Electromagnetics & Radiation

July 15, 2015 at 4:00 p.m. Prof. Levent Gurel will be presenting “Parallel-MLFMA Solutions of Large-Scale Problems Involving Dielectric and Composite Metamaterial Structures”. Speaker: Prof. Levent Gürel CEO, ABAKUS Computing Technologies Adjunct Professor, Dept. of ECE, University of Illinois at Urbana-Champaign Day & Time: Wednesday, July 15, 2015 4:00 p.m. – 5:00 p.m. Location: Room BA 1210 Bahen Centre University of Toronto – St. George Campus 40 St. George Street Click here to see the Map Organizer: IEEE Electromagnetics & Radiation Joint Chapter Abstract: It is possible to solve extremely large electromagnetics problems accurately and efficiently by using the multilevel fast multipole algorithm (MLFMA) and parallel MLFMA. This has important implications in terms of obtaining the solution of previously intractable physical, real-life, and scientific problems in various areas, such as (subsurface) scattering, optics, bioelectromagnetics, metamaterials, nanotechnology, remote sensing, etc. Accurate simulations of such real-life electromagnetics problems with integral equations require the solution of dense matrix equations involving millions of unknowns. Most recently, we have achieved the solutions of larger than 1,000,000,000×1,000,000,000 (one billion!) dense matrix equations! Solutions of these extremely large problems cannot be achieved easily, even when using the most powerful computers with state-of-the-art technology. Instead, we have been solving some of the world’s largest integral-equation problems in computational electromagnetics by employing fast algorithms implemented on parallel computers. For more information: www.abakus.computing.technology In this talk, following a general introduction to our work in computational electromagnetics, I will present integral-equation and MLFMA formulations of dielectric/composite structures. Then, I will continue with rigorous modeling of three-dimensional optical metamaterial and plasmonic structures that are composed of multiple coexisting dielectric and/or conducting parts. Such composite structures may possess diverse values of conductivities and dielectric constants, including negative permittivity and permeability. It is possible to formulate and use different types of integral equations depending on which ones have better conditioning properties. I will briefly mention the development of effective Schur-complement preconditioners specifically for dielectric problems. Solutions of complicated real-life problems involving metamaterial structures, red blood cells, and dielectric photonic crystals will be presented. If time permits, various challenges encountered during the solutions may be touched upon. Biography: Prof. Levent Gürel (Fellow of IEEE, ACES, and EMA) received the M.S. and Ph.D. degrees from the University of Illinois at Urbana-Champaign (UIUC) in 1988 and 1991, respectively, in electrical and computer engineering. He worked at the IBM Thomas J. Watson Research Center, Yorktown Heights, New York, in 1991-94. During his 20 years with Bilkent University, he served as the Founding Director of the Computational Electromagnetics Research Center (BiLCEM) and a professor of electrical engineering. He is also an Adjunct Professor at UIUC. Prof. Gürel is the Founder and CEO of ABAKUS Computing Technologies, a company that is geared towards advancing the use of cutting-edge computing technologies for solving difficult scientific problems with important real-life applications and societal benefits. He is conferred the UIUC ECE Distinguished Alumni Award in 2013 and the IEEE Harrington-Mittra Award in Computational Electromagnetics in 2015. He was named an IEEE Distinguished Lecturer for 2011-2014 and is still serving in emeritus capacity. He was invited to address the 2011 ACES Conference as a Plenary Speaker and a TEDx Conference in 2014. Among other recognitions of Prof. Gürel’s accomplishments, the two prestigious awards from the Turkish Academy of Sciences (TUBA) in 2002 and the Scientific and Technological Research Council of Turkey (TUBITAK) in 2003 are the most notable. Since 2003, Prof. Gürel has been serving as an associate editor for Radio Science, IEEE Antennas and Wireless Propagation Letters, IET Microwaves, Antennas & Propagation, JEMWA, PIER, ACES Journal, and ACES Express.

Tuesday November 17, 2015 at 4:00 p.m. Vladimir Okhmatovski, Associate Professor in the Department of Electrical and Computer Engineering at the University of Manitoba, will be presenting “Novel Single-Source Integral Equation for Solution of Electromagnetic Scattering Problems on Penetrable Objects”. Speaker: Vladimir Okhmatovski Associate Professor Department of Electrical and Computer Engineering at the University of Manitoba Day & Time: Tuesday, November 17, 2015 4:00 p.m. Location: Room BA1210 Bahen Center for Information Technology 40 St. George Street, Toronto M5S2E4 Organizer: IEEE Toronto Electromagnetics & Radiation Chapter Contact: Costas D. Sarris, Email:costas.sarris@utoronto.ca Abstract: A new Surface–Volume–Surface Electric Field Integral Equation (SVS-EFIE) is discussed. The SVS-EFIE is derived from the volume integral equation by representing the electric field inside the scatterer as a superposition of the waves emanating from its cross section’s boundary. The SVS-EFIE has several advantages. While being rigorous in nature, it features half of the degrees of freedom compared to the traditional surface integral equation formulations such as PMCHWT and it requires only electric-field-type of Green’s function instead ofboth electric and magnetic field types. The latter property brings significant simplifications to solution of the scattering problems on the objects situated in multilayered media. Both scalar and vector formulations of the SVS-EFIE equation has been developed for solution of 2D scattering problems on penetrable cylinders under TM and TE polarizations. The SVS-EFIE has been also been applied to the solution of the quasi-magneetostatic problems of current flow in complex interconnects in both homogeneous and multilayered media. Detailed description of the method of moment discretization and resultant matrices is discussed. Due to the presence of a product of surface-to-volume and volume-to-surface integral operators, the discretization of the novel SVS-EFIE requires both surface and volume meshes. In order to validate the presented technique, the numericalresults are compared with the reference solutions. Biography: Vladimir Okhmatovski received Ph.D. degree in antennas and microwave circuits from the Moscow Power Engineering Institute, Moscow, Russia in 1997. He was a Post-Doctoral Research Associate with the National Technical University of Athens from 1998 to 1999 and with the University of Illinois at Urbana-Champaign from 1999 to 2003. From 2003 to 2004, he was with the Department of Custom Integrated Circuits at Cadence Design Systems in Tempe, Arizona. In 2004, he joined the Department of Electrical and Computer Engineering, University of Manitoba, where is currently an Associate Professor. His research interests are the fast algorithms of electromagnetics, high-performance computing, modeling of interconnects, and inverse problems.

Friday December 11, 2015 at 4:00 p.m. Prof. Nader Behdad of University of Wisconsin – Madison, will be presenting “Applications of Miniaturized-Element Frequency Selective Surfaces in Designing Microwave Lenses, Reflectarrays, and Polarization Converters”. Speaker: Prof. Nader Behdad University of Wisconsin – Madison Day & Time: Friday, December 11, 2015 4:00 p.m. Location: Room BA1210, Bahen Center for Information Technology 40 St. George Street, Toronto, ON, M5S 2E4 Organizer: IEEE Toronto Electromagnetics and Radiation Chapter Contact: Sean Victor Hum Abstract: Over the past several years, we have conducted research on a class of frequency selective surfaces with building blocks that consist of cascaded arrays of non-resonant, sub-wavelength periodic structures. Due to the small lateral dimensions and thicknesses of their unit cells, these structures are referred to as miniaturized-element frequency selective surfaces (MEFSSs). As spatial filters, MEFSSs can be designed to provide a wide range of response types with arbitrary levels of selectivity. MEFSSs capable of operating at extremely high incident power levels have also been developed and experimentally demonstrated for operation as spatial filters in HPM systems. Finally, MEFSSs having suppressed harmonics over extremely broad bandwidths have been developed for reduction of radar signatures of antennas and other objects. In addition to acting as spatial filters, the building blocks of MEFSSs can be used to serve other purposes as well. For example, by using the unit cells of a band-pass or a low-pass MEFSS as a spatial phase shifter or a spatial time-delay unit (TDU), wideband, true-time-delay lenses and reflectarrays may be designed. By using anisotropic versions of these spatial TDUs, wideband linear-to-circular polarization converters or polarization selective surfaces can be designed. In this presentation, I will first briefly discuss the principles of operation of MEFSSs and present examples of spatial filters developed for different applications. Subsequently, I will discuss three specific applications where the unit cells of MEFSSs are used as transmissive or reflective time-delay units. These include the development of wideband true-time-delay microwave lenses and reflectarrays as well as broadband linear-to-circular polarization converters designed using anisotropic time delay units. Biography: Nader Behdad received the B.S. degree in Electrical Engineering from Sharif University of Technology (Tehran, Iran) in 2000 and the M.S. and Ph.D. degrees in Electrical Engineering from University of Michigan (Ann Arbor, MI, U.S.A.) in 2003 and 2006 respectively. He was an Assistant Professor with the Department of Electrical Engineering and Computer Science, University of Central Florida, Orlando, FL, USA, from 2006 to 2008, and the Department of Electrical and Computer Engineering, University of Wisconsin–Madison, Madison, WI, USA, from 2009 to 2013, where he is currently an Associate Professor. His research expertise is in the area of applied electromagnetics with emphasis on electrically-small antennas, antenna arrays, antennas for biomedical applications, biomedical applications of RF/microwaves, periodic structures, frequency selective surfaces, passive high-power microwave devices, metamaterials, and biomimetics and biologically inspired systems in electromagnetics. Prof. Behdad was a recipient of the IEEE R. W. P. King Prize Paper Award in 2014, the IEEE Piergiorgio L. E. Uslenghi Letters Prize Paper Award in 2012, the CAREER Award from the U.S. National Science Foundation in 2011, the Young Investigator Award from the United States Air Force Office of Scientific Research in 2011, and the Young Investigator Award from the United States Office of Naval Research in 2011. He received the Office of Naval Research Senior Faculty Fellowship in 2009, the Young Scientist Award from the International Union of Radio Science (URSI) in 2008, the Horace H. Rackham Predoctoral Fellowship from the University of Michigan in 2005-2006, the best paper awards in the Antenna Applications Symposium in Sep. 2003, and the second prize in the paper competition of the USNC/ URSI National Radio Science Meeting, Boulder, CO, in January 2004. His graduate students were the recipients of the ten different awards/recognitions at the IEEE Pulsed Power & Plasma Science in 2013, IEEE AP-S/URSI Symposium in 2010, 2012, 2013, and 2014, and the Antenna Applications Symposium in 2008, 2010, and 2011. He serves as an Associate Editor for IEEE Antennas and Wireless Propagation Letters and served as the co-chair of the technical program committee of the 2012 IEEE International Symposium on Antennas and Propagation and USNC/URSI National Radio Science Meeting.