Elimination of Non-Idealities for Multi-Channel Phased Array Systems with Zero-IF Receiver

In radar systems, the widespread adoption of phased arrays has highlighted challenges such as increased power consumption and costs, particularly when employing zero-IF architectures. These architectures, despite their high integration and simplified design, suffer from inherent non-idealities like DC offset and I/Q mismatch, which degrade signal quality. In multi-channel phased array systems, inter-channel deviations further exacerbate these issues. To address these challenges, we propose a comprehensive dynamic calibration scheme. This scheme incorporates recursive averaging algorithms for DC offset calibration and blind estimation algorithms for I/Q mismatch calibration. Additionally, we utilize cross-correlation functions combined with independent component analysis (ICA) to correct inter-channel mismatches. Furthermore, the digital beamforming (DBF) algorithm is implemented to steer the beam in the desired direction while suppressing unwanted signals, thereby enhancing system performance in high-noise environments and for multi-frequency signals. Simulation results show a significant improvement, with Error Vector Magnitude (EVM) and Image Rejection Ratio (IRR) improving by 17 dB and 70 dB, respectively. A hardware platform has been developed to validate the effectiveness of the proposed calibration techniques in practical scenarios, confirming the accuracy and robustness of baseband data transmission. This calibration approach not only addresses critical non-idealities in multi-channel zero-IF receivers but also significantly enhances the reliability and efficiency of phased array radar systems, paving the way for advancements in radar technology and its applications.