Experimental validation of an 8 GHz EBG based common mode filter and impact of manufacturing uncertainties

Common mode noise associated to the differential signal propagation represents a major concern for crosstalk and EMI issues. The common mode filter based on electromagnetic band-gap (EBG) structures have been shown to be cost effective and easy to design, since they are made using the standard PCB technology. The coupling between the differential interconnect and the EBG cavity converts the energy associated to the common mode into the cavity resonant mode, thus reducing the common mode noise reaching the receiver. A simple design procedure is reviewed in this paper for a quick design, and it is applied to a 8 GHz filter. The filter is then manufactured on a 6 layer PCB and its performances are investigated through measurements both in frequency and time domain. The filter topology as well as the design procedure are validated through model-to-hardware correlation..