G-Band Load-Pull Characterization of High-Efficiency Emitter-Fin InP/GaAsSb DHBTs

We report the small- and large-signal results of 250 nm InP/GaAsSb Double Heterojunction Bipolar Transistors (DHBTs) in G-band. We characterized the frequency behavior of the saturated output power P
OUT,SAT
and of power-added efficiency (PAE) in class-A operation. At 140 GHz, we find P
OUT,SAT
= 11.1 dBm with a simultaneous record PAE = 39.2%. Together with the smallsignal cutoff frequencies f
T
/f
MAX
> 0.48/1.1 THz, these data demonstrate the suitability of InP/GaAsSb DHBTs for highpower and high-efficiency sub-mm power amplifiers (PA).