INTRINSIC LIMITS ON THE Q AND INTERMODULATION OF LOW-POWER HIGH-TEMPERATURE SUPERCONDUCTING MICROSTRIP RESONATORS

Cuprate superconducting thin films are being used to make compact low power microwave devices. In recent years, with improved materials and designs, there has been a steady improvement in device performance, no tably an increase in resonator Q and a decrease in the nonlinear inter modulation. It is important to understand how much improvement can be expected. Here we discuss the intrinsic limiting behavior that one mig ht achieve with a perfect film, review the present status, and discuss what the limiting behavior implies for high temperature superconducti ng filters. Our analysis indicates that increases in unloaded Q to sim ilar to 10(6) and decreases in intermodulation by a factor of similar to 10(4), compared with today's values, might be achieved. (C) 1998 Am erican Institute of Physics. [S0021-8979(98)06322-1].