For humidity and temperature sounding of Earth’s atmosphere, a single-antenna/LNA (low-noise amplifier) is needed in place of two separate antennas for the two frequency bands. This results in significant mass and power savings for GeoSTAR that is comprised of hundreds of antennas per frequency channel. Furthermore, spatial anti-aliasing would reduce the number of horns. An anti-aliasing horn antenna will enable focusing the instrument field of view to the “hurricane corridor” by reducing spatial aliasing, and thus reduce the number of required horns by up to 50 percent.
The single antenna/receiver assembly was designed and fabricated by a commercial vendor. The 118–183-GHz horn is based upon a profiled, smoothwall design, and the OMT (orthomode transducer) on a quad-ridge design. At the input end, the OMT presents four very closely spaced ridges [0.0007 in. (18 μm)]. The fabricated assembly contains a single horn antenna and low-noise broadband receiver front-end assembly for passive remote sensing of both temperature and humidity profiles in the Earth’s atmosphere at 118 and 183 GHz. The wideband feed with dual polarization capability is the first broadband low noise MMIC receiver with the 118 to 183 GHz bandwidth.
This technology will significantly reduce PATH/GeoSTAR mass and power while maintaining 90 percent of the measurement capabilities. This is required for a Mission-of-Opportunity on NOAA’s GOES-R satellite now being developed, which in turn will make it possible to implement a Decadal-Survey mission for a fraction of the cost and much sooner than would otherwise be possible.
This work was done by Daniel J. Hoppe, David M. Pukala, Bjorn H. Lambrigtsen, Mary M. Soria, Heather R. Owen, Alan B. Tanner, Peter J. Bruneau, Alan K. Johnson, Pekka P. Kangaslahti, and Todd C. Gaier of Caltech for NASA’s Jet Propulsion Laboratory. NPO-47351
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Single-Antenna Temperature- and Humidity-Sounding Microwave Receiver
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Overview
The document outlines the development of a Single-Antenna Temperature- and Humidity-Sounding Microwave Receiver, designed by NASA's Jet Propulsion Laboratory (JPL) for passive remote sensing of atmospheric temperature and humidity profiles at frequencies of 118 GHz and 183 GHz. This innovative technology aims to improve the efficiency and effectiveness of satellite missions, particularly for applications like the GeoSTAR/PATH and SWOT radiometers, which traditionally require separate antennas for each frequency band.
The project builds on previous successful developments in low-noise amplifier (LNA) technology at JPL, which achieved noise temperatures below 400 K across the specified frequency range. The new receiver assembly features a custom-designed LNA DC bias board and a wideband feed with dual polarization capability, allowing it to operate effectively in both frequency bands. The design optimizes the receiver's performance, achieving a significant improvement in noise temperature—1.5 to 2 times better than earlier narrowband receivers.
The significance of this advancement lies in its potential to reduce the mass and power requirements of satellite instruments while maintaining 90% of their measurement capabilities. This is particularly crucial for the upcoming NOAA’s GOES-R satellite mission, which aims to enhance weather monitoring and forecasting. The technology is expected to facilitate a Decadal-Survey mission at a fraction of the typical cost and timeline, thereby enabling timely advancements in atmospheric science.
The document also highlights the collaborative efforts of various researchers involved in the project, as well as references to related publications that provide further insights into the technology's development. The information is part of NASA's Commercial Technology Program, which aims to disseminate aerospace-related developments with broader technological, scientific, or commercial applications.
In summary, this document presents a significant technological advancement in microwave receiver design, showcasing JPL's commitment to enhancing remote sensing capabilities for atmospheric studies. The Single-Antenna Temperature- and Humidity-Sounding Microwave Receiver represents a leap forward in satellite instrumentation, promising to improve our understanding of Earth's atmosphere while optimizing resource use in space missions.
