High Extinction Ratio Circular Polarizer With Conical Double-Helical Metamaterials

Recently, circular polarizer with cylindrical double-helical metamaterials has been proposed to broaden the operation band of cylindrical single-helical metamaterials, but its extinction ratio is deteriorated. In this paper, we proposed a circular polarizer with conical double-helical metamaterials, which have a large extinction ratio of 83:1, more than four times higher than that of cylindrical double-helical metamaterials. Furthermore, we gave a qualitative interpretation about this phenomenon through analyzing the interaction between two helical wires in one unit cell of the circular polarizer.