Design of a Circular Polarized Horn Antenna with an Anisotropic Metamaterial Slab

In this paper, a novel design of a circular polarized horn antenna is presented. An anisotropic metamaterial slab with metal periodic structures printed on a substrate is designed and its constitutive parameters and S parameters are analyzed. It shows that the metamaterial is anisotropic and can turn a linearly polarized wave to a circular polarized one. Then a novel horn antenna composed of a conventional rectangular horn antenna and the metamaterial slab is fabricated and measured. The results show that the novel horn antenna radiates a left handed circular polarized wave with an axis ratio below 3 dB at 16 GHz, and its gain and radiation pattern are the same as those of the conventional rectangular horn antenna.