Parametric Study of UC-PBG Structure in Terms of Simultaneous AMC and EBG Properties and its Applications in Proximity-coupled Fractal Patch Antenna

In this paper, a parametric study of conventional Uniplanar Compact Photonic Band Gap (UC-PBG) structures, with different dimensions, is investigated. The studied structure operates as an ArtificialMagnetic Conductor (AMC) and Electromagnetic Band Gap (EBG) in which the performances aremainly characterized by the resonant frequency and bandwidth of band gap. Simulation and numerical analysis have been carried out using CST Microwave Studio software, which is based on Finite Difference Time Domain (FDTD), and Ansoft HFSS which is based on Finite Element Method (FEM).Results show that different dimensions affect the AMC’s and EBG’s performances. The increase in the length and width of the UC-PBG slot will result in lower resonant frequencies and bandwidth degradation, while the frequency band position will increase and the bandwidth of band gap willdecrease when the branch width are increased. Furthermore, a prototype of a microstrip line proximityfed to a fractal patch antenna on a UC-PBG substrate is designed and simulated. Computed results show that the antenna mounted on the UC-PBG substrate has over 9.2% wider impedance bandwidth than the same antenna etched on a grounded dielectric slab with the same characteristics, due to inphase reflection phase of UC-PBG structure. Compared with the reference antenna at 7.2GHz, the back lobe is reduced by 7.86dB in E plane and 7.68dB in H plane. Cross-polarization level remains below - 10dB in both E and H planes