Generation of Characteristic Basis Functions by using Sparse MoM Impedance Matrix to Construct the Solution of Large Scattering and Radiation Problems

Several approaches to circumventing the problem of excessive memory and computing time associated with large method-of-moments (MoM) impedance matrices have been explored. Most of these approaches rely on iteration methods to solve large problems, and this can lead to convergence difficulties when dealing objects with multi-scale features. In contrast, the CBMOM technique significantly differs from the above approaches in several aspects. Most importantly, CBMoM uses a new type of high-level basis function, called the characteristic basis functions (CBF), which are used to represent the unknown induced current. The computation of the CBFs allows the iteration methods to be bypassed altogether. The computation of the CBFs represents the most time-consuming and memory demanding task in the CBMoM. To obviate these limitations, a new approach for generation of the CBF matrix equation is proposed in this paper. It utilizes a sparsified MoM impedance matrix, whose use not only simplifies the calculation of the CBFs, but reduces the storage requirement and computational time as well. Numerical results are presented below to validate the proposed method