Computer-aided modeling of superconducting striplines with ground planes using critical state models

摘要

The effect of ground planes on the current-induced critical states and flux penetration for a thin superconducting strip carrying a microwave current has been calculated numerically. The nonlinear response represented by the dependence of the surface resistance and reactance were also calculated. We find that when the distance d between the ground planes is smaller than the width a of the strip, i.e., d≤a, the ground planes affect the nonlinear response significantly. In particular we study the effects of ground planes placed at a distance d=a/5. We compare and contrast these effects with the results of similar models without the ground planes. The ground planes reduce the current crowding at the film edges, thus reducing the nonlincarities arising from critical state flux motion. The numerical procedure can be incorporated into computer-aided design of superconducting microwave circuits.