A novel mixed basis functions for method of moments

The basis functions defined on triangular patches have been widely used in the method of moments for the radiation and scattering prediction of 3D structures. However, traditional RWG basis functions cannot describe the singular current on the object´s boundary edges effectively. Although the new TL basis functions can describe the edge current, it generates so many unknowns. To alleviate this problem, a mixed basis functions, called STL+RWG basis, have been presented in this paper. The new STL basis functions are only defined on the triangular patches with boundary edges, which are added to the RWG basis defined on all the triangular patches. It is validated and demonstrated by the numerical examples that the mixed basis can describe the edge current much better compared with the RWG basis. At the same time, the mixed basis functions need much fewer unknowns than the TL basis, on the premise of ensuring the calculation accuracy.