New 3D discontinuous sheet for finite element time domain modelling of thin metallic films

A dual surface method is presented for the modelling of thin metallic film surfaces. Improved accuracy is achieved over existing single surface techniques by way of enforcing the field discontinuity across the thin film layer. The implementation of the discontinuous sheet in the wave equation is described for the time domain finite element method. The computational domain, a closed boundary microwave heating system, is discretised using edge elements. Results are presented where the use of the discontinuous sheet is considered in a food active package application placed within a multimode microwave applicator.