EMI/EMC Analysis of Printed Circuit Boards Subject to Near-Zone Illuminations

Previously, we proposed a hybrid S-matrix approach for general electromagnetic interference/electromagnetic compatibility (EMI/EMC) analysis of electronic systems. However, that approach was limited to plane wave excitations. In this short paper, we propose a generalization of the hybrid S-matrix approach to near-zone excitations. Such excitations lead to a continuous spectrum of forced modes that are not readily decomposed using the generalized pencil of function method. Herewith, we employ the discrete Fourier transform, with a priori knowledge of the natural transmission line modes, to extract the coefficients of all dominant spectral components. These are subsequently used to generate the hybrid S -matrix entries under near-zone EMI illuminations.