title: Effective impedance modeling of metamaterial structures.
abstract: We present methods for retrieving the effective impedance of metamaterials from the Fresnel reflection coefficients at the interface between two semi-infinite media. The derivation involves the projection of rigorous modal expansions onto the dominant modes of the two semi-infinite media. It is shown that the effective impedance can also be written as a ratio of averaged field quantities. Thus, a number of effective impedance formulas, previously obtained by field averaging techniques, can also be derived from the scattering-based formalism by an appropriate choice of projection. Within the effective medium limit, it is observed that a simple semianalytic modeling technique based on the effective impedance can be used to reliably compute the reflection coefficients of metamaterials over a wide range of incidence angles. We use this technique to model planar metamaterial waveguides or surface modes.
authors.forename: Kokou B
authors.initials: KB
authors.lastname: Dossou
authors.forename: Christopher G
authors.initials: CG
authors.lastname: Poulton
authors.forename: Lindsay C
authors.initials: LC
authors.lastname: Botten