Efficient Analysis of EM Scattering by Using Higher-Order Hierarchical Linear-Linear Basis Functions

In this letter, the curve linear-linear (CLL) basis functions are extended to higher-order hierarchical linear-linear (HOLL) basis functions. The accuracy of method of moments (MoM) solution for both the magnetic field integral equation (MFIE) and the combined field integral equation (CFIE) can be improved by use of the proposed HOLL basis functions for electromagnetic scattering problems with larger meshes. In this way, the number of unknowns can be saved largely when compared to the low-order basis functions. Moreover, the multilevel fast multipole algorithm (MLFMA) is introduced to accelerate the calculation. Numerical results demonstrate that the proposed technique is efficient for the analysis of EM scattering from PEC objects.