On the Accuracy and Efficiency of Surface Formulations in Fast Analysis of Plasmonic Structures via MLFMA

We consider the accuracy and efficiency of surface integral equations, when they are used to formulate electromagnetic problems involving plasmonic objects at optical frequencies. Investigations on the iterative solutions of scattering problems with the multilevel fast multipole algorithm show that the conventional formulations, especially the state-of-the-art integral equations, can significantly be inaccurate, in contrast to their performances for ordinary dielectrics. The varying performances of the formulations with strong dependency on the material properties explain conflicting results in the literature. Based on our observations, we also present improved formulations that can provide both accurate and efficient solutions of plasmonic problems.