Predicting the Effects of HPEM Radiation on a Transmission Line Terminated With Linear/Nonlinear Load in Perforated Metallic Enclosure Using FDDM/VF

Abstract

High-power electromagnetic (HPEM) pulse affects electronic devices that have linear/nonlinear characteristics. To protect the electronic circuit board, the use of metallic enclosure as an electromagnetic shield is one of the best methods. Apertures and slots in the body of metallic enclosure is the path of coupling HPEM fields to electronic board and equipment. In this article, we are following to evaluate the effect of HPEM fields on the microstrip line with nonlinear load that is enclosed by perforated metallic enclosure. For this purpose, a method has been proposed that uses the benefits of the time domain analysis and frequency domain analysis. The whole electromagnetic system of the problem is decomposed into linear and nonlinear subsystems. Thevenin’s equivalent circuit of the linear subsystem from the connection point to nonlinear load has been evaluated by using finite difference delay modeling (FDDM) in the frequency domain. By vector fitting method and by using rational functions, Thevenin’s equivalent circuit is converted to circuits with RLC elements and the time domain voltage source. This circuit can be analyzed in Spice. Results obtained from this model are well adopted with those that are calculated by CST-Microwave studio for linear and nonlinear load and have better time efficiency.