A Double-Layer Chiral Metamaterial with Negative Index

In this paper, a double-layer metamaterial is proposed composing of twisted metallic foil pairs and dielectric spacer. Negative refractive index can be realized originating from chiral configuration of this metamaterial. With precious tuning of rotated angle in each metallic foil pair and dielectric thickness h, different chirality parameters and negative refraction indices can be obtained. These results help to give a more profound understanding on chirality and to design new chiral metamaterial.