Modified Combined Tangential Formulation for Stable and Accurate Analysis of Plasmonic Structures

We present a modified combined tangential formulation (MCTF) for stable solutions of plasmonic problems involving metallic objects that are modeled as penetrable structures. For a wide range of negative real permittivity values, corresponding to the varying characteristics of the metals at infrared and visible frequencies, MCTF provides both accurate and efficient solutions in comparison to the conventional formulations. We explain the stability of MCTF in terms of the discretized operators for the limit case and demonstrate its stability on canonical scattering problems involving plasmonic spheres.