Accurate Load-pull on InP HBT and InP HEMT Devices, Achieving Above 30% PAE at 220 GHz

In this paper we report record power added efficiency (PAE) on a vector load-pull system at 220 GHz, with minimal measurement error, of 31.3±0.8% for an Indium Phosphide (InP) Heterojunction Bipolar Transistor (HBT) and 26.9±1.4% for an InP High-Electron Mobility Transistor (HEMT). We minimize measurement error by using on-chip shielded multi-line thru-reflect-line (mTRL) standards to eliminate unwanted modes of propagation and with WR4.3 probes that have minimal crosstalk coupling. We demonstrate crosstalk mitigation by calibrating the load-pull data using a conventional 8-term mTRL and 16-term crosstalk mTRL, resulting in a 0.4% error in peak PAE. We quantify the measurement errors due to power and waveguide calibration repeatability, probe placement, and 50 Ω reference system error. A ±0.1% spread in peak PAE was obtained with repeat power and waveguide calibrations. The on-wafer measurement error resulted in a peak PAE spread of ±0.8% and ±1.4% for the HBT and HEMT devices, respectively.