Representation of Electromagnetic Responses in Time Domain Using State Space System Identification Method

Speaker: Prof. Krishna Naishadham (School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, Georgia, USA)

Date: 27/03/2018 at 17.00

Location: Room “Maxwell” (DET conference room, Cittadella Politecnica, 5th floor)

Abstract

This seminar presents a control system methodology based on system identification to derive state matrices and system dynamics for the extrapolation of simulated time-domain electromagnetic (EM) responses using both input and output data. The method is applied to model transient responses for a dielectric resonator and a wideband slot antenna computed by the finite integration method (CST Microwave Studio) using non-Gaussian excitation pulses typically employed in digital signals. Using state space system identification formulation, a compact representation of the output time-domain signal is derived, including the early-time transient responses, and its numerical implementation depicts no instability (oscillations) in late-time responses plotted well beyond the steady state. Furthermore, all the system poles are found to lie within the unit circle in the complex plane. Excellent model corroboration is achieved with independently computed frequency domain data or measured results. Application of the state space method to improve efficiency in FDTD simulations will also be presented with an example on a printed antenna and a bandpass filter

Short Bio

Krishna Naishadham received M.S. from Syracuse University, and Ph.D. in Electrical Engineering from the University of Mississippi. His Ph.D. thesis formulated rigorous asymptotic methods for transient electromagnetic (EM) scattering from arbitrarily curved objects. He spent a year as Post-Doc with Prof. Leo Felsen in New York working on high-frequency spectral numerical approaches extending his thesis. Dr. Naishadham served on the faculty of Electrical Engineering as a tenured Full Professor for 15 years at the University of Kentucky and Wright State University, in the US. He taught several courses and short courses in EM, microwave and antenna design. From 2002-2008, he worked as a Senior Research Scientist at MIT Lincoln Laboratory, where he contributed novel computational EM methods and state space spectral estimation methods for radar scattering. In 2008, he joined Georgia Institute of Technology, where he is a Research Professor with ongoing research on low-power wireless chemical and biosensors, 5G antenna design and novel multifunctional antenna arrays. His research is internationally recognized, with several publications, invited talks and collaborations in these areas. He was an Associate Editor for the ACES Journal and currently serves as an Associate Editor of the International Journal of Microwave Science and Technology. He currently serves on a high-profile Review Panel at the National Institutes of Health, USA, on wireless sensors for health applications.

For any further information please contact prof. Patrizia Savi (e-mail: patrizia.savi@polito.it)

Meta-Atoms for 3D Printing Metamaterials

Prof. Yiannis Vardaxoglou, Fellow IEEE

Head of the Wireless Communications Research Group

Loughborough University, UK

Date: Thursday 14/09/2017 at 3.00 pm

Venue: Room “Nyquist” (DET meeting room, Cittadella Politecnica, 4th floor)

Abstract

In this seminar, Prof. Vardaxoglou will introduce the concept and uses of MeTa-Atoms (MTAs) in electromagnetic and egineered metamaterials. MTAs are meso scale inclusions in a host material. These meta-atoms could be varied in constitution and geometry to augment a variety of artificial and novel magneto-dielectric properties. Various 3D-printed multi-layered metamaterials with different periodicities fo dielectric or metallic inclusions will be shown. The effect of the periodicity (space between adjacent elements) on the effective metamaterials properties is examined by placing the 3D-printed samples in a waveguide simulator or on a resonator measuring system. Some of these structures have already been applied in engineering applications such as antennas, microwave lenses and electronic devices.

Biography

Yiannis Vardaxoglou is the Head of the Wireless Communications Research Group (WiCR) researching wide- ranging topics applicable to cutting-edge wireless communications technology. His research focuses primarily on metamaterial structures for electronic devices, antennas in microwave and mm-wave engineering. He has authored 300 publications and several book chapters and a pioneering book on Frequency Selective Surfaces. WiCR collaborates with many internationally leading universities and companies and is home to the internationally renowned Loughborough Antennas & Propagation Conference (LAPC).

For any further information please contact prof. Paola Pirinoli (e-mail: paola.pirinoli@polito.it)