Enhanced Gain mm- Wave Ridge Gap Waveguide Antenna based on Two Partially Reflective Layers

This paper discusses a novel wideband partially reflective unit cell (PRUC) for improving the gain of mm-wave printed ridge gap waveguide slot antenna (PRGWSA). The proposed PRUC is composed of two different metal-dielectric layers spaced by an air-gap. Over the frequency range of around 60 GHz, the PRUC exhibits a positive reflection phase slope and a high reflectivity. An array of 4×4 PRUCs is placed at an optimum distance from the PRGWSA to enhance its gain. A gain enhancement of 12.6 dB is achieved compared to the antenna without the array of PRUCs. The proposed antenna operates between 55.4 to 66.6 GHz (18% bandwidth) with a 3-dB gain bandwidth ranging from 58.6 to 66.4 GHz (12.5%), and it shows high directive symmetrical radiation patterns.