Negative index metamaterial for selective angular separation of microwaves by polarization

摘要

Materials with simultaneously negative electric permittivity and magnetic permeability are referred to as left handed, and are also called backward wave and double negative media. The first experimental demonstration of such a metamaterial combined metallic split ring resonators with posts etched on opposite sides of dielectric boards. The boards are usually stacked in parallel planes with insulating spacers to form highly anisotropic prisms. We have demonstrated that this anisotropic. prism exhibits both positive and negative refractive indices and can split an incident beam into two components. The positive and negative indices are accessible by the choice of polarization of the electric field. Using an electric field parallel to the posts, negative refraction is observed. Rotating the electric fields 90/spl deg/ yields a positively refracted signal. Intermediate angles of polarization can achieve refraction in both negative and positive directions simultaneously, or the receiver polarization can be chosen to select either signal separately, The values of the positive and negative index and the wedge angle of the prism determine the separation angle of the output beams. This effect has potential application for a unique type of angular beam splitter.