High efficiency ultra broadband GaN amplifier using series-shunt inductor matching network

This paper reports on a Gallium Nitride High Electron Mobility Transistor (GaN HEMT) Monolithic Microwave Integrated Circuit (MMIC) high power amplifier (HPA), which features high efficiency and high power over C-Ku band with 115 % relative bandwidth. The amplifier uses a series-shunt inductor matching network to reduce chip size and the impedance transformation ratio in the interstage matching. The fabricated MMIC chip dimensions are 4.15 mm by 4 mm. Measured small signal gain exceeds 15.4 dB and the output power reaches 40.2 ~ 41.6 dBm with PAE of 17.3 ~ 30.5% over the C-Ku band at 25 V power supply voltage. With a CW output power ripple of 1.4 dB, this work shows significant improvement compared to previous work. Further, the reported output power and PAE are state-of-the-art for amplifiers with more than 100% relative bandwidth operating up to Ku-band.