Numerical simulations of dielectric properties of composite material with periodic structure

Artikel i vetenskaplig tidskrift, 2005

Results of computer simulations and measurements of frequency-dependent dielectric properties of a binary composite material are presented. The studied composite had well-defined 3D periodic structure and was made of paraffin and paper laminate. In the considered frequency range (10(-3) 10(3) Hz), both the constituents were characterized by significantly different dispersive properties of complex dielectric permittivities. These frequency-dependent parameters were measured and were used for 3D numerical simulations of the effective dielectric properties of the mixture. The simulations were performed using two methods, the finite-volume method and the finite-element method. Frequency variations of the computed effective complex permittivity of the composite are discussed and are compared with the experimental data. The results of the simulations show that the distributions of the micro-scale electric field and dielectric losses in the volume of the composite material are strongly frequency dependent. This effect is also analyzed using classical models for composite dielectric structures.