Microwave measurement of surface impedance of high-T/sub c/ superconductor

Abstract

Perturbation formulas for a TE/sub 011/ mode dielectric resonator and for a TE/sub 011/ mode circular cavity are derived to determine the surface impedance, z/sub s/, of superconductors from measured values of resonant frequency and unloaded Q. The Z/sub s/ values for a YBCO plate with a diameter of 30 mm were measured at 8.7, 10.4, and 23.7 GHz using these formulas. The measured results are presented as functions of temperature.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>