Computer aided design for an Ku-band GaAs MMIC power amplifier

A two-stage monolithic microwave integrated circuit (MMIC) power amplifier for phased-array applications and fabricated on gallium arsenide is described. The device technology used is 0.25 um pHEMT having an f_t=50 GHz and power density of 300 mW/mm, and a substrate thickness of 100 um. This design consists of two single ended stages having a 400 um gate width output FET and a gate bias network. The amplifier measured output power at P_1dB is about 50 mW at 14.5 GHz with a corresponding power-added efficiency of 29%. The peak output power of about 107 mW at 14.5 GHz with a corresponding peak power-added efficiency of 39% is also achieved. The measured and predicted small signal gain is between 15-17 dB over process. Several analysis techniques were used to insure that the required performance for this circuit was achieved using a single design iteration. The circuit area requires less than one sq. mm through use of extensive EM modelling of passive structures