Analysis of electromagnetic scattering from perfect electric conducting targets using improved characteristic basis function method and fast dipole method

The characteristic basis function method (CBFM) is an efficient approach to analyze electromagnetic problems through the size reduction of the original matrix in the method of moments equation. However, adequate plane waves (PWs) must be set in each sub-block to construct characteristic basis functions (CBFs), thus increasing the number of CBFs and causing higher time consumption in singular value decomposition. In addition, the reduced matrix calculation procedure is time-consuming because numerous vector–matrix–vector products (VMVPs) are contained. To mitigate these problems, an improved CBFM is presented. This method fully considers the mutual coupling effects among sub-blocks to obtain the secondary level characteristic basis function (SCBF). Therefore, the number of PWs, as well as the number of CBFs, is significantly reduced. The fast dipole method is also used to accelerate the matrix–vector products in the construction of SCBFs and VMVPs in the calculation of the reduced matrix. Numerical results demonstrate that the proposed method is accurate and efficient.