“Open-stub electromagnetic bandgap” structures loaded with capacitive transmission line segments for bandgap frequency control

An electromagnetic bandgap (EBG) structure is an effective tool to suppress power plane noise (PPN) in gigahertz region. Here we propose a concept and a new EBG structure enabling to control bandgaps for applications, including multiband wireless communication. The EBG strcture based on an open-end transmission line has such an advantage as its compactness. Also, in this structure voltage distribution along the transmission line is dependent on frequency, and such dependency can provide control of the bandgap by an appropriate selection of a position of a loaded capacitance. In this paper, the capacitance in the EBG structure is obtained by an additional open-end transmission line segment. The proposed structures achieve both the compactness and multiband operation. Here we present results of equivalent circuit analysis and measurement of evaluation boards for developed EBG structures.