A K-Band GaAs FET Amplifier with 8.2-W Output Power

An 8.2-W GaAs FET amplifier with 38.6+-0.5-dB gain over a 17.7-19.1 GHz frequency band has been developed. This amplifier combines the outputs of eight multistage amplifier modules utilizing a radial combiner. This state-of-the-art power level has been achieved with AM/PM of less than 2°/dB. The third-order intermodulation products at 1-dB gain compression were 20 dBc, and variation in group delay over the frequency band was less than +-0.25 ns. Tests show that the amplifier is unconditionally stable and follows the graceful degradation principle.