Stripline Resonator Measurements of Z(s) versus H(rf) in YBa2Cu3O(7-x) Thin Films

摘要

Many Rs measurements for the high-Tc superconducting materials have been reportedin the literature, and films of YBa2Cu3O(7-x) deposited by a variety of methods by numerous laboratories have shown low enough values of Rs to be of practical importance. There have also been numerous reports of practical devices demonstrated with the new materials (see, for example. Almost all of the reported Rs measurements, however, have been carried out at low power and thus at low values of Hrf, the microwave-frequency magnetic field generated by the RF current flowing in the stripline. It has been known for some time that the values of Rs are dependent on the level of microwave power used in the measurement. This has been noted in measurements of Q or Rs in stripline resonators as well as in cavities. Much higher values of Hrf can be reached at a given power level in stripline structures than in the usual cavity geometries because the narrow transmission line concentrates the current and leads to higher current density and higher Hrf.