Realization of a voltage tunable gradient-index fishnet loaded with liquid crystal

The realization of voltage tunable gradient-index fishnet metamaterials for the Ka- and mm-band is presented. For the dielectric layer of the fishnet, nematic liquid crystal is used to achieve a continuous voltage tuning of each column of the array. To control the direction of the emitted wave, a gradient in the phase profile over the aperture is introduced. Simulation and measurement results are presented for a prototype at a frequency of 27.5 GHz with a beam scanning range of ±5° as well as a design for a frequency of 329 GHz with arbitrary scan angles.