Research On Electromagnetic Scattering Calculation Method Of Typical Targets Based On FDTD

With the development of radar,people increasingly realize the importance of target electromagnetic scattering characteristics,which is an indispensable key input data in the follow-up research or imaging.Therefore,how to obtain the target electromagnetic scattering characteristics accurately,efficiently,and conveniently plays an important role in the research of radar.This paper research the electromagnetic scattering calculation of metal target,dielectric target,and mixed material target by cell-wise,which can get the accurate calculation of the electromagnetic scattering characteristics of each unit of the target at the cell level,realize the more detailed calculation and observation of the target,and also add Doppler information to the calculation results of each cell can achieve the purpose of quickly calculate the electromagnetic scattering characteristics and echo in each azimuth.The main work includes the following:First,the modeling method of electrically large size complex target based on FDTD is presented,and the modeling of single-material and multi-material targets is described from the aspects of shape modeling and material assignment respectively.For the subsequent cell-wise calculations,to ensure that the extrapolated boundary is in the scattered field,the traditional total field calculation area is removed and the pure scattered field FDTD is used instead.The iterative equation of pure scattering field FDTD and the adding method of incident wave are studied.Second,a computational method for the cell-wise electromagnetic scattering characteristics of the target under single-polarized conditions is proposed for the problem of extrapolating only to the overall target by existing algorithms.The integral boundary and the extrapolation center point of the traditional extrapolation algorithm are modified so that the Huygens surface only packages and extrapolates to a single cell.By calculating the outer cells position and the exposed surfaces position of the outer cells,the cell-wise electromagnetic scattering characteristics can be calculated for metal,dielectric and mixture targets,respectively.Thirdly,a cell-wise extrapolation method for calculating the electromagnetic scattering characteristics of the polarized radar target is presented.The cell-wise electromagnetic scattering characteristics of four polarizations(HH,HV,VH,VV)are calculated for metal target,dielectric target and mixture by setting different polarizations of incident wave,and a pseudo-color map is generated to verify the phase information.