Real-Time 141 GHz JCAS Channel Sounder: Near-Field Switched Beamforming, Carrier Multiplexing, and Context Awareness

We have developed a real-time 141 GHz joint communications and sensing (JCAS) channel sounder, with focus on this article on 3-D near-field imaging (less than 50 cm range) for applications such as finger recognition. To achieve this, we integrated phased-array antennas into the channel sounder—to the best of our knowledge, we are the first to do so in the D-band—and adapted the switched beamforming technique we developed previously, to realize real-time near-field beamforming. We also propose another novel technique, coined carrier multiplexing, to extend the instantaneous bandwidth of the phased arrays to their full radio frequency (RF) passband—by a factor of two for our current arrays and by a factor of ten for our next edition. Finally, we integrated camera and Lidar systems that are temporally and spatially synchronized with the channel sounder to generate real-time digital twins of the target while sounding, enabling machine learning on multimodal data. We showcase system performance with controlled experiments on metal cylinders, demonstrating imaging resolution on the order of a centimeter.