Modelling and design of 2D UC-PBG structure using transmission line theory

Photonic bandgap (PBG) structures usually mean the periodic structures in which propagation of certain bands of frequencies is prohibited. The results of the research on PBG structures in the optical frequency region have been being adopted in microwave regions through a proper frequency scaling. One of the popular PBG structures for suppression of surface waves is the uniplanar compact photonic band gap (UC-PBG) structure. In this paper, the 2D UC-PBG structure is modelled by a R, L, C equivalent circuit using the transmission line theory. To verify the usefulness of the method, the 2D UC-PBG structure is designed for enhancement of isolation between microstrip antennas based on the proposed equivalent circuit.