From Spaceborne C-Band SAR Down to Single Chip GaN Front-Ends
GaN MMIC technology enables the integration of high-power amplification, transmit-receive switching and low-noise performance in a single robust chip, making this an ideal choice for the development of new radar front-ends. This presentation will start by examining the front-end specifications from a system point of view, using the example of a spaceborne C-band SAR radar system. From these system aspects the MMIC specifications will be derived, showing the advantage of using a single-chip GaN front-end. After this top-down analysis a bottom-up approach will follow, with a closer look at the GaN transistors (load pull measurements and impact of harmonic optimization), and the building blocks of the front-end chip. Specific attention will be given to aspects such as robustness (e.g. operating the front-end without circulation/isolator or limiter) and derating for reliable operation in space.