Sub-THz D-Band Integrated Analog Beamforming Front-End Prototyping and 6G Outdoor Trials

This paper reports the development outcomes of the world's first integrated analog beamforming - transmit and receive - wireless front-ends operating in the D-band (a sub-THz band), particularly designed to operate within 150 GHz to 170 GHz frequency range. Front-end hardware development includes monolithic microwave integrated circuit (MMIC) chips of the multichannel power amplifier, multichannel low-noise amplifier, and RF switches. Moreover, the development includes an analog beamforming RF network and a low-profile microstrip 1-by-8 uniform linear antenna array, which were both developed on a resistive silicon substrate. The paper also features a successful long-range (320-meter) line-of-sight unidirectional point-to-point wireless transmission experiment, utilizing a 5G-NR orthogonal frequency division multiplexing (OFDM) waveform over a 160-GHz carrier frequency. The experiment demonstrated a successful transmission of OFDM waveforms using up to a 16-QAM (quadrature amplitude modulation) scheme in the D-band.