Abstract:
Metamaterials refer to artificial electromagnetic media, featuring flexibly tailorable electromagnetic parameters—permittivity and permeability. In recent years, near-zero-index (NZI) metamaterials with exceptional parameters, i.e., permittivity or permeability approaches zero, have garnered significant attention. Within such media, electromagnetic fields exhibit infinitely large wavelengths and phase velocities, leading to distinct electromagnetic properties, such as tunnel supercoupling, spatial–temporal decoupling, and single-point tuning by photonic doping. On the other hand, the research on terminal antennas remains a focal area in both academia and industry, with their performance enhancement primarily constrained by the compact system size. This talk focuses on introducing the concept of NZI metamaterials into space-limited terminal systems to boost the radiation performance of terminal antennas. Unlike traditional NZI metamaterials constructed by periodically arranging sub-wavelength elements, the NZI metamaterials adopted in this talk is equivalent to non-periodic electromagnetic structures. The design fully leverages the compact space of terminal systems, enabling the realization of three high-performance antenna prototypes: a wideband antenna for tablet with full-metal backcover, a wideband antenna for tablet with small clearance, and a miniaturized circular-polarized antenna for smartphone with ultra-narrow bezel.
Biography:
Yongjian Zhang received the B.S. degree in communication engineering from Tongji University, Shanghai, China, in 2018, and the Ph.D. degree in electronic engineering from Tsinghua University, Beijing, China, in 2023. During 2023 to 2025, he was a Postdoctoral Fellow with the Department of Electronic Engineering, Tsinghua University, Beijing, China. He is currently an Associate Professor with the Unmanned System Research Institute, Northwestern Polytechnical University, Xi’an, China. His research interests include metamaterials, artificial index-near-zero media, terminal antennas and phased array antennas. Dr. Zhang received the Best Paper Awards from IEEE Asia-Pacific Conference on Antennas and Propagation (APCAP) in 2020, International Symposium on Antennas, Propagation and EM Theory (ISAPE) in 2021, and PhotonIcs & Electromagnetics Research Symposium (PIERS) in 2021. He is serving as a Reviewer for IEEE Transactions on Antennas and Propagation, IEEE Antennas and Wireless Propagation Letters and Electromagnetic Science.
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