Study On Electromagnetic Scattering Between Rough Surface And Target Under Electromagnetic Pulse Excitation

With the extensive application of pulse radar,cable detection,cable security protection,target identification,target tracking and other technical development needs to study the transient electromagnetic scattering problem.In order to avoid the problem of large computation when the traditional frequency domain method is directly used to solve the composite model transient field problem,The Finite Difference Time Domain(FDTD)method is used to calculate the coupling scattering between random rough background and coaxial cable below and above,as well as with multi-conductor target above.The following is a detailed introduction:1.According to the actual problem of rough underground cable detection,the composite calculation of broadband electromagnetic scattering of ground and buried double coaxial cable is realized by using FDTD method.The plane differential Gaussian pulse is used for the incident wave,and the random rough ground is constructed by Monte Carlo method combined with gaussian power spectral density.Considering the practical problems such as cable identification,radar signal monitoring and cable safety protection in complex desert environment,FDTD method is used to calculate the transient composite electromagnetic scattering of coaxial cable between rough desert background and above.The incident wave is planar differential Gaussian pulse,the desert surface is constructed by Monte Carlo method combined with Gaussian power spectral density,and the permittivity of desert soil is calculated by the general relation proposed by Herkelrath.2.In view of the practical requirements of target identification and reconnaissance in complex desert environment,FDTD method is used to realize the composite operation of broadband electromagnetic scattering of rough desert background and multi-metal target above.The incident wave selects plane Gaussian pulse,and the desert surface is constructed by Monte Carlo method combined with Gaussian power spectral density.The permittivity of desert soil is calculated using the general relation proposed by Herkelrath.Near by FDTD iteration,near-far field extrapolation,Fourier transform,calculated by the normalized scattering cross section to the curve of the composite scattering coefficient changing with the incident wave frequency,analyses the rough surface geometry of statistical parameters and target parameters,the influence law of medium constitutive parameters on the scattering coefficient,got a rough background with the corresponding target wide-band electromagnetic scattering characteristics of relatively complete.These numerical results are of great significance to the development of cable nondestructive testing and target identification and tracking technology under rough background.