GaAs MESFET performance

Abstract

The operating frequency of RCA's power GaAs MESFET amplifiers has been extended to 18 GHz. We have achieved 225 mW CW output power with 4.5 dB gain at 18 GHz from a 1200 µm source periphery device. At 15 GHz the same device yielded 451 mW output power with 5.2 dB gain with a power added efficiency of 12.5%. Under class B operating conditions we have achieved power added efficiencies as high as 68% at 4 GHz with a power output of 261 mW and a gain of 9.6 dB. The drain efficiency at this point was 77%. At 8 GHz, the highest power added efficiency achieved was 41.5% with 302 mW output power and 6.9 dB gain. A theoretical model has been formulated for the MESFET class B amplifiers. The calculated results are in good agreement with experimental data.