Wideband rectangular printed monopole antenna for circular polarisation

A wideband printed rectangular monopole antenna for circularly polarised wave is proposed. The radiation characteristics of the wideband circular polarisation are achieved by designing the antenna asymmetrically. With simulations, the relationships between the antenna´s geometrical parameters and the antenna´s characteristics (axial ratio of circularly polarised wave and return loss) are clarified. The operational principle for wideband circular polarisation is explained by the simulated electric current distributions. Moreover, the simulated axial ratio, return loss, radiation patterns and gain are compared with the measured results. The simulated and measured bandwidths (3 dB axial ratio with a 10 dB return loss) are ~56.2% (1.78-3.17 GHz) and 51.4% (1.82-3.08 GHz), respectively.