Scattering computation using the fast multipole method

The fast multipole method (FMM) computes scattering cross sections from large targets with several orders of magnitude reduction in the CPU time and memory storage compared to traditional method of moments (MoM) techniques. The authors compare the memory usage and CPU times for FMM with traditional MoM results using both direct and iterative solvers. It is shown that dramatic reductions in CPU and memory requirements can be realized by using the FMM to compute scattering and radiation from large objects. In the test cases considered, 2D objects with perimeters longer than about 12 wavelengths required less memory than using traditional MoM techniques. Using the FMM to compute scattering from objects with perimeters larger than about 30 wavelengths required less CPU time than using iterative solvers with a dense Z matrix.<>