Impact of grid resolution in FDTD for effective wire medium with strong spatial dispersion

An ordinary finite-difference time-domain (FDTD) simulation normally requires a grid resolution of λ/20. However, since the effective wire medium possesses spatial dispersion, the impact of the grid resolution in FDTD is studied in terms of transmission coefficient and imaging quality in this paper. The numerical results show that the simulation of the evanescent wave requires much finer mesh resolution. For low spatial harmonics, the numerical error increases roughly proportionally to the grid size; while for high spatial harmonics, the error increases much faster in a nonlinear way. Considering the trade-off between computation resources and accuracy, a reasonable grid resolution in FDTD should be chosen with regard to the highest spatial harmonics of interest.