General Lecture 1 (11:00-12:00, Wednesday, August 1, 2018)
(coming up soon)
General Lecture 2 (11:00-12:00, Thursday, August 2, 2018)
Challenges in Metamaterial and Metasurfaces Design for Practical Antenna Applications
Speaker: Raj Mittra, University of Central Florida, USA
Metamaterials (MTMs) were introduced to the EM world by Veselago in a seminal paper back the 60’s, in which he argued that materials with DNG (double-negative) characteristics, whose e and m are both negative, would exhibit exotic properties such as subwavelength resolution, when used in devices such as lenses. Since then other interesting properties of MTMs have been identified, and their applications to cloaking, performance enhancement of small antennas, and related areas, have been proposed. More recently, there has been considerable interest in the topic of Metasurfaces (MTSs), as opposed to volume-type materials, that have been employed to control the propagation of EM waves with applications to communication antennas.
Despite a flood of publications on MTMs and related topics—literally thousands during the last 10 years—the number of real-world applications in which MTMs and MTSs have been utilized have been rather limited. The primary reason for this is the lack of availability of the materials needed to fabricate devices such as those that reduce the size of antennas without compromising their performance in terms of gain, bandwidth, and efficiency, for instance, or shrouds (cloaks) that suppress the electromagnetic scattering from radar targets, to name just a few. A similar situation arises when one attempts to design an antenna, or a similar device, using Transformation Optics (TO), a relatively new concept which was recently introduced by Pendry, among others. In this approach, the transformation of one coordinate system to another is used to modify the geometry of an antenna, without altering its performance, by replacing the original material properties with new ones that can be rigorously determined by applying the principles of TO to Maxwell’s equations. An example of such a device is a flat Luneburg lens which is derived by transforming the conventional spherical Luneburg lens, to render it easier to fabricate. The caveat is that the TO algorithm calls for e and m materials that are not available naturally, e.g., MTMs. The same is also true for a wide variety of other devices, such as flat GRIN (graded index) lenses and Reflectarrays (RAs), which require materials that are unavailable off-the-shelf and, hence, must be synthesized artificially.
In light of this background on MTMs, this presentation will focus on the topic of artificial synthesis of materials with real-world applications in mind. We will review the different strategies that have been proposed, will identify the ones that have been successfully implemented, provide several practical examples of the same, and go on to discuss the challenges that still need to be met--not the least of which is cost-effective fabrication--to satisfy the ever-increasing demands posed by emerging technologies, such as IoT and 5G.
The topic of Additive Manufacturing for low-cost fabrication of MTMs also being pursued a by several groups around the world will be covered, and some issues particularly related to this topic will be examined.
Raj Mittra is a Professor in the Department of Electrical Engineering & Computer Science department of the University of Central Florida in Orlando, FL., where he is the Director of the Electromagnetic Communication Laboratory. Prior to joining the University of Central Florida, he worked at Penn State as a Professor in the Electrical and Computer Engineering from 1996 through June, 2015. He was a Professor in the Electrical and Computer Engineering at the University of Illinois in Urbana Champaign from 1957 through 1996, when he moved to the Penn State University. Currently, he also holds the position of Hi-Ci Professor at King Abdulaziz University in Saudi Arabia.
He is a Life Fellow of the IEEE, a Past-President of AP-S, and he has served as the Editor of the Transactions of the Antennas and Propagation Society. He won the Guggenheim Fellowship Award in 1965, the IEEE Centennial Medal in 1984, and the IEEE Millennium medal in 2000. Other honors include the IEEE/AP-S Distinguished Achievement Award in 2002, the Chen-To Tai Education Award in 2004 and the IEEE Electromagnetics Award in 2006, and the IEEE James H. Mulligan Award in 2011.
Recently he founded the e-Journal FERMAT (www.e-fermat.org) and has been serving as the co-editor-in-chief of the same. Dr. Mittra is a Principal Scientist and President of RM Associates, a consulting company founded in 1980, which provides services to industrial and governmental organizations, both in the U.S. and abroad.
General Lecture 3 (11:00-12:00, Friday, August 3, 2018)
(coming up soon)
General Lecture 4 (11:00-12:00, Saturday, August 4, 2018)
(coming up soon)