High efficiency and high linearity 70 nm GaN technology for future SatCom applications

In this work, we report on the development of a high efficiency and high linearity 70 nm GaN power amplifier technology. DC-characteristics reveal a gm,max ≈ 500 mS/mm and low DC to pulsed-IV current collapse (< 15 %). Small signal characteristics exhibit a cutoff frequency of fT = 122/95 GHz at VDS = 7/15 V as well as an fMAX > 350 GHz. Large-signal characteristics give a PAE (MAX) = 58.6 % and maximum output power POUT (MAX) = 2.46 W/mm at 38 GHz. Signal linearity was assessed by two-tone load-pull measurements which gave an PAE = 54.4 % and POUT = 1.01 W/mm under back-off conditions (IMD3 < 30 dBc) in line with SatCom requirements. Efficiency under back-off conditions is among the highest reported values in any GaN-technology on a transistor level so far, which demonstrates the potential use in future applications.