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Optical Design and Radiometric Tests for the Multibeam Limb Sounder STEAMR

Applicant Murk Axel
Number 130517
Funding scheme Project funding (Div. I-III)
Research institution Institut für angewandte Physik Universität Bern
Institution of higher education University of Berne - BE
Main discipline Technical Physics
Start/End 01.04.2010 - 31.03.2012
Approved amount 148'874.00
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All Disciplines (4)

Discipline
Technical Physics
Climatology. Atmospherical Chemistry, Aeronomy
Electrical Engineering
Astronomy, Astrophysics and Space Sciences

Keywords (9)

optics; antenna measurements; radiometer; autocorrelator; multibeam limb sounder; submillimeter wave optical design; antenna simulations and measurements; radiometry; digital autocorrelation spectrometer

Lay Summary (English)

Lead
Lay summary
The PREMIER satellite is a candidate for the next ESA Earth Explorer Core Mission, which aims to advance our understanding of the processes that link trace gases, radiation and chemistry in the upper troposphere and lower stratosphere. In this region the radiative effects of water and clouds are at a maximum. It is also a region characterized by small-scale processes that have not been studied by previous missions. The instrumentation consists of an infrared limb-imaging spectrometer and the millimeter wave limb sounder STEAMR.The STEAMR instrument utilizes an array of 14 receivers, which will image different altitudes simultaneously, thereby providing unique information about the 2-D structure of the Earth's atmosphere. Key components of the instrument are the focal plane array optics and the Ritchey-Chrétien telescope with a 1.6m x 0.8m aperture. The novel STEAMR receivers consist of sideband separating mixers operating around 340 GHz and digital autocorrelation spectrometers with an unprecedented wide bandwidth. An accurate knowledge of the sideband ratio of these receivers and a high radiometric linearity of the spectrometers are crucial requirements to meet the scientific goals of the PREMIER mission. The Institute of Applied Physics, University of Bern, is responsible for the development of the STEAMR focal plane array optics. It consists of a facet reflector assembly and profiled corrugated feed horns, which have to be optimized to ensure low side lobes and closely spaced beam pattern for all receiver channels. With additional PRODEX funding from ESA a breadboard model of the unit will be built. It will allow us to verify the design by planar near field antenna measurements using our submillimeter wave vector network analyzer. The optical design will be complemented by Physical Optics simulations of the complete STEAMR instrument, including the telescope and the calibration subsystem. In order to assess the radiometric performance of the STEAMR receivers we will characterize prototypes of the sideband separating mixers and autocorrelation spectrometer. In particular we will investigate the image rejection capabilities of different mixer designs, and the linearity as well as the effective noise performance of the autocorrelation spectrometer in comparison to other digital backends. As a final test we are planning an end-to-end verification of the STEAMR radiometer by first atmospheric observations from the high altitude research station Jungfraujoch.
Direct link to Lay Summary Last update: 21.02.2013

Responsible applicant and co-applicants

Employees

Publications

Publication
Optical design of the stratosphere-troposphere exchange and climate monitor radiometer (STEAMR) instrument
Whale M, Renker M, Murk A, Janson O, Frisk U (2012), Optical design of the stratosphere-troposphere exchange and climate monitor radiometer (STEAMR) instrument, in Antennas and Propagation (EUCAP), Proceedings of the 5th European Conference on, 275 -279.
Analysis and Simulation of Edge Effects of Focal Plane Array Facet Reflectors with High Filling Factor
Matthias Renker, Mark Whale, Axel Murk, Anthony Murphy, Richard Wylde (2011), Analysis and Simulation of Edge Effects of Focal Plane Array Facet Reflectors with High Filling Factor, in 33rd ESA Antenna Workshop on Challenges for Space Antenna Systems, 1-8.

Scientific events

Active participation

Title Type of contribution Title of article or contribution Date Place Persons involved


Associated projects

Number Title Start Funding scheme
146388 KAP-MIRA: Key Atmospheric Parameters by Microwave Radiometry 01.04.2013 Project funding (Div. I-III)
119908 Beam Shaping and Feed Optimization for Terahertz Waves 01.04.2008 Project funding (Div. I-III)
141032 Optical Design and Radiometric Tests for the Multibeam Limb Sounder STEAMR 01.04.2012 Project funding (Div. I-III)
133791 R'EQUIP Microwave Vector Network Analyzer 01.02.2011 R'EQUIP
141032 Optical Design and Radiometric Tests for the Multibeam Limb Sounder STEAMR 01.04.2012 Project funding (Div. I-III)
134684 WADI+: Atmospheric Water vapour from the ground to the mesopause: Detection and Interpretation 01.04.2011 Project funding (Div. I-III)

Abstract

STEAMR is a 310-360GHz multibeam limb sounder for atmospheric research which is currently being developed for the ESA mission PREMIER. We are planning to optimize its optical design and to verify the performance of an optics breadboard model of the focal plane array and calibration subsystem by measurements with our vector network analyzer. In addition we will characterize the radiometric performance of prototypes of its sideband separating mixers and its wideband digital autocorrelation spectrometer.
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