Efficient RCS computation for multiple incident angles using the FMM/MNM technique

We extend the MNM (Markov and Maxwell) technique, originally developed for frequency sweeping in the context of RCS computation, to speed up the iterative solution of MoM matrix equations with multiple right hand sides, corresponding to different angles of incidence. We show that the use of this technique can reduce computation time while preserving the accuracy of the solution. The MNM itself places little additional computational burden on the iteration process and usually requires less than the time required for a single iteration in the CG (conjugate gradient) process. The time-saving realized over the zero initial guess can be significant, especially when the angular increment is small, which is needed to capture rapid variations of the RCS, typically associated with large or complex scatterers.