IN THIS SECTION
ORC Seminar Series
"Magneto-inductive waves - applications of metamaterials in MRI systems"
Speaker: Professor Richard Syms, Imperial College, London
Date: 27 May 2009
Venue: B53 Seminar Room
Periodic structures have long been of interest in electrical engineering, and many different arrangements of reactive elements have been devised over the last 150 years for signal transmission, filters and slow-wave circuits. Renewed interest in periodic electrical structures was sparked by the realisation they can act as artificial media with novel properties, such as negative permittivity, permeability or refractive index. Such has been the explosion of activity that ‘metamaterials’ is now an entire field. Although many applications concentrate on exploitation of negative parameters (for example, perfect imaging and cloaking), other important engineering applications exist. In these areas, the conductor losses inherent in RF metamaterals degrade performance and are a key barrier to exploitation. In this talk, applications in magnetic resonance imaging of a particular metamaterial supporting magneto-inductive waves are described. Theoretical background and experimental results are presented for lumped-element and distributed-element passive MI waveguides in both linear and ring resonator geometries. A three-frequency parametric amplification scheme is then proposed and demonstrated for unit cells and lattices, and demonstrated at MHz frequencies using varactors. Practical applications in patient protection in internal imaging and the detection of RF signals in MRI are described.
Richard R.A.Syms was born in Norfolk, VA, in 1958. He obtained a BA in 1979 and a D.Phil. in 1982, both in Engineering Science from Oxford University. He has been Head of the Optical and Semiconductor Devices Group in the EEE Dept, Imperial College London, since 1992 and Professor of Microsystems Technology since 1996. He lectures on guided wave optics and electromagnetic theory. He has published over 140 journal papers, 80 conference papers and two books on holography, integrated optics, laser and amplifier devices, microengineering and metamaterials. Most recently he has been developing electrical MEMS such as micro-connectors and switches, optical MEMS such variable attenuators and tunable lasers, RF MEMS such as quadrupole mass spectrometers and probes for magnetic resonance imaging, and metamaterial devices for MRI. He is an Associate Editor for the Journal of Microelectromechanical Systems and for Metamaterials.
Image sourced from www3.imperial.ac.uk/opticalandsemidev/aboutthegroup/people/
Copyright University of Southampton 2006