On the Use of the Antenna Theory Model of Lightning Return Stroke With Distributed Current Source for EMC Analysis

A full-wave solution method of Maxwell's equations is adopted for the electromagnetic analysis of the lightning return stroke channel. The method is based on a numerical solution of the electric field integral equation by the method of moments. The lightning channel is modeled as a wire monopole antenna with current sources distributed along its length. The method makes it possible to consider phase shift and amplitude decay between consecutive current sources in the frequency domain. The implementation of any engineering models of lightning in the integral form of Maxwell's equations is thus realizable. Special attention is devoted to the consequences of a limited channel length. Indeed, taking into account a finite channel length generates undesirable reflections from the top of the channel, which limits the use of the proposed method for electromagnetic compatibility analysis. Procedures are proposed to mitigate the effects of a limited channel length on the obtained results. Transient and frequency analyses of various lightning related problems demonstrate the applicability of the method to the analysis of complex electromagnetic problems.