We describe the first, to our knowledge, 60-GHz channel sounder with phased-array antennas found in literature. The system features a 1-GHz bandwidth and measures the angle-of-departure / angle-of-arrival of channel multipath components by sweeping the antenna space of the transmitter / receiver through 5.6° steerable beams electronically synthesized by the arrays; the associated 26.1 dBi gain of the beams enables sounding to hundreds of meters. Both ends integrate multiple arrays to extend the ±45° field-of-view of the individual arrays to an omnidirectional view; the additional advantage of integrating multiple arrays is to speed up the channel sweep time to just 262 μs, corresponding to a maximum closing velocity of 33 km/h for vehicle-to-vehicle scenarios. The receiver is mounted on an untethered mobile robot equipped with a navigational system for rapid, autonomous data collection. Over-the-air (OTA) methods to characterize the array beams patterns, calibrate the system impulse response, and compensate for clock drift are applied such that properties of the multipath components can be estimated with high fidelity through super-resolution techniques. To substantiate the latter, we compare estimated properties against ground-truth values from extensive field measurements. The average estimation angle error was reported as 1.5° with a standard deviation of 0.85°.
IEEE Transactions on Microwave Theory and Techniques
double-directional, over-the-air calibration, 60 GHz, super-resolution