A fast solution to the VSIE for EM scattering by using the P-FFT with floating stencils

A fast solution to the volume-surface integral equation (VSIE) for scattering from 3-D composite conducting- dielectric objects is implemented by using the precorrected-FFT (P-FFT) method with improved stencil topology. The composite conducting-dielectric objects are discretized into triangle elements for the metallic region and tetrahedron elements for the material region, respectively, and then the method of moments (MoM) and the precorrected-FFT method are used to solve the VSIE for EM Scattering. When the P-FFT method is being employed, the projection and interpolation stencils are based on an improved stencil topology named "floating stencils", in which each grid corresponds to a stencil center and each basis function is linked to the stencil with its center nearest to the basis function. Numerical result shows that the implemented solver can solve VSIE for EM scattering from composite conducting-dielectric objects efficiently, and that the floating stencil topology can significantly reduce near-zone interactions to be pre-corrected, as well as memory and CPU time.