Watt-level non-uniform distributed 6-37 GHz power amplifier MMIC with dual-gate driver stage in GaN technology

This paper reports on a wide bandwidth monolithic power amplifier suitable for wide bandwidth applications up to the Ka-band such as electronic warfare systems. The MMIC is based on a 100nm AlGaN/GaN T-gate HEMT microstrip transmission line technology with an f(T) >80 GHz. The designed and fabricated amplifier uses the non-uniform distributed power amplifier topology and covers a frequency range from 6GHz to 37 GHz, whereas the lower band edge is limited by the on-chip DC bias network. The MMIC is a dual-stage topology which employs dual-gate HEMTs in the driver stage in order to boost the gain of the overall amplifier. The measured S(21) is (17 +/- 1) dB. This is a significant increase of 3 dB as compared to a driver stage using standard common-source HEMTs. An output power well beyond 1W over the entire frequency range is obtained. To the authors' knowledge, this is the highest output power achieved by a distributed amplifier at this frequency range.