Ka-Band GaAs Power FETs

Ka-band results using submicrometer gate length, air-bridged, soldered flip-chip GaAs power FETs in finline, ridge-waveguide circuits are reported. Conventional photolithography was used to fabricate FETs with submicrometer gate lengths by using the undercut associated with chemical etching. At 35 GHz an output power of 91 mW at 3 dB gain and 4.5% efficiency was measured.