The Impact of Link-Delay Difference on RTS MIMO OTA Measurement

Multiple input and multiple-output (MIMO) has been one of the essential techniques for the long-term evaluation (L TE) wireless terminals and the fifth generation (5G) wireless systems. MIMO over the air (OTA) measurement for the receiver sensitivity evaluation plays a significate role in research and development for wireless equipment. To perform MIMO measurement, the radiated two-stage (RTS) is developed for both 2D and 3D throughput tests with high accuracy and low cost. In OT A measurement, the engineers try their best to reduce the measurement uncertainties, as well as improve the measurement reliability and repeatability. Hence, the uncertainty caused by the link-delay difference, which has been ignored in the OT A test, is analyzed herein. In this paper, the relationship between the link-delay difference and the isolation of MIMO antennas is investigated and qualified. The proposed suggestions could reduce the uncertainty of MIMO throughput measurement when designing a MIMO anechoic chamber.