Research On Transient Electromagnetic Scattering Of 3D Conducting Objects

In this paper, the time domain integral equation method (TDIE) and its application for transient scattering of arbitrarily shaped 3D conducting objects are studied. The main works include: the research of the stability solution of TDIE, the optimization of the parameter of time domain basis function set that is derived from the Laguerre functions, and its application is also presented.In the first part, the fundamental theory of time-domain electromagnetic is introduced. The time-domain methods include the time-domain differential equation (TDDE) methods and the time-domain integral equation (TDIE) methods. The general concepts of FDTD, TDFEM, FD-MoM and TD-MoM are discussed respectively, and the advantage and disadvantage between TDIE and TDDE are also pointed out. A traditional method to solve the TDIE has two fatal weaknesses, one is the late-time instability; the other is the computation complexity which make it impossible to accurately analysis for the electrically large object subjects.A stable method called MOD algorithm to solve the TD-CFIE is introduced. In this algorithm, the weighted Laguerre basis functions are chosen as the time domain basis function, while the RGW functions as spatial basis. The characteristics of weighted laguerre basis functions are discussed, and the emphasis is how to optimize its parameters.Next, a general solution method of MOD is introduced, and its numerical result is compared with the Inverse Discrete Fourier Transform (IDFT) of frequency domain combined integral equation (FD-CFIE).Finally, a method for efficient generation of MOM matrices based on equivalent dipole to solve the TD-CFIE coupled with the MOD algorithm is presented.