Research on Methods of Targets RCS Near-field-to-far-field Transformation Based on 3-D SAR Imaging

Microwave 3-D imaging technique can accurately separate and extract the attractive targets from the background noise. So it can be utilized to analyze and study the ElectroMagnetic (EM) scattering characteristics of the outfield targets. Thus researching the EM scattering characteristics of targets from the perspective of 3-D SAR imaging is becoming an emerging hot field. Based on the background above, firstly, the near field 3-D imaging process in wave-number domain is deduced from the Stratton-Chu integral equation and the physical meaning of 3-D SAR imaging is explained. Then, the principle of targets Radar Cross Section (RCS) Near-Field-to-Far-Field Transformation (NFFFT) based on 3-D SAR imaging is elaborated and the method of scattering center extraction from 3-D SAR image is introduced and the algorithm of targets RCS NFFFT based on 3-D SAR imaging technique is presented. Finally, though some experiments using the FEKO software, five scattering points observing angle characteristic curve and frequency characteristic curve are gotten. Through the comparative experiments with the ideal situation, the effectiveness of the RCS NFFFT algorithm is validated.