A Wideband and High-Gain All-Metallic Perpendicular-Corporate-Fed Multi-Layered Parallel-Plate Slot Array Antenna

An all-metallic multi-layered parallel-plate slot array antenna operated in the 60-GHz band with wide impedance bandwidth and high-gain characteristics is proposed. The
$16\,{\times }\,16$
-slot antenna is composed of
$2\,{\times }\,2$
-slot subarrays perpendicularly-fed by a hollow waveguide corporate feeding network. The subarray is partitioned into three functional layers including a bottom one for feeding, a mediate one for radiating and a parasitic one atop for bandwidth enhancement. An undesired resonance of a high-order mode introduced with the parasitic layer is eliminated by loading metal grids between the slotted plates. The contribution of the parasitic layer on bandwidth improvement is verified by a measured 19.2% bandwidth of the antenna with reflection below −10 dB. The removal of the dielectric plate loaded in the conventional double-layered counterpart also contributes to the better performance of the array. The all-metallic feature exempts the design from dielectric loss and beneficial for realizing a higher gain. A high aperture efficiency over 90% is realized over a 19.3% bandwidth and an antenna efficiency over 70% is obtained over a 18.5% bandwidth for the fabricated prototype antennas. The measured realized gain is up to 33.2 dB and the antenna efficiency is 87.2% at 62.0 GHz.