Gain enhancement in ultra-wideband antennas backed by a suspended ground or covered with metamaterial superstrates

This paper presents compact directional ultra-wideband (UWB) antenna designs with two different techniques. The first design is based on a monopole printed on a RT5880 printed circuit board (PCB) backed by a suspended ground in order to achieve directionality. The other design utilizes a metamaterial superstrate above the monopole antenna. In both cases, directional radiation patterns are achieved. Using a suspended ground achieves more gain enhancement. However, the antenna overall size is smaller using superstrate covering the monopole antenna.