The Study Of Wideband Electromagnetic Scattering Characteristic From Moving Target In Complex Environment

In computational electromagnetic field, the electromagnetic scattering characteristic of moving target in complex environment has important research significance and practical application value. The numerical scattering calculation of moving target is complex research topics, because of the interactions between target and complex environment. According to the calculation problem of moving target electromagnetic scattering in complex environments, the paper calculate the wideband electromagnetic scattering characteristics of composite moving target in the case of multi-angle incident, using rough surface to simulate the complex environmental background and by introduce the new broadband algorithm (spectrum finite-difference time-domain) combined with periodic boundary conditions and movement relativistic boundary conditions. The specific analysis is divided into sections as follow.The first part introduces the basic principles of the spectrum time domain finite difference method and its key concept of constant transverse pulse wave, and defined the formula of constant transverse pulse wave from frequency domain to time domain. Then the paper describes the knowledge of periodic boundary conditions and the specific formula in the algorithm. The computational model of specific objectives also has been established. Finally, the characteristic of constant transverse pulse wave has been analyzed by the numerical example. The computational results proved that the spectral FDTD method is accurate and effective.The second part describes the modelling method of randomly rough surface and the computational method of its scattering properties. The paper gives out the generative process of randomly rough surface using the Monte Carlo method and analyses the effect of rough surface parameters to the rough surface profile. Then, the rough surface be as example, the paper focus on the PM power spectrum and JONSWAP power spectrum and generate specific roughly ocean using the Monte Carlo method. Finally, several approximation methods and numerical methods of randomly rough surface electromagnetic scattering have been briefly introduced.The third section presents the electromagnetic relativistic boundary conditions in state of motion. The paper gives the specific derivation of motion Doppler theoretical formula and movement relativistic boundary conditions. On the basis of the arguments above, then numerical example verifies the correctness of movement relativistic boundary conditions by FDTD method combined with movement relativistic boundary conditions.The last part of the paper calculated the wideband electromagnetic scattering characteristic of moving target in the complex rough sea surface environment background under multi-angle incident, using the spectrum FDTD method combined with periodic boundary conditions and movement relativistic boundary conditions. First, the calculation model of moving target in complex environment has been set up. After that, the reflection coefficient and radar cross section of independent rough sea surface and in case of target existed have been discussed.The paper analysis the change law of composite electromagnetic scattering curve in different cases about moving target by comparison.