Directive emission based on anisotropic metamaterials

In this paper, we demonstrate highly directive emission based on anisotropic metamaterials with spatial dispersion of very narrow hyperbola. By embedding the source inside a slab of such material, the emitted energy, both inside and outside the material, is concentrated around the normal of the slab, and a perfect far-field radiation is thus achieved. This effect is verified experimentally in the microwave domain, and a directivity that is far larger than the best one to our knowledge is obtained from the constructed antenna.