An integral-equation method using interstitial currents devoted to the analysis of multilayered periodic structures with complex inclusions

摘要

An efficient surface integral equation-based method is proposed for theanalysis of electromagnetic scattering from multilayered media containingcomplex periodic inclusions. The proposed method defines equivalent currents atthe interfaces between layers in order to eliminate the need to compute thelayered medium Green's function. Hence, the background medium in a given layercan be treated as a homogeneous unbounded medium for which the computation ofthe Green's function for an infinite doubly periodic array is sufficient. Theresulting method-of-moments interaction matrix has a block tridiagonalstructure, which leads to computational complexity proportional to the numberof layers for both matrix filling and solution. When all layers are identical,the filling time essentially reduces to that of a single layer, and theinteraction matrix has a Toeplitz structure. Numerical results are provided forthe reflectivity of multilayered periodic arrays of spherical silvercore-silica shell nanoparticles, excited by a plane wave at opticalfrequencies. Comparisons with results obtained with an FDTD-based commercialsoftware validate the accuracy and efficiency of the proposed method.