Near-to-far-field transformation scheme utilizing a modified sinc interpolation method for PSTD simulations

We present a near-to-far-field (NTFF) transformation scheme tailored for pseudospectral time-domain (PSTD) simulations. Surface currents on the NTFF boundary are computed using a modified sinc interpolation method, eliminating the need for local averaging required infinite-difference time-domain (FDTD) simulations. Numerical results for dielectric sphere scattering, compared with Mie solutions, demonstrate that the proposed PSTD scheme achieves root-mean-square errors an order of magnitude lower than FDTD for the far-field patterns. The sinc interpolation method exhibits exceptional accuracy, even when applied to coarse grids.