High-order Convolution Perfectly Matched Layer Algorithm Based On Complex Envelope FDT

Finite-difference-time-domain(FDTD)algorithm is one of the most efficient methods to solve electromagnetic field simulation.At present,there are few studies on the complex envelope(CE)FDTD algorithm at home and abroad,so this paper mainly conducts in-depth research on the complex envelope CE-FDTD algorithm.Perfect Matched Layer(PML)is one of the most effective absorption boundary conditions in FDTD algorithm simulation.Among them,convolutional Perfectly matched Layer(CPML)is a convolution operation method of Complex Frequency Shifted Perfectly Matched Layer(CFS-PML),it has wide application value.However,there are few researches on PML of CE-FDTD algorithm.Therefore,the main research content of this paper is the combination of CE-FDTD algorithm and higher order CPML(HOCPML),and the higher order CPML used in this paper uses special partial fraction decomposition.According to the particularity of CE algorithm,the CE-HO-CPMLFDTD algorithm is improved.In this paper,the CE algorithm of Alternating Direction Implicit(ADI)FDTD based on unconditional stability algorithm is also proposed,that is,CE-ADI-HO-CPML algorithm.The following is the specific content of the algorithm proposed in this paper:1.A higher order CPML algorithm(CE-HO-CPML-FDTD)based on CE-FDTD is proposed to cut off the computational domain of unmagnetized plasma.A special partial fraction decomposition method is used,and the higher order CPML is improved according to the CE algorithm.The proposed algorithm is simulated by twodimensional and three-dimensional computing domains,and it is concluded that: In the set plasma computational domain,the maximum relative reflection error of twodimensional CE-HO-CPML-FDTD is-74 d B,which is 9d B lower than the low-order CPML of CE-FDTD,and the maximum relative reflection error of three-dimensional CE-HO-CPML-FDTD is-75 d B.It is 14 d B lower than the first-order CPML of CEFDTD.This chapter also uses a metal plate numerical example to verify the superiority of the algorithm.Through simulation verification,it can be concluded that the maximum relative reflection error of the proposed algorithm is-74 d B,11 d B lower than that of CE-FO-CPML-FDTD.2.This paper also proposes a higher order CPML algorithm based on CE-ADIFDTD(CE-ADI-HO-CPML),which is unconditionally stable with the ADI-FDTD algorithm.The effectiveness and superiority of the proposed algorithm are verified by two-dimensional plasma domain and two-dimensional plasma plus metal plate domain.The results are as follows: In the two-dimensional plasma computing domain(without metal plates),when CFLN=4 and 8,and the BRRE is reduced by about 5d B and 1d B,respectively.The absorption effect is better than that of the traditional ADI higher order CPML algorithm.When the metal plate is added to the two-dimensional plasma domain,when CFLN=4,compared with the traditional higher order CPML algorithm,the BRRE is reduced by about 5d B.In this section,a left-handed material medium is also used to simulate CE-ADI-HO-CPML.When CFLN= 1,4 and 8,the BRRE of the proposed algorithm PML is 6d B,5d B and 4d B lower than that of CL-ADI-HO-CPML,respectively.