System and method for testing microwave complex permittivity of dielectric material

Abstract

The invention provides a system and a method for testing microwave complex permittivity of a dielectric material. The system comprises a coaxial-open-type resonant cavity and a coupling quantity adjuster. The method includes the steps: a, recording resonant frequency f0 of the system without any sample loaded in a testing range and a quality factor Q0 of a corresponding frequency point; b, testing thickness d of a to-be-tested sample, and testing to acquire resonant frequency f1 of the system after the sample is loaded in the testing range and a Q1 of a corresponding loaded quality factor; c, utilizing a perturbation theory of the resonant cavity to extract complex permittivity of a to-be-tested material. By the system and the method, high-accuracy testing of the complex permittivity of the microwave dielectric material is realized, and troublesome precise calibration does not need to be performed on a network analyzer, so that testing time is reduced, and requirements, on sample manufacturing, of testing are lowered.

Description

technical field [0001] The invention belongs to the technical field of electromagnetic parameter testing of microwave and millimeter wave materials, and specifically relates to a system and method for testing complex permittivity of dielectric materials composed of a coaxial open resonator (Open Coaxial Resonator) and a test fixture . Background technique [0002] As the transmission medium of microwave, microwave materials are widely used in microwave integrated circuits, microwave communication, radar stealth, electronic countermeasures, missile guidance and other fields. The electromagnetic parameters of microwave materials generally refer to complex permittivity and complex permeability, usually in the form of complex numbers ε(jω)=ε'(jω)-jε"(jω), μ(jω)=μ'(jω)-jμ "(jω) means that they are the two most basic characteristic parameters describing the interaction between electromagnetic fields and materials. As the operating frequency of wireless communication is getting h...

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Problems solved by technology

Japan's Ryotaro Inoue and Yasuhiko Odat et al. proposed a method of using a coaxial open resonator to test the complex permittivity of dielectric materials, but this method needs to draw a vacuum during the test, and the operation is relatively cumbersome, which is only suitable for low loss The test of the dielectric material, and the test frequency band is relatively narrow; Zhang Xiucheng and others from Huazhong University of Science and Technology in China have also proposed the use of reflective rectangular resonators and the selection of TE with a high quality factor 105 In the working mode, the dielectric material is placed by drilling a small circular hole in the center of the wide side. This method can only test the dielectric material at a single frequency point, and the dielectric material cannot be accurately positioned in the circular small hole, which will affect the test result in a certain impact;

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