Efficient complementary metamaterial element for waveguide-fed metasurface antennas

We present a metamaterial element designed as an efficient radiator for waveguide-fed metasurface antennas. The metamaterial element is an electrically-small, complimentary electric-LC (cELC) resonator designed to exhibit large radiated power while maintaining low ohmic losses. The shape of the element is tapered to simultaneously achieve broadband operation and suppression of cross polarization radiation. Full-wave numerical studies at the K-band are conducted to examine its performance when etched into a microstrip line. In this configuration, the element shows a radiation efficiency of 90.2% and a fractional bandwidth of 8.7%. To investigate the potential benefits of the proposed element in two-dimensional platforms, the radiative characteristics of the element are calculated when the element is embedded in a dielectric-filled parallel-plate waveguide. This efficient metamaterial element has potential application as a building block for metasurface devices used in imaging, sensing, wireless power transfer, and wireless communication systems.