The study of wideband single fed CP ring antenna

The bandwidth of microstrip antenna usually results in a very narrow axial ratio (AR) bandwidth (approximately 1 %). This paper described a novel single-fed ring antenna (SFRA) consists of stacked structure of an annular ring patch, which is designed for left-hand circular polarized (LHCP) at a center frequency of 2.1GHz. The impedance and 3-dB AR bandwidths are large as compared to the conventional CP microstrip antenna. The simulation results verify that the antenna has an impedance bandwidth (VSWR<2) of 36 % and 3 dB AR bandwidth 34 %.