CAD model for circuit parameters of superconducting-based hybrid planar transmissionlines

Abstract

Using the concept of surface impedance associated with a superconductor or normalconductor’s plate, we extend the CAD (computer aided design) formalisms on modelingand simulation of superconducting and normal transmission lines (STL and NTL) in orderto include hybrid transmission lines (HTL). STL and NTL are entirely made ofsuperconductor or normal conductor materials, respectively. In this paper, HTL refersto a planar transmission line (TL) such as parallel plate (PPTL), microstrip (μTL) and coplanar waveguide (CPW) whose ground plate is superconductingand whose top/center strip is a normal conductor or vice versa. We developand present a set of closed-form equations in a tidy and succinct form foreach configuration (STL, NTL and HTL) for widely-used planar TLs (PPTL,μTL and CPW). They can be easily implemented in a systematic way by the user for thepurpose of fast TL design. The results obtained with this CAD tool are compared withpreviously reported results in the literature, and good agreement is observed.