Intermediate level circuit model for time-domain analysis of shielding using SPICE

Time domain as opposed to frequency domain analysis is necessary in certain cases, for instance, to determine the effect of transients on non-linear systems. Time domain analysis methods however have the disadvantage of being significantly more complex and requiring much longer solution times than frequency domain analysis methods. Conventional methods for time domain waveguide analysis include the finite difference time domain method and the method of moments. Intermediate level circuit modeling methods have been shown to be far more efficient than these conventional methods. A novel equivalent circuit of a waveguide section suitable for intermediate level circuit modeling is proposed that has the advantage of being easier and quicker to formulate, and requires significantly less time to reach a solution than conventional time domain methods. The time domain solution is arrived at by utilizing a circuit simulator (SPICE) to analyze the intermediate level circuit for waveguide sections. Results obtained using the proposed circuit in SPICE were found to be credible when compared to known analytical results.