Computations of unloaded Q0-Factor and resonant frequency of the TE011 mode Hakki–Coleman dielectric resonators with coupling structures using ANSOFT HFSS

Abstract

Microwave characterization of materials using dielectric resonators is based on measurements of the Q-factor of the resonator containing a sample under test and on the loss equation for the test structure. The loss equation contains geometrical factors, which are calculated assuming an ideal metallic cavity of the resonator. In this paper a rigorous analysis of cylindrical parallel plate dielectric resonators has been performed to assess the influence of the presence of coupling holes and cables on the unloaded Q-factor and resonant frequency. Calculations have been done for the TE011 mode resonators with differing cavity to dielectric diameter ratio, conductivity of the cavity material, loss tangent and relative permittivity of the dielectric rod, position of the coupling loops and size of the coupling cables. Results have shown that Qo-factors calculated for real resonators were smaller than Qo-factors for ideal resonators. Also this paper presents a brief history of analysis of dielectric resonators.