A Self-Consistent Extrapolation Method for the Complex Permittivity and Permeability Based on Finite Frequency Data

We describe a method of extrapolation based on a truncated Kramers-Kronig relation for the complex permittivity ($epsilon$) and permeability ($mu$) parameters of a material, based on finite frequency data. Considering a few assumptions, such as the behavior of the loss tangent and the overall nature of corrections, the method is robust within a small relative error, if the assumed hypotheses hold at the extrapolated frequency range.