Closed-Loop Iterative Self-Calibration of Initial Phase in Phased Arrays

This paper proposes a closed-loop iterative automatic initial phase calibration scheme. Under the condition that the direction of the calibration source and the signal frequency are known, the complex readback data of all array elements are obtained. The theoretical phase of each array element is calculated in advance and removed. Then, conjugate multiplication with a reference element is performed to eliminate the common phase error and construct the relative phase residual. Finally, the relative phase residual is fed back to the phase compensation table and iteratively updated, thereby achieving rapid automatic calibration of the phased array. The simulation results show that, for a 256-element array, the digital computation time of the proposed method is approximately 1.6 ms, excluding signal acquisition and readback time, and the phase compensation table can converge rapidly. Based on the simulated results and normalized comparison of the array factors before and after calibration, the peak response in the target main-lobe direction is improved by approximately 14.69 dB, while the highest side-lobe level relative to the main lobe is further reduced by approximately 12.72 dB. These results demonstrate that the proposed algorithm can effectively improve beam focusing performance and side-lobe suppression, providing a new implementation scheme for initial phase calibration of large-scale phased arrays.