Wave propagation in microstrip lines with gyrotropic magnetic substrate

The time domain numerical modelling at microwave frequencies of a microstrip line that incorporates a saturable magnetic substrate is considered. The strip line is subjected to a DC magnetic field bias such that the quiescent operating point is near or above the saturation knee point. An algorithm that ensures numerical stability in the time domain is described. The predicted scattering parameters are shown to be in good agreement with measured data.