FDTD Technique Analysis On The Scattering Of Targets Coated With Plasma

In this thesis, the Finite Difference Time Domain (FDTD) method and its application in the EM scattering of targets coated with plasma are introduced. The EM scattering of targets coated with isotropic unmagnetized and anisotropic magnetized plasma is calculated by the FDTD method, respectively. The EM scattering of targets coated with time-varying plasma is also calculated and analyzed with the FDTD approach. The main works are as follows:Firstly, based on the principle of the FDTD method, the EM scattering by FDTD is depicted in detail, including the difference iteration formulas, the MUR and UPML absorbing boundary, the wave incidence, as well as the near-to-far field transformation boundary.Secondly, the EM scattering of different targets coated with isotropic unmagnetized plasma is presented. The reflection and transmission coefficients through a unmagnetized plasma slab are calculated by the SO-FDTD method. In addition, the EM scattering of cylinder coated with unmagnetized plasma is calculated by the ZT-FDTD method. The EM scattering of 3D targets coated with isotropic unmagnetized is discussed by the JEC-FDTD.Thirdly, the bistatic radar cross sections of the metallic cylinder and square column are calculated by the ZT-FDTD method with the harmonic wave incidence. The effect of magnetized plasma is studied in different plasma thickness, plasma cyclotron frequency and collision frequency. The backscattering radar cross section of the metallic sphere and ellipsoid is calculated by the JEC-FDTD method with the transient wave incidence. Numerical results show that plasma cover layer can greatly reduce echo energy of radar targets if appropriate parameters of plasma are chosen.Finally, The electromagnetic wave propagation in time-varying plasma are studied. The distribution of electron density, the transfer characteristic and the phase characteristic for time-varying plasma are analyzed in detail. The EM scattering of 2D and 3D targets are calculated by the JEC-FDTD method, and the effect of time-varying magnetized plasma is discussed for different plasma thickness, plasma cyclotron frequency, collision frequency, electron density and relaxation time.