ANALYSIS OF SUPERCONDUCTING MICROSTRIP RESONATOR AT VARIOUS MICROWAVE-POWER LEVELS

The real and imaginary parts of the surface impedance of YBCO supercon ductors have been studied at different microwave power levels. Using t he relations for the critical current density and the grain boundary r esistance, a relation for calculating the power dependence of the surf ace resistance has been obtained. Also, a relation to find the resonan t frequency of a superconducting microstrip resonator at various input power levels has been derived. Measurements have been carried our on various microstrip resonators to study the variation of surface resist ance and resonant frequency at different rf power levels, The experime ntal results are in good agreement with theoretical results. (C) 1997 American Institute of Physics.