Modeling of Spatially-Dispersive Wire Media: Transport Representation, Comparison With Natural Materials, and Additional Boundary Conditions

Natural and artificial wire materials exhibiting spatial dispersion are considered using a transport (drift-diffusion) model. The connection between drift-diffusion and electron transport in natural materials is highlighted, and then applied to various forms of wire media, leading to the definition of effective conductivity and diffusion parameters that characterize the material. It is shown that the effective material parameters lead to a Debye length that provides a quantitative measure of the strength of spatial dispersion for wire mediums. Further, it is shown that Pekar´s additional boundary condition applies in many instances to natural materials as well as artificial wire media, and can be derived from elementary electromagnetics.