Wave propagation in media having negative permittivity and permeability

摘要: Wave propagation in a double negative (DNG) medium, i.e., medium having permittivity and permeability, is studied both analytically numerically. The choices of the square root that leads to index refraction wave impedance DNG are determined by imposing analyticity complex frequency domain, corresponding properties associated with each choice presented. These monochromatic concepts then tested critically via one-dimensional finite difference time domain (FDTD) simulation causal, pulsed plane matched, lossy Drude model medium. causal responses different spectral regimes positive or refractive indices varying carrier narrowband pulse excitations. smooth transition phenomena from its early-time nondispersive behavior late-time response explored wideband FDTD results show conclusively leading correct one, this consistent overall causality response. An analytical, exact solution scattering slab also given used characterize several physical effects. This independent roots for impedance, thus avoids any controversy may arise connection signs these constituents. examine perfect lens concept suggested recently Pendry. It shown effect exists only under special case $\ensuremath{\epsilon}(\ensuremath{\omega})=\ensuremath{\mu}(\ensuremath{\omega})=\ensuremath{-}1$ lossless nondispersive. Otherwise, closed form solutions field structure reveal converts an incident spherical into localized beam whose parameters depend on values $\ensuremath{\epsilon}$ $\ensuremath{\mu}.$ characterized paraxial approximation solution. again numerically two-dimensional cylindrical slab. demonstrate electromagnetic power flow through channeled beams rather being focused and, hence, Pendry not realizable realistic metamaterial.