W-Band MMIC PA With Ultrahigh Power Density in 100-nm AlGaN/GaN Technology

A three-stage W-band GaN monolithic microwave integrated circuit power amplifier (MMIC PA) is reported. Electron-beam lithography has been employed to define a 100-nm T-shaped gate on the AlGaN/GaN HEMT structure with ultra-high aluminum content. The MMIC PA offers a peak small signal gain of 16.7 dB in the 90-97 GHz bandwidth. Moreover, it achieves a peak 1.66-W (32.2 dBm) output power at 93 GHz in a continuous-wave mode, with an associated power added efficiency of 21% and an associated power gain of 13.7 dB. Most notably, the peak power density is 3.46 W/mm with a 480-mu m wide output stage, which exceeds 3 W/mm in AlGaN/GaN HEMT at W-band for the first time.