EMPERICAL MODEL OF THE MICROWAVE PROPERTIES OF HIGH-TEMPERATURE SUPERCONDUCTORS

This paper presents simple correct models of high-temperature supercon ductor(HTS) film parameters at microwave frequencies. The models are b ased on the enhanced two-fluid model of a superconductor. The quasi-pa rticle scattering and peculiarities of the normal conductivity of the HTS at microwaves, including residual resistance of a material, are ta ken into account. The difference between the known Gorter and Casimir two-fluid model of low-temperature superconductor and the enhanced two -fluid model of HTS is proven. A simple quasi-static model of current distribution across the microstrip line and coplanar waveguide is used for a simulation of a contribution of the superconductor transport pr ocesses into impedance per unit length of the transmission lines consi dered. The models developed were applied to a simulation of microstrip line and coplanar waveguide resonators. Good agreement of simulated r esults and measurements in a wide temperature range has been demonstra ted. The model presented can be considered as a starting point for the formation of the computer-aided design (CAD) package of HTS microwave components.