A novel technique for enhancing the directivity of microstrip patch antennas using an EBG superstrate

This paper presents a novel and systematic approach for enhancing the directivity of an antenna/EBG composite, comprising of a microstrip patch antenna covered by an FSS superstrate. The method is based on the initial simulation of the composite operating in the receive mode, mapping the field distribution in the Fabry-Perot type cavity region formed by the superstrate and the ground plane. Additionally, we correlate the results for the frequency response of an associated two-layer structure — formed by the superstrate and its image through the ground plane — by using the Finite Difference Time Domain (FDTD) method. Furthermore, the field distributions inside the cavity for oblique incidence are investigated, again when operating in the receive mode, to relate the angular response with the antenna pattern.