Propagation and Negative Refraction

In this article, we present a new theory to explain the phenomenon of negative refraction in bulk metamaterials. Unlike earlier theories, it does not rely on the existence of a single mode of propagation in materials with negative constitutive parameters. It is based on the interaction and phase reversal effects caused by the existence of two simultaneous electromagnetic (EM) modes in uniform inhomogeneous metamaterial structures. The theory is general in the sense that it may be applied with equal validity to quasilumped circuit-based microwave metamaterials and to optical negative refraction in bulk nanowire metamaterials. Validity of the theory is demonstrated with EM simulations of microwave and optical metamaterials.