Enhancing Antenna in Package Array Calibration: A Hybrid Multi-Axis Scanner Enabling Near-Field and Far-Field Measurements for Over-the-Air Calibration

This paper introduces an innovative testing system designed for the characterization and calibration of W-band active phased array antennas utilizing antenna-in-package (AiP) technology. The proposed system is a multi-axis scanner with nine degrees of freedom, used to perform near-field and far-field measurements with same setup. The multi-axis system allows precise positioning of the antenna and the probe, allowing accurate measurements of the antenna radiation patterns in both near-field (NF) and far-field (FF) regions. Experimental results show that the proposed hybrid multi-axis scanner significantly improves the calibration accuracy of the antennas on-chip at 77 GHz compared to traditional far-field systems. Using the hybrid scanned (near-field and far-field) provides a versatile and effective test procedure to even characterize additional electromagnetic artifacts that may be present during the test. The proposed system enables accurate calibration and measurements by providing precise control over the positioning of the antenna and probe, while minimizing the effects of interference from the surrounding environment. Excellent agreement between the antenna array pattern measured in the near-field and far-field is achieved post-calibration. Moreover, the suggested system supports both automated and manual calibration, rendering it versatile and adaptable across various applications.