Common mode filtering performances of planar EBG structures

This paper approaches the filtering behavior of electromagnetic bandgap (EBG) structures. The transfer function, in terms of S-parameters, of a single ended and a differential microstrip line referenced to an EBG plane are considered: the notches (causing signal attenuation) and flat regions (causing signal propagation) are related to the geometry and characteristics of the EBG structure and can be designed to filter out unwanted harmonic components of the signal. A different EBG-like structure is proposed and its performances analyzed.