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Tutorials

Computational Methods in Electromagnetics: Applications in Electromagnetic Compatibility, Ground Penetrating Radar, Bioelectromagnetics and Magnetohydrodynamics

Dragan Poljak, PhD

University of Split, FESB, Croatia

The lecture starts with some general aspects of computational electromagnetics and electromagnetic compatibility (EMC). The introduction outlines some well-established analytical and numerical methods.
First, a crash-course on the theory of thin wires is given and related numerical solution methods for various integral equations in both frequency and time domain will be outlined. Computational examples pertaining to dipoles, Yagi-Uda arrays and logarithmic-periodic dipole antennas (LPDA) will be presented. Then, some applications to air trafic control and ground penetrating radar (GPR) will be discussed, as well.
Furthermore, full wave (antenna) models for various thin wire structures, from rather simple to realistic complex geometries, will be outlined. This will be followed by analysis of overhead and buried transmission lines, respectively. In particular, a trade-off between the use of rigorous full wave models and approximate transmission line (TL) approach will be carried out. Particular attention will be focused to the study of PLC (Power Line Communications) configurations, modeling of lightning channel, transient analysis of realistic grounding systems (with particular emphasis to wind turbines).
Then Tutorial will tackle the human exposure to non-ionizing electromagnetic fields. Low frequency, high frequency and transient exposures related to possible adverse health effects will be discussed. Some biomedical application of electromagnetic fields, with particular emphasis on transcranial magnetic stimulation (TMS) and nerve fiber stimulation, will be also mentioned.
Furthermore some stochastic analysis methods (featuring the use of stochastic collocation (SC) technique) applied to area of GPR, grounding electrodes, human exposure to electromagnetic fields and biomedical application of electromagnetic fields will be presented.
The presentation will end up with some topics in magnetohydrodynamics pertaining to the modeling of plasma physics phenomena for the application sin thermonuclear fusion.

poljakDragan Poljak was born on 10 October 1965. He received his BSc in 1990, his MSc in 1994 and PhD in electrical engineering in 1996 from the University of Split, Croatia. He is the Full Professor at Department of Electronics, Faculty of electrical engineering, mechanical engineering and naval architecture at the University of Split, and he is also Adjunct Professor at Wessex Institute of Technology. His research interests include frequency and time domain computational methods in electromagnetics, particularly in the numerical modelling of wire antenna structures, and numerical modelling applied to environmental aspects of electromagnetic fields. To date Professor Poljak has published nearly 200 journal and conference papers in the area of computational electromagnetics, seven authored books and one edited book, by WIT Press, Southampton-Boston, and one book by Wiley, New Jersey. Professor Poljak is a member of IEEE, a member of the Editorial Board of the journal Engineering Analysis with Boundary Elements, and co-chairman of many WIT International Conferences. He is also editor of the WIT Press Series Advances in Electrical Engineering and Electromagnetics. In June 2004, professor Poljak was awarded by the National Prize for Science. In 2013 he was awarded by the Nikola Tesla Prize for achievements in Technical Sciences, in 2016. He received the prize for the achievements in engineering education from Croatian IEEE chapter and in 2017 he received the prize for science from the University of Split.
From 2011 to 2015 professor Poljak was the Vice-dean for research at the Faculty of electrical engineering, mechanical engineering and naval architecture. In 2011 professor Poljak became a member of WIT Bord of Directors. In June 2013 professor Poljak became a member of the board of the Croatian Science Foundation.

Mathematical modelling with applications in antenna theory, EMC and actuarial mathematics

Milica Rančić, PhD

Mälardalen University, UKK, Division of Applied Mathematics, Västerås, Sweden

Tutorial describes some approaches to mathematical modelling of physical problems. Applications will be illustarted on examples from the areas of antenna theory, grounding systems analysis, modelling of discharge currents and actuarial mathematics.
We start with problems related to numerical analysis of sources in presence of a lossy medium. A well-known problem of dealing with so-called Sommerfeld type integrals occurs in these analysis. Their approximate evaluation has been of great interest for researchers in the areas of antenna theory and grounding systems analysis. These integrals arise in the expressions describing the electromagnetic field in the surroundings of such structures when they are located above/inside a semi-conducting media. The fact that these integrals don’t have a closed form solution, enticed researchers to approximately evaluate them either by employing a numerical integration technique, or using some kind of procedure that will approximate them and allow their analytical evaluation.
Second part of the tutorial deals with modelling of ligthning and electrostatic discharge currents. A general function that would be able to reproduce desired waveshapes of theses currents is needed, such that analytical solutions for their derivatives, integrals, and integral transformations, exist. We present a review of existing models, their advatages and disadvartages and possible extensions.
Finally, we discuss modelling of mortality rates of living organisms or equipment. Variation of mortality over a life span has different characteristics that put constraints and requirements on a model developed to represent it. A well-know problem that complicates modelling of human mortality rates is the “accident hump” occurring in early adulthood. We review existing models and discuss their properties and application to mortality forcasting and pricing life insurances.

rancicMilica Rančić was born in Niš, Serbia, in 1977. She received the Dipl. ing, M.Sc. and Ph.D. degrees from the Faculty of Electronic Engineering of University of Niš in 2002, 2008 and 2012, respectively.
Her research interests are numerical methods with application to antenna theory, grounding sys-tems, lightning and electrostatic discharge modelling, and financial engineering. As an author or co-author, she has published a number of journal, conference papers, and book chapters treating mentioned problems. As a researcher she has contributed five scientific projects funded by the Ministry of Science and Technological Development of Republic of Serbia, three international Joint German-South-Eastern European Network projects supported by the DAAD foundation, and EUROWEB project in the frame of the Erasmus Mundus programme.
In the period of 2003-2004 she has been employed as a research/teaching assistant at the Dept. of Metrology, Faculty of El. Engineering, University of Niš, Serbia, and during 2004-2013 at the Dept. of Theoretical El. Engineering at the same University. During the period 2013-2014 she was a postdoc fellow at Mälardalen University, UKK, Division of Applied Mathematics where she now works as a senior lecturer, head of the division and programme coordinator for BSc in Analytical finance and MSs in Financial Engineering.

Managment of the variability and uncertainty in electromagnetism and dosimetry using advanced parsimonious stochastic methods

Joe Wiart, PhD

LTCI, Telecom ParisTech, France

Thanks to the important progress in high performance calculation, numerical simulations have an increasing role in applied electromagnetics and in particular in numerical dosimetry. Numerical methods such as the Finite Difference in Time Domain (the well known FDTD) are more and more used to design system, antennas and assess performances and quantities such human exposure. Despite such increasing progress in high performance calculations, the versatile use of the RF communication devices and the increasing complexity of the networks have created challenges for the usual ”deterministic ”approaches used for assessment of the human population RF exposure. Statistical methods and meta-modeling can help to overcome these limits
The tutorial will introduce the concepts of the the meta-modeling, uncertainty propagation and quantification using advanced statistical methods.The introduction will outline first well-established statistical methodshen, Then advnced parsimonious methods such as Planning Experiment, Polynomial Chaos Expansion, Kriging or Low rank tensors approximation aiming to built meta-model, having a quick computation time, able to be substituted to time consuming calculation methods such as FDTD. The talk, illustrated with studies performed in dosimetry will explain how manage variability, perform uncertainty quantification and carry out sensitiviity analysis.

wiartJoe Wiart PhD (95), Engineer of Telecommunication (92) is the holder of the Chair C2M (Caractérisation, Modélisation et Maitrise) of the Institut Mines Telecom – Telecom-ParisTech (http://chairec2m.mines-telecom.fr). He was previously the head of the dosimetry research unit of Orange (former France Telecom). He is the present chairman of the TC106x of the European Committee for Electrotechnical Standardization (CENELEC) and of International Union of Radio Science (URSI) commission K. He has been the Chairman of the French chapter of URSI and consultant of ICNIRP. He is emeritus member of The Society of Environmental Engineers (SEE) since 2008 and senior member of Institute of Electrical and Electronics Engineers (IEEE) since 2002. He has led several national and European projects dedicated to dosimetry (e.g LEXNET project http://www.lexnet-project.eu/ 2012-2015). His research interests are RF dosimetry, numerical methods and statistic applied in electromagnetism and dosimetry. His works gave rise to more than 120 publications in journal papers and more than 150 communications (among which of numerous invited communications).

Structuring Electromagnetic Problems – A Clear Path in the Design of Electromagnetic Structures

Zvonimir Šipuš, PhD

Faculty of Electrical Engineering and Computing, University of Zagreb, Croatia

Design of electromagnetic devices in most cases is a very demanding engineering task. As analytical solutions can only be carried out for canonical geometries, in practice the design of electromagnetic structures is done solely with the help of commercial numerical programs. The lecture will consider the importance of structuring the electromagnetic problem we need to solve. In other words, for a successful construction of a structure, it is necessary to have a clear electromagnetic concept of the device we would like to design, that is, we should not rely solely on the optimization potential offered by every commercial electromagnetic program. The importance of structuring electromagnetic problems will be illustrated by a few examples – on soft and hard surfaces and waveguides with periodic structures having electromagnetic bandgap property. Furthermore, the theorem of equivalence allows us to divide the complex electromagnetic problem into a few simpler sub-problems that can be much simpler to solve. In this way we can build our own software support for the analysis of complex electromagnetic structures. This possibility will be illustrated in several examples, from the construction of an algorithm for calculating Green’s functions of multilayer structures to the analysis of an electromagnetic invisible cloak.

sipusZvonimir Šipuš was born in Zagreb, Croatia, in 1964. He received the B.Sc. and M.Sc. degrees in electrical engineering from the University of Zagreb, Croatia, in 1988 and 1991, respectively, and the Ph.D. degree in electrical engineering from Chalmers University of Technology, Gothenburg, Sweden, in 1997.
From 1988 to 1994, he worked at Rudjer Boskovic Institute, Zagreb, Croatia, as Research Assistant, involved in the development of detectors for explosive gases. In 1994, he joined the Antenna Group at Chalmers University of Technology, where he was involved in research projects concerning conformal antennas and soft and hard surfaces. In 1997, he joined the Faculty of Electrical Engineering and Computing, University of Zagreb, where he is now a Professor. Currently, he is the Head of the Department of Wireless Communications. From 1999 to 2005, he was also an Adjunct Researcher at the Department of Electromagnetics, Chalmers University of Technology. Since 2006 he was engaged in teaching in the European Doctoral School of antennas (ESoA). His main research interests are in the area of analysis and design of electromagnetic structures and in the area of optical communication and sensor systems.
Prof. Šipuš is the author or co-author of more than 50 scientific papers published in scientific journals. He is also the co-author of several EM softwares for analyzing planar and conformal antennas and scatterers. He received the annual national science award in 2006 for research of conformal antennas and periodic structures.

Matrix Pencil Method applied to smart metering, electromagnetics and bioelectromagnetics phenomena

Khalil El Khamlichi Drissi, PhD

Institut Pascal, CNRS, UMR6602, Clermont Auvergne University, France

Tutorial will deal with the Matrix Pencil method, an efficient numerical method to identify deterministic signals based on either simulation or measurement. The method is usually referred to as a high-resolution technique as it is capable to identify non-stationary signals, even in the presence of numerical or experimental noise, respectively. The basis functions are complex exponentials with a damping factor. Those functions are rather appropriate to identify electromagnetic waves or distributed currents with an optimal number of elements. The method is applied either in time, frequency or in space domain providing one to identify the original signal by means of a limited number of singular values, poles and residues.
The applications of interest in this tutorial are: Non-Intrusive identification and load monitoring in residential areas, radiated ElectroMagnetic Field by multiconductor Transmission Line system and also UWB radar for communication, localization and/or target identification.
The talk will end up presenting our recent application: based on this high-resolution method, reliable, rapid and reproducible, one analyze the activity of peripheral fibers Aδ and C transporting nociceptive information from peripheral nervous system. Using electrophysiological recordings such as the electroneurogram (ENG) or electroencephalogram (EEG), the main objective is to extract specific identifiers for migraine pain.

drissiKhalil El Khamlichi Drissi received the Diploma Engineer, M. Sc., and PhD degrees in Electrical Engineering from Ecole Centrale de Lille and the University of Lille, in 1987 and 1990 respectively. He received the Habilitation in electronics, the highest qualification in France; at the Doctoral School “Sciences Pour l’Ingénieur” of Blaise Pascal University, in 2001. He became Full Professor at the Department of Electrical Engineering where he was the dean in the period from 2007 to 2011. He is also senior researcher at Pascal Institute.
Pr. El Khamlichi Drissi is an IEEE member, in Electromagnetic Compatibility and Power Electronics societies. He is also member of EEA and chairman of SEE Auvergne since 2002 (Society of Electricity, Electronics and Information and Communication Technologies), appointed senior member on 2003.
Pr. El Khamlichi Drissi became Vice President of Research Valorisation, UBP chancellor board from 2012 to 2016. Currently, he is Vice Regional Delegate of Research and Technology (DRRTA) for The Auvergne-Rhône-Alpes Region.
Pr. El Khamlichi Drissi research interests include EMC in Power Electronics and Power Systems, in particular; numerical modeling, EMI reduction and converter control. He authored or coauthored more than 200 scientific papers published in peer-review journals and presented at international conferences and 6 WO patents. He has been chairperson and member of scientific committees at international conferences. He is expert for different French agencies (ANRT, ANR, HCERES, DGRI), for the Croatian Science Foundation and for the Shota Rustaveli National Science Foundation. He is project leader and responsible for several international projects related to EMC (FP7 Marie Curie, Econet, Cogito, Integrafm, Cedre, Toubkal, Tassili, etc.…) and a partner within the Brain City Research Institute. He currently has an on-going collaboration with different companies (IFPEN, EDF, France Telecom and Landis+Gyr).

Main research experience
• Power converter control based on Space Vector Modulation
• Common mode reduction in power converter
• Modeling of full-wave methods for the solution of electromagnetic problems by using Transmission Lines Methods in Frequency Domain and Time Domain
• Automatic Target classification based on radar backscattered UWB signals
• Numerical identification based on Matrix Pencil Method in time domain and in frequency domain