Time Domain Parabolic Equation Method Analysis Of Electromagnetic Propagation And Scattering

How to quickly and accurately analyze the electromagnetic characteristics of electrically large objects is always the key problem of electromagnetic system.The traditional numerical methods include the Method of Moment(MoM),the Finite Difference Time Domain(FDTD),the Finite Element Method(FEM)and so on.Compared to other numerical methods,these numerical methods have the obvious advantage of high computational accuracy when it is used to analyze the electromagnetic scattering or propagation problems.However,a large number of computational resources are needed for electrically large targets.On the other hand,the high frequency methods have lower accuracy with less computational resources.The parabolic equation(PE)is an approximation of the wave equation,which can give encouraging accuracy with limited computational resources.An efficient time domain parabolic equation(TDPE)method is proposed in this thesis.The main works of this thesis are showed as follows:Firstly,the basic principles of parabolic equation,vector parabolic equation and rotational parabolic equation method are introduced.The modeling and boundary conditions are described in detail.Moreover,the wider angle parabolic equation method is also studied in this part.At last,the vector parabolic equation and its rotating method are introduced.Secondly,the time domain method of parabolic equation is applied for wave propagation problems,including the single edge peak environment,multi edge peak environment,irregular terrain and so on.Finally,an efficient TDPE method is proposed to fast analyze the wide-angle wideband EM scattering properties of electrically large targets to reduce the calculation time.The discretization schemes of the wide-angle TDPE based on the Crank-Nicolson method,alternating direction implicit method and alternating direction explicit method are derived.At last,numerical examples demonstrate the efficiency of the proposed method.