Novel Method for Calculation and Measurement of Unloaded Q-Factor of Superconducting Dielectric Resonators

Abstract

The dielectric resonator technique is recognised as the best method for the measurement of surface resistance (Rs) of High Temperature Superconducting thin films. The Rs is calculated from the Unloaded Q-factor (Q0) of the resonator, and to obtain accurate values of the Q0-factor multi-frequency measurements of S21, S11 and S22 and data circle fitting are required. As a result, surface resistance measurements at varying temperatures are very time consuming. In this paper we introduce a simplified method for calculations the Q0-factor, which require measurements of S11 and S 22 at the lowest temperature only. For all other temperatures only S21 measurements are needed. The method has shown to give sufficiently accurate Q0 values and hence the surface resistance.