Design, Development, and Prelaunch Calibration of a Low Cost 118.75 Ghz Temperature Sounding Radiometer for Cubesat Missions
The 118.75 GHz eight-channel, double-side-band scanning temperature sounding radiometer “MiniRad” for CubeSat missions is intended to serve as a demonstrator for a constellation of low cost, quick turn-around millimeter wave and higher frequency passive sounders and imagers for weather forecasting a...
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ftunicolboulder:oai:scholar.colorado.edu:ecen_gradetds-1195 2023-05-15T13:49:37+02:00 Design, Development, and Prelaunch Calibration of a Low Cost 118.75 Ghz Temperature Sounding Radiometer for Cubesat Missions Periasamy, Lavanya 2019-01-01T08:00:00Z application/pdf https://scholar.colorado.edu/ecen_gradetds/192 https://scholar.colorado.edu/cgi/viewcontent.cgi?article=1195&context=ecen_gradetds unknown CU Scholar https://scholar.colorado.edu/ecen_gradetds/192 https://scholar.colorado.edu/cgi/viewcontent.cgi?article=1195&context=ecen_gradetds Electrical, Computer & Energy Engineering Graduate Theses & Dissertations 3d printed corrugated horn cubesat radiometer microwave filterbank offset reflector and feed prelaunch antenna calibration prelaunch radiometer calibration Electrical and Computer Engineering Electromagnetics and Photonics Remote Sensing text 2019 ftunicolboulder 2019-07-12T23:29:36Z The 118.75 GHz eight-channel, double-side-band scanning temperature sounding radiometer “MiniRad” for CubeSat missions is intended to serve as a demonstrator for a constellation of low cost, quick turn-around millimeter wave and higher frequency passive sounders and imagers for weather forecasting at high spatial and temporal resolution. This radiometer payload, built at the Center for Environmental Technology in partnership with the Colorado Space Grant Consortium and the National Snow and Ice Data Center at the University of Colorado at Boulder, can provide a 3D temperature map from the earth's surface to an altitude of 18~km. For precise prelaunch antenna calibration, an HE11 mode full wave electromagnetic field analysis was developed in Matlab for determination of an optimal feed horn and offset paraboloidal reflector geometry such that the main beam and spillover efficiencies of the system are maximized, and these and the antenna phase center location that maximizes phase efficiency are precisely known. Results from this analysis were also compared with HFSS and GRASP simulations of the antenna subsystem. The efficacy of employing a 3D-printed corrugated conical horn, operable between 110 and 127 GHz, as the feed for the reflector was addressed due to its very low cost and rapid manufacturability. Horn measurements indicated a reflection coefficient below -15 dB and an 89% average spillover efficiency at the main reflector subtending a 16 degree half-angle. The need for a compact intermediate frequency spectrometer for operation between 50 MHz and 7 GHz resulted in the design and development of an eight-channel lumped element filterbank with bandwidths between 0.25 and 2.2 GHz. Laboratory experiments implemented to characterize the MiniRad helped in achieving radiometer sensitivities close to theoretical limits. Initial performance obtained from airborne measurements over Antarctica during the NASA Operation IceBridge experiment in Oct-Nov 2016 suggested a well-focused scanning antenna subsystem and good separation between the radiometer channels. After final system integration, measurements obtained from prelaunch experiments indicated the antenna 3-dB beamwidth to be broader by ~0.1 degree compared to the idealized simulated pattern, and radiometer sensitivities that agreed to better than 0.5 K with theoretical estimates across all eight channels. Text Antarc* Antarctica National Snow and Ice Data Center University of Colorado, Boulder: CU Scholar |
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Open Polar |
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University of Colorado, Boulder: CU Scholar |
op_collection_id |
ftunicolboulder |
language |
unknown |
topic |
3d printed corrugated horn cubesat radiometer microwave filterbank offset reflector and feed prelaunch antenna calibration prelaunch radiometer calibration Electrical and Computer Engineering Electromagnetics and Photonics Remote Sensing |
spellingShingle |
3d printed corrugated horn cubesat radiometer microwave filterbank offset reflector and feed prelaunch antenna calibration prelaunch radiometer calibration Electrical and Computer Engineering Electromagnetics and Photonics Remote Sensing Periasamy, Lavanya Design, Development, and Prelaunch Calibration of a Low Cost 118.75 Ghz Temperature Sounding Radiometer for Cubesat Missions |
topic_facet |
3d printed corrugated horn cubesat radiometer microwave filterbank offset reflector and feed prelaunch antenna calibration prelaunch radiometer calibration Electrical and Computer Engineering Electromagnetics and Photonics Remote Sensing |
description |
The 118.75 GHz eight-channel, double-side-band scanning temperature sounding radiometer “MiniRad” for CubeSat missions is intended to serve as a demonstrator for a constellation of low cost, quick turn-around millimeter wave and higher frequency passive sounders and imagers for weather forecasting at high spatial and temporal resolution. This radiometer payload, built at the Center for Environmental Technology in partnership with the Colorado Space Grant Consortium and the National Snow and Ice Data Center at the University of Colorado at Boulder, can provide a 3D temperature map from the earth's surface to an altitude of 18~km. For precise prelaunch antenna calibration, an HE11 mode full wave electromagnetic field analysis was developed in Matlab for determination of an optimal feed horn and offset paraboloidal reflector geometry such that the main beam and spillover efficiencies of the system are maximized, and these and the antenna phase center location that maximizes phase efficiency are precisely known. Results from this analysis were also compared with HFSS and GRASP simulations of the antenna subsystem. The efficacy of employing a 3D-printed corrugated conical horn, operable between 110 and 127 GHz, as the feed for the reflector was addressed due to its very low cost and rapid manufacturability. Horn measurements indicated a reflection coefficient below -15 dB and an 89% average spillover efficiency at the main reflector subtending a 16 degree half-angle. The need for a compact intermediate frequency spectrometer for operation between 50 MHz and 7 GHz resulted in the design and development of an eight-channel lumped element filterbank with bandwidths between 0.25 and 2.2 GHz. Laboratory experiments implemented to characterize the MiniRad helped in achieving radiometer sensitivities close to theoretical limits. Initial performance obtained from airborne measurements over Antarctica during the NASA Operation IceBridge experiment in Oct-Nov 2016 suggested a well-focused scanning antenna subsystem and good separation between the radiometer channels. After final system integration, measurements obtained from prelaunch experiments indicated the antenna 3-dB beamwidth to be broader by ~0.1 degree compared to the idealized simulated pattern, and radiometer sensitivities that agreed to better than 0.5 K with theoretical estimates across all eight channels. |
format |
Text |
author |
Periasamy, Lavanya |
author_facet |
Periasamy, Lavanya |
author_sort |
Periasamy, Lavanya |
title |
Design, Development, and Prelaunch Calibration of a Low Cost 118.75 Ghz Temperature Sounding Radiometer for Cubesat Missions |
title_short |
Design, Development, and Prelaunch Calibration of a Low Cost 118.75 Ghz Temperature Sounding Radiometer for Cubesat Missions |
title_full |
Design, Development, and Prelaunch Calibration of a Low Cost 118.75 Ghz Temperature Sounding Radiometer for Cubesat Missions |
title_fullStr |
Design, Development, and Prelaunch Calibration of a Low Cost 118.75 Ghz Temperature Sounding Radiometer for Cubesat Missions |
title_full_unstemmed |
Design, Development, and Prelaunch Calibration of a Low Cost 118.75 Ghz Temperature Sounding Radiometer for Cubesat Missions |
title_sort |
design, development, and prelaunch calibration of a low cost 118.75 ghz temperature sounding radiometer for cubesat missions |
publisher |
CU Scholar |
publishDate |
2019 |
url |
https://scholar.colorado.edu/ecen_gradetds/192 https://scholar.colorado.edu/cgi/viewcontent.cgi?article=1195&context=ecen_gradetds |
genre |
Antarc* Antarctica National Snow and Ice Data Center |
genre_facet |
Antarc* Antarctica National Snow and Ice Data Center |
op_source |
Electrical, Computer & Energy Engineering Graduate Theses & Dissertations |
op_relation |
https://scholar.colorado.edu/ecen_gradetds/192 https://scholar.colorado.edu/cgi/viewcontent.cgi?article=1195&context=ecen_gradetds |
_version_ |
1766251887000027136 |