Design, fabrication, and characterization of monolithic microwave GaAs power FET amplifiers

The design, fabrication, and characterization of three- and four-stage monolithic GaAs power FET amplifiers are described. Each of the amplifier chips measures 1 mm × 4 mm. Procedures for characterizing these monolithic amplifiers are outlined. Output powers of up to 1 W with 27-dB gain were achieved with a four-stage design near 9 GHz. The circuit topologies used were flexible enough to allow external bondwires to be used as shunt inductors for amplifier operation at C- or S-bands. An output power of 2 W with 28-dB gain and 36.6-percent power-added efficiency was achieved at 3.5 GHz, using a modified four-stage amplifier.