Wideband directive emission based on hyperbolic metamaterials

Wideband directive emission properties operating in the canalization regime are found in hyperbolic metamaterials (HMMs). Based on the two-dimensional composite right/left-handed transmission line (CRLH TL) with lumped elements, the proposed HMM exhibits a very flat wave vector iso-frequency dispersion diagram over a wide frequency range. The emitted electromagnetic energy is concentrated around the normal of the HMM slab for all incident angles, and a subwavelength focusing is thus achieved. Canalization-induced abnormal propagations including wideband highly directive emission and subwavelength focusing are verified experimentally in the microwave domain.