A mm-Wave Hybrid Stirring Technique for Over-the-Air Testing in Reverberation Chambers

Over-the-Air methodologies are the potential solutions for the characterization of next-generation wireless devices that rely on the emulation of a realistic channel model in a controlled laboratory environment. A highly attractive concept is the hybrid chamber, combining properties of anechoic chambers and reverberation chambers. By altering the mechanical stirrers of a mm-Wave reverberation chamber, a novel loading condition to achieve a directive channel for 5G NR FR2 applications is proposed: a hybrid stirrer. This is done by partly covering the stirrers with radio-frequency absorbers, as a first step towards a hybrid chamber. In future generations, this may be used to intentionally break uniformity in a controlled manner. Moreover, a more conventional loading configuration is investigated as a counterpart. A spatial uniformity study based on the chamber's power transfer function measurements is carried out for two case scenarios. It has been shown that the proposed configurations are capable of altering spatial uniformity, giving 0.52 dB and 1.46 dB for the conventional and hybrid stirrer method, respectively. Both result in a frequency-flat channel with the required coherence bandwidth for the successful demodulation of the signals.