Analysis of Waveguides with Nonlinear Material : Application to Superconductor Microwave Lines

This paper presents an analysis and a simulation of the nonlinearity in superconducting microwave devices. The analysis is performed in the time domain, since it can not be done simply in frequency domain. The high critical-temperature superconductor (HTS) model is based-on the Ginzburg-Landau (GL) theory. A full-wave electromagnetic model is used in conjunction with the HTS nonlinear model. The three-dimensional finite-difference time-domain (FDTD) technique simultaneously solves the resulting equations. The three dimensions solution is essential for the nonlinear analysis. The fields in the HTS device are presented. Interesting aspects of the nonlinearity in HTS material are observed. The nonlinear effective dielectric constant and the nonlinear attenuation constant for an HTS microstrip line are calculated as function of the applied magnetic field.