A Cascaded Multi-Drive Stacked-SOI Distributed Power Amplifier With 23.5 dBm Peak Output Power and Over 4.5-THz GBW

This article presents a cascaded distributed power amplifier (DPA) topology with greater than 4.5-THz gain-bandwidth (GBW) product. The DPA uses stacking with multi-drive inter-stack coupling to compensate for the stacked gain cells and input transmission-line (TL) losses. The techniques improve the gain and output power without compromising the bandwidth (BW). The cascaded DPA employs eight-shaped TLs to allow inter-stack coupling in a compact area and for field confinement. A 33-dB gain, 101.5 GHz BW DPA is realized in the 45-nm RFSOI GlobalFoundries process. The amplifier maintains P_1dB and P_SAT > 18.7 and 21 dBm, respectively, up to 60 GHz, with over 60 GHz P_SAT 3-dB BW, while demonstrating >14 dBm of average P_OUT for a 30-Gb/s 64-QAM modulated signal, with an error vector magnitude (EVM) <; 5%. The DPA is also able to provide a 72-Gb/s 64-QAM signal with 13.6 dBm average P_OUT from a 13 GHz carrier frequency. To the best of our knowledge, the cascaded multi-drive DPA achieves the highest reported GBW, continuous-wave (CW) P_SAT, and average P_OUT for 64-QAM 30-Gb/s modulated signal, in a compact core area compared to published silicon-based DPAs with comparable power levels.