A general approach to extend Berenger's absorbing boundary condition to anisotropic and dispersive media

Recent studies have focused on the extension of the Berenger's absorbing boundary condition (ABC)-the perfectly matched layer (PML)-to anisotropic and dispersive media. In this letter, we describe how the PML can be extended for anisotropic and/or dispersive media (or even bianisotropic media) with little analytical effort, in a simple and general conceptual setting, by using an analytical continuation of the coordinate space of the Maxwell's equations to a complex variables domain. Using this approach, there is no conceptual distinction between the derivation of PML for more complex media and the derivation for isotropic, dispersionless media.