Extraction of the Complex Permittivity of Dispersive Materials with a Stochastic Optimization Technique

A stochastic technique is used in this paper to extract the parameters of three models (Havriliak- Negami, Cole-Cole and Debye models) of the complex relative permittivity of dispersive materials. From the aperture admittance of an open-ended coaxial probe, the complex permittivity is determined by means of a Parti- cle Swarm Optimization (PSO) algorithm. The validity of the proposed technique is proved by the agreement of the results obtained with literature experimental data for methanol. The general character of the procedure makes it applicable to different materials, dielectric relaxation models and measurement techniques.