Efficient Modeling of Large Gratings

A robust, numerically stable and efficient method for simulation of the wave diffraction by flat finite gratings containing large number of perfectly conductive rods is presented. The approach is twofold. At first, we use further development of analytical regularization. At second, we select two domains of the gratings. One of them is the middle part of the grating, and another one - end-set rods - consists of the rods near the ends of the gratings. The currents on the rods in the middle set are nearly the same as ones for the infinite grating of the same structure. End-set rods can be managed with the grating of much smaller size. The solutions of both these auxiliary problems are constructed by means of Analytical Regularization Method.