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Your search keyword '"Ran, Lixin"' showing total 28 results
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28 results on '"Ran, Lixin"'

1. Analytical Method for Metasurface-Based Cloaking Under Arbitrary Oblique Illumination

Author

Zhang, Yi, Fan, Haiyan, Zhang, Yujie, Ran, Lixin, Ye, Dexin, and Chen, Xudong

Subjects
Physics - Optics, Physics - Computational Physics
Abstract

The performance of antennas can severely deteriorate in the presence of adjacent electrically-large scatterers. In this work, we use a conducting hollow cylinder to shield the scatterer. The cylinder is shelled with single layer dielectric and electromagnetic metasurface. The scattering field analysis with respect to the surface impedance is derived. By optimizing the anisotropic impedance distribution, the scattering cross-section can be effectively reduced. The proposed method is valid for both TMz, TEz and non-TM/TE incident field. The accuracy and effectiveness of the method are verified by four cloaking scenarios in microwave regime. We demonstrate that with the surface impedance obtained by our method, a metasurface is designed with physical subwavelength structure. We also show a cloaking scenario under magnetic dipole radiation, which is closer to the case of a realistic antenna. This method can be further applied to cloaking tasks in terahertz and optical regimes., Comment: 16 pages, 10 figures

Published
2023

2. Ultra-wideband Antireflection Assisted by Continuously Varying Temporal Medium

Author

Zhang, Yi, Peng, Liang, Huang, Zhengjie, Ran, Lixin, and Ye, Dexin

Subjects
Physics - Optics, Physics - Applied Physics
Abstract

We demonstrate that reflectionless propagation of electromagnetic waves between two different materials can be achieved by designing an intermediate temporal medium, which can work in an ultra-wide frequency band. Such a temporal medium is designed with consideration of a multi-stage variation of the material' s permittivity in the time domain. The multi-stage temporal permittivity is formed by a cascaded quarter-wave temporal coating, which is an extension of the antireflection temporal coating by Pacheco-Pe\~na et al [[1] Optica 7, 323 (2020)]. The strategy to render ultra-wideband antireflection temporal medium is discussed analytically and verified numerically. In-depth analysis shows that the multi-stage design of the temporal media implies a continuously temporal variation of the material' s constitutive parameters, thus an ultra-wideband antireflection temporal medium is reasonably obtained. As an illustrative example for application, the proposed temporal medium is adopted to realize impedance matching between a dielectric slab and free space, which validates our new findings., Comment: 9 pages, 5 figures, 1 table

Published
2021

8. Wide‐angle beam steering achieved by an array‐fed phase reconfigurable metasurface.

Author

Xi, Qiangli, Li, Yun, Li, Xiaojun, Zhang, Qian, Zhang, Bin, and Ran, Lixin

Subjects
BEAM steering, PHASED array antennas, BEAMFORMING
Abstract

In this letter, we propose and experimentally demonstrate a space‐fed beamforming approach capable of steering beams up to ±70° with a focal ratio (F/D) reduced to 0.27 and a scan loss remained 4 dB. It is implemented based on an mmWave phase reconfigurable metasurface, and an unconventional array‐fed architecture. By doing so, while the total profile of conventional space‐fed phased arrays can be significantly reduced, specifications such as scan range and scan loss can be simultaneously improved. Compared with conventional phased array systems, such specifications are unique, and can be used to realize low‐profile, cost‐effective, space‐fed phased arrays requiring ultrawide coverages at mmWave frequencies. [ABSTRACT FROM AUTHOR]

Published
2024
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28. Fourier metasurface cloaking: unidirectional cloaking of electrically large cylinder under oblique incidence.

Author

Zhang Y, Fan H, Zhang Y, Ran L, Ye D, and Chen X

Abstract

The existence of a non-electrically-small scatterer adjacent to the source can severely distort the radiation and lead to a poor electromagnetic compatibility. In this work, we use a conducting hollow cylinder to shield a cylindrical scatterer. The cylinder is shelled with a single dielectric layer enclosed by an electromagnetic metasurface. The relationship between the scattering field and the surface impedance is derived analytically. By optimizing the Fourier expansion coefficients of the surface impedance distribution along ϕ-dimension, the scattering cross-section can be effectively reduced. This unidirectional cloaking method is valid for both TM/TE and non-TM/TE incident field and is not limited to a plane-wave incident field. The accuracy and effectiveness of the method are verified by four cloaking scenarios in microwave regime. We demonstrate that with the surface impedance obtained by the proposed method, a metasurface is designed with physical subwavelength structures. We also show a cloaking scenario under a magnetic dipole radiation, which is closer to the case of a realistic antenna. This method can be further applied to cloaking tasks in terahertz and optical regimes.

Published
2024
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