Omnidirectional 2-D Leaky-Wave Antennas with Reconfigurable Polarization

Fabry-Perot cavity 2-D leaky-wave antennas with polarization-reconfigurable omnidirectional conical beam are proposed. The antenna cavity is bounded by an annular, locally periodic metal partially-reflective surface and is loaded by a dielectric or a wire-medium slab, in order to suppress undesired radiation from the fundamental quasi-TEM mode. A suitable design of the partially-reflective surface and of the loading slab, based on a dispersion analysis of the linearized structure, allows for equalizing the phase and attenuation constants of the first higher-order TM<formula><tex>$_1$</tex></formula> and TE<formula><tex>$_1$</tex></formula> leaky modes around a given frequency. Omnidirectional beams with full polarization reconfigurability are then achieved through independent excitation of such modes with a pair of azimuthally independent sources. Preliminary designs, aimed at producing a conical beam with circular polarization, are presented and optimized with state-of-art simulation software.