Lu, Y.; Huang, Y.; Chattha, H. T. (Department of Electrical Engineering and Electronics, The University of Liverpool, L69 3GJ, UK)
Most portable UWB antennas generate near omni-directional radiation pattern which is not suitable for some applications. In this paper, we present a numerical and experimental investigation of a wideband (4.5GHz to 8.5GHz) microstrip slot antenna of reduced size which produces a directional pattern. It is found that the optimum design of this antenna can be achieved by cutting a wide slot at the edge of the ground plane with a properly designed 50ohms and 100ohms microstrip feed line. Compared to the conventional half wavelength slot antenna fed by a fork like microstrip line, this antenna size is almost reduced to half of its counterpart. Furthermore, a reflector can be added on one side of it to achieve a unidirectional radiation pattern.