Polarization-Current-Based FDTD Near-to-Far-Field Transformation

TL;DR

This paper introduces a novel near-to-far-field transformation method for 3D FDTD simulations that directly uses polarization currents, reducing numerical errors associated with traditional methods.

Contribution

It presents a new algorithm based on polarization currents, eliminating spatial offset errors in standard near-to-far-field transformations for FDTD.

Findings

Validated against Lorentz-Mie solutions for dielectric and metallic spheres.

Reduces numerical errors compared to traditional methods.

Effective for large scatterers with strong forward scattering.

Abstract

A new near-to-far-field transformation algorithm for three-dimensional finite-different time-domain is presented in this article. This new approach is based directly on the polarization current of the scatterer, not the scattered near fields. It therefore eliminates the numerical errors originating from the spatial offset of the E and H fields, inherent in the standard near-to-far-field transformation. The proposed method is validated via direct comparisons with the analytical Lorentz-Mie solutions of plane waves scattered by large dielectric and metallic spheres with strong forward-scattering lobes.