Modeling of EMI filters with shields placed between the filter components

Mutual couplings between EMI filter components are of key concern when designing EMI filters for EMI attenuation in high frequency range. To reduce the parasitic couplings and improve EMI attenuation conductive shields can be placed between the components. This paper presents modeling and measurements of EMI filters with copper shields placed between the filter components. 3D electromagnetic field modeling software CST MWS is used to model the filters in wide frequency range. Modeling and measurements are performed for different positions of capacitors and inductors on double-sided PCBs. Modeling results are compared to measurement results to verify CST MWS ability to accurately predict transfer coefficients of EMI filters with conductive shields placed between the filter components.