pair is shown in FIG. 14, the empirical value of the real part of dielectric constant of dry soil is 4, the empirical value of the real part of dielectric constant of air is 1, the mean value of the real part of dielectric constant of the soil-air mixed dielectric material measured this time is 2.0729, and the data are in the range of the empirical value; the imaginary part of the dielectric constant of the dry soil is generally less than 0.05, the imaginary part of the air dielectric constant is 0, the mean value of the imaginary parts of the dielectric constant of the soil-air mixed dielectric material measured at this time is 0.4671, and the soil-air mixed data verifies the feasibility of the experiment on the measurement of the mixed dielectric constant within the empirical value range.

In the seventh step provided by the embodiment of the present invention, the foil material is cut, the number of the foil strips is controlled to control the filling rate, the polypropylene film material is used for packaging, the air-mixed dielectric constant of the foil strips is measured, and the data is recorded and stored, specifically:

taking out the tested soil sample, cleaning the periphery of the rectangular waveguide sheet, recovering the sample to be tested, and preparing a medium sample: processing as carefully as possible, keeping the flatness of the medium sample, cutting the foil strips into strips, placing the strips along the length direction of the rectangular waveguide, filling 2, 4, 6, 8, 10, 12, 14 and 16 foil strips respectively for testing, recording experimental data and observing data rules. The real part and the imaginary part of the foil strip air mixing dielectric constant are shown in the graphs with the frequency change of figures 15-30. Table 1 is the mean of the real and imaginary parts of the filling rate foil strip air mix permittivity.

TABLE 1 mean value of real and imaginary parts of filling rate foil strip air-mix dielectric constant

Number of filling foil strips	Mean value of real part of mixed dielectric constant	Mixed dielectric constant imaginary mean
			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 experimental data, the number of the foil strips is increased in a certain range, and the real part and the imaginary part of the air-mixed dielectric constant of the foil strips are increased; the real part and the imaginary part of the dielectric constant show regular changes under different filling rates; and the fact that the imaginary part of the mixed dielectric constant has negative value is found in the test process, which provides important data for the research of novel materials.

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

In the experimental process, because the foil strips are extremely fine, the foil strips can only be stretched and flattened as much as possible in the placing process, and errors of experimental data can be caused.

In the above embodiments, the implementation may be wholly or partially realized by software, hardware, firmware, or any combination thereof. When used in whole or in part, can be implemented in a computer program product that includes one or more computer instructions. When loaded or executed on a computer, cause the flow or functions according to embodiments of the invention to occur, in whole or in part. The computer may be a general purpose computer, a special purpose computer, a network of computers, or other programmable device. The computer instructions may be stored in a computer readable storage medium or transmitted from one computer readable storage medium to another, for example, the computer instructions may be transmitted from one website site, computer, server, or data center to another website site, computer, server, or data center via wire (e.g., coaxial cable, fiber optic, Digital Subscriber Line (DSL), or wireless (e.g., 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, etc., that includes one or more of the available media. The usable medium may be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., solid state disk (ssd)), among others.

The above description is only for the purpose of illustrating the present invention and the appended claims are not to be construed as limiting the scope of the invention, which is intended to cover all modifications, equivalents and improvements that are within the spirit and scope of the invention as defined by the appended claims.

Claims

1. A foil strip air-mixed dielectric constant measuring method is characterized by comprising the following steps:

2. The method for measuring the air-mixed dielectric constant of the foil strip as claimed in claim 1, wherein in the first step, the experimental site is selected, an experimental instrument and a material to be measured are prepared, the computer and the vector network analyzer are connected, the power supply is switched on to supply power to the equipment, and whether the connection of the circuit is correct or not is checked, and the method comprises the following steps:

(3) before connecting the power supply, paying attention to the protection of the vector network analyzer, paying attention to the maximum bearing power, protecting the high-power damaged port, switching on the power supply, turning on the vector network analyzer and the computer, checking whether a circuit is switched on by using measurement software on the computer, and carrying out experimental measurement after the switching on is finished;

in step two, the connecting the coaxial line to the port of the vector network analyzer, and opening the computer measurement software to set parameters includes:

3. The method for measuring the air-mixed dielectric constant of the foil strip according to claim 1, wherein in the third step, the calibration is started, two-port scattering parameters of the vector network analyzer are calibrated to two end faces of the measurement waveguide, and errors caused by loss of experimental elements in the experimental process are eliminated, and the method comprises the following steps:

4. The method for measuring the air-mixed dielectric constant of the foil strip according to claim 1, wherein in the fourth step, the essence of measuring the dielectric constant by using the waveguide method is that the sample to be measured is used as a two-port network, and the data measured by a vector network analyzer is the scattering parameter of the medium, namely the S parameter S of the two ports₁₁，S₁₂，S₂₁，S₂₂The method for deriving the dielectric constant of the sample to be measured by using the scattering equation of the NRW transmission/reflection method comprises the following steps:

when electromagnetic wave propagates in waveguide transmission line, its transmission characteristics are independent of position, and only reflection and transmission occur at medium boundary surface, V_IRepresenting the incident voltage, V_RRepresenting reflected voltage, V_TRepresents the total transmission voltage, the following relationshipIt is true, also the definition of the scattering parameters, that is:

V_R＝S₁₁·V_I；

V_T＝S₂₁·V_I；

S₁₁＝V_R；

S₂₁＝V_T；

setting:

V₁＝S₂₁+S₁₁；

V₂＝S₂₁-S₁₁；

the derivation yields:

wherein, mu_rIs the relative complex permeability, epsilon, of the material_rIs the relative complex dielectric constant, is the propagation constant of the sample section under test, λ₀Is the operating wavelength in air, λ_cIs the cut-off wavelength of the waveguide transmission line, j is the imaginary unit;

T＝e^-γd；

deducing by the following formula:

wherein Z is₀The characteristic impedance of the air region in the transmission line is represented, and Z represents the characteristic impedance of the measured medium sample section;

the reflection coefficient Γ is expressed as:

in the formula (I), the compound is shown in the specification,

and has:

wherein λ is_gFor the waveguide wavelength of the sample to be measured, the cut-off wavelength lambda is used for the measurement system of the coaxial transmission line_cInfinity, cut-off wavelength λ for a rectangular waveguide based measurement system_c＝2a；

5. The method for measuring the air-mixed dielectric constant of the foil strip as claimed in claim 1, wherein in the fifth step, 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 the condition is measured, the stored data is recorded, and the polypropylene film material is verified to have no influence on the method for measuring the dielectric constant of the medium by the rectangular waveguide method by comparing the dielectric constant data of the air without encapsulation, and the method comprises the following steps:

(2) packaging both ends of a rectangular waveguide sheet by using a polypropylene film material, connecting the rectangular waveguide sheet to a coaxial waveguide converter, measuring the dielectric constant of the polypropylene film material packaged by using test software in a computer, recording data, comparing the real part and the imaginary part of the measured air dielectric constant, and eliminating the influence of the polypropylene film material on the method for measuring the dielectric constant of the medium by using a rectangular waveguide method;

6. The method for measuring the air mix dielectric constant of the foil strip as claimed in claim 1, wherein in step seven, the cutting of the foil strip material, the control of the number of the foil strips to control the filling rate, the encapsulation with the polypropylene film material, the measurement of the air mix dielectric constant of the foil strip, and the recording and storing of the data comprise:

(2) preparation of the medium sample: processing as carefully as possible, keeping the flatness of a medium sample, cutting foil strips into long strips, placing the long strips along the direction of the rectangular waveguide, filling 2, 4, 6, 8, 10, 12, 14 and 16 foil strips respectively for testing, recording experimental data and observing data rules;

7. A foil air mix dielectric constant measuring system applying the foil air mix dielectric constant measuring method according to any one of claims 1 to 6, wherein the foil air mix dielectric constant measuring system comprises:

8. A computer device, characterized in that the computer device comprises a memory and a processor, the memory storing a computer program which, when executed by the processor, causes the processor to carry out the steps of:

selecting an experimental site, preparing an experimental instrument and a material to be tested, connecting the experimental instrument and the material to be tested with a computer and a vector network analyzer, switching on a power supply to supply power to equipment, and checking whether the connection of a circuit is correct; connecting the coaxial line to a port of a vector network analyzer, and opening computer measurement software to set parameters; starting calibration, calibrating scattering parameters of two ports of the vector network analyzer to two end faces of the measurement waveguide, and eliminating errors caused by loss of experimental elements in the experimental process; the essence of measuring the dielectric constant by using the waveguide method is that a sample to be measured is used as a two-port network, data measured by a vector network analyzer is scattering parameters of a medium, namely S parameters S of two ports₁₁，S₁₂，S₂₁，S₂₂Deducing the dielectric constant of the sample to be measured by using a scattering equation of an NRW transmission/reflection method;

9. A computer-readable storage medium storing a computer program which, when executed by a processor, causes the processor to perform the steps of:

10. An information data processing terminal, characterized in that the information data processing terminal is adapted to implement the foil strip air mix permittivity measurement system of claim 7.