Metamaterial properties, designs, and antenna applications

Metamaterials have the potential to allow engineers to tailor the electromagnetic responses of the materials incorporated in antenna systems to enhance their performance. Several examples of the exotic properties of electromagnetic metamaterials will be given. One class of metamaterials that has already demonstrated its usefulness with antennas is the artificial magnetic conductor (AMC). It has been demonstrated that this metamaterial configuration can yield a highly resonant radiating system. The resonances occur for particular combinations of shell sizes and metamaterial properties; they result in significant enhancements of the radiated power. These resonance results have been extended to lossy DNG and epsilon negative (ENG) metamaterials. We have also demonstrated reciprocity between these source results and the scattering of plane waves from the corresponding metamaterial coated spheres. We have shown with HFSS numerical simulations that realistic center-fed electrically small dipole antennas surrounded with an ENG spherical shell and coaxially-fed monopole antennas surrounded with an ENG hemispherical shell can be made to be resonant and matched to an external source. These electrically small antenna systems have very high radiation efficiencies and Q factors near the Chu limit. A review of these metamaterial-based electrically small antenna systems will be presented and current progress toward a proof-of-principle experiment will be discussed