A compact millimeter wave (mmWave) mid-field over the air (OTA) RF performance test system for 5G massive MIMO devices

A 5G mmWave Massive MIMO device needs to perform the phase coherency calibration and RF parametric measurement over the air (OTA). The device size and the array size make it very challenging to do RF parametric measurement in the true far field OTA environment from the space, link budget and cost aspects. To meet the requirement on very compact size, a mmWave mid-field OTA RF performance test system is designed in this paper. This system can do the phase coherency calibration and support the RF parametric measurements per the 3GPP requirements. An overview of the system design challenges and measurement approaches is provided together with the experiment validation of the functionalities of the system to prove the effectiveness of the system for 5G massive MIMO device OTA RF calibration and parametric measurement.