Calculation of residue error in FDTD method for numerical dosimetry

In this paper, a residual error indicating an accuracy of numerical solutions obtained by finite-difference time-domain (FDTD) method is calculated at a single frequency. The method extends a methodology of finding the convergence of the FDTD solutions previously proposed by the authors. By using our approach, the accuracy of the FDTD solutions is preserved by values of the calculated residue error. It is also shown that the residual error converges to a constant value at a steady-state condition.