Characterization of finite waveguide arrays using a new generalized scattering matrix approach

Finite arrays are typically analyzed using the infinite array approximation that enables one to work with the Floquet's modal expansion of only a single unit cell. We present a new hybrid generalized scattering matrix/spectral decomposition (GSM/SD) approach to analyze finite but large arrays. The proposed technique combines the numerical efficiency of the mode matching (MM) procedure, applied to the unit cell, with the capability of the SD to treat the finite problem as though it were doubly periodic and infinite. Representative numerical examples are presented to demonstrate the effectiveness of the method.