Overview of Wideband Fabry-Pérot Cavity Antennas with Thick Partially Reflective Surface

Radiation characteristics of wideband Fabry-Perot cavity (FPC) antennas formed by a cavity covered by thick partially reflective surfaces (PRSs) are shown analytically and verified numerically. Thick PRSs are designed and optimized to exhibit a reflection phase with positive slope with a non-Foster-like response in the antenna operational bandwidth. By satisfying the antenna resonance condition over a wide frequency band, a wide radiated-power bandwidth is obtained. A more general and direct relation between the thick-PRS's reflection coefficient and the radially propagating leaky-wave inside the cavity structure is reported. In addition, a leaky-wave based power intensity formula is studied and verified numerically using PRSs formed by stacks of metal-dielectric layers.