Impedance interaction and EMI attenuation in converters with an integrated transmission-line filter

integrated transmission-line filters were previously proposed to attenuate conducted electro-magnetic interference (EMI) produced by high-frequency switching power converters. In this work, such a filter is manufactured using planar processing technologies, and it is tested for the first time with a 500W, front-end, single-phase power factor correction converter switching at 400 kHz. Impedance interactions between the filter, the converter, and the EMI measurement set-up are discussed, evaluated, measured, and improved to minimize undesired resonances and increase low-frequency EMI attenuation. Experimentally measured attenuation provided by the filter in the range from 100 kHz to 100 MHz was 20-50 dB.