Compact frequency selective surface for polarisation transform

The polarisation transforming properties of a compact frequency selective surface (FSS) are reported. Although known designs made with meander lines employ several cascaded surfaces with many interconnects, the design methodology presented uses a single planar surface of very closely arrayed metallic meander lines impedance loaded with rectangular metal patches. A simulated axial ratio of ≤ -3 dB was obtained over a 40% bandwidth, from 2.10 to 3.2 GHz and optimised for 2.75 GHz. Simulation of normal and oblique incidence in both planes of polarisation shows a ±30° wide range of angles of incidence for polariser performance. A unit cell of the FSS circular polariser is λ_o/12 in size at the optimised operating frequency. The FSS circular polariser was manufactured and attached to a horn antenna aperture and measurement confirmed axial ratio performance.