Efficient analysis for nonlinear microwave characteristics of high-power HTS thin film microstrip resonators

Abstract

This paper investigates the nonlinear effects of high-Tc superconducting (HTS) thin film in high-power applications. A nonlinear model for complex surface impedance has been proposed for the efficient analysis of the nonlinearity of HTS thin films. Further, using the developed model, analysis of HTS-MSR has been done using the spectral domain method (SDM). The SDM formulation has been modified to account for finite conductivity and thickness of HTS films by incorporating a complex resistive boundary condition. The results have been validated with the experiments performed with microstrip resonators (MSRs) based on YBa2Cu3O7−x (YBCO) thin films made by a laser ablation technique on LaAlO3 substrates, characterized for their characteristics, namely, resonant frequency and quality factor measured as a function of temperature and input RF power. A close agreement between the theoretical and measured results has been achieved validating the analysis.