Measurement of Complex Permittivity of Materials Using a Double-Ridge Waveguide Resonator

Abstract

A double-ridge waveguide resonator loaded with rod like dielectric material was analyzed based on the electromagnetic simulation software HFSS and microwave resonant cavity perturbation technique in this paper. The perturbation method is used to calculate the complex permittivity of the material due to the change of the resonator's tiny change. The calculation expression of complex permittivity was deduced and proper test system was built for the validation at several specific frequencies, the resonant parameters of the cavity were measured by the external Agilent vector network analyzer, according to the calibration of standard quartz sample, the complex permittivity of the quartz, sapphire and PTFE samples were calculated. Experimental result showed that the method has a good performance for measuring the complex permittivity of low dielectric loss dielectric materials.