Accurate and stable solutions to electromagnetic scattering problems by means of the electric field integral equation augmented by a weak combined source condition

The combined source (CS) condition isemployedtoaugment the electric field integral equation (EFIE), whereby the CS condition is implemented as a modification of the weak form Leontovich impedance boundary condition. By doing so, both electric and magnetic surface current densities can be modeled with Rao-Wilton-Glisson (RWG) basis functions. Strict point-wise orthogonality of electric and magnetic currents is not fulfilled. However, rotated RWG functions or Buffa-Christiansen functions, which are both often utilized in method of moments formulations, are avoided. The conditioning of the CS integral equation (CSIE) is improved as compared to the standard EFIE with Love currents, whereas the very good accuracy of the EFIE is retained. Objects that show poor accuracy when solved with magentic field and combined field integral equations, e.g. objects with sharp edges, can be solved very accurately with the proposed CSIE.