Gain Enhancement of a Wideband Fabry-Pérot Cavity Antenna Using Sparse Array Feed

This paper demonstrates the use of a 2-D sparse array feeding as a primary excitation source of a wideband planar Fabry-Pérot Cavity (FPC) antenna for gain enhancement. The antenna is constructed from a thick partially reflective surface (PRS) mounted on top of an air-filled cavity. The antenna is fed by a 2×2 array of magnetic dipoles (slots) located on the ground plane. A proper choice of the array interelement distance gives a maximum gain of 18.1 dB and a 3 dB gain-bandwidth of 36.4%, which is remarkable for an FPC antenna. Results show a significant enhancement in the broadside gain by employing sparse array feeding with 2.7 times improvement in the gain-bandwidth product as compared to the conventional single element excitation source.