With the increasing use of mobile computing devices such as PDAs, laptops, and the expansion of wireless local area networks (WLAN), there is growing interest in increasing productivity and efficiency through enhancing received signal power. This research demonstrated a band pass square-loop frequency selective surface (FSS) in walls to increase the efficiency of certain communication systems. The FSS is simulated by Empire XCcel. Remcom `Wireless InSite' is used to simulate indoor propagation and to predict the performance. Significant improvements are shown using an FSS based surface.