Development of a Three-Frequency Spaceborne Radar for Cloud and Precipitation Measurement

In order to provide for simultaneous three-dimensional measurements of clouds and precipitation from space, we have developed a radar design that leverages new advances in microwave monolithic integrated circuits (MMICs) and microfabrication to enable an electronically-scanned radar with Ku-band (13.4 GHz), Ka-band (35 GHz) and W band (94-GHz) channels. This system uses a three-frequency linear active electronically-steered array (AESA) combined with a parabolic cylindrical reflector. This configuration provides a large aperture (3m x 5m) with electronic-steering but is much simpler than a two-dimensional AESA of similar size. Still, the W-band frequency requires element spacing of approximately 2.5 mm, presenting significant challenges for signal routing and incorporation of MMICs. By combining (Gallium Nitride) GaN MMIC technology with microfabricated radiators and interconnects and silicon-germanium (SiGe) beamforming MMICs, we are able to meet all the performance and packaging requirements of the linear array feed and enable simultaneous scanning of Ka-band and W-band radars over swath of up to 100 km. Acknowledgement: This work was performed at the Jet Propulsion Laboratory / California Institute of Technology under contract with the National Aeronautics and Space Administration