Low loss RF modified fishnet metamaterials with optimized negative, zero and unity refractive index behavior

Two planar multilayer negative/zero/unity index metamaterials using cascaded modified fishnet metal screens were considered. The structures were optimized by a GA to have refractive indexes equal to -1, 0, and 1 at predetermined frequencies as well as low absorption loss and an effective impedance matched to free space. The dielectric layers were constrained so that they could be fabricated from existing (commercially available) high performance materials. High figures of merit for both of the refractive indexes and impedances, as well as low transmission losses were achieved. Efforts are currently in progress to fabricate a prototype sample based on our designs and to experimentally validate the predicted n_eff and Z_eff.