Intrinsic limits on the Q and intermodulation of low power high temperature superconducting microstrip resonators

Hammond RB, Soares ER, Willemsen BA, Dahm T, Scalapino DJ, Schrieffer JR. Intrinsic limits on the Q and intermodulation of low power high temperature superconducting microstrip resonators. Journal of Applied Physics. 1998;84(10):5662-5667.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, notably an increase in resonator Q and a decrease in the nonlinear intermodulation. It is important to understand how much improvement can be expected. Here we discuss the intrinsic limiting behavior that one might achieve with a perfect film, review the present status, and discuss what the limiting behavior implies for high temperature superconducting filters. Our analysis indicates that increases in unloaded Q to similar 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 American Institute of Physics. [S0021-8979(98)06322-1]