A MMIC power amplifier in GaN on Si technology for next generation Q band high throughput satellite systems

this paper deals with the design, realization and test of a Microwave Monolithic Integrated Circuit (MMIC) power amplifier (PA) for next generation Q-band high throughput satellite systems. The MMIC, based on a four-stage architecture, was realized on a commercial 100 nm gate length Gallium Nitride on Silicon (GaN-Si) process. Accounting for the peculiarities of the selected technology, especially the lossy substrate and the relevant thermal resistance, particular care was devoted to identify effective circuital solutions able to mitigate the insertion loss of the matching networks and the temperature increase in the active devices. Experimental results carried out directly on-wafer show that the PA can achieve a saturated output power of roughly 36dBm with a gain and a power added efficiency higher than 20 dB and 23%, respectively, in the operative band from 37.5 GHz to 42.5 GHz. The chip area is 3.54 × 3.5 mm2. Such results are close to others state-of-art PAs realized in more expensive GaN processes based on Silicon Carbide, thus demonstrating that high resistivity Silicon substrate can be efficiently adopted also in such a peculiar application.