Note on interpolational basis functions in the method of moments [EM scattering]

Efficient basis sets for the method of moments may be obtained using quasi-localized bandlimited interpolational functions that, broadly speaking, are defined relative to a mean sampling rate that is adjusted to curvature and proximity to edges, thus reflecting the local spatial-frequency bandwidth. Computed scattering data in a number of structures, including perfectly conducting circular and elliptical two-dimensional cylinders as well as a flat infinite strip, indicate that reasonable accuracy can be obtained with an average rate of between 2.5 and 3 basis functions per wavelength. Average sampling rates need not correspond strictly to the bandwidth of the basis functions, and there is considerable latitude with respect to random variation of sampling intervals. Although each basis function typically extends over several sample points, required integrals can be obtained speedily by the use of standard sampling-theoretical methods