CONDITIONS FOR AND LIMITATIONS OF HIGH-POWER HANDLING CAPABILITIES OFPLANAR YBA2CU3O7-X FILTERS

The conditions for the design of compact high-power HTS filters are de duced from basic considerations, and related to the microwave properti es of the HTS films and the substrates. Potential mechanisms limiting the linear microwave response of HTS films are analyzed systematically . Magnetic and thermal field breakdowns are found to confine the power handling capability to comparable field levels. While magnetic limita tion is related to flux penetration at the lower critical field B-c1, thermally induced quenches occur dependent on the presence of defects and on the thermal conductivity of the substrate. The detrimental role of film inhomogeneities for the linear microwave response is confirme d experimentally for microwave fields at 19 GHz and for dc fields at 8 7 GHz.