Single-Element Patch Antenna with Multi-Port Feeding for Dual-Circularly Polarized Radiation

A dual-circularly polarized (DCP) S-band antenna is proposed based on a sequential rotation technique whilst exploiting only a single patch element. The antenna offers left-handed circular polarization (LHCP) or right-handed circular polarization (RHCP) by proper sequential phase rotation of its eight ports. Impedance matching bandwidths (BWs) of about 20% are observed and realized gain values approach 9.5 dBic. Also, low axial ratio values are achieved (0.5 dB or below) over this same operating BW. These DCP performances metrics and the noted polarization agility can be useful for satellite connectivity, for example, and other RF challenged environments where the dominant polarization is not known a priori. Other applications include signal transmission and reception duplex communications as well as other wireless communication systems where antenna diversity and general structure compactness is required.