Time-Domain Modeling of Noisy Electromagnetic Field Propagation

This paper presents a detailed treatment of modeling of noisy electromagnetic field propagation as well as a formulation for its numerical implementation along with numerical and experimental examples. Modern electromagnetic interference measurement systems operate in time domain (TD) and exhibit gigahertz bandwidths together with short measurement times. Two-point near-field scanning with two field probes allows recording of near-field autocorrelation and cross correlation data as a basis for the TD simulation of noisy electromagnetic (EM) field propagation, also in complex environments. TD modeling yields results for the whole frequency band under consideration with a single computational run and is advantageous if results for a broad frequency range are of interest. We introduce a correlation dyadic-based approach for noisy EM field modeling using analytic TD Green's functions. For experimental validation of the method, we have computed spatial cross correlations in the far field from experimental near-field scanning data of a digital circuit board under test. The propagated results are compared to cross correlations obtained from measurements performed directly in the far field.