1W/mm GaAs pHEMT for realization of linear power amplifier in the K band.

The realization and characterization of Al0.22Ga0.78As/In0.22Ga0.78As/GaAs power pHEMT are reported. This structure was optimized to obtain a quasi flat transconductance profile to increase the device linearity near the compression. A maximum single carrier output power higher than 0.8 W/mm for 2 dB compression has been obtained, with more than 30 % power added efficiency and 7.4 dB linear gain at 18.5 GHz. Two tones intermodulation distortion have shown a C/I ratio of 19.9 dBc and 42.3 dBc to the 3 rd and 5 th order respectively, for an input two tones power corresponding to 1 dB compression input power in CW.