Multi-Tone Amplitude-Phase Calibration for Active Phased Array Antennas in a Compact Multi-Probe OTA Chamber

A multi-tone measurement method for active phased array antennas (PAAs) operating in sub-6 GHz is proposed in a cost-effective, compact multi-probe over-the-air (OTA) chamber. Using our method, amplitude-phase calibration for a 128-channel active antenna unit (AAU) with wide-angle scanning can be carried out in the mentioned anechoic chamber with dimensions of $2\times 2\times 2$ m. The key principle is to calibrate amplitude-phase variations of each antenna port of an AAU so as to improve the beamforming capability in fifth-generation (5G) systems.