Prediction of Electromagnetic Coupling in Complicated Enclosures With External Excitation Through an Aperture Using Extended Random Coupling Model

For the prediction of electromagnetic (EM) coupling in a complex (wave-chaotic) enclosure, the random coupling model (RCM) has proven useful. The applicability of RCM has been demonstrated using various complex enclosures, but their reported validations are mostly with the input and output ports placed within the enclosure. However, since many practical scenarios consist of EM coupling through an aperture of the enclosure from external sources, an extension of the RCM to accommodate such scenarios would be of interest. In this article, we present an extended RCM approach that provides an effective statistical prediction of EM coupling in a complex enclosure for an aperture excitation scenario. Here, we treat the entire wave propagation paths as a cascaded system of two-port networks with an analysis of the aperture using the transmission line theory. This allows us to accurately extract the cavity-specific loss parameter which is required for the RCM prediction of EM coupling, even for an aperture excitation scenario. The overall experimental results suggest that the statistics of the voltages induced on the target port inside the cavity are accurately predictable even in the case of aperture excitation.