Frequency Selective Surface Effects on a Coplanar Waveguide Feedline in Fabry–Perot Cavity Antenna Systems

Planar array designs and three-dimensional (3-D) high-density integration can degrade antenna performance due to feedline interference and coupling. To minimize this effect, a single source element with feedline is combined with a frequency selective surface (FSS) to form a Fabry–Perot Cavity antenna (FPCA) system. The FSS focusing of the antenna radiation also focuses the feedline energy, which can degrade the overall FPCA system radiation pattern. This letter presents a technique to reduce undesired feedline radiation enhanced by an FSS. Orientation-sensitive FSS designs are studied to minimize feedline electric field concentration above the FSS. Feedline radiation focusing above the FSS can be minimized from 4.95 to −2.4 dBi in the far field.