PIERS 2018 Toyama Pre-Conference Workshop
Prior to the conference, a Workshop will be held on July 31, 2018, where all the paid registrants of PIERS 2018 Toyama are invited to attend without any extra fee nor any advance reservation.
Date: July 31, 2018
Time: 13:30-17:45 (Registration Desk will open at 12:30.)
Venue: Toyama International Conference Center
Fee: Free (included in the PIERS 2018 Toyama registration fee)
Talk 1 (13:30-14:15)
A Simple Collective Ray Description For The EM Radiation By Conformal Phase Scanned Antenna Arrays On Locally Smooth Convex Surfaces
Speaker: Prabhakar H. Pathak, Professor Emeritus, The Ohio State University, USA
A collective uniform geometrical theory of diffraction (UTD) ray solution is described for efficiently analyzing the radiation from large phase scanned antenna arrays mounted conformally on locally smooth convex surfaces. This collective UTD describes the radiation from an entire, large, phased array in terms of just a few rays; this is in contrast to the brute force array element by element field summation via UTD. In so doing, the collective UTD provides a vivid physical description for the array radiation mechanisms. The UTD solution is useful in predicting the radiation performance of large conformal phased arrays on larger locally convex but otherwise complex platforms which may occur in modern applications. The basic ideas are demonstrated via the analysis of canonical problems involving the radiation by finite size linear periodic phased arrays placed either along the axial or along the circumferential directions on a PEC circular cylinder, and excited with a uniform amplitude and appropriate phase distribution for scanning in a given direction. An asymptotic high frequency analysis, which is applicable here, is seen to yield a collective UTD description for the fields of the array in terms of basically three rays which arrive at an observation point in the near or far zone in the region external to the array but not too close to it. One such ray originates from an appropriate point interior to the array and constitutes the Floquet modal ray which exists as if the axial array was infinitely long, or the circumferential array completely wrapped the cylinder. The remaining two rays arrive from each end of the finite linear array and thus constitute the Floquet modal diffracted fields arising from the array truncation. An extension of this work to tapered array source distributions and to surface array distributions (as opposed to linear arrays) will also be briefly discussed.
Prabhakar H. Pathak received his Ph.D. (1973) in Electrical Engineering from the Ohio State University (OSU). Currently he is Professor Emeritus at OSU, and Adjunct Professor at the Univ. of South Florida. Prof. Pathak is regarded as a codeveloper of the uniform geometrical theory of diffraction (UTD). His research interests continue to be in the development of new UTD ray solutions in both the frequency and time domains, as well as in the development of fast beam and hybrid (ray and numerical) methods for analyzing electrically large electromagnetic (EM) antenna and scattering problems, including reflector systems and conformal phased arrays. His work includes the development of analytical tools for predicting EM radiation and mutual coupling associated with antennas/arrays on large airborne/spaceborne platforms. He is also working on novel methods related to near field measurements of far zone antenna patterns. Prof. Pathak has been presenting short courses and invited talks at conferences and workshops both in the US and abroad. He has authored/coauthored over hundred journal and conference papers, as well as contributed chapters to seven books. Prior to 1993, he served two terms as an associated editor for IEEE Trans AP. He was appointed IEEE AP-S distinguished lecturer during 1991-1993, and was later appointed as chair of the distinguished lecturer program for the IEEE AP-S during 1995-2005. He was an IEEE AP-S AdCom member in 2010. He received the 1996 Schelkunoff best paper award from IEEE AP-S; the ISAP 2009 best paper award, the George Sinclair award (1996) from the OSU ElectroScience Laboratory, and the IEEE Third Millenium medal from AP-S in 2000. Prof. Pathak received the IEEE AP-S distinguished achievement award in 2013. He is an IEEE Life Fellow and a member of URSI commission B.
Talk 2 (14:15-15:00)
Stochastic Method for Solving Certain EM Field Computation Problems
Speaker: Ramakrishna Janaswamy, The University of Massachusetts Amherste, USA
Stochastic method, wherein the solution of a boundary value problem in electrostatics or electrodynamics is represented as an ensemble average of a stochastic process generated by the underlying partial differential equation, is very attractive in electromagnetics because (i) it permits the solution in any subregion of a computational domain without having to determine the field everywhere, (ii) the solution is amenable to complete parallelization, and (iii) the solution can be generated without an explicit mesh. We discuss here the basics of the stochastic formulation and apply the method to the solution of Poisson’s equation and the Helmholtz equation. The latter will involve examples below the first resonance for normal media and for any frequency in plasmonic media.
Ramakrishna Janaswamy is a Professor in the Department of Electrical & Computer Engineering, University of Massachusetts, Amherst. His research interests include deterministic and stochastic radio wave propagation modeling, analytical and computational electromagnetics, antenna theory and design, and wireless communications. He is Fellow of IEEE and an elected member of U.S. National Committee of International Union of Radio Science, Commissions B and F. He is a recipient of the R. W. P. King Prize Paper Award of the IEEE Transactions on Antennas and Propagation and the IEEE 3rd Millennium Medal. He served as an Associate Editor of Radio Science, the IEEE Transactions on Vehicular Technology, the IEEE Transactions of Antennas and Propagation and the IET Electronics Letters. He is an IEEE Standards Activity member representing the IEEE Antennas and Wave Propagation Standards. He is the author of the book Radiowave Propagation and Smart Antennas for Wireless Communications, Kluwer Academic Publishers, November 2000, and a contributing author in Handbook of Antennas in Wireless Communications, L. Godara (Ed.), CRC Press, August 2001 and Encyclopedia of RF and Microwave Engineering, John Wiley and Sons, 2005.
Talk 3 (15:00-15:45)
Metamaterials, Anapoles and Flying Donuts
Speaker: Nikolay Zheludev, University of Southampton, UK & Nanyang Technological University, Singapore
Metamaterials have been the platform for experimental development of a new chapter in electrodynamics devoted to toroidal and anapole modes of excitation and the generation of electromagnetic flying donuts. Electromagnetic toroidal dipoles can be represented as currents flowing on the surfaces of tori. They provide physically significant contributions to the basic characteristics of matter including absorption, dispersion, and chirality. They give rise to dynamic anapoles, illusive non-radiating charge-current configurations. Toroidal excitations also exist in free space as spatially and temporally localized electromagnetic pulses propagating at the speed of light and interacting with matter in a way different from conventional electromagnetic transvers pulses. We discuss these recent findings and the role of localized and propagating electromagnetic toroidal excitations in light-matter interactions, spectroscopy and telecommunications.
Nikolay Zheludev, directs the Centre for Photonic Metamaterials at Southampton University, UK and Centre for Disruptive Photonic Technologies at Nanyang Technological University, Singapore. He is also deputy director of the Optoelectronics Research Centre at Southampton and co-Director of the Photonics institute at NTU, Singapore. His research interests are in nanophotonics and metamaterials. His personal awards include the Thomas Young Medal for “global leadership and pioneering, seminal work in optical metamaterials and nanophotonics”, Senior Professorships of the Engineering and Physical Sciences Research Council (UK) and the Leverhulme Trust and the Royal Society Wolfson Research Fellowship. Professor Zheludev is the Editor-in-Chief of the IOP "Journal of Optics" and advisor to the Nature-Springer publishing group.
Talk 4 (16:15-17:00)
Contribution of Electromagnetics to Humanitarian Demining and UXO Clearance
Speaker: Motoyuki Sato, Tohoku University, Japan
Humanitarian demining and UXO clearance have gathered interest all over the world last 20 years, however, it is still quite important activity in many mine/UXO affected countries. Since the Ottawa treaty established in 1997, land mine problems have been widely known, and we have continued efforts to demolish all the landmines including buried mines in mine affected countries. Even though, we have noticed that in many mine affected countries, mine clearance is not an easy task and we have to continue this effort. It is reported that accidents caused by landmines occurred in 56 countries in 2016, and more than 9,000 people were killed or injured. As of November 2017, landmines remains in 61 countries.
In order to detect buried landmines and UXO, electromagnetic techniques have widely been used. Electromagnetic Induction Sensor (EMI sensor) is one of the most commonly used sensor for detection of metal objects. Most of UXO are made of metal and most types of landmines contain metal components, which can be detected by EMI sensor. In addition, recently, Ground Penetrating Radar (GPR) has also been used for humanitarian demining, because it can detect non-metal objects. In this workshop, at first I will introduce these techniques.
Then, we introduce more actual activities. Tohoku University has developed ALIS for humanitarian demining. ALIS is a handheld “Dual sensor” which combines EMI sensor and GPR. This is a hand held sensor, equipped with position tracking system, therefore ALIS can acquire the EMI and GPR signal together with its position information, while it is scanned on the ground surface by an operator by hand manually. Then, the data can be processed using Synthetic Aperture Radar (SAR) processing (migration) and can reconstruct 3-D subsurface image. GPR of ALIS operates at 1-3GHz, and the penetration depth of the GPR is 20- 50cm. The development of ALIS started in 2002, and after evaluation test in some mine affected countries including Afghanistan, a long-term evaluation test has been conducted in Cambodia since 2009.We found that the prototype of ALIS is capable for imaging buried mines, and can reduce the false alarm ratio drastically. We have detected more than 80 buried land mines in Cambodia mine fields. The ALIS is based on these practical evaluation conducted together with CMAC (Cambodian Mine Action Center). The new ALIS system is compact and light weight which is less than 3.1kg, and can be used for more than 6 hours. It was evaluated in CMAC test site in 2018, and we demonstrated its high performance.
Motoyuki Sato received the B.E., M.E degrees, and Dr. Eng. degree in information engineering from the Tohoku University, Sendai, Japan, in 1980, 1982 and 1985, respectively. Since 1997 he is a professor at Tohoku University and a distinguished professor of Tohoku University since 2007, and he was the Director of Center for Northeast Asian Studies, Tohoku University during 2009-2013. In 1988, he was a visiting researcher at the Federal German Institute for Geoscience and Natural Resources (BGR) in Hannover, Germany. His current interests include transient electromagnetics and antennas, radar polarimetry, ground penetrating radar (GPR), borehole radar, electromagnetic induction sensing, interferometric and polarimetric SAR. He has conducted the development of GPR sensors for humanitarian demining, and his sensor ALIS which is a hand-held dual sensor, has detected more than 80 mines in mine fields in Cambodia. He received 2014 Frank Frischknecht Leadership Award from SEG for his contribution to his sustained and important contributions to near-surface geophysics in the field of ground-penetrating radar. He received IEICE Best paper award (Kiyasu Award), and IEEE Ulrich L. Rohde Innovative Conference Paper Awards on Antenna Measurements and Applications both in 2017. He is a visiting Professor at Jilin University, China, Delft University of Technology, The Netherlands, and Mongolian University of Science and Technology.
Talk 5 (17:00-17:45)
Computational Bioelectromagnetics: Human Safety, Healthcare and Medical Applications
Speaker: Akimasa Hirata, Nagoya Institute of Technology, Japan
The adverse health effects caused by the electromagnetic field exposures at low- and radio-frequencies are the stimulation and thermal effect, respectively. International guidelines/standards for human exposure safety have been set to prevent from the effects. In the guidelines/standards, the limits are prescribed in terms of the internal physical quantities; in-situ electric field at low frequencies and specific absorption rate (SAR) at radio frequencies. The SAR is a surrogate of the temperature elevation.
When providing the rational for the guidelines/standards, the threshold for inducing the health effect should be assessed. The computational electromagnetics, in addition to the thermodynamics for radio-frequency exposure, is powerful and essential tool in the standardization. Computational techniques for electromagnetics in human have been developed for exposure safety; magneto-quasi-static approximation techniques at low frequencies and full-wave analysis at radio frequencies. A committee on EMF dosimetry modeling has been formed under the IEEE International Committee on Electromagnetic Safety.
Combining computational electromagnetics with modeling techniques of human body from medical images, integrated computational techniques are used for healthcare and medical applications. For example, in the non-invasive brain stimulation (e.g., transcranial magnetic stimulation, transcranial direct current stimulation etc), personalized electrostimulation strategy using combined computational techniques becomes common. This is the same for hyperthermia, radio-frequency ablation, etc.
In this talk, computational techniques for bioelectromagnetics in different frequency ranges will be reviewed first, and then the role of computational bioelectromagnetics for setting the limit in the safety guidelines will be explained, together with current research agenda. A risk management system of heat-related illness and diagnosis systems for the brain function will be reviewed, together with future perspective in this research field.
Dr. Hirata is Director and Professor of Research Center of Bioelectromagnetic Engineering, Nagoya Institute of Technology. He serves as WHO Expert and a member of the main commission of International Commission on Non-Ionizing Radiation Protection (ICNIRP) where he leads a project group on dosimetry (engineering/physics modeling). He also serves administrative member and chairperson of subcommittee 6 of IEEE International Committee on Electromagnetic Safety. He won several awards including Japan Academy Medal (2018), IEEE EMC-S Technical Achievement Award (2015), Prizes for Science and Technology (2014 Public Understanding Category and 2011 Research Category) from Ministry of Education, Culture, Sports, Science and Technology, Japan. He is Fellow of IEEE and Institute of Physics.