Fast near-field calculation for volume integral equations for layered media

An efficient technique based on the fast Fourier transform (FFT) for calculating near-field scattering by dielectric objects in layered media is presented. A higher order method of moments technique is employed to solve the volume integral equation for the unknown induced volume current density. Afterwards, the scattered electric field can be easily computed at a regular rectangular grid on any horizontal plane using a 2-dimensional FFT. This approach provides significant speedup in the near-field calculation in comparison to a straightforward numerical evaluation of the radiation integral since it eliminates the very time-consuming computations of the dyadic Green's functions for layered media.