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

In this letter, we report record power added efficiency (PAE) on a vector load–pull system at 220 GHz of 31.3%$\pm ~0.8\%$for an indium phosphide (InP) heterojunction bipolar transistor (HBT) and 26.9%$\pm ~1.4\%$for an InP high-electron mobility transistor (HEMT) with minimal measurement error. We first minimize measurement error by using on-chip shielded multiline thru-reflect-line (mTRL) standards to eliminate unwanted modes of propagation and by using WR4.3 probes that have minimal crosstalk coupling. We then demonstrate crosstalk mitigation by calibrating the load–pull data using a conventional eight-term mTRL and a 16-term crosstalk methods, resulting only in a 0.4% error in peak PAE. We quantify the remaining measurement errors due to absolute power and waveguide calibration repeatability as well as the on-wafer errors in the probe placement and error in the$50~\Omega $reference system. A ±0.1% uncertainty in peak PAE was obtained from repeated waveguide and power calibrations. The on-wafer measurement error resulted in a peak PAE uncertainty of ±0.8% and ±1.4% for the HBT and HEMT devices, respectively.