3D imaging of a manmade target with weak scattering centres by means of UWB-radar

In this paper a 3D bi-static, fully polarimetric Ultra-Wideband (UWB) imaging system which satisfies superresolution conditions is presented. The objective is to inspect a target with weak scattering centres and to prove the performance of recent imaging methods under these conditions. This issue is handicapped further by spanning a suboptimal synthetic array, i.e. the main beam of the antennas is not aligned with the orientation of the weak scatterers. An opened laptop with a knife fixed at the back of the display is used as the target for an experimental validation. The radar cross section of the keyboard in this position can be assumed to be very small which reveals very weak multibounce scattering mechanisms. The evaluation of the imaging is performed by the real-time capable revised range point migration (RRPM) and the conventional Kirchhoff migration. The experimental validation is carried out with a pair of two tapered slot line Vivaldi antennas both integrated in a conical shaped teflon rod and an M-sequence Radar device with 100% fractional bandwidth at a carrier of 9 GHz.