Dual-Polarized Low Sidelobe Fabry-Perot Antenna Using Tapered Partially Reflective Surface

A novel dual-polarized Fabry-Perot (FP) cavity antenna with low sidelobes is proposed. Low sidelobes are obtained by using a tapered partially reflective surface (PRS) in the form of circular lattice instead of the conventional rectangular lattice. As the PRS can be regarded as a 2D leaky wave surface on which cylindrical waves propagate outward radially in the form of concentric rings, so arranging the PRS elements in the form of circular lattice and then applying tapering on it yields low sidelobes in both the E- and H-planes. The performance of the proposed PRS is validated by fabricating a dual-polarized FP antenna and measuring its radiation patterns. Peak realized gains of 18.6 and 18.5 dBi are obtained for horizontal and vertical polarizations respectively, giving an aperture efficiency of around 42%. Measured sidelobe levels are reduced to lower than -21.3 dB in both the E- and H-planes for the two orthogonal polarizations.