Experimental Comparison of On–Off and All-On Calibration Modes for Beam-Steering Performance of mmWave Phased Array Antenna-in-Package

Antenna-in-package (AiP) technology has been implemented for millimeter-wave (mmWave) phased array design with antenna elements and radio frequency (RF) chips integrated. The radiation pattern beam of mmWave phased array AiP is typically steered after the in-homogeneous RF branches are aligned (i.e., AiP calibration). The RF branch discrepancies among elements are directly obtained with one element enabled sequentially each time (i.e., on-off mode) by default in the industry. A recent study has reported that the AiP element branch discrepancies obtained in the on-off mode might be different from those obtained in the normal all-on working mode with all elements active. However, experimental results that demonstrate the impact of the difference between the two calibration modes on the beam-steering performance of mmWave phased array AiP have been rarely reported in the literature. In this article, the beam-steering performance of two mmWave AiPs after the two calibration modes is experimentally compared, which is demonstrated by the beam-steering pattern defined in this article. Following the statement on the source of difference between the two calibration modes of AiP, the system model is described for the calibration and beam-steering measurements of AiP in the experimental campaign. Experimental results show that the on-off calibration mode obtains the same beam-steering performance as the all-on mode for the main beam pattern, though element branch discrepancies obtained in the two modes are different.