Comparison of the near field coupling using spherical and spheroidal harmonics

An important way to decrease the EMC issue is to predict near-field coupling between components. The using of their electromagnetic equivalent model in spherical multipolar expansion, allow to calculate the near-field magnetic coupling. The method cannot be properly applied when the sources are too close. In this paper we use a spheroidal expansion system, propose to solve the problem which enable to extend the efficiency of the method when the sources are close.