Reflector-Assisted Millimeter-Wave Over-the-Air Handset Antenna Test Method in Multiprobe Anechoic Chamber

This article proposes a reflector-assisted over-the-air (OTA) test method of handset antennas at millimeter-wave (mmWave) frequencies in a multiprobe anechoic chamber, aiming to reduce the number of active probes required for spatial field emulation at a test zone for evaluating fifth-generation (5G) mmWave handset antennas. The emulated field, represented by the power angular profile (PAP) observed from reference antennas, corresponds to a selected wireless channel, derived from either a standard channel model or a measured snapshot. The proposed method defines the reflector geometry and probe placement analytically based on the PAPs, suggesting that spatial fields coming from multipath signals can be emulated using reflectors instead of active probe antennas. The proposed method was validated through full-wave simulations and experiments in an anechoic chamber where universal software radio peripherals (USRPs) were used for probe signal weighting and real-time calibration of transceiver chains. The emulated PAPs of typical outdoor and indoor channels closely match the target PAPs at 28 GHz according to the PAP similarity percentages (PSPs) and root mean square error even when some probes are replaced by a metallic cylinder, thereby demonstrating the possibility of reducing complexity of the test setup.