Highly-Linear InP/GaAsSb DHBTs with 18.2 dBm OIP3 at 45 GHz: Comparison of Common-Base and Common-Emitter Structures

Abstract— Linear power amplifiers (PAs) are critical in high-capacity modern telecom systems. We characterize the linearity of common-emitter (CE) and common-base (CB) mm-wave InP/GaAsSb double heterojunction bipolar transistors (DHBTs) at 18/45 GHz. When matched for maximum linearity, 3
^rd
order intercepts (OIP3) of 23.4 and 18.2 dBm are found in single-finger (0.3 × 10) μm
²
CE-DHBTs at 18 and 45 GHz. For CB-DHBTs, the OIP3 is 21.1 and 5 dBm at 18 and 45 GHz. Small-signal load-pull linearity and large-signal power contours of CE-DHBTs show overlapping regions of high output power and linearity near 50 Ω, making them devices well-suited to the development of highly linear power amplifiers (PAs). The effect of device bias on linearity is also examined. The ACLR performance of CE devices meets 5G NR requirements. At 94 GHz, CE and CB devices deliver P
SAT
= 11.3 and 10.6 dBm, respectively with PAEs of 28.5 and 23.2 %.