ABSTRACT
Broadband, low-loss metamaterial surfaces provide an excellent alternative to conventional enhancements for horn feeds. Metasurface-enabled horn antennas promise to provide comparable or better operation than conventional alternatives, such as corrugated or dielectric core horns, while reducing weight, reducing cost, or improving operating bandwidths. Simple circular feed horns exhibit high cross-pol as a result of the field line configurations of their associated mode distributions. The first decade of the 2000s saw an abundance of research on electromagnetic metamaterials, including metamaterial surfaces, high-impedance surfaces, electromagnetic band-gap materials, and artificial magnetic conductors (AMCs), all of which have shown promise for a variety of antenna applications. In order to model a horn antenna lined with a metasurface, it is convenient to employ a homogeneous material model with effective permittivity and permeability values, rather than an infinitesimally thin boundary with the corresponding anisotropic surface impedances. Based on the promising results afforded by the simulations, a prototype antenna was constructed.
