Recent Trends in Electromagnetics and Optics
Organized by the Electronics and Telecommunication Engineering Department | IIEST, Shibpur
DST-SERB sponsored Workshop
Prof. Fernando L. Teixeira
Ohio State University, USA
Topic of Lecture:
TIME-REVERSAL TECHNIQUES for ULTRA-WIDEBAND MICROWAVE IMAGING IN RANDOM MEDIA
Abstract of Lecture:
Microwave Imaging of Obscured Objects in Random Inhomogeneous Media is of Interest in Numerous Applications. Time-reversal (TR) Imaging Techniques involve the Retransmission of Signals acquired by a Set of Transceivers in a Time-reversed Fashion to exploit the TR Invariance of the Wave Equation. TR yields Super-resolution & Statistical Stability Properties, which are not available in most Imaging Methods.
In this Presentation, we review TR-based Signal Techniques applied to Ultra-wideband (UWB) Microwave Imaging of Objects embedded in Random Inhomogeneous Media. We first considered “Signal-space” TR Methods that Multi-static Data Matrices obtained from Antenna Arrays. These methods employ an Eigenvector Decomposition of the TR Operator across the Available Bandwidth to provide the Required Time-domain Excitation Signals to be retransmitted by the Antenna Array for Selective Focusing of Multiple Targets. Next, we describe “Null-space” Methods that utilize the Eigenvectors associated with the (Approximate) Null Space of the TR Operator to obtain Desired Target Images.
We then discuss the Use of Compensation (Inverse) Filters as a means to Extend TR Techniques to Lossy Media, where the TR Invariance is broken. This is followed by a Discussion of the Relation between the Excitation Bandwidth of the Signal & the statistical stability of the Images in Random Media. Finally, we provide some Illustrative Applications including Ground Penetrating Radar, Medical Imaging & Through-wall Imaging.
A Bit About Prof. Teixeira
Fernando L. Teixeira is a Professor in the Department of Electrical and Computer Engineering and Faculty Member of the ElectroScience Laboratory at The Ohio State University (OSU). Dr. Teixeira received his Ph.D. in Electrical Engineering from the University of Illinois at Urbana-Champaign in 1999 and served as a Post-doctoral Research Associate at the Massachusetts Institute of Technology during 1999-2000, prior to joining OSU in 2000. His Research Interests & Expertise are in the Broad Area of Electromagnetics & Optics. His Present Activities include Research on Computational Electromagnetics, Process Tomography, Electromagnetic Imaging, Geoelectromagnetics, and Metamaterials. Dr. Teixeira has published over 200 Journal Papers, over 200 Conference Publications, and several US Patents on Topics related to his Areas of Research. He has served as the Main Advisor for more than 20 Ph.D. Graduates. His Research has been sponsored by several US Federal Agencies & various Industrial Organizations. He is Co-author of the Books Radiowave Propagation: Physics & Applications (Wiley, 2010) & Tropospheric and Ionospheric Effects on Global Navigation Satellite Systems (Wiley-IEEE Press, 2022). Dr. Teixeira is an IEEE Fellow & Elected Member of Commissions B and F the International Union of Radio Science (URSI).