Radiation patterning enabled by ε-near-zero reconfigurable metamaterial lenses

We analyze and experimentally demonstrate a novel class of reconfigurable microwave lens components based on the ultrafast propagation properties and anomalous impedance matching features of arrays of thin waveguide channels operated at cut-off, which are shown to realize low-loss, ε-near-zero (ENZ) metamaterials impedance matched to free-space. Using this concept, we realize a compact microwave lens that can transform cylindrical wavefronts, excited by a simple coaxial source, into arbitrary wavefront patterns, obtained by simply reconfiguring the lens output interface. We are able to experimentally observe uniform-phase, oblique, converging, and “brick” patterns. We envision applications to realize a multitude of antenna reconfigurable radome and lens designs, impedance matched to free-space independent of the excitation.