Design of compact EBG structure for array antenna application

In this paper, a compact electromagnetic bandgap (EBG) structure is presented. In order to achieve the size reduction, additional equivalent capacitance and equivalent inductance are produced in three design steps. The total capacitance and inductance of the proposed structure will be increased much more than the one of the mushroom-like EBG in the literature. Dispersion diagram is presented to show the bandgap characteristics. The comparison between the proposed EBG structure and different EBG structures are carried out. The proposed EBG structure exhibit a tremendous size reduction of 61%. With the aim of reducing the mutual coupling of the array patch antenna, a 2×7 EBG cells are inserted between two elements of an array antenna operating at 5.1 GHz. As the measured results, the mutual coupling has been reduced 20 dB than the one of array antenna without EBG structures.