Tunable bilayered metasurface for frequency reconfigurable directive emissions

The directive emission from a bilayered metamaterial surface is numerically and experimentally reported. The LC-resonant metasurface is composed of both a capacitive and an inductive grid constituted by copper strips printed on both sides of a dielectric board. By the incorporation of varactor diodes in the capacitive grid, resonance frequency and phase characteristics of the metamaterial can be tuned. The tunable phase metasurface is used as a partially reflecting surface in a Fabry-Perot resonance cavity. Far field radiation patterns obtained by direct measurements show the reconfigurability of emission frequency while maintaining an enhanced directivity. (C) 2010 American Institute of Physics. [doi:10.1063/1.3478214]