Analysis of Periodic Structures at Oblique Incidence by Iterated Finite-Difference Time-Domain Method

An iterated FDTD method is shown here which can be used for analysis of periodic structures at oblique incidence. The main principle of the algorithm is that the future field for the current iteration is replaced approximately by the field produced in the previous iteration with the time-shifted method. The calculated reflection coefficient of infinite gold plate agrees well with the analytical solution. Furthermore, the method is introduced into the simulation of three dimensional dispersive structure, and the ultra-transmission phenomenon of the structure with nano cylinder on silicon surface is verified theoretically. The results clearly show that the method overcomes the shortcomings compared with traditional method by the limitation of incidence angle, the lack of time domain field evolution procession and the need for large meshes, which provides a new solution for the transmission properties of dispersive periodic structures under oblique incidence conditions.