Snell-corrected electric parameter scaling for 2-D FDTD dispersion reduction in layered tissues

This study extends dispersion-reducing medium scaling to 2-D TM z FDTD simulations of layered biological tissues under oblique incidence. A Snell-corrected scaling factor is derived to modify the electric constitutive inputs in each layer. The implementation uses the scaled electric parameters in the FDTD update and retains physical tissue density together with the update conductivity in the SAR post-processing to avoid double counting. Using a fine-grid reference (Δ x = 0.4~mm), the modified medium reduces the mean centreline | E z | error from 30.7% to 25.4% at 0 ∘ and from 37.9% to 26.3% at 90 ∘ on the coarsest grid (Δ x = 1.5~mm), whereas the benefit remains limited around 45 ∘ . A layer-by-layer implementation recipe and additional dosimetric indicators are also reported.