Keynote 1

Multibeam Antennas Without BFN

Stefano Maci, University of Siena, Siena, Italy

Abstract

Recent developments in gradient-index (GRIN) and metasurface-based antennas are enabling low-cost, compact, and highly directive multibeam solutions without the need for traditional beamforming networks (BFNs). By replacing complex RF feeding systems with passive spatial field control, these approaches provide substantial reductions in hardware complexity, size, and overall cost. This talk highlights efficient GRIN lens synthesis techniques tailored for multifocal and multibeam operation. A generalized design methodology—going beyond classical ray-based assumptions—enables accurate refractive-index profiles that maintain stable radiation characteristics over wide frequency ranges. Supported by a fast geometrical optics solver based on the Fast Sweeping Method, this approach allows the direct computation of spatial index distributions required to produce prescribed field patterns, enabling precise passive beam shaping and steering. In addition, we present several metasurface (MTS) antenna solutions based on both space-wave manipulation and surface-wave excitation by multiple point sources. These planar architectures employ engineered impedance or phase profiles to efficiently transform guided or incident waves into multiple directive free-space beams, entirely without BFNs. The proposed MTS antennas are inherently thin, low-profile, and compatible with low-cost fabrication techniques.  Overall, the talk presents a comprehensive set of MTS antenna solutions spanning multiple architectures and operating over large frequency ranges, demonstrating the versatility and effectiveness of GRIN and metasurface concepts for next-generation multibeam antenna systems

Biography

Stefano MACI is a Professor at the University of Siena (UNISI). Since 2000, he has been P.I. of 10 research projects funded by the European Union (EU) and by the European Space Agency (ESA). He is a Fellow of IEEE since 2004. In 2004 he founded the European School of Antennas (ESoA), a PhD school that presently comprises 35 courses on Antennas, Propagation, and Electromagnetic Theory, and 200 teachers, among them 20 IEEE Fellow. He graduated more than 40 PhD students. He has been former member of IEEE Antennas and Propagation Society (AP-S) AdCom, the Chair of the Award Committee of the IEEE AP-S, member of the AP Executive Board of IET (UK), Distinguished Lecturer of IEEE and of EurAAP. He was recipient of several prizes and awards, among which the EurAAP Award 2014, the Chen-To Tai Distinguished Educator award 2016, of the Shelkunoff Transaction Prize in 2015, and of the URSI Dellinger Gold Medal in 2020. He is presently Director of ESoA. He has been TPC Chair of the METAMATERIAL 2020 and and General Chair of EuCAP 2023. He was the president of the IEEE Antennas and Propagation Society 2023.  In the last ten years he has been invited 60 times as key-note speaker in international conferences. His research activity is documented in 200 papers published in international journals, (among which 100 on IEEE journals), 10 book chapters, and about 450 papers in proceedings of international conferences.  

Keynote 2

 Metamaterials in electromagnetics

Ari Sihvola, President of the International Union of Radio Science — URSI ; Aalto University, Finland

Abstract

One of the game-changing directions of research in electromagnetics engineering in the present century is the field of metamaterials. This new paradigm does focus not only on the volumetric material level but also designs like metasurfaces, metadevices, and metasystems have been introduced and developed in the present-day engineering research. Furthermore, metamaterials are no longer a privilege of electrical engineering: there exists a large amount of scientific literature about acoustic, thermal, and mechanical metamaterials, to name some of the fields in which this new approach to look at materials and systems has penetrated.

However, one may raise the question whether this approach is new and novel. By metamaterials one usually refers to man-made, carefully designed composite structures whose geometrical arrangements and material properties of the elements create novel properties on a macroscopic level, such properties that are not present in the constitutive materials that compose the continuum. Hence the analysis of metamaterial properties can be seen as a homogenization process. From this point of view, metamaterials are not a totally new innovation of the present century but they can be seen as continuation of research on heterogeneous and complex (even random) materials in which new phenomena may appear, like anisotropy, non-reciprocity, optical activity, dispersive effects, etc. In the presentation, I will take a historical view on the development of metamaterials research and illuminate the richness of the wider field of complex media electromagnetics.

Biography

Ari Sihvola received the degree of Doctor of Technology in 1987 from the Helsinki University of Technology (TKK), Finland (presently Aalto University). Besides working for TKK, Aalto, and the Academy of Finland, he was visiting engineer in the Research Laboratory of Electronics of the Massachusetts Institute of Technology, Cambridge, in 1985–1986. In 1990–1991, he worked as a visiting scientist at the Pennsylvania State University, State College. In 1996, he was visiting scientist at the Lund University, Sweden. He was visiting professor at the Electromagnetics and Acoustics Laboratory of the Swiss Federal Institute of Technology, Lausanne (academic year 2000–01), in the University of Paris 11, in Orsay (June 2008), and in the University of Rome La Sapienza (May–June 2015). His research interests include waves and fields in electromagnetics, modeling of complex media and metamaterials, remote sensing, education in physics and engineering, and history of electrical engineering. He is presently professor in the School of Electrical Engineering at the Aalto University. Ari Sihvola is President of the International Union of Radio Science (URSI) and Life Fellow of IEEE.

Keynote 3

Solutions to Butler Matrix Limitations

Ahmed A. Kishk

Concordia University, Montreal, Canada

Abstract

The talk presents a quick review of the analog beamforming network based on the Butler Matrix (BM). BM components are usually hybrid couplers, phase shifters, and crossovers. Basic BM provides beams equal to the number of input ports, with an order of 2N × 2N, meaning the number of beam ports is 2N, which equals the antenna ports. Therefore, BM is of order M x M. Due to orthogonality, all beams can be simultaneously formed into a multibeam system. Basic BM provides one-plane scanning, except for the 4 x 4 BM, which can be used for a 2x2 planar array that provides four beams in two different planes. For 2D scanning, two stacks of conventional BMs are cascaded in an orthogonal configuration, with each stack responsible for one scanning plane. Such an arrangement provides 2D scanning capabilities, but it is bulky and complicated. As BM orders increase, the number of components increases significantly. Therefore, in this talk, we will present solutions for the limited number of beams and the bulky structure of the BM for 1D and 2D scanning. A proposed solution for a compact BM using multilayers is also presented.

In the first subject, a scheme to extend the BM's beam count by using reconfigurable couplers is presented and experimentally verified. The beam count of a traditional 2N × 2N BM is increased to 3∙2N by replacing all hybrids with reconfigurable couplers, while maintaining the original structure and other components. Moreover, only N distinct parameter sets are required for these couplers. The principle, properties, and generalized expressions for the N sets of parameters are discussed and exhibited. The properties of the extended beams are illustrated in terms of beam directions and crossover levels. As an example, a switchable 12-beam forming network based on a 4 × 4 Butler matrix for 2.4 GHz applications is fabricated and tested. Over a 30% relative bandwidth, phase errors are less than ±12°, amplitude unbalances are lower than ±1.7 dB, isolation is better than -15.5 dB, and return loss is better than 11.5 dB.

The second subject presents the principles and design methods of two novel devices: the two-dimensional Butler matrix (2D-BM) and the phase-shifter group. The 2D-BM has 2M+N × 2M+N configurations that can be built from the traditional 2M×2M and 2N×2N BMs, and all output ports can be arranged in a parallelogram configuration to fit the planar array. The main features of traditional BMs, such as perfect matching, lossless transmission, spatially orthogonal beams, and equal-power division, can be entirely retained in 2D BMs. As an integral component of 2D-BMs, phase-shifter groups are employed to provide more than two distinct phase delays along various paths without reference lines. The design procedure of the 2D-BM and the analytical solution of the phase-shifter group are discussed and illustrated. As experimental verification, a 2D-BM with a 16 × 16 configuration feeding a 4 × 4 square array for 2.4 GHz applications is fabricated and tested. Satisfactory performance in matching, isolation, equal-power division, and progressive phase differences across all ports is observed over a 17% relative bandwidth.

Biography

Ahmed A. Kishk received a BSc in Electronics and Communication Engineering from Cairo University, Cairo, Egypt, in 1977, and a BSc in Applied Mathematics from Ain Shams University, Cairo, Egypt, in 1980. In 1981, he joined the Department of Electrical Engineering at the University of Manitoba in Winnipeg, Canada, where he obtained his M.Eng. and Ph.D. degrees in 1983 and 1986, respectively. From 1977 to 1981, he served as a research assistant and instructor at the Faculty of Engineering, Cairo University. From 1981 to 1985, he was a research assistant in the Department of Electrical Engineering at the University of Manitoba. From December 1985 to August 1986, he was a research associate fellow in the same department. In 1986, he joined the Department of Electrical Engineering at the University of Mississippi as an assistant professor. He was on sabbatical leave at the Chalmers University of Technology, Sweden, during the 1994-1995 and 2009-2010 academic years. He was a Professor at the University of Mississippi (1995-2011). He was the director of the Center for Applied Electromagnetic System Research (CAESR) from 2010 to 2011. He has been a professor at Concordia University, Montréal, Québec, Canada (since 2011) and Tier 1 Canada Research Chair in Advanced Antenna Systems (2011-2025). He was an Associate Editor of Antennas & Propagation Society Newsletters from 1990 to 1993. He is a distinguished lecturer for the Antennas and Propagation Society (2013-2015). He was the Editor of Antennas & Propagation Magazine (1993-2014). He was a Co-editor of the special issue, “Advances in the Application of the Method of Moments to Electromagnetic Scattering Problems,” in the ACES Journal. He was also an editor of the ACES Journal in 1997. He was the Editor-in-Chief of the ACES Journal from 1990 to 2001. He was the chair of the Physics and Engineering Division of the Mississippi Academy of Science (2001-2002). He was a Guest Editor of the special issue on artificial magnetic conductors, soft/hard surfaces, and other complex surfaces in the IEEE Transactions on Antennas and Propagation, January 2005. He was a co-guest editor for IEEE Antennas and Propagation and IEEE Wireless Letters on the special cluster, “5G/6G enabling antenna systems and associated testing technologies.” He served on the technical program committees of several international conferences. He was a member of the AP-S AdCom (2013-2015). He was the 2017 AP-S president.

Prof. Kishk's research interest is broad in Electromagnetic Applications. He has recently worked on millimeter-wave antennas for 5G/6G applications, Analog beamforming networks, Electromagnetic Bandgap Structures, artificial magnetic conductors, soft and hard surfaces, phased array antennas, reflectarrays/transmitarrays, and wearable antennas. In addition, he is a pioneer in Dielectric resonator antennas, microstrip antennas, small antennas, microwave sensors, RFID antennas for readers and tags, Multi-function antennas, microwave circuits, and Feeds for Parabolic reflectors. He has published over 507 refereed journal articles, 570 international conference papers, and 125 local and regional conference papers. He co-authored four books and 13 chapters and served as the editor of eight books. He offered several short courses at international conferences. According to Google Scholar, his work has been cited over 39,378 times, with an H-index of 84 and an i10-index of 487. The bibliometric data used to estimate citation-based metrics were collected on February 2, 2026. Prof. Kishk was ranked first at Concordia University, 23rd in Canada, and 401st worldwide. ScholarGPS has placed Dr. Kishk in the top 0.05% of all scholars worldwide, with #231 in Electrical Engineering, #4 in Antennas, #5 in Dielectric, and #78 in Microwave.

Prof. Kishk and his students received several awards. He won the 1995 and 2006 Outstanding Paper Awards for papers published in the Journal of the Applied Computational Electromagnetics Society. He received the 1997 Outstanding Engineering Educator Award from the IEEE Memphis Section. He received the Outstanding Engineering Faculty Member of the Year in 1998 and 2009 and the Faculty Research Award for outstanding research performance in 2001 and 2005. He received the Distinguished Technical Communication Award from the IEEE Antennas and Propagation Magazine in 2001. He also received the Valued Contribution Award for an outstanding invited presentation, “EM Modeling of Surfaces with STOP or GO Characteristics – Artificial Magnetic Conductors and Soft and Hard Surfaces,” from the Applied Computational Electromagnetic Society. He received the Microwave Theory and Techniques Society Microwave Prize in 2004. He received the 2013 Chen-To-Tai Distinguished Educator Award from the IEEE Antennas and Propagation Society. In recognition, “For contributions and continuous improvements to teaching and research to prepare students for future careers in antennas and microwave circuits, Kishk is a Fellow of IEEE since 1998, Fellow of the Electromagnetic Academy, and a Fellow of the Applied Computational Electromagnetics Society (ACES). He is a Life Fellow of the IEEE and a member of several IEEE societies, including the Antennas and Propagation Society, Microwave Theory and Techniques Society, Electromagnetic Compatibility Society, Communications Society, and Vehicular Technology Society, as well as the Signal Processing Society. He is a Senior Member of the International Union of Radio Science, Commission B.

Keynote 4

New Frontiers in Computational Electromagnetics
for Brain Imaging and Diagnostics

Francesco P. Andriulli

Politecnico di Torino,Italy

Abstract

Electroencephalography (EEG) from scalp potentials is one of the primary non-invasive strategies for functional imaging of the human brain. By recording external potentials, it provides crucial insights into neural activity and remains a cornerstone of clinical neuroimaging. Its importance is particularly evident in epilepsy diagnostics: in focal epilepsy, accurate source characterization and localization are essential steps prior to surgical intervention. At the same time, EEG is a foundational technology for Brain–Computer Interfaces (BCIs), enabling direct communication between the brain and external devices. High-resolution EEG systems, however, are computationally intensive technologies, where a significant part of the imaging process relies on advanced electromagnetic modeling of brain propagation. Innovations in computational methods, modeling strategies, and algorithmic approaches are currently at the heart of major cross-disciplinary research efforts, originating from Computational Electromagnetics (CEM) and advanced electromagnetic engineering.

This talk will present some of the most recent strategies and advances in the field of CEM-empowered neuroimaging: technologies for brain diagnostics, therapy, and interaction where computational power, advanced algorithms, and ad hoc platforms have enabled exciting discoveries, therapeutic progress, and impactful applications. Current trends and open Grand Challenges will be outlined, alongside past achievements and ongoing research efforts, including those within the EIC Pathfinder project “CEREBRO.” Without over-indulging in technicalities, the talk will showcase recent theoretical and experimental breakthroughs, always in connection with their promising applications in diagnostics, mind–machine interfaces, and immersive neurofeedback.

Biography 

Francesco P. Andriulli received the Laurea in electrical engineering from the Politecnico di Torino, Italy, in 2004, the MSc in electrical engineering and computer science from the University of Illinois at Chicago in 2004, and the PhD in electrical engineering from the University of Michigan at Ann Arbor in 2008. From 2008 to 2010 he was a Research Associate with the Politecnico di Torino. From 2010 to 2017 he was an Associate Professor (2010-2014) and then Full Professor with the École Nationale Supérieure Mines-Télécom Atlantique (IMT Atlantique), Brest, France. Since 2017 he has been a Full Professor with the Politecnico di Torino, Turin, Italy. His research interests are in computational electromagnetics including frequency- and time-domain integral equation solvers, well-conditioned formulations, fast solvers, low-frequency electromagnetic analyses, and modeling techniques for antennas, wireless components, microwave circuits, and biomedical applications with a special focus on brain imaging.

Prof. Andriulli received several best paper awards at conferences and symposia (URSI NA 2007, IEEE AP-S 2008, ICEAA IEEE-APWC 2015) also in co-authorship with his students and collaborators (EMTS 2025, ICEAA IEEE-APWC 2021, EMTS 2016, URSI-DE Meeting 2014, ICEAA 2009) with whom received also a second prize conference paper (URSI GASS 2014), a third prize conference paper (IEEE–APS 2018), seven honorable mention conference papers (ICEAA 2011, URSI/IEEE–APS 2013, 4 in URSI/IEEE–APS 2022, URSI/IEEE–APS 2023) and other three finalist conference papers (URSI/IEEE-APS 2012, URSI/IEEE-APS 2007, URSI/IEEE-APS 2006, URSI/IEEE–APS 2022)). Moreover, he received the 2014 IEEE AP-S Donald G. Dudley Jr. Undergraduate Teaching Award, the triennium 2014-2016 URSI Issac Koga Gold Medal, and the 2015 L. B. Felsen Award for Excellence in Electrodynamics.

Prof. Andriulli is a Fellow of the IEEE and of the International Union of Radio Science (URSI), and a member of Eta Kappa Nu, Tau Beta Pi, and Phi Kappa Phi. He serves as the 2026 President-Elect of the IEEE Antennas and Propagation Society and served as IEEE AP-S Vice-President of Publications 2025, as Editor-in-Chief of the IEEE Antennas and Propagation Magazine, Track Editor for the IEEE Transactions on Antennas and Propagation and as an Associate Editor for the IEEE Antennas and Wireless Propagation Letters, IEEE Access, URSI Radio Science Letters, and IET-MAP.

Keynote 5

Emerging Antenna Technologies for Cancer Thermal Therapy

Koichi Ito, Center for Frontier Medical Engineering (CFME), Chiba University, Japan

Abstract

RF and microwave antenna technologies have greatly contributed to the advancement of cancer thermal therapy including hyperthermia and ablation which utilize the thermal effect of electromagnetic fields generated by heating antennas placed on or in the human body.

Hyperthermia basically exploits the difference of thermal sensitivity between tumors and normal tissues. The target tumor is usually heated up to the range 42-45 °C resulting in less damage to the surrounding normal tissues. For external heating, sophisticated phased array antennas have been developed and employed. For internal heating, an array of well-designed thin antennas is directly inserted into the tumor.  Ablation has been applied mainly for treatment of small-sized tumors. A thin antenna is directly inserted into the tumor to heat well over 60 °C and its treatment time is usually around a few minutes, much shorter than hyperthermia treatment.

Image-guided thermal therapies have been developed and employed to further improve QOL (quality of life) of patients and to ease an operation for medical doctors. A magnetic resonance (MR) guided system has been introduced as a promising tool, although the cost is still rather high. A typical example is an MR-guided annular phased array which can produce therapeutic temperatures at any depth in the human body and visualize real-time 3D temperature mapping.

It is difficult to use real human bodies for experimental evaluation of antenna performances. Instead, computer simulation is usually performed with digital human-body models. However, experiments with physical human-body phantoms are indispensable to validate numerical simulations and to minimize animal experiments.

Finally, a couple of further compelling challenges will be addressed at the end of the presentation including “theranostics” for cancer treatment that means a combination of therapeutics and diagnostics.

Biography

 Koichi Ito received the Ph.D degree from Tokyo Institute of Technology, Japan.  He is currently a Professor Emeritus and Visiting Professor at the Center for Frontier Medical Engineering (CFME), Chiba University, Japan.  He served as Deputy Vice-President for Research and Director of the CFME, Chiba University.  His main research interests include antennas for medical applications, small antennas for mobile communications, research on evaluation of the interaction between electromagnetic fields and a human body by use of phantoms, and antenna systems for body-centric wireless communications.  Dr. Ito is a Life Fellow of IEEE, a Fellow of URSI, a Fellow of IEICE, Japan, and an Honorary Member of the Japanese Society for Thermal Medicine (JSTM).  He is the recipient of the 2020 Balthasar van der Pol Gold Medal from URSI.  He served as an Associate Editor for the IEEE Transactions on Antennas and Propagation, an AdCom member for the IEEE AP-S, a Distinguished Lecturer for the IEEE AP-S, a BoD member for the Bioelectromagnetics Society, General Chair of ISAP2012, an elected Delegate to the European Association on Antennas and Propagation, an Editor for the International Journal of Hyperthermia, a Vice-President of JSTM, Chair of URSI Commission K, and IEEE AP-S President for 2019.  He currently serves as the inaugural Chair of the IEEE AP-S Technical Directions Committee.

Keynote 6

Circularly Polarized Metamaterial Antennas with Low-Profile Structure
Hisamatsu Nakano, Hosei University, Koganei, Tokyo, Japan

Abstract
Antennas operating with propagation behavior characterized by a negative phase constant are referred to as metamaterial antennas. These antennas exhibit electromagnetic properties not found in conventional designs. This presentation begins by introducing the theoretical formulations underlying metamaterial antennas, followed by a detailed exploration of circularly polarized (CP) metamaterial antennas:

1. Metaline Array Antennas
(1) Dynamic CP beam scanning within the azimuth plane
(2) Beam scanning within the elevation plane

2. Metaloop Antennas
(1) Dual-band counter-CP radiation characteristics at nion and hion frequencies
(2) CP gain characteristics with a parasitic patch

3. Metaspiral Antenna
(1) CP beam scanning using multiple arms
(2) Null-field formation within CP radiation patterns

4. Metacurl Antenna
(1) Gain behavior
(2) Balanced gain for both left-handed and right-handed CP waves

These antennas share a low-profile architecture, with physical dimensions on the order of λ/100, making them highly advantageous for modern, space-constrained wireless systems.

Biography

Hisamatsu NAKANO has been with Hosei University since 1973, where he is currently an Honorary Professor and a Special-appointment Researcher with the Electromagnetic Wave Engineering Research Center attached to the graduate school. He has published over 380 articles in peer-reviewed journals and 12 books/book chapters, including “Low-profile Natural and Metamaterial Antennas (IEEE Press-Wiley, 2016).” His significant contributions are (1) the development of five integral equations for line antennas in free space and printed on a dielectric substrate, (2) the invention of an L-shaped wire/strip antenna feeding method, and (3) the realization of numerous wideband antennas, including curl, metaspiral, metahelical, and Body of Revolution antennas. He received the H. A. Wheeler Award in 1994, the Chen-To Tai Distinguished Educator Award in 2006, and the Distinguished Achievement Award in 2016, all from the IEEE Antennas and Propagation Society. He was also a recipient of The Prize for Science and Technology from Japan's Minister of Education, Culture, Sports, Science and Technology in 2010. Recently, he was selected as a recipient of the Antenna Award of the European Association on Antennas and Propagation (EurAAP) in 2020. Most recently, he was selected by the Japanese government as a recipient of The Order of the Sacred Treasure, Gold Rays with Neck Ribbon on November 3 (Japan Culture Day), 2023.

Keynote 7

Multipole Engineering – in Space and in Time

                     Richard W. Ziolkowski,Department of Electrical and Computer Engineering, The University of Arizona,USA

Abstract

Highly directive antenna systems are being sought to address the perceived needs of FutureG wireless systems and their applications. Practical alternatives to complex, power-hungry phased arrays are truly desired. A potential approach is to develop and employ compact superdirective systems.

The concept of “needle” radiation and the accompanying abstraction of superdirectivity was introduced by Oseen in the physics community over 100 years ago. Numerous applied electromagnetics (EM) papers then followed over the last half of the last century that discussed the interesting attributes of unlimited directivity, i.e., superdirectivity, from arbitrarily small source regions and arrays. Those original theoretical notions of superdirectivity have been confirmed recently with explicit solutions of Maxwell’s equations based upon vector spherical wave expansion analyses. These solutions, the physics they have revealed, and the associated implications for achieving superdirective systems will be discussed.

The multipole engineering paradigm that has evolved from them equips us with several practical approaches to realizing both superdirective broadside-radiating and endfire-radiating systems. They include unidirectional mixed-multipole antennas (MMAs) based on combinations of electric and magnetic near-field resonant parasitic (NFRP) elements that radiate multipole fields when they are excited by simple driven dipoles. Another strategy is to employ a sector of a uniform circular array (UCA) of Huygens dipole antennas (HDAs) that are excited with custom-designed amplitudes to radiate mixtures of azimuthal multipoles. Yet another technique exploits MMAs with independently-driven electric and magnetic dipole elements to excite their counterpart electric and magnetic multipoles within a multilayered spherical dielectric lens and to then engineer the combination of their radiated fields into unidirectional superdirective beams.

While these unidirectional systems have been developed in the frequency domain, current investigations of their time domain analogues will be described. Significant technical nuances arise when EM radiators are pulse-excited rather than CW-excited. They will be reviewed briefly and then exploited to explain the performance characteristics of a pulse-driven HDA in its near, mid-range, and far field regions. Understanding these time-domain fields everywhere in space is essential for both near-field and far-field sensing and communication applications. Ultrafast (hence, UWB) zero-area pulses (ZAPs) will be highlighted; they lead to superior energy (hence, information) transference.

Biography

Richard W. Ziolkowski received the B.Sc. (magna cum laude) degree (Hons.) in physics from Brown University, Providence, RI, USA, in 1974; the M.S. and Ph.D. degrees in physics from the University of Illinois at Urbana-Champaign, Urbana, IL, USA, in 1975 and 1980, respectively; and an Honorary Doctorate degree from the Technical University of Denmark (DTU), Kongens Lyngby, Denmark in 2012.

He is currently a Professor Emeritus with the Department of Electrical and Computer Engineering at The University of Arizona, Tucson, AZ, USA. He was a Litton Industries John M. Leonis Distinguished Professor in the College of Engineering and was also a Professor in the College of Optical Sciences until his retirement in 2018. He was also a Distinguished Professor in the Global Big Data Technologies Centre in the Faculty of Engineering and Information Technologies (FEIT) at the University of Technology Sydney, Ultimo NSW Australia from 2016 until 2023. He was the Computational Electronics and Electromagnetics Thrust Area Leader with the Engineering Research Division of the Lawrence Livermore National Laboratory before joining The University of Arizona in 1990.

Prof. Ziolkowski was the recipient of the 2019 IEEE Electromagnetics Award (IEEE Technical Field Award). He is an IEEE Life Fellow, as well as a Fellow of OPTICA (previously the Optical Society of America, OSA) and the American Physical Society (APS). He was the 2014-2015 Fulbright Distinguished Chair in Advanced Science and Technology (sponsored by DSTO, the Australian Defence Science and Technology Organisation). He served as the President of the IEEE Antennas and Propagation Society (AP-S) in 2005 and has had many other AP-S leadership roles. He is also actively involved with the URSI (International Union of Radio Science) Commission B and the European Association on Antennas and Propagation (EurAAP). He is the co-Editor of the best-selling 2006 IEEE-Wiley book, Metamaterials: Physics and Engineering Explorations, as well as the co-author and co-Editor, respectively, of the recent Wiley-IEEE books: Advanced Antenna Array Engineering for 6G and Beyond Wireless Communications (2022) and Antenna and Array Technologies for Future Wireless Ecosystems (2022).

Keynote 8

On the Opportunities of Glide Symmetries for Antennas and Microwave Circuits

Oscar Quevedo-Teruel, KTH Royal Institute of Technology,Sweden

Abstract

Glide symmetry appears widely in nature—from fossils, worms, and sea pens to something as simple as human footprints—and has long fascinated humans. One of its most notable early artistic representations is found in the Moorish tessellations of the Alhambra Palace in Granada, Spain, which later inspired the Dutch artist M. C. Escher and his mathematically rich works.

In electromagnetics, glide symmetry was first investigated in the 1960s and 1970s, revealing remarkable properties in periodic structures. However, research interest waned for several decades before being revived in 2015 through practical demonstrations relevant to modern microwave devices. These advances have enabled applications in 5G terrestrial communications, millimetre-wave satellite systems, and automated contactless measurement techniques.

In this presentation, Prof. Quevedo-Teruel reviews recent discoveries on glide-symmetric periodic structures, including widened stopbands, reduced dispersion, and enhanced anisotropy and magnetic response. He also highlights their application in practical devices such as filters, gap waveguide components, low-leakage flanges, compressed lenses, low-reflection transitions, and leaky-wave antennas.

Biography

Oscar Quevedo-Teruel received his Telecommunication Engineering and Ph.D. Degrees from Carlos III University of Madrid, Spain in 2005 and 2010. In 2014, he joined the KTH Royal Institute of Technology (Stockholm, Sweden), where he is presently a Full Professor in the Department of Communication Systems in the School of Electrical Engineering and Computer Science. He is also the responsible for the Antenna Laboratory and Director of the Master Programme in Electromagnetics Fusion and Space Engineering. 

He was a distinguished lecturer of the IEEE Antennas and Propagation Society for the period of 2019-2022. He is an IEEE Fellow for his contributions to glide symmetry based metasurfaces and lens antennas. He has been a member of the EurAAP Board of Directors since January 2021. Since January 2022, he is presently the EurAAP vice-chair.

He was an Associate Editor of the IEEE Transactions on Antennas and Propagation since 2018-2022, and he acts as Track Editor in IEEE TAP since 2022. He is the founder and editor-in-chief of the EurAAP journal Reviews of Electromagnetics since 2020.

He has made scientific contributions to periodic structures with higher symmetries, lens antennas, metasurfaces, physical optics and ray tracing. He is the co-author of more than 160 papers in international journals and more than 250 at international conferences.