%0 Journal Article %T A Constant Gain Ultra-Wideband Antenna with a Multi-Layer Frequency Selective Surface %A Yogesh Ranga %A Ladislau Matekovits %A Andrew R. Weily %A Karu P. Esselle %J PIER Letters %D 2013 %I EMW Publishing %R 10.2528/PIERL13021007 %X An ultra-wideband (UWB) antenna with a novel multi-layer frequency selective surface (FSS) reflector is presented. A significant enhancement in the gain has been achieved in a low profile design while maintaining the excellent impedance bandwidth of the UWB antenna. The average peak gain of the antenna has been increased from 4 dBi to 9.3 dBi as a consequence of the use of the FSS reflector. More importantly the gain variation within the frequency range from 3 GHz to 15 GHz is only ¡À0.5 dB. This is a significant improvement from ¡À2 dB gain variation of the UWB slot antenna without the reflector. This optimized FSS reflector provides the exibility of mounting a planar antenna close to conducting bodies, including screens and cases. %U http://www.jpier.org/pierl/pier.php?paper=13021007