Determination of the Complex Permittivity of Dispersive Materials Without Assuming a Dielectric Relaxation Model

This paper presents a procedure to extract the complex relative permittivity of a dispersive material without assuming a dielectric relaxation model. To assess and validate the procedure, published experimental data for methanol were considered. The frequency behaviour of the extracted complex relative permittivity is in good agreement with that of three classic dielectric relaxation models (Havriliak-Negami, Cole-Cole and Debye models). The advantage of this approach is noticeable when applied to new developed materials or materials whose frequency dependence is not known a priori. A proper dielectric relaxation model can be chosen and easily built over the whole frequency range of measurement through a quick interpolation of the complex relative permittivity values found.