Research On The Applications Of FDTD For The Analysis Of The Electromagnetic Problems

Finite-Difference Time-Domain (FDTD) Method has applied to many different fields of electromagnetic problems such as radiation, scattering, electromagnetic compatibleness etc. Compared with other numerical methods, FDTD is superior in dealing with the kind of problems where involved objects have complex shape or material construction. This paper deals with some applications arising from practical demands based on the research on FDTD method.This paper discusses concrete techniques using FDTD method to realize the simulation of electromagnetic wave propagation in waveguide and the analysis of radiating field radiated by open waveguide, horn antenna and slotted array antenna. The total field - scattering field technique is extended to be used in the introduction of excited source in sort of waveguide problems. The fidelity of excited signal can be guaranteed as long as some parameters of modulated Gaussian pulse are properly selected. Besides, the radiating field of open waveguide excited by modulated Gaussian pulse is discussed, the result of which is in good agreement with the measured result, showing the validity of the proposed method.The relative techniques to FDTD method for tackling the scattering field of plasma and complex object involving rocket plume are proposed. The FDTD time-stepping relations are deduced based on Z-transformation where plasma is taken as the specific example of dispersive medium. The result from such algorithm is in good agreement with that from Mie theory. Furthermore, the influence of plasma frequency and plasma collision frequency on characteristics of the plasma object is given after examination of the computational results. Also, the scattering characteristics of complex objects with plume are explained depending on the numerical result from ZT-FDTD method on MPI parallel platform.To develop FDTD software of practical usage, it is important to make it on a platform that allows for ready access, highly efficient computation and unquestionable accuracy. For these reasons, a type of software developed by the author is particularly introduced. The main techniques used in such software involve OpenGL, the mixed programming of Fortran and Visual C++, the mixed programming of Matlab and Visual C++. At last, two engineering examples demonstrate the friendly user's interface and highly accuracy of the FDTD software.