Standalone removable EBG-based common mode filter for high speed differential signaling

A new structure is proposed in this paper to realize a common mode filter based on the EBG technology. It is based on the geometry previously proposed as a sequence of two or more EBGs resonating at the filtering frequency; however the new filter is placed on top of the PCB as a standalone component, instead of being included within the PCB stackup. The filter can be easily removed and substituted by another one designed to filter a different frequency. The new frequency design should ensure the same external size of the component as the original filter which can be achieved by choosing the permittivity of the dielectric as well as the relationship among the EBG parameters appropriately. The electromagnetic behavior of the filter is studied based on the current path responsible for the excitation of the EBG resonance; the methodology for a correct design is developed proposing different design configurations.