Geometric phase coded metasurface: from polarization dependent directive electromagnetic wave scattering to diffusion-like scattering

Chen, Ke; Feng, Yijun; Yang, Zihao; Cui, Li; Zhao, Junming; Zhu, Bo; Jiang, Tian

doi:10.1038/srep35968

Cited by 121 publications

(70 citation statements)

References 36 publications

(50 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It calculates the radiation far field by the equivalent currents technique using the aperture field method, [37] and the required compensation phase ϕ ij for each unit cell ijth of a reflectarray can be computed by using the following formula: [38] In virtue of different paths from the incident wave of the feed to the metasurface, the reflection phase of each unit cell is different.…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Machine‐Learning Designs of Anisotropic Digital Coding Metasurfaces

Zhang

Liu

Wan

et al. 2018

Advcd Theory and Sims

128

View full text Add to dashboard Cite

Digital coding representations of meta-atoms make it possible to realize intelligent designs of metasurfaces by means of machine learning algorithms. Here, a machine-learning method to design anisotropic digital coding metasurfaces is proposed, and meta-atoms may require any absolute phase values at different positions and under different polarizations. A deep-learning neural network to predict the vast and complex system is proposed, in which only 70 000 training coding patterns are used to train the network. Another 10 000 randomly chosen coding patterns are employed to validate the neural network, showing an accuracy of 90.05% of phase responses with 2°error in the 360°phase. Using the learned network, the correct coding pattern among 18 billion of billions of choices for the required phase can be readily found in a second, finishing automatic design of anisotropic meta-atoms. Three functional 1-bit anisotropic coding metasurfaces are intelligently achieved by the learned network. It is convenient to realize dual-beam scattering with left-handed circular polarization (LHCP) for one beam while right-handed circular polarization (RHCP) for the others, dual-beam scattering with circular polarization for one beam while linear polarization (LP) for the others, and triple-beam scattering with LHCP and RHCP for two beams while LP for the third one.

show abstract

Section: Methodsmentioning

confidence: 99%

“…[37,38] However, such anisotropic coding elements have a fixed phase difference (e.g., 180°) under the orthogonal polarizations to reach dual functionalities. [37,38] However, such anisotropic coding elements have a fixed phase difference (e.g., 180°) under the orthogonal polarizations to reach dual functionalities.…”

Section: Introductionmentioning

confidence: 99%

Machine‐Learning Designs of Anisotropic Digital Coding Metasurfaces

Zhang

Liu

Wan

et al. 2018

Advcd Theory and Sims

128

View full text Add to dashboard Cite

show abstract

“…Moreover, Figure 12. The standard deviations for the field uniformity of the test zone, which loaded the rotatable 1-bit random coding diffusion metasurface in the RC, and the purple lines are the tolerance requirements for the standard deviation of scalability of these coding metasurfaces to frequencies in the range of THz or optical is possible, allowing for the controllability of reflection, and scattering of EM waves in these frequency domains [11].…”

Section: Discussionmentioning

confidence: 99%

Coding Metasurfaces and Applications

Sun¹,

Gu²,

Li³

et al. 2019

Metamaterials and Metasurfaces

View full text Add to dashboard Cite

Metasurfaces are the planar counterparts of metamaterials, and they consist of a singlelayer or a few-layers stack of planar structures, which can be fabricated using lithography and nanoprinting methods. Such artificial structures are usually described by effective medium parameters at the macroscopic scale. In this chapter, we deal with "coding metasurfaces," composed of only two types of unit cells, with 0 and π phase responses, from which electromagnetic (EM) waves can be manipulated and different functionalities can be realized. We review the recent progress in the physics of metasurfaces operating at wavelengths ranging from microwave to visible. We provide an overview of key metasurface concepts, such as diffusion, anomalous reflection and refraction, and introduce metasurfaces based on some optimization methods to design metasurfaces, as well as their use in wave-front shaping and beam-forming applications, followed by a discussion of polarization conversion in few-layer metasurfaces and their related properties. An overview of diffusion coding metasurface reveals their ability to realize unique functionalities to reduce the radar cross-section (RCS). We also describe diffusion coding metasurfaces that can improve the field uniformity in reverberation chambers. Finally, we conclude by providing our opinions on opportunities and challenges in this rapidly developing research field.

show abstract

“…As can be seen the reflection phase is continuous and there is about 180 o ±27 o phase difference between x-and y-polarized reflections between 14.1 GHz and 23.3 GHz. According to PB phase theory [9], [23], if the unit cell has a high reflection magnitude under LP wave illumination with around 180 o reflection phase difference between orthogonal linearly x-and y-polarized incidences. Then when the unit cell is illuminated by a CP wave the cross-pol reflection will be significantly reduced, leading to high co-pol reflection.…”

Section: Pb Meta-atom Designmentioning

confidence: 99%

Aperiodic Sunflower-Like Metasurface for Diffusive Scattering and RCS Reduction

Al-Nuaimi

Wang

Whittow

2020

Antennas Wirel. Propag. Lett.

View full text Add to dashboard Cite

Abstract-This article presents the design of aperiodic sunflower-like metasurface for circularly polarized (CP) wave diffusion and radar cross section (RCS) reduction using Pancharatnam-Berry (PB) meta-atoms. The distribution of the PB meta-atoms across the metasurface aperture is non-uniform and has a distribution inspired by sunflower seeds, i.e., an outwardly logarithmic spiral lattice with no transitional periodicity. The proposed metasurface has 600 PB meta-atoms of sub-wavelength size of 5 mm ≈ 0.33λ 20GHz and exhibits a randomly chosen diffusive reflection phase between 0 o and 360 o . Both simulated and experimental results demonstrate that the proposed sunflower-like metasurface can efficiently diffuse the backscattered energy into numerous directions when normally illuminated by a CP-wave with RCS reduction > 7 dB between 16 GHz and 23.8 GHz. Furthermore, the low-level diffuse scattering can be preserved under oblique incidence up to 60 o . As a result of using this PB concept, the polarization sensitivity of the proposed metasurface is released and this is highly desired in applications when the polarization of the incoming wave is unknown.

show abstract

Geometric phase coded metasurface: from polarization dependent directive electromagnetic wave scattering to diffusion-like scattering

Cited by 121 publications

References 36 publications

Machine‐Learning Designs of Anisotropic Digital Coding Metasurfaces

Machine‐Learning Designs of Anisotropic Digital Coding Metasurfaces

Coding Metasurfaces and Applications

Aperiodic Sunflower-Like Metasurface for Diffusive Scattering and RCS Reduction

Contact Info

Product

Resources

About