An automatized time-domain set-up for on-wafer charaterization, doherty oriented, of high power GaN HEMTS

This paper presents an automatized on-wafer time-domain active load-pull set-up specifically developed for the characterization of High Power GaN High-Electron Mobility Transistors (HEMTs). This set-up is associated to a specific methodology for the design of Doherty Power Amplifier (DPA). This methodology has been applied to a GaN technology transistor: from the on-wafer measured Time-Domain Waveforms (TDW) acquisition, all data required for the design of a Doherty power amplifier are directly extracted. Designers have the direct knowledge of the optimal characteristics of high power transistors along the output back-off (OBO) at fundamental frequency and also the maximum obtainable operating bandwidth of the final desired Doherty PA.