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302 results on '"Lee, YoungPak"'

2. Enhancing Wireless Power Transfer Performance Based on a Digital Honeycomb Metamaterial Structure for Multiple Charging Locations.

Author

Huu Nguyen, Bui, Thanh Son, Pham, Hiep, Le Thi Hong, Anh, Nguyen Hai, Tung, Do Khanh, Khuyen, Bui Xuan, Tung, Bui Son, Lam, Vu Dinh, Zheng, Haiyu, Chen, Liangyao, and Lee, YoungPak

Subjects
WIRELESS power transmission, HONEYCOMB structures, WIRELESS localization, METAMATERIALS, LEAKAGE
Abstract

Enhancing the efficiency is an essential target of the wireless power transfer (WPT) technology. Enabling the WPT systems requires careful control to prevent power from being transferred to unintended areas. This is essential in improving the efficiency and minimizing the flux leakage that might otherwise occur. Selective field localization can effectively reduce the flux leakage from the WPT systems. In this work, we propose a method using a digital honeycomb metamaterial structure that has a property operation as a function of switching between 0 and 1 states. These cavities were created by strongly confining the field by using a hybridization bandgap that arose from wave interaction with a two-dimensional array of local resonators on the metasurface. A WPT efficiency of 64% at 13.56 MHz was achieved by using the metamaterial and improved to 60% compared to the system without the metamaterial with an area ratio of Rx:Tx~1:28. Rx is the receiver coil, and Tx is the transmitter one. [ABSTRACT FROM AUTHOR]

Published
2024
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7. Quasi-dark Mode in a Metamaterial for Analogous Electromagnetically-induced Transparency

Author

Thuy, Vu Tran Thanh, Tung, Nguyen Thanh, Park, Jinwoo, Lu, Yuehui, Lee, YoungPak, and Rhee, Joo Yull

Subjects
Physics - Optics
Abstract

We study a planar metamaterial supporting electromagnetically-induced transparency (EIT)-like effect by exploiting the coupling between bright and quasi-dark eigenmodes. The specific design of such a metamaterial consists of a cut-wire (CW) and a single-gap split-ring resonator (SRR). From the numerical and the analytical results we demonstrate that the response of SRR, which is weakly excited by external electric field, is mitigated to be a quasi-dark eigenmode in the presence of strongly radiative CW. This result suggests more relaxed conditions for the realization of devices utilizing the EIT-like effects in metamaterial, and thereby widens the possibilities for many different structural implementations., Comment: 11 pages, 4 figures

Published
2010
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8. Plasmonic electromagnetically-induced transparency in symmetric structures

Author

Jin, Xingri, Lu, Yuehui, Zheng, Haiyu, Lee, YoungPak, Rhee, Joo Yull, and Jang, Won Ho

Subjects
Condensed Matter - Materials Science
Abstract

A broken symmetry is generally believed to be a prerequisite of plasmonic electromagnetically-induced transparency (EIT), since the asymmetry renders the excitation of the otherwise forbidden dark mode possible. Nevertheless, according to the picture of magnetic-plasmon resonance (MPR) mediated plasmonic EIT, we show that the plasmonic EIT can be achieved even in the symmetric structures based on the second-order MPR. This sharpens our understanding of the existing concept, but also a profound insight into the plasmonic coherent interference in the near-field zone., Comment: 13 pages, 4 figures

Published
2009

9. Role of Magnetic Plasmon Resonance in Plasmonic Electromagnetically-Induced Transparency

Author

Lu, Yuehui, Xu, Hua, Tung, Nguyen Thanh, Rhee, Joo Yull, Jang, Won Ho, Ham, Byoung Seung, and Lee, YoungPak

Subjects
Condensed Matter - Materials Science
Abstract

We find that the magnetic plasmon resonance plays a vital role in plasmonic electromagnetically-induced transparency (EIT) proposed by Zhang et al. [\prl \textbf{101}, 047401 (2008)] as well as the localized surface plasmon polaritons. Based on this picture, the plasmonic EIT control through single optical field is suggested in a modified scheme for active plasmonic switching by simply adjusting the incident angle of the optical field. The tunability of plasmonic EIT in this scheme is exhibited sufficiently., Comment: 13 pages, 4 figures

Published
2009

16. Metamaterial Perfect Absorbers for Controlling Bandwidth: Single-Peak/Multiple-Peaks/Tailored-Band/Broadband.

Author

Zheng, Haiyu, Pham, Thanh Son, Chen, Liangyao, and Lee, Youngpak

Subjects
ELECTROMAGNETIC wave absorption, RADIATION absorption, ELECTROMAGNETIC radiation, METAMATERIALS, BANDWIDTHS
Abstract

Metamaterial absorbers have garnered significant interest due to their unique electromagnetic properties, which facilitate the efficient absorption of electromagnetic radiation in a specific frequency range or multiple frequency ranges. The metamaterial absorbers are designed based on artificially engineered structures that enable tailored absorption properties. These structures might include multiple resonances or incorporate electrical resistive components to achieve broadband absorption. This review paper provides a comprehensive analysis of the progress made in the field of the bandwidth of metamaterial absorbers, encompassing the underlying design principles, key performance characteristics, diverse applications, and perspectives for further research. The paper draws to a conclusion by outlining the potential future directions for further advancements in this exciting area of research, and highlighting the challenges that need to be addressed for the widespread adoption of metamaterial absorbers. [ABSTRACT FROM AUTHOR]

Published
2024
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48. Manipulation of the near-field coupling in metamaterial for multi-band absorber.

Author

Tung, Bui Son, Khuyen, Bui Xuan, Kim, Young Ju, Hwang, Ji Sub, Lam, Vu Dinh, Chen, Liang-Yao, and Lee, YoungPak

Subjects
METAMATERIALS, RESONATORS, RESONANCE, ABSORPTION, MICROWAVES, UNIT cell, ALGEBRAIC field theory
Abstract

In this work, a metamaterial perfect absorber (MPA) in the microwave region is numerically and experimentally demonstrated based on the near-field coupling of resonators. By decreasing the distance between split-ring resonators (SRRs), the coupling of SRRs is enhanced. Consequently, the original resonance of SRRs splits, leading to a multi-band perfect absorption. In addition, the proposed multi-band MPA is polarization-insensitive and can maintain the high absorption in a wide range of incident angle. Our work is expected to provide a different way to create the potential devices by using the multi-band and the broadband MPAs. [ABSTRACT FROM AUTHOR]

Published
2021
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49. Control of diffracted magneto-optical enhancement in Ni gratings

Author

Lu, Yuehui, Cho, Min Hyung, Kim, JinBae, Lee, YoungPak, Rhee, Jooyull, and Lee, Jae-Hwang

Subjects
Diffraction -- Analysis, Magnetooptics -- Analysis, Business, Electronics, Electronics and electrical industries
Abstract

The so-called diffracted magneto-optical (MO) effects, in which the MO responses of diffracted beams are measured in the off-specular geometry, have been utilized to change the amplitude and the sign of MO signals. An enhancement of MO effect of the first-order diffraction was found. In this paper, the rigorous coupled-wave analysis implemented as Airy-like internal reflection series was developed to simulate the diffracted longitudinal MO Kerr effect. We demonstrate that the enhancement of the MO effect is controllable for a certain diffraction order by adjusting the geometrical parameters of Ni gratings. Furthermore, it is believed that the absolute magnitude and the MO enhancement can be more effectively tuned by designing the grating profile and carefully selecting the gyrotropic materials. Index Terms--Diffraction, magneto-optical (MO) effect, Ni grating.

Published
2008

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