High power AlGaAs/GaAs HBTs for Ka-band operation

AlGaAs/GaAs power HBTs have been developed for operation in the 26 GHz band. The HBTs were designed for improved thermal stability and power gain. A common-base HBT with a 480-/spl mu/m/sup 2/ emitter area achieved a 0.65 W CW output power with 34% collector efficiency, 16% power-added efficiency, and 6 dB linear power gain at 26.85 GHz. A 960-/spl mu/m/sup 2/ CB HBT produced an output power of 0.8 W with 5.6 dB linear power gain at 26.2 GHz.