Accurate Analytical Prediction of EMI Filter Attenuation by Considering Intercomponent Coupling Phenomena

Designing of low-cost and more compact electromagnetic interference (EMI) filters must be achieved by considering intercomponent coupling. Actually, magnetic coupling, arising from the proximity of the components constituting the filter, has a major influence on the filter performance. The aim of this paper is to present a methodology for filter design, which takes into account intercomponent coupling and, therefore, can predict filter attenuation very accurately, whatever the structure and the topology of the filter may be.

I. Introduction

In filter design, intercomponent coupling plays a major role in the filter response. It was presented in [1]–[3] that the magnetic coupling, which exists between the passive components of a filter, has a major influence on the filter performance. Fig. 1 presents an example of a Pi filter composed of two capacitors and an inductor. Fig. 1.

Electrical model of a Pi filter by considering magnetic couplings between components.