D-Band Adaptive Beamforming for 6G Sub-THz Communications: Feasibility and Experimental Results

This study investigates the application of adaptive beamforming techniques within D-band sub-terahertz (sub-THz) communi cation systems tailored for 6G applications. We present a hardware-in-the-loop transmission system utilizing newly developed prototypes of transmit and receive front ends operating in the frequency range from 150 to 170 GHz. The front ends’ analog beamforming architecture enables the generation of eight distinct beams with 6°separation in azimuth, thus creating a field of view with 48°one dimensional angular scanning range on either side of the link. The system implements dynamic beamforming based on the 5G New Radio (NR) waveform’s design principles for the initial access/beam acquisition procedure. Experimental performance assessments conducted in an indoor environment prove the system’s potential to support mobility and mitigate the effects of signal blockage. Specifically, when encountering a lineof-sight link blockage event, the system successfully transi tioned to a reflected propagation path, incurring approximately 4 dB of loss. Additionally, a mobile receiver could be tracked while maintaining a 1 dB variation in the wireless link budget. These results demonstrate the feasibility of D-band adaptive beamforming.