Equivalence of two calculation methods for common-mode excitation on a printed circuit board with narrow ground plane

Two models for evaluating the common-mode current on a printed circuit board with a narrow ground plane are compared theoretically and experimentally. One model is the ground inductance model; while the other is a new model we call the "imbalance difference model". The structure of the new model is simpler and more convenient for field application. The theoretical equivalence between the two models is demonstrated analytically, and numerical results agreed for two models to the level of 2 dB with experiments made in an anechoic chamber.