Calderón preconditioner: From eFIE and MFIE to n-mller equations

The N-Mller equations for scattering by a dielectric object are derived by preconditioning the electric-field integral equations (EFIE) and the magnetic-field integral equations (MFIE) with Caldern preconditioners. By employing the Caldern relation and the Caldern identities, it is shown that the sum of the preconditioned EFIE and MFIE equations yields the N-Mller equations, which explains the good spectrum property of the N-Mller equations from a different aspect. The N-Mller equations are discretized and solved by using the n̂× Buffa-Christiansen (BC) functions as testing functions, which avoids the appearance of the contour integral. It is demonstrated that the proposed solution of the N-Mller equations has a fast convergence and an excellent accuracy and is free of internal resonance corruption.