Design and analysis of a compact wideband pattern-reconfigurable antenna with alternate reflector and radiator

Abstract
The authors present a novel compact wideband pattern-reconfigurable antenna with alternate reflector and radiator. The proposed antenna consists of a pair of step-shape patches, four switches and a coplanar waveguide feeding line. By setting the switches ON or OFF, the two step-shape patches can alternately switch between the radiator and the reflector. As a result, the proposed antenna is able to provide two-directional radiation patterns whose main beams are roughly directed in opposing directions from 3.7 to 6 GHz. Compared with other current pattern-reconfigurable antennas, the proposed antenna exhibits advantages of better back-to-front radiation ratio, more compact antenna size and wider operating band. In this investigation, the optimised size of the proposed antenna is 20×20 mm2, which equates to 0.25×0.25λ02 (λ0 is the wavelength at the low edge of the operating frequency band). In addition, the time-domain characteristics of the proposed antenna are presented and analysed. The antenna shows a good time-domain performance. Measured results are presented.