Accuracy of the higher order moment method

The authors have presented a spectral convergence theory for the higher order method of moments approach to electromagnetic analysis. The spectral error due to discretization, which determines the solution error, is made up of two contributions: approximation error, and aliasing of high order eigenfunctions. The high order eigenfunctions of the operator are locally determined, since the fields radiated by these modes decay exponentially away from the source. Thus, the absolute spectral aliasing error is insensitive to the global geometry of the scatterer, and the results can be extrapolated to arbitrary smooth scatterers.