Smf-dbf: subband match filtering and digital beamforming for mimo-sar echo separation to reduce the system complexity

To address the echo separation issue involved in multiple-input multiple-output (MIMO) synthetic aperture radar (SAR), the elevation beamforming solution has become increasingly popular and been widely investigated. However, the current elevation digital beamforming (DBF) schemes usually require high hardware complexity, which is not allowed for practical MIMO-SAR systems. To alleviate this problem and achieve a low-cost MIMO-SAR system, we here detail an improved two-stage echo separation scheme, i.e., subband match filtering and DBF (SMF-DBF). First, the subband match filtering enables the number of interference components to be halved. Afterwards, the remained interferences from far arrival angles will be suppressed by DBF techniques. The two-stage processing can considerably simplify the array configuration and reduce the system complexity. Numerical simulations have demonstrated the feasibility and potential of the proposed method for channel-limited MIMO-SAR systems.