Full-wave analysis of superconducting microstrip lines on anisotropic substrates using equivalent surface impedance

A computationally efficient full-wave technique is developed to analyze superconducting microstrip lines on M-plane sapphire in which the optical axis is in the plane of the substrate at an arbitrary angle with respect to the propagation direction. To increase the efficiency of the method, the superconducting strip is replaced by an equivalent surface impedance which accounts for the loss and kinetic inductance of the superconductor. The complex propagation constant and characteristic impedance are calculated. The calculated results show good agreement with previously published data and with the results of the more rigorous volume-integral-equation method. >