Strategies for Enhancing the Gain Bandwidth of Fabry-Pérot Cavity Antennas: a review of recent advances

We analyze strategies to realize high-gain wideband antennas using leaky waves excited in a Fabry-Pérot Cavity (FPC). Three main strategies are conceivable now: (1) implementing an electrically thick partially reflective surface (PRS) with its internal resonance, (2) exciting the FPC with a sparse array, and (3) combining these two methods. We also discuss other less practical methods that are still valid as principles. The broadside 3 dB gain bandwidth (GBW) is significantly enhanced compared to the conventional FPC antenna structure, which has a single feed and an electrically thin PRS.