Mid-field OTA RF test method: new developments and performance comparison with the compact antenna test range (CATR)

In this paper, new mid-field developments, including the gray box approach and a mid-field prototype system covering both frequency range one and two, are presented to address challenges in 5G massive MIMO (mMIMO) base station (BS) OTA RF test. Simulations and measurements prove the effectiveness of the new developments. Further analysis of 3GPP BS OTA RF measurement metrics and performance requirements indicate that the mid-field system can measure most of those required metrics with enough dynamic range. Comparative test results with a CATR system using a commercial 5G BS prove that the mid-field system can achieve comparable test results as the CATR system. The comparability with the CATR system, the broad overage of 3GPP measurement metrics, and the compact size show that the mid-field system is an effective system for 5G mMIMO BS OTA RF test in both frequency range one and two.