Heuristic Over-the-Air Calibration of Beamformer ICs in Active mm-Wave Phased Arrays

A heuristic calibration-before-operation method based on near-field-measurements of integrated circuit (IC) responses is proposed and tested for an active 64-element 5G millimeter-wave (24–28 GHz) phased array. The IC phase shifter and variable gain settings are digitally tuned to minimize the relative differences in complex transmission coefficients on broadside at each element. It is shown that, by means of calibration, it is possible to increase the array gain, decrease the peak side lobe level and remove the beam pointing errors.