| Summary: | 碩士 === 國立海洋大學 === 電機工程學系 === 90 === In this thesis, we use the method of moment (MOM) to solve the electromagnetic scattering problems. A three-dimensional conducting object of arbitrary shape is divided into triangular patches, and the electric field integral equation (EFIE) is discretized by the MOM. Then the conjugate gradient method (CGM) is used to solve the matrix equation for the unknown expansion coefficients of the surface current. But when the number of unknowns becomes very large, the CGM takes much time at each iteration. In view of this, we use the multilevel fast multipole algorithm (MLFMA) to speed up the matrix-vector multiplication in the CGM. The MLFMA reduces the complexity of a matrix-vector multiplication from N square to NlogN , where N is the number of unknowns. This algorithm requires less memory, and hence, large-sized objects and more practical problems can be solved on a PC.
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