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
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.