Preliminary Construction Of Computational Platform For Unifying Time-domain Electromagnetic Field And Simulation For Time Varying Media

With fast advancement of electronic information technology,electromagnetic theory and technology have been widely in many areas.To solve many practical problems,many time-domain electromagnetic simulation methods have been developed.Although their mathematical bases appear different,they can be derived from the method of weighted residual minimization which presents a possibility of a generic method of unifying all time-domain numerical methods.Based on it,this thesis presents a preliminarily set up of a unifying computational platform for time domain electromagnetic modeling.At the same time,to improve the performance of electronic devices and components,scientists have developed the advanced materials such as space-time varying materials and time-varying materials.However,there is little work on numerical modeling of the varying materials.In this paper,an unconditional stable method has been presented for a kind of time-varying materials.First,application of the functional methods to electromagnetic field problem is studied and selection criteria for the expansion basis functions and test functions are summarized.With the concepts of the functional and the method of weighted residuals,the conventional FDTD is derived.A preliminary time-domain computational platform in time-domain is constructed using C++ and is applied to the FDTD method.Finally,because of the study for conventional FDTD,in this paper,the iterative formula,the absorbing boundary,the stability condition and the numerical dispersion have been derived and analyzed.The explicit FDTD is studied in a matrix form for modeling time-varying materials and unstable modes that cause numerical instability are identified.Then,by removing unstable modes,an unconditional stable explicit FDTD is proposed for simulation of time-varying materials without instability.