Abstract
In this letter, a technique to improve the gain of ultra-wideband (UWB) planar antennas, by using low-profile frequency selective surface (FSS) based reflectors, is proposed. This technique not only enhances the gain of the planar UWB antennas but also guarantees a constant gain of maximum variation of 0.5 dB across the entire UWB, while keeping their attractive merits. To prove the effectiveness of the proposed technique, UWB coplanar waveguide (CPW) fed circular-disc antenna is installed above the proposed reflectors. As result, constant gain UWB antenna has been obtained.
