High Efficiency 5W/10W 32-38GHz Power Amplifier MMICs Utilizing Advanced 0.15μm GaN HEMT Technology

This paper describes the design and measured performance of two high efficiency Ka-band 32 - 38 GHz power amplifier MMICs fabricated with an advanced 0.15 mu m Gallium Nitride (GaN) HEMT technology process. The process features a 50 mu m thin Silicon Carbide (SiC) substrate and compact transistor layouts with individual source via (ISV) grounding. The designs utilize an optimum transistor arrangement with both single-ended and balanced approaches. The 2-stage single-ended power amplifier MMIC demonstrates 4.5 - 5.2 W of output power with 25 - 34% PAE over 32 - 38 GHz band. For the second MMIC, two 3-stage power amplifiers are combined to achieve 9.0 - 11.2 W output power with 30 - 35% PAE over the same frequency range. A benchmark of 1.45W/mm(2) FOM (output power to die area ratio) with high efficiency is reported at this frequency band.