Advanced Radiometer Instrumentation for Earth Observation
Submitting InstitutionQueen's University Belfast
Unit of AssessmentElectrical and Electronic Engineering, Metallurgy and Materials
Summary Impact TypeTechnological
Research Subject Area(s)
Physical Sciences: Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics
Technology: Communications Technologies
Summary of the impact
Research on Frequency Selective Surface (FSS) structures has led to major
advances in the design and manufacture of the world's most advanced
payload instrumentation for use in Earth observation satellites. This
technology has provided the core element of the radiometer instrumentation
needed for more accurate global weather forecasts and better understanding
of climate change. The advances described have made it possible to combine
all of the different functions of the MetOP-SG radiometer into one
instrument, thereby halving the footprint of the satellite payload
resulting in a [text removed for publication] cost saving.
Key researchers involved Robert Cahill (Reader) 2000-, Vincent
Fusco (Professor) 2000-, Neil Mitchell (Senior Lecturer) 2008-, Harold
Gamble (Professor, now retired) 2000-2010, Alex Schuchinsky (Reader)
2005, and Raymond Dickie (PhD student then RA/Engineer) 2003-.
Time period, 2000-2013
Space borne radiometers enable the retrieval of a wide range of
geophysical parameters on a global scale. Between 1996 and 2005, 220,000
people were killed by weather related disasters, down from 2.6m in the
period 1956 to 1965. This reduction is due, in part, to increasingly
accurate early weather warnings. Improved understanding of climatic
processes requires satellite instruments to monitor the changes and
provide a health check on the environment. European mandatory programmes
have been initiated to provide, for the first time, detailed observations
for climate monitoring. The core sensing instrument deployed for this
purpose is the radiometer.
Within the radiometer it is necessary to separate naturally occurring
electromagnetic molecular emissions in the sub-millimetre range,
250GHz-850GHz, by frequency. This frequency range encompasses many of the
natural resonances associated with green house gases. These emissions are
extremely weak thus high receiver sensitivity is required. The key to the
success of these Earth observation missions is predicated on frequency
selective surface (FSS) filters which exhibit ultra-low insertion loss. In
2000 when missions for 2020 and beyond were being planned it was
recognised by the European Space Agency, ESA, that all relevant existing
filter technologies could not achieve the system level insertion loss
requirement. Therefore there was an urgent requirement to address this gap
QUB were invited by ESA to undertake research to minimise mission risk
through the creation of new advanced FSS technologies. Since 2000 to 2013
supported by EPSRC, ESA, RAL, Centre for Earth Observation
Instrumentation, new modelling, microelectronics fabrication and metrology
techniques were developed in order to produce a new class of substrateless
FSS which resulting in the core research [1-3] underpinning this case
study. The span of the work ranged from, technology concept formulated
(2003), to system prototype demonstration in an operational environment
(2012), to actual system, (2013).
The core underlying research necessary for this progression was as
follows. In  we described an advanced micromachining technique that was
used to create a multilayer freestanding FSS for single sideband filtering
in a space borne radiometer. The work demonstrated that the structure
exhibited significantly lower insertion and reflection losses than a
conventional dielectric backed FSS, and, moreover, is structurally more
robust hence better able to survive the forces of a launch vehicle. In 
we described the electromagnetic design, fabrication and measurement of
the first ever ultra-low loss space qualified frequency selective
filter. This gave instrument designers, for the first time, the ability to
detect vertical and horizontally polarised sub-mm wavelength signals
simultaneously, thereby opening the possibility for radically simplified
radiometer architecture development. These FSS were fabricated in the
UoA13 Advanced Microsystems Centre, using specially developed precision
micromachining techniques as described in , and have been successfully
passed rigorous mechanical and thermal analysis, testing by the space
industry as well as being approved for patent grant, .
References to the research
Four publications covering/underpinning this research are listed below.
These have undergone rigorous peer review and the research funded through
the externally peer-reviewed external grants shown. The three highlighted
papers* are considered indicative of the quality underpinning the
IEEE Transactions on Antennas and Propagation is one of
the most cited peer reviewed electrical and electronic communication
engineering journals (Impact Factor 2.151) specifically aimed at
theoretical and experimental advances in antenna research, design and
IEEE Transactions on Terahertz Science and Technology is
a recently published bimonthlypeer-reviewed scientific journal covering terahertz
science, technology, instruments, and applications.
* Dickie R, Cahill R, Gamble HS, Fusco V F, Schuchinsky, A, and Grant
N : `Spatial Demultiplexing in the sub-mm wave band using multlayer
free-standing frequency selective surfaces', Proc IEEE Antennas and
Propagation, 53, (6), 2005, pp. 1903-1911, doi
Cited by 22 Scopus.
* Dickie R, Cahill R, Gamble HS, Fusco VF, Henry M, Oldfield ML,
Huggard PG, Howard P, Grant N, Munro Y, and de Maagt P: `Submillimetre
Wave Frequency Selective Surface with Polarisation Independent Spectral
Responses', Proc IEEE Antennas and Propagation, 57, (7), 2009, pp.
1985 - 1994, doi 10.1109/TAP.2009.2021933. Cited by 15 Scopus.
* Dickie R, Cahill R, Gamble H S, Fusco VF, and Mitchell N: `THz
Frequency Selective Surface Filters for Earth Observation Remote Sensing
Instruments', Proc IEEE Terahertz Science and Technology, 1, (2), 2011,
pp. 450 - 461, doi10.1109/TTHZ.2011.2129470.
 Cahill, R., Dickie, R., Fusco, V, Gamble, H, Improvements in or
Relating to Frequency Selective Surfaces, European Patent EP1 861 896 B1,
2007, and Frequency Selective Surfaces, US 7,982 686 B2, 2011.
R. Cahill, R. Dickie, V. Fusco and N Mitchell; "Quasi-Optical Network for
Microwave Sounder", European Space Agency, 4000/12/NL/BJ, -
January 2013, 500K€ .
R.Cahill, R. Dickie, V. Fusco and H. Gamble; "Quasi-Optical Filter for
Post-EPS Mission", European Space Agency, 22938/09/NL/JA, -
November 2009 - Feb 2012, 355K€.
R.Cahill, R. Dickie, V. Fusco and H. Gamble; "Frequency Selective Surface
Filter Technology for Submillimetre Wave Radiometers", UK Centre
for Earth Observation Instrumentation (CEOI), Feb 2007 - Feb
R.Cahill, R. Dickie, V. Fusco and H. Gamble; "Innovative Low Loss
Frequency Selective Surface Structures", European Space Agency
- 19854/06/NL/JA, May 2006 - Feb 2009, 265K€.
R.Cahill, V. Fusco and H. Gamble; "Multilayer Mesh Filters for Quasi
Optical Beamsplitting Applications", EPSRC, GR/S13828/01,
July 2003 - November 2005, £171K.
Details of the impact
The space industry is a UK Government prioritya high growth
sector with growing market in climate monitoring. QUB has made a
significant and recognised contribution to this growth by developing new
technologies and IP which have contributed directly to the UK space
industry (not defined here — but below) securing a [text removed for
publication] contract for advanced instrument development which is
guaranteed to use QUB technology.
The UoA has been responsible for significant technology transfer to the
UK and EU space industry. The main stakeholders, ESA, Astrium, RAL Space,
the UK Space Agency and the UK Centre for Earth Observation
Instrumentation (CEOI — www.ceoi.ac.uk) fund programmes which bring
together academia and industry to identify and advance critical instrument
technologies. In 2008 a consortium comprising these organisations and the
UoA was formed1 with the express purpose to put the UK in an
extremely strong bidding position for known future millimetre wave
radiometry programmes through engagement with a series of carefully
selected projects. These projects were chosen to reflect UK priorities, by
identifying gaps in short- and mid-term radiometer instrumentation
enabling technology requirements, where UK developed technology would have
the largest impact.
FSS technology is a key enabler for improved sensitivity of remote
environmental monitoring instrumentation. Since 2008 we have developed a
variety of world leading patented FSS devices, European Patent EP1 861 896
B1, 2010, US patent US 7982 686 B2, 2011, based on advanced micromachined
fabrication techniques. Consequently the UoA is the current main supplier
of FSS to ESA. Working in partnership with RAL Space (2003-2008), QUB has
supplied prototype micromachined frequency selective filters: quartz based
FSS (2003); and improved air-spaced FSS (2008).
Several of these FSS have been used in PREMIER-Ex (Kiruna, Sweden 2010)
and ESSenCe (Kiruna, Sweden 2011) scientific space instrumentation
programmes resulting in two-to three-fold improvements in sensitivity in
all observing channels. The higher-quality spectra obtained in these
Swedish campaigns has resulted in more accurate retrieval of atmospheric
constituent profiles. Another mission currently employing patented
technology is the MARSCHALS radiometer. MARSCHALS is an airborne testbed
for a new class of millimetre wave limb sounder and is the first such
instrument to be explicitly designed and built for the purpose of Upper
Troposphere and Lower Stratosphere composition sounding. By 2011 MARSCHALS
represented approximately [text removed for publication] worth of business
A major mission deploying QUB FSS technology is the Microwave Sounder
Instrument (MWS), part of the MetOP-SG mission. When launched in 2020 this
will be the world's most advanced meteorological data acquisition system.
In 2008 the UoA started work on developing the different FSS structures
for the MWS breadboard instrument. In (2012) ESA awarded QUB mandatory
tender status for this mission-critical FSS work3. One of these
structures — delivered in Feb 2013 - makes it possible to combine all of
the scientific functions of the mission into one instrument thus saving
more than [text removed for publication]3 and halving the
footprint of the payload on the satellite platform.
In Feb 2013 ESA preselected Astrium UK as the prime contractor to supply
the advanced radiometer instrument for the MetOP mission. The QUB
contribution to the proposal was critical to the success of the UK's bid
to supply the instrument and QUB are guaranteed as the FSS prime for the
instrument4. The value of the contract to Astrium is [text
removed for publication] and the project will provide an estimated [text
removed for publication] jobs in the UK resulting directly and indirectly
Sources to corroborate the impact
Director of the UK Centre for Earth Observation Instrumentation
Head of Millimetre Technology Group
Science & Technology Facilities Council
Rutherford Appleton Laboratory
Head of Antenna and Submillimetre Wave Section
Electromagnetics & Space Environments Division
European Space Agency
Head of Future Programmes Astrium Ltd.