Gain Enhancement of a V-Band Antenna Using a Fabry-Pérot Cavity With a Self-Sustained All-Metal Cap With FSS

Gain enhancement of a V-band planar antenna in the form of a low-profile Fabry-Pérot cavity (FPC) is proposed. This simple design is based on placing a perforated metallic cap, forming a frequency-selective-surface (FSS), over a printed-circuit-board (PCB). An integrated slot-dipole antenna is etched in a thin layer of copper (the ground plane) printed on the other side of the PCB. The metallic cap is self-sustained with surrounded metallic sidewalls. Besides showing the simplicity of such design, we also provide a novel comprehensive analysis using a transmission-line model of a FPC along with the two-port circuit model of the thick FSS. The leaky-wave interpretation for the cavity radiation is also addressed to estimate the effective radiation area and therefore the size of the cap. It will be shown that placing the cap on top of the PCB, besides enhancing the directivity of the feeding-slot reduces its backward radiation. A FPC prototype operating in the 60 GHz wireless band, is fabricated and measured showing good agreement between the simulated and measured results.