Single-port coaxial line complex permittivity measuring device and method based on mode matching

Abstract

The invention provides a single-port coaxial line complex permittivity measuring device and a method based on mode matching. The single-port coaxial line complex permittivity measuring device comprises a coaxial line cable connector, a coaxial waveguide section and a terminal short circuit metal plate, wherein the coaxial line cable connector, the coaxial waveguide section and the terminal short circuit metal plate are connected in sequence, the lateral dimension of the coaxial waveguide section is not dependent on the size of the coaxial line cable connector, and the coaxial waveguide section works in a multimode state. The measuring method relates to the measuring device and a vector network analyzer. A reflection coefficient of a sensing device which is filled in substance to be measured is measured through the vector network analyzer and then through data processing, a complex permittivity of the substance is achieved through inversion. Due to the fact that a multimode matching model is used in the inversion process, the coaxial waveguide section can works in the multimode state, so that the design and processing demands of measuring and sensing devices are lowered and an upper limit of working frequency is improved.

Description

technical field [0001] The invention relates to a single-port coaxial line type complex dielectric constant measuring device and method based on mode matching. Background technique [0002] Measuring the complex permittivity of substances is of great significance in scientific research and industrial production, especially in the radio frequency microwave band. With the rapid development of electronic technology, the measurement frequency range and accuracy of vector network analyzers are getting larger and higher. The frequency domain measurement method of complex permittivity based on vector network analyzers has been widely studied, and one of the commonly used The broadband measurement method is the coaxial line method, which measures the reflection-transmission coefficient of the coaxial waveguide filled with the tested sample, and inverts the different frequencies according to the mathematical relationship between the reflection-transmission coefficient and the complex...

AI Technical Summary

Problems solved by technology

The traditional coaxial line method requires that only TEM waves exist in the coaxial waveguide filled with the sample to be tested, so the mathematical model is relatively simple, but in practical applications, it is necessary to specially design the joints of coaxial lines of different sizes to ensure that there is no Higher order modes are excited out

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