Wideband and compact Fabry-Perot cavity antenna using a dual-layer periodic planar structure

A wideband Fabry-Perot cavity antenna, powered by a rectangular waveguide and characterized by an extremely compact size (60 mm × 60mm × 20mm), is designed at the central frequency of 14 GHz. Using both parabolic approximation of the wave equation and the infinite array analysis, a second cavity composed by two metal-dielectric layers is designed to enlarge the cavity bandwidth, by performing an anomalous phase inversion in a wide range. A simple transition is used to couple a standard WR-75 waveguide to the cavity. A peak gain of about 20 dB and a 13.5% bandwidth (according to a -3dB gain) is numerically demonstrated.