Calibration of a MIMO Radar for 3-D Near-Field Scattering Imagery

Multiple input multiple output (MIMO) radars are getting more and more applications for near-field scattering imagery. However, high sidelobes and radar cross section (RCS) calibration uncertainty are the major challenges for such measurement requirements due to array nonuniformity, imperfect channels, and antenna pattern tapering. These shortcomings prevent a MIMO radar from obtaining high quality images with enough dynamic range and RCS accuracy. In this paper, an extended adaptive weighting (EAW) is proposed, where the complex weights are optimized for exact amplitude and phase error calibration of a 3-D Near-Field MIMO imaging radar to reduce sidelobes. Outdoor experiments are conducted using a near- field MIMO imaging radar over 14GHz-16 GHz frequency band. It is shown that after calibration, the high-quality images are obtained, validating the proposed technique for a 3-D nearfield MIMO radar imaging of complex targets.