[IEEE AP-S/MTT-S Seminar] Tailoring EM Waves at Will with Discrete Metasurfaces and Active Directional Sources
July 22 @ 3:00 pm - 4:00 pm
Please join us for an upcoming seminar by Dr. Alex Wong, Associate Professor at City University of Hong <a href="http://Kong.
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Date: Tuesday, 22 July 2025
Time: 3 – 4 pm (ET)
Location: University of Toronto, Room BA 2135, Bahen Centre for Information Technology, 40 St George St, Toronto, M5S 2E4
Abstract:
Electromagnetic meta-devices of various kinds have emerged in the last 20 years to manipulate electromagnetic waves with unprecedented freedom, implicating microwave to optical frequencies, enhancing our understanding on fundamental physical phenomena and finding applications in microscopy, biomedicine and wireless communication and power transfer, to name a few. In this talk, I will review recent progress in my research group into main electromagnetic meta-devices: the discrete metasurface and the directional <a href="http://source.
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The discrete metasurface is an approach to treat the metasurface as an inherently pixelated surface with spatially discrete electromagnetic properties. Through taking this approach, we understand how discretization changes the metasurface performance and to what degree the metasurface can tolerate discretization. In some cases, we can also achieve functionalities which are impossible or unobvious to the continuous metasurface. Aggressive discretization can help to enlarge the size of the meta-atom, enabling enhanced bandwidth, reduction of fabrication tolerance, and the design of multifunction and intelligent metasurfaces for sensing, communication and <a href="http://imaging.
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Directional electromagnetic sources have attracted much recent attention as they form building blocks to meta-devices that manipulate the travel direction of electromagnetic waves. We juxtapose the near- and far-field properties of the circular, Huygens, and Janus dipoles, and show that the Huygens and Janus dipoles both exhibit directional near-field coupling behavior, but possess very different far-field radiation behaviors. This gives them complementary application potentials. While existing Janus dipoles are essentially sub-wavelength structures that scatter a small part of an incident wave, we introduce the Janus antenna – an active Janus dipole fed by a transmission line, which dramatically increases the power throughput and the bandwidth over which the near-field directional behavior can be achieved. The Janus dipole can be used as either an antenna a meta-device or a meta-atom, with promising potentials in directional switching, MIMO antenna and compact WPT <a href="http://systems.
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Alex M. H. Wong (M’ 2014, SM’2019) received the B.A.Sc. degree in engineering science (electrical option) and the M.A.Sc. and Ph.D. degrees in electrical and computer engineering from the University of Toronto, Toronto, ON, Canada, in 2006, 2009, and 2014, respectively. He was a Post-Doctoral Fellow with the University of Toronto. He is currently an Associate Professor with the Department of Electrical Engineering, City University of Hong Kong, Hong Kong, where he is also a Member of the State Key Laboratory of Terahertz and Millimeter Waves. He has advanced multiple projects in applied electromagnetics on next-generation RF, infrared, and optical metasurfaces, super-resolution imaging and radar systems. Particularly, he has made academic contributions to research on wave shaping using discrete Huygens’ metasurfaces and far-field imaging based on super-oscillation waves. His current research interests include metasurfaces, metamaterials, superresolution systems, bioelectromagnetics, and wireless power <a href="http://transfer.
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Prof. Wong is a member of IEEE Antennas and Propagation Society, Microwave Theory and Technology Society, and Photonics Society. He received accolades include an IEEE RWP King Award (for the best annual publication by a young author in IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION), the URSI Young Scientist Award, the Raj Mittra Grant, the IEEE Doctoral Research Awards from the AP and MTT societies, and the Canada Graduate Scholarship (doctoral level). He has served as the General Co-Chair for the 2025 International Workshop in Electromagnetics: Applications and Student Innovation Competition (iWEM 2025), the General Co-Chair for the 2022 IEEE HK AP-MTT Postgraduate Student Conference, and the TPC Vice-Chair for the 2020 Asia-Pacific Microwave Conference (APMC 2020). He has taken on various program committee, session chair, technical judge, and reviewer duties for IEEE conferences and journal publications in the AP and MTT societies, as well as relevant venues in applied <a href="http://physics.
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Speaker(s): Dr. Alex Wong,
Room: BA 2135, Bldg: Bahen Centre for Information Technology, 40 St George Street, Toronto, Ontario, Canada, M5S 2E4