Curve linear–linear basis functions of magnetic-field and combined-field integral equations for EM scattering problems

The curve linear-linear (CLL) basis functions are proposed to improve the accuracy of both the magnetic-field integral equation (MFIE) and the combined-field integral equation (CFIE) for electromagnetic scattering from PEC objects. The CLL basis functions are derived first and then the multilevel fast multipole algorithm is applied to accelerate the matrix-vector multiplication. The accuracy of the CLL basis functions for both the MFIE and the CFIE are compared with both the curve RWG basis functions and the linear-linear basis functions. Numerical results demonstrate the efficiency of the proposed method.