Gain enhancement of a Wi–Fi 5.8 GHz antenna using a single square loop-based FSS superstrate for smart navigation systems

Abstract

A compact gain-enhancement method employing a single square loop as a frequency-selective surface (FSS) superstrate installed over a 5.8 GHz microstrip rectangular antenna is presented and experimentally validated. Unlike conventional FSS designs requiring large periodic arrays, the proposed single-cell architecture generates controlled surface-wave leakage at 0.12λ spacing, achieving a peak gain enhancement of 2.70 dB ( 7.72 dBi peak gain) across 5.55–5.98 GHz without increasing the physical footprint. To validate practical utility, the proposed FSS-loaded antenna was integrated into an indoor navigation system made with software-defined radios to transmit and receive control commands, floor maps, and image data for suitable applications in unmanned aerial vehicles, unmanned ground vehicles, and smart home devices. Experimental results across six indoor navigation nodes reveal superior link reliability compared to a standard VERT2450 antenna, maintaining maximum average bit error rate and the average packet error rate values below 1.39×10−6 and 0.63%, respectively. This study demonstrates that minimalist FSS engineering can deliver compact, low-profile, and highly reliable antenna solutions for autonomous multi-agent systems.