L-to-Ka-band AlGaN/GaN HEMT power amplifiers with high efficiency

This paper describes highly-efficient GaN/AlGaN HEMT and MMIC power amplifiers for RF-frequencies between 0.5 GHz and 30 GHz fabricated on three-inch s.i. SiC substrates. Three GaN HEMT technologies introduced are based on 500 nm, 250 nm, and 150 nm gate technology, respectively. The mobile communication power GaN HEMT process yields an average power density of 10 W/mm at 2 GHz for small devices and V(ind DS)=50 V. The average PAE is 61%. Packaged powerbars yield the same PAE of 61% and 18 dB of gain with 45 W of output power at 2 GHz when operated in cw at V(ind DS)=50 V. This process yields an extrapolated lifetime of >=2x10(exp 5) h at V(ind DS)=50 V at a channel temperature of 90 °C. Optimized GaN HEMTs based on 0.25 µm gate-technology yield PAE of >37% when operated in the Ku-band at 16 GHz with >= 3 W/mm of output power density. Efficient operation is also proven for the Ka-band (26-40 GHz). At 27 GHz optimized power cells yield a PAE of 28% with an associated power density of more than 2 W/mm