Generalized mode solver for plasmonic transmission lines embedded in layered media based on the Method of Moments

This paper presents an integral equation formulation for the calculation of the propagation characteristics of plasmonic transmission lines embedded within a multi-layered structure. The Method of Moments (MoM) technique is adopted in this paper due to its superior advantages over other techniques including the finite difference and finite element methods. Plasmonic transmission lines consist of a number metallic strips of arbitrary shapes immersed within a stack of planar dielectric or metallic layers. These transmission lines can support one or more mode, each of which has its characteristic mode profile and it propagates with a certain propagation and attenuation constants. The developed solver is tested for different plasmonic transmission line topologies surrounded by various layered media. The obtained results are compared to CST commercial software for verification. Very good agreement between the proposed solver and CST has been observed. The developed MoM solver requires much smaller number of unknowns if compared with those based on Finite Difference Time Domain (FD-TD) or Finite Element Method (FEM) such as Lumerical and CST.