Design of a novel ebg structure and its application in fractal microstrip antenna

Abstract

In this paper, a novel electromagnetic bandgap structure (EBGs) is proposed, which is similar to the mushroom-like EBG. By introducing double reverse split rings (RSR) into the square patch, the size of EBG cell is reduced by 30%, and the bandgap achieves bandwidth about 65%. A fractal microstrip antenna is implemented using the EBGs as a ground plane, and the measured results show that the reduction in the surface wave level is remarkable. Compared with the reference antenna at 5 GHz, an approximately 8 dB improvement of the return loss is achieved, and the back lobe is reduced by 10 dB in E plane and 8.73 dB in H plane at the resonant frequency, respectively. The front-back ratios of the antenna have significantly increased from 4.9 GHz to 5.2 GHz.