An accelerated implementation of the FMIR-MoM algorithm

The recently published FMIR-MoM (Frequency and Material Independent Reactions for the Method of Moments) algorithm [1] allows for the fast solution of surface scattering equations while sweeping through the frequency, permittivity, conductivity and/or permeability of an object under test and/or its surrounding medium. The technique calculates MoM matrices for homogeneous dielectric or metallic scatterers in a computationally efficient way. This is achieved first by calculating a small number of pre-sweep geometry dependent (wave number and intrinsic impedance independent) matrices. MoM matrices may then be generated for any arbitrary wave number and intrinsic impedance by scaling each of the pre-sweep matrices by a simple scalar, adding them together and performing an element by element multiplication with a matrix of extracted phases. This paper briefly reviews the method. It then demonstrates that the pre-sweep matrices may be generated in a fashion more efficient than presented in the original publishing of the FMIR-MoM technique. The new method is shown to decrease the computation time by 40 %. In addition the paper applies FMIR-MoM to the calculation of the RCS of an elementary Perfect Electrical Conducting (PEC) scatterer. This problem is used to compare the technique with that of quadratic impedance matrix interpolation. In the scenario tested FMIR-MoM used less memory and half the processing time than quadratic interpolation.