Accurate Rotman lens (Rotman, W. and Turner, R.F., 1962) analysis must include computing the full scattering matrix of the lens, including mutual coupling between the feed ports and internal reflections. Options to include the most common lens feed port and substrate configurations are also required for maximum utility. Because of the large electrical area of the lens (typically >100 square wavelengths), analysis using completely rigorous methods, such as MoM, FE or FDTD, may not be feasible. Three methods for solving the problem are described and results are summarized. A recent application utilizing 2D Rotman lens stack beamformers for SHF and EHF commercial SATCOM and MILSATCOM applications is summarized.