Title: Small, Low-mass Radar Components for Wideband Passive Radar Reflectivity Measurements
Presenting Author: Douglas Linkhart
Organization: Metmagnetics, Inc.
Co-Author(s): Anton Geiler, Timothy C. Tiernan, Lee Burns

Abstract:
The NASA 2017-2027 Decadal Survey entitled "Thriving on Our Changing Planet: A Decadal Strategy for Earth Observation from Space" has defined the Clouds, Convection, and Precipitation Mission as critical for assessing low and high cloud feedbacks, seasonal and interannual climate variability and climate prediction. multiple frequencies (e.g. Tropical Rainfall Measuring (TRMM), Global Precipitation Measurement (GPM), and CloudSat provide heritage for new instruments and have demonstrated the utility of satellite-based Ku-, KA-, and W-band (e.g. 14, 35, and 94 GHz) radar observations for profiling the full spectrum of condensed water throughout the atmosphere. Development of the key antenna technologies for Tri-band (KU/KA/W), scanning precipitation and cloud radar is a required milestone in preparation for multiple missions, among them the expected evolution of the Aerosol/Clouds/Ecosystems (ACE) concept, and the Global Cloud and Precipitation Measurement (GPCM) mission concept in early formulation by a joint NASA and the Japanese Aerospace Exploration Agency JAXA. Size and mass limitations inherent to space instruments make it desirable to transmit radar signals and receive reflections containing information about precipitation in the atmosphere using the same antenna, sometimes at the same time and even at the same frequency. Historically, a key component in radar Transmit/Receive modules, the solid-state circulator, is prohibitively large and massive. Metamagnetics developed a small, low mass KA-band, self-biased (magnet-less) circulator and isolator technology, funded in part by the NASA ESTO Advanced Component Technology program. These low-loss, low-profile devices conform to planar circuit topologies, substantially reduce circulator size and mass, and allow small element spacings for phased arrays. Metamagnetics has accomplished close, heterogeneous (multi-chip module) integration of its circulators with MMICs and is actively pursuing development of a W-band circulator to complement its KU- and KA-band self-biased (magnet-less) circulator for future NASA missions.