Post-Manufacturing Calibration Procedure for Medium-Sized Silicon-Based Active Phased Arrays for mm-Wave Wireless Communications

The next generation radio access networks (5G) will make use of active phased array antennas to enable beamforming. Calibration of the array is an essential step to maximize its performance. The calibration procedure of an active phased array can be divided into two different phases: post-manufacturing calibration and online calibration. In this paper, a post-manufacturing calibration procedure using over-the-air measurements is presented. This procedure is applied to an 8x8 active phased array containing low-cost silicon-based ICs. It is shown that with this procedure, it is possible to steer the main lobe of the array as far as ±40°, while maintaining a side lobe level of around -20 dB. The measurements were performed at a frequency of 29.5 GHz.