A cryogenic post dielectric resonator for precise microwave characterization of planar dielectric materials for superconducting circuits

Abstract

A novel dielectric resonator operating at cryogenic temperatures (14–85 K) at a frequency of 10 GHz for measurements of permittivity and loss tangent of dielectric substrates for HTS microwave circuits is presented. We have fabricated a prototype post dielectric resonator, with superconducting (DyBa2Cu3O7) end plates and silver-plated copper sidewalls to improve the sensitivity and resolution of loss tangent measurements. Also a numerical technique for calculations of permittivity and loss tangent from the resonant frequency and the Q-factor is presented in the paper. For verification of the technique, measurements of the real part of the permittivity of a single crystal quartz substrate have been performed and a very good agreement with published data using the whispering gallery mode technique has been obtained.