Microwave Properties of High-Tc Superconductors

The rf surface impedance of bulk and electrophoretically deposited polycristalline Y1Ba2Cu3O7-x samples was determined at 3.5 and 21.5 GHz via perturbation measurements in normal and superconducting TE011 - cavities as a function of temperature and surface magnetic field strength. The results indicate that the fall off of the surface resistance below the critical temperature of 92 K is strongly influenced by the preparation conditions. With respect to the material available at present polycristalline YBaCuO can expect short term applications to passive microwave components only in the frequency range below 20 GHz.