Unambiguous determination of constitutive parameters of a metamaterial slab

Abstract

The constitutive parameters of a metamaterial slab showing negative refractive index over the 9–12 GHz frequency range are unambiguously retrieved from complex scattering parameters upon using the phase unwrapping method. Such a technique relies on properly adding to the phase of the complex transmission coefficient a stepwise function constructed from the resonance frequencies at which the phase of the transmission coefficient reaches ∓ π.