Design of spiral slot-based dual-wideband dual-sense CP antenna

A dual-wideband dual-sense circularly polarised (CP) planar slot antenna with a simple structure is presented and studied in this study. By etching a simple spiral slot on the planar ground, adopting an L-shaped strip as the radiator, and employing smooth transition structure, the dual-wideband impedance bandwidths (IBWs) and dual-wideband 3 dB axial-ratio bandwidths (ARBWs) of the proposed CP antenna can be easily realised. The measured 10 dB return loss IBWs is 111.1% (0.88-3.08 GHz) for the lower band [left-hand CP (LHCP)] and 42.1% (3.64-5.58 GHz) for the upper band [right-hand CP (RHCP)]. The measured 3-dB ARBWs is 92.9 and 39.4%, with respect to 1.83 GHz (LHCP) and 4.6 GHz (RHCP), respectively. The radiation patterns of this antenna are good within both two CP bands. This antenna is very suitable for multi-band communication systems for its dual-wideband CP performance.