Mixed-order basis functions for the locally-corrected Nyström method

The paper presents a thorough study of the application of the mixed-order basis proposed by F. Caliskan and A.F. Peterson (see IEEE Antennas and Wireless Propag. Lett., vol.2, p.72-3, 2003) for the locally corrected Nystrom (LCN) method when analyzing electromagnetic scattering by targets composed of both dielectric and conducting materials. The integral formulation is based on a superposition of the classical combined field integral equation (CFIE) operator (Peterson et al., 1998) for metallic surfaces and a Muller formulation for penetrable objects (Muller, C., 1969; Mautz, J.R. and Harrington, R.F., 1979). It is demonstrated that for general scattering objects, mixed-order basis functions accelerate the convergence of the LCN solution, eliminate spurious charges for singular geometries, and can significantly reduce the condition number of the impedance matrix.