A novel multilayer photonic band-gap (PBG) structure for microstrip circuits and antennas

The concept of the uniplanar compact PBG (UC-PBG) is extended to a novel architecture, which consists of several UC-PBG plates stacked up in the direction perpendicular to the plane of the substrate. This novel multilayer PBG is introduced here as the substrate for a microstrip line, and the resulting configuration builds a low-pass filter. In this design, the multilayer PBG includes two UC-PBGs with different periodicities. Simulated and measured transmission parameters in comparison with the corresponding monolayer UC-PBG show that the introduction of a second UC-PBG drastically enhances the width of the stop-band, as a result of the overlap of stop-bands associated with each UC-PBG layer.