InP/GaAsSb DHBT Power Performance with 30% Class-A PAE at 94 GHz

The present work characterizes the 94 GHz class-A large-signal load-pull performance of mm-wave InP/GaAsSb double heterojunction bipolar transistors (DHBTs) with different emitter lengths LE. When matched for maximum power, a 10.3 dBm (1.09 mW/μm) output is realized in a 10 μm transistor with a 24.5 % power-added efficiency (PAE). When matched for maximum PAE, a 30% Class-A PAE is achieved in a 7.5 μm long device, with the simultaneous output power and power gain of 9.0 dBm and 5.9 dB. The load-pull contours exhibit a combination of good output power and high PAE for a wide range of load impedances in the vicinity of 50 Ohm. This makes InP/GaAsSb DHBTs very good candidates for power amplification well into the mm-wave range of frequencies.