Sparse-matrix methodology for finite-element time-domain modal non-reflecting boundary condition simulations

A sparse-matrix finite-element time-domain (FETD) formulation using a modal non-reflecting boundary condition (MNRBC) is proposed for the modelling of plane wave scattering from cylinders of arbitrary cross-section. Unlike the standard FETD-MNRBC formulation, the proposed formulation does not generate full sub-matrices following the discretisation of the boundary integral. Hence, it requires less computation memory than the standard formulation. The accuracy of the proposed sparse-matrix FETD-MNRBC formulation is demonstrated, in two dimensions, by comparing its bistatic scattering width results with those of the standard FETD-MNRBC formulation, the finite-element frequency-domain method and with analytical or published results.