A Hybrid Electromagnetic-Circuit Method for Electromagnetic Interference Onto Mass Wires

A current decomposition method is proposed for the analysis of field coupling to mass wires near complex structures. The foremost attribute of the method is the decomposition of the current on each wire into push-pull and push-push mode currents. The former refers to the perturbation current accounting for the interactions among the wires within the bundle, whereas the latter represents the interactions between the mass wire bundle and the surrounding structure. Multiconductor transmission line theory is employed to compute the push-pull mode current by using one of the wires in the bundle as the return/reference conductor. Current induced on a test wire located along the reference line is used to compute the push-push mode. For this analysis, we employed the method of moments for the electromagnetic analysis of surrounding structure and simulation program with integrated circuit emphasis (SPICE)-like simulators for the analysis of a circuit model of the transmission lines extracted via the partial element equivalent circuit method. Several validation examples (including transmission lines inside an automobile) are presented. It is also shown that the traditional transmission line theory based on quasi-static analysis fails with increasing complexity of the surrounding structure.