Planar PBG structures: Basic properties and applications

This paper reviews recent progresses in the research and development of pla nar photonic band-gap (PBG) structures, also called electromagnetic crystal s, for microwave and millimeter-wave applications. Planar Electromagnetic c rystals are particularly attractive and intensively investigated bt cause o f their easy fabrication, low cost, and compatibility with standard planar circuit technology. Two configurations and their applications are described in this paper: a square lattice of holes etched in a ground plane and the recently developed Uniplanar Compact PEG (UC-PBG) structure. Basic properti es as well as applications to microwave circuits are reported. These includ e harmonic tuning in power amplifier, leakage suppression in conductor-back ed coplanar waveguide (CB-CPW), realization of planar slow-wave structure, and performance improvement in microstrip filters and patch antennas.