A CW 20W Ka-band GaN high power MMIC amplifier with a gate pitch designed by using one-finger large signal models

This paper reports a 20 W Ka-band GaN high power MMIC (Monolithic Microwave Integrated Circuit) amplifier under continuous wave (CW) operation. The one-finger large signal models were made to take account of both the phase difference of RF gate voltage at a gate feeder and thermal effect. By using this model, the gate pitch length of unit cell transistor was optimally designed to obtain maximum output power as MMIC amplifier under CW operation. As a result, 21.7W output power under CW operation was successfully achieved with power added efficiency (PAE) of 19.8% at Ka-band by a single-ended MMIC. To the best of authors' knowledge, this output power is state-of-the-art for GaN MMIC amplifiers under CW operation at Ka-band.