Novel wideband low-profile dual-circularly polarized metasurface antenna

A novel low-profile dual-circularly polarized metasurface antenna with wideband and widebeam circular polarization (CP) radiations is proposed. It is constructed by an array of polarization-rotation metasurface (PRMS) cells and fed by a new cross aperture with four narrow slots in the ground plane. Due to the polarization-rotation property of the PRMS structure, a pair of linear-polarization (LP) aperture-coupling feedings can respectively inspire left-hand and right-hand CP (LHCP, RHCP) radiations. Furthermore, the proposed antenna has a compact structure with a low profile of 0.07λ0 at 5 GHz. Simulated results show that the 10-dB impedance bandwidths for LHCP and RHCP states are respectively 36.0% (3.78-5.58 GHz) and 24.6% (4.26-5.44 GHz). The 3-dB axial ratio (AR) bandwidth for the LHCP state is 17.4% (4.19-5.42 GHz) with large 3-dB AR beamwidths of 103.22° and 55.65° in the xoz and yoz planes, while for the RHCP state, the AR bandwidth is 17.0% (4.50-5.35 GHz) with large beamwidths of 77.93° and 99.67° at the two planes. In addition, the polarization isolation within the two AR bands is over 15 dB.