A KU-BAND T-SHAPED GATE GAAS POWER MESFET WITH HIGH BREAKDOWN VOLTAGEFOR SATELLITE-COMMUNICATIONS

GaAs power MESFET's with 0.5-mu m T-shaped gate for Ku-band power appl ications have been developed using a new self-aligned and optical lith ography, It displays a maximum current density of 350 mA/mm, an unifor m transconductance of 150 mS/mm and a high gate-to-drain breakdown vol tage of 35 V. Both the high breakdown voltage and the uniform transcon ductance were achieved by the new MESFET design incorporating an undop ed GaAs cap and a thick lightly doped active layers. The breakdown vol tage is the highest one among the values reported on the power devices . The device exhibits 0.61 W/mm power density and 47% power added effi ciency with 9.0 dB associated gain at a drain bias of 12 V and an oper ation frequency of 12 GHz.