Near Field Phase Correction for Cascaded Radar

The cascaded radar imaging system consists of four 79GHz Radar chips, each has 3Tx and 4Rx. Sparse Uniform Linear Array (ULA) configurations of 16 microstrip patch antennas are arranged in azimuth and 4 element of Minimum Redundancy Array (MRA) is considered for elevation. A sparse 86-by-7 Uniform Planar Array (UPA) for measuring three-dimensional (3D) high angular resolution is achieved by using Multiple-In Multiple-Out (MIMO). Calibration and near field applications become very challenge topics for these kinds of radar system with very large aperture. This paper presents an algorithm of near field phase correction for cascaded radar imaging. The phase errors among MIMO virtual channels are modeled and compensated. Near field radar imaging is generated by beamforming approach, where the results are compared with and without using the optimized phase correction algorithm. The complexity and performance of the proposed near field correction algorithm are analyzed and evaluated by simulated data and real scene test.