71–95 GHz (23–40% PAE) and 96–120 GHz (19–22% PAE) high efficiency 100–130 mW power amplifiers in InP HBT

Abstract

Two solid-state power amplifiers with record high power added efficiency (PAE) and 100–130 mW output power in 250 nm InP HBT are reported. The 71–95 GHz PA demonstrates 20.7 dB S21 and 25 GHz 3-dB bandwidth at 432.5 mW PDC. Pout is 105–138 mW (21–36% PAE) and RF power density is 1.64–2.15 W/mm. At 81 GHz, 135.6 mW Pout is achieved with 36.0% PAE and 14.1 dB gain. At 81 GHz with reduced input-stage bias, 129.6 mW Pout is achieved with 40.0% PAE and 13.0 dB gain. The 96– 120 GHz PA demonstrates 17.8 dB S21 and 26 GHz 3-dB bandwidth at 442.4 mW PDC. Pout is 84.9–107 mW and RF power density is 1.33–1.64 W/mm. At 102.5 GHz, 98.1 mW Pout is achieved with 21.2% PAE and 12.1 dB gain. The results were obtained class-A DC biasing the PA's. The amplifiers utilizes a novel, compact, and stackable power cell topology for multi-finger HBTs operating at mm-wave and THz frequencies, where 8-way PA cell combining can be realized for future 0.6–0.8 W Pout designs - these designs are currently under development. This work represents record PAE for 100 mW PA's at these frequencies. 40% PAE at E-band (81 GHz) is demonstrated for the first time under class-A bias, as well as PAE greater than 23% across the 71–76, 81–86, and 92–95 GHz bands. The 18.9–22.5% PAE at 100 mW power for the 96–120 GHz PA is a 1.5–3× improvement to state-of-the-art PAE at these frequencies.