Three-Dimensional Metamaterials with an Ultrahigh Effective Refractive Index over a Broad Bandwidth

Abstract
The authors introduce a general mechanism, based on electrostatic and magnetostatic considerations, for designing three-dimensional isotropic metamaterials that possess an enhanced refractive index over an extremely large frequency range. The mechanism allows nearly independent control of effective electric permittivity and magnetic permeability without the use of resonant elements.