Spatial Spectrum Analysis:A metrology for accurate analysis of signal beam field aberration by planar optical components in quasi-optical feed systems
Lead Research Organisation:
Queen Mary University of London
Department Name: Sch of Electronic Eng & Computer Science
Abstract
Many great scientific discoveries from medicine to astronomy have been the result of painstaking attention to detail and careful measurement. Classic examples of these have been the discovery of the double helix of DNA by Crick and Watson which critically dependended on the careful x-ray analysis of the DNA molecule by Wilkins and Franklin. But for the want of such high-quality measurements, the famous chemsit Linus Pauling would likely have achieved the correct solution earlier. Similarly, the discovery of Pluto was the result of careful attention to fine detail in the slight perturbations that were observed in the orbit of its neighbour, Neptune.This project is to do with such a concern for making measurements to a high accuracy, and thereby understand and control sources of error. The particular error of concern is the distortion that a cm or mm wavelength radio signal beam suffers when it travels through a box that can have many flat or focussing mirrors or other flat components that can condition a signal, by for example, either splitting the beam into different paths or, joining many signal beams of differing wavelength into one path. The mirror components in the box that focus or shape the beams have been well studied, and their distorting effects are well understood. The flat components that can perform a wide variety of signal conditioning functions, have not been so well studied. Their effects to distort a radio signal beam need careful measurement. The importance for measuring and controlling their effects to mis-shape a beam, stem from their wide and vital use in instruments that are used for remote sensing. These so-called quasi-optical wave guiding structures enable the electromagnetic wave to be guided with little loss, just as visible light can be with mirrors. Remote sensing has a vital role to play in gathering and supplying data that is being used now, for example, in monitoring global weather patterns. Specifically, a radiometer operating from 90-200 GHz can detect the natural emission from the upper atmosphere, process it into frequency bands with a quasi-optical system and, after processing, give information about the water vapour content. This is vital to accurate weather prediction. With higher quality data, achieved by having better-performing components in the measuring instrument, more reliable models can be made for instance in understanding and verifying global warming, or plotting the growth of the holes in Earth's ozone layer at its poles. Quasi-optical systems have many current and potential applications in areas ranging from medical diagnotics to security. This project therefore aims to build a facility that will enable accurate measurements of beam distortion caused by these lesser-studied, but indispensible, flat signal-conditoning components.
Publications
Yang Bin
(2011)
Reassessment of the electromagnetic reflection response of human skin at W-band
in OPTICS LETTERS
Yang B
(2011)
Enhanced rapid and accurate sub-THz magneto-optical characterization of hexaferrite ceramics
in Journal of Magnetism and Magnetic Materials
Yang B
(2011)
Experimental characterization of hexaferrite ceramics from 100 GHz to 1 THz using vector network analysis and terahertz-time domain spectroscopy
in Journal of Applied Physics
Yang B
(2010)
Determination of the Gyrotropic Characteristics of Hexaferrite Ceramics From 75 to 600 GHz
in IEEE Transactions on Microwave Theory and Techniques
Yamsiri A
(2008)
Validation of QO design tool for FSS analysis
Wang Y
(2014)
Micromachined Thick Mesh Filters for Millimeter-Wave and Terahertz Applications
in IEEE Transactions on Terahertz Science and Technology
Tang H
(2007)
An optically controlled phase shifter employing the organic semiconductor poly(3-hexylthiophene)
in Applied Physics Letters
Sun W
(2013)
Accurate determination of terahertz optical constants by vector network analyzer of Fabry-Perot response.
in Optics letters
Huang J
(2015)
Microwave and terahertz dielectric properties of MgTiO3-CaTiO3 ceramics
in Materials Letters
A Yamsiri
(2007)
Spatial spectrum analysis for measurement of beam aberration by FSSs
Description | A distortion that a millimeter wavelength (mm-wave) radio signal suffers when it travels through the train of conic-section reflectors or planar signals conditioning components can be identify by use of beam mode optics and Fourier Optics. The reflectors used in mm-wave application have been well studied, and their distortion effects are well understood. However, the planar signal conditioning components, also known as a planar frequency selective surface (FSS), have not been so well studied in |
Exploitation Route | findings are already in use in funding work with RAL and ESA. it has recently supported initial experiments to form the basis of a responsive-mode application to EPSRC in the microwave/advanced materials area (designated for growth). this is a joint application involving the schools of physics, chemistry and materials at QMUL. |
Sectors | Aerospace Defence and Marine Chemicals Healthcare |
URL | http://antennas.eecs.qmul.ac.uk |
Description | since award lab, facilities and capability have grown and been called upon principally by Thomas Keating Ltd (SME in space-deployed horn antennas etc) and the Rutherford Appleton Laboratory (Millimetre wave Group). Since Dec 2013 we have been subcontracted to RAL working on Pre-Development of Quasi-Optical Network for the Microwave Sounder of MetOp-SG. This is employing expertise developed under the First Grant in Spatial Spectrum Analysis. |
First Year Of Impact | 2012 |
Sector | Aerospace, Defence and Marine,Chemicals,Healthcare |
Impact Types | Economic |
Description | Pre-Development of Quasi-optical Network for the Microwave Sounder of MetOp-SG |
Amount | £800,000 (GBP) |
Organisation | European Space Agency |
Department | European Space Research and Technology Centre (ESTEC) |
Sector | Public |
Country | Netherlands |
Start | 03/2013 |
End | 08/2014 |
Description | Pre-Development of Quasi-optical Network for the Microwave Sounder of MetOp-SG |
Amount | £800,000 (GBP) |
Organisation | European Space Agency |
Department | European Space Research and Technology Centre (ESTEC) |
Sector | Public |
Country | Netherlands |
Start | 03/2013 |
End | 08/2014 |