Abstract

In practical applications of their theory, Huttner and Barnett advocate the use of phenomenological expressions for the dielectric permittivity [1]. However, it has been suggested recently that this approach runs into difficulties when applied to some phenomenological permittivities [2]. We show that Huttner and Barnett's interpretation of the function they call ε(ω) [1] as the permittivity is correct, but that some types of permittivity cannot be described by their microscopic model.

© 1998 IEEE