Virtual Cable Calibration For Ota Testing Of 5g Mmwave Devices

5G New Radio (NR) is the first standard to use the mmWave frequency region for highest data transfer rates. The highly integrated front-ends and array antennas necessitate advanced over-the-air (OTA) testing methods and new RF test metrics for assessing current and future mobile communication. Such test metrics include virtual cable calibration (VCC), which is mandatory for reproducible and reliable OTA throughput testing. For performance tests where fading is emulated such as radio resource management (RRM) conformance and demodulation testing the VCC method is crucial to assess defined antenna correlations with minimal crosstalk from the OTA link. The measurement results presented in this article demonstrate the proposed concepts for VCC can be applied to ensure device compliance to the 3GPP standard.