A D-Band GaN Power Amplifier With 28-dBm P sat, a Power Density of 0.2 W/mm2, and Loss-Optimized Matching Networks

In this paper, we present a D-Band power amplifier (PA) monolithic microwave integrated circuit (MMIC), manufactured in a gallium nitride (GaN)-on-silicon carbide (SiC) high electron-mobility transistor (HEMT) technology. The PA comprises six stages of 70-nm gate-length HEMTs and features 4-way corporate power combining, which results in a total gate-width of 352 µm in the output stage. We develop and analyze a loss-optimized inter-stage matching network (ISMN) topology, which is crucial for driving the output stage. As a result, the PA delivers a saturated output power (Psat) of more than 25.2 dBm between 125 and 151 GHz, and a peak-Psat of 28 dBm at the center of the frequency band. The high Psat and a small chip size (3.125 mm2 ) translate into a power density (Pdens) of more than 0.2 W/mm2 . To the best of the authors’ knowledge, this PA MMIC demonstrates the highest Psat and Pdens at D-Band across all technologies.