New Resistance Measurement Technique Applicable to High-TemperatureSuperconducting Materials at Microwave Frequencies

摘要

A two-gap electrically floating resonant strip is used for surface resistancemeasurements of the high-temperature superconductor, YBa2Cu3O(7-delta). The method used has the advantages of simplicity, no electrical contact, operation at various resonant frequencies, and of requiring only a small sample. An analysis was used that allows for the accurate design of the strip dimensions to produce a desired resonant frequency. Experimental measurements on resonant frequencies in X and Ku-band (8-18 GHz) agree well with the calculations. The method allows one to extract the normalized surface frequency. These normalized values were found to compare favorably to the Mattis-Bardeen theory taken in the local limit. The resonant strip in waveguide should have applications in high-temperature superconductive material characterization and in the development of waveguide superconductive filters. Keywords: Reprints; Superconductors; Microwave measurements; Strip discontinuities; Loss characteristics. (rh)