Wideband and metal‐only linear to circular polarization converter using multi‐slot elements

A wideband, metal-only, and low-cost transmission-type polariser is proposed in which a plane wave with linear polarization impinging on the structure converted to circular other side vice versa. The quad-layer frequency selective surface that its unit cell composed of two sets multi-slot elements placed perpendicular each achieve wideband polariser. In this cell, by changing length slots, amplitude phase transmission coefficient can be controlled, are used create 90-degree difference between vertical horizontal components incident electric field. 9 × $9\times 9$ array simulated fabricated shows bandwidth 22% (11.7–14.7 GHz) for an axial ratio below −3 dB efficiency more than 85%.