Multilayer Partially Reflective Surfaces for Broadband Fabry-Perot Cavity Antennas

A high-gain broadband Fabry-Perot-type antenna is proposed, based on multilayer periodic partially reflective surfaces (PRSs). Three layers of PRSs are employed, consisting of metallic patches printed on thin dielectric substrates and placed in front of a ground plane, forming three open cavities. The antenna performance is based on the reflection characteristics of the PRS array, which are obtained using periodic analysis. An equivalent circuit approach is presented for the design of the multilayer PRSs showing very good agreement with full-wave analysis. The geometry has been optimized using full-wave simulations (CST Microwave Studio). An antenna of around 20-dBi gain at an operating frequency of 14.5 GHz is obtained with a 3-dB bandwidth of about 15%, outperforming earlier antenna designs based on two-layer PRS. A prototype has been fabricated and tested, validating the simulation results.