CMOS Power-Amplifier Design Perspectives for 6G Wireless Communications

The power amplifier (PA) for future 6G sub-THz wireless transmitters needs to offer wide bandwidth, high output power and reliable stability. This article, for the first time, studies the notion of wideband operation in sub-THz PAs incorporating neutralization techniques. Quantitative analyses are conducted to better understand the trade-offs among Gmax, stability Kf, and the bandwidth for a widely adopted differential pair under (over) neutralization. Next, a comparative study for transmission-line (T-line)-based and transformer-based matching networks is undertaken to give insights to the design of inter-stage matching networks. It is shown that transformer-based matching networks essentially introduce multi-stagger tuning, thereby leading to higher operation bandwidth suitable for 6G applications.