Application of the iterative moment method for dielectric scattering calculations

• Main Author: Huang, Xiaomin
• Language: English
• Published: 2009
• Online Access: http://hdl.handle.net/2429/5138

In this thesis, the calculation of the electromagnetics(EM) scattering of three dimensional, irregular, inhomogeneous and lossy dielectric objects is discussed. The iterative moment method (MM) which can solve problems involving a large number of unknowns than the conventional MM is used. For result comparison and checking, conventional MM is discussed too. Generally, the method also applies for any arbitrarily shaped penetrable body with arbitrary dielectric distributions which will have importance in communication, medical, biological, meterological and military studies. A new melting-snow particle model is presented in this thesis, based on physical observations or assumptions. The EM scattering cross-sections of the new melting-snow model are evaluated at certain frequencies, melting factors and rain rates by the iterative MM. The analyses of the new model give us a better understanding to the EM scattering property of melting snow particles at the early stage and to the effect of outer layer water distributions on the scattering of melting snow. The results obtained are compared with those of two other existing models. The comparison shows that the different melting snow particle models have different scattering properties; the different melting water distributions assumed significantly affect the scattered fields. The validity of the iterative MM for large number of unknowns has been shown. The numerical calculation examples in this thesis prove the equivalence of the two moment methods at special choice of basis functions and weighting functions. The thesis also discusses the computer realization of the two moment methods, compares their advantages and disadvantages. Conclusions regarding the choice of subcell size and the initial guess, the convergence and precision, computer memory, and computing time are obtained which will have academic interests.