Fast analysis of 2-D electromagnetic crystal devices using a periodic Green function approach

A novel integral equation-based method for simulating wave propagation in two-dimensional (2-D) electromagnetic crystal (EC) devices is presented. A small number of irregular defects aside, the targeted devices are obtained by removing cylinders from infinite, doubly periodic, and defectless electromagnetic crystals. Integral equations in terms of equivalent currents that reside on the surfaces of the voids left by the removed cylinders are constructed by using Green functions innate to the defectless electromagnetic crystal. The sparse system of equations that results upon discretizing these integral equations is solved efficiently by a multifrontal method. The scheme is ideally suited to extract electromagnetic crystal device S parameters as it permits imposing modal excitations and exact absorbing boundary conditions. The scheme is applied to the analysis of two multiplexer-demultiplexer devices, a filter, and a bended EC waveguide, thereby demonstrating its versatility and computational efficiency.