Sub-THz MIMO Hybrid Beamforming: D-Band Dual-Channel Analog Beamforming Front-Ends Prototyping

This paper presents the design and implementation of novel dual-channel (MIMO hybrid) beamforming wireless front-ends operating in the D-band (sub-THz range), optimized within the 150 to 170 GHz frequency spectrum. The development incorporates analog beamforming networks realized through two 16×16 microstrip Rotman microwave lenses and dual sets of 1-to-16 RF MMIC switches, in conjunction with a 16×2 antenna array comprised of low-profile on-silicon patch antenna elements and a PTFE elliptically extruded dielectric lens. The resulting architecture produces 32 distinct RF beams bifurcated into two sets of 16 beams, each oriented at two elevation angles. Each set is characterized by beams spaced 4 degrees apart in azimuth, collectively resulting in a 64-degree azimuthal scanning capability. Furthermore, the transmit front end is outfitted with 32 parallelized power amplifiers distributed across 8 InGaAs MMIC chips, equipping it to yield approximately 50 dBm effective isotropic radiated power (EIRP). In parallel, the receive front end comprises 32 low-noise amplifiers (LNAs) similarly arrayed across 8 InGaAs MMIC chips, each delivering an active gain exceeding 30 dB, which augments the overall passive antenna array gain of 25 dBi.