Abstract
In this paper, we present a systematic design methodology for enhancing the directivity of microstrip patch antennas (MPAs), by using it as an exciter of a Fabry-Perot (FP) [6] resonant cavity. The design procedure involves three steps: (i) determing the resonance frequency of the empty cavity, with the MPA removed, when operating in the receive mode; (ii) designing the patch antenna to operate at the same frequency in the presence of the superstrates; (iii) finally, we operate the composite system in the transmit mode to investigate its aperture distribution that provides us a clue for enhancing the directivity. We show that the directivity can be enhanced by more than 8 dB, over that of the MPA without the superstrate, by using either planar or curved superstrates as covers for the MPA.