Experiments on high-performance beam-scanning antennas made of gradient-index metamaterials

A planar lens made of gradient index metamaterials can transform cylindrical waves to plane waves, and the beam direction of plane waves is controlled by adjusting the refractive-index distributions of the lens. Based on such properties, we present high-performance beam-scanning antennas experimentally using the gradient-index planar lens and horn antenna. The lens is carefully designed with metamaterials to achieve different refractive indices and good matching of impedance. The near-field distributions of antennas are measured using a two-dimensional near-field microwave scanning apparatus, and the radiation patterns are presented to show the high directivity and low sidelobe. (C) 2009 American Institute of Physics. [DOI: 10.1063/1.3223608]