Modelling and investigation of HTS planar resonators and filters on sapphire substrate

A semi-empirical model is developed for high-T-c superconducting (HTS) plan ar transmission lines on anisotropic sapphire substrates. The model takes i nto account the anisotropic dielectric permittivity of sapphire and its tem perature dependence. A CAD tool is developed for a simulation of HTS transm ission line propagation characteristics. The contribution of the HTS film s urface impedance to the line propagation parameters is considered in linear and nonlinear approaches. The model is verified by the experimental invest igation of a half-wavelength resonator. The model is developed for a multic oupled line structure and applied to a multi-pole filter design. Eight-pole pseudo-interdigital filters based on YBCO films on r-cut sapphires substra te with a golden ground plane have been designed, manufactured and measured . The results confirm a prospective application of YBCO films on sapphire s ubstrates in microwave electronics.