Calibration of a Digital Phased Array by Using NCO Phase Increasing Algorithm

Lijie YANG  Ruirui DANG  Chunyi SONG  Zhiwei XU  

IEICE TRANSACTIONS on Communications   Vol.E102-B   No.4   pp.948-955
Publication Date: 2019/04/01
Online ISSN: 1745-1345
DOI: 10.1587/transcom.2018EBP3120
Type of Manuscript: PAPER
Category: Sensing
amplitude-phase error,  internal calibration,  digital phased array,  radiation pattern,  

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All digital phased arrays generate multiple beams concurrently through the digital beam forming technique, which features digital processing with multiple identical receiving/transmitting channels in RF or microwave frequencies. However, the performance of this process strongly depends on accurately matching the amplitude and phase of the channels, as mismatching is likely to degrade radar performance. In this paper, we present a method to calibrate receiving array by using NCO phase increasing algorithm, which simplifies array system by removing the external far-field calibration signals often needed in array systems. Both analysis and simulation results suggest that the proposed method attains better calibration performance than existing approaches, even with a low SNR input signal. Experiments also varify that the proposed calibration method is effective and achieves a desired radiation pattern. We can further boost calibration accuracy and reduce calibration time by programming NCO phase width and NCO phase resolution.