TECHNOLOGY I GaN RELIABILITY
Artist rendering of a GPS III satellite deployed in a medium-earth orbit (MEO). Credit: The Aerospace Corporation.
Are GaN RF devices reliable enough for space missions? Can concerns over the likes of intrinsic and extrinsic reliability, mechanical integrity and radiation hardness scupper the chances of GaN HEMTs from being deployed on lengthy satellite missions? BY JOHN SCARPULLA FROM THE AEROSPACE CORPORATION IT IS NOW BEYOND QUESTION that GaN-based microwave devices, that is transistors and MMICs, offer a high enough level of maturity to be deployed in many terrestrial and airborne applications. However, they are have yet to be incorporated in space satellite missions lasting up to 15 years, where ultra-reliability is paramount. A lack of deployment in these space missions is certainly not due to any issue associated with 28 ISSUE I 2022
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performance. When GaN HEMT-based devices are used to construct power amplifiers, they outpace the GaAs HEMTs of the previous era by a substantial margin, delivering far higher power densities while operating at higher temperatures and voltages. Hunt for the details and you’ll find that when judged by those crucial metrics, GaN HEMTs offer about a ten-fold hike in the current-per-unit-gate-width when compared with their GaAs equivalents, while running at a channel temperature of 200°C or more
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