Research On Novel Microwave Sensing Technology Applied To Dielectric Material Detection

As an important property of materials,dielectric constant provides a lot of valuable information.With the continuous development of microwave technology,microwave sensing detection technology is gradually applied in various fields.With the non-contact and non-destructive characteristics of microwave detection methods,microwave sensing systems that can effectively detect the dielectric constant of materials are widely used in agriculture,industry,and medical care.And other fields.However,traditional microwave sensors often need to rely on large-scale detection equipment such as vector network analyzers,which have disadvantages such as large size,high cost,and poor portability.This article aims to develop a microwave dielectric sensor with both high portability and low cost.The main content and innovations of this article are as follows:1.The meter developed an interferometric dielectric constant sensing system for solid material detection.First,the system framework and basic principles are explained,and then the plane sensitive unit based on the complementary compact microstrip resonant unit(CCMRC)is developed and the electric field distribution of CCMRC and the influence of the dielectric constant on its transmission characteristics are analyzed in the three-dimensional electromagnetic simulation software.At the same time,a voltage-controlled phase shifter with a wide range of linearly adjustable is designed to meet system application requirements.2.For the measurement of liquid materials,the design theory is further deepened and the system framework is improved.After that,a plane sensitive unit based on the grounded coplanar waveguide(CPWG)was developed and combined with electromagnetic simulation technology to explore the internal reasons that the medium affects the transmission characteristics.On this basis,a sensor structure for broadband dielectric constant measurement is proposed,which can realize the simultaneous measurement of the real and imaginary parts of the material's dielectric constant.3.The emphases are on the simulation and measurement accuracy of two sets of sensing systems.For the solid measurement system,the operating frequency is 5 GHz,and the measured relative permittivity(real part)ranges from 1 to 10.For liquid materials,the measurement of complex permittivity in a wide frequency band of 3 to 5 GHz has been achieved.The measurement range of the real part of the complex permittivity is within 20,and the loss tangent is within 1.According to the results of multiple actual measurements on the two sensing systems,an error rate of less than 5%has been achieved.