Studying the interactions between mushroom-type EBGs, transmission lines and vias

In this paper, the interactions between mushroom-type electromagnetic bandgap (EBG) structures, transmission lines and vias are studied. The EBG, which has a dimension of 50mm X 80mm, was designed to operate from 750 MHz to 3.2 GHz - a frequency band used for many wireless communication standards (e.g., GSM, UMTS, WLAN, Bluetooth?). Within this band, the proposed EBG creates a stopband, so that SSN caused by digital components can not be coupled to sensitive RF/analogue components. When integrated together with transmission lines and vias between the parallel-plates of a power distribution network (PDN), the EBG prevents the coupling of power away from the transmission lines and vias. The insertion loss of each of these interconnects become free of resonances and hence, signal integrity is preserved. Our results also revealed that the presence of either transmission lines or vias causes a change in the effective inductance (L) and capacitance (C) of the power-ground cavity. Since the stopband bandwidth of the EBG is dependent on the L & C of this cavity, the presence of these interconnects thus causes a change in the filtering properties of the EBG.