Статті в журналах: "Electromagnetic invisibility"

1

Kan, Yao, Li Chao, and Li Fang. "Electromagnetic Invisibility of Elliptic Cylinder Cloaks." Chinese Physics Letters 25, no. 5 (May 2008): 1657–60. http://dx.doi.org/10.1088/0256-307x/25/5/037.

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2

Mitri, F. G. "Active electromagnetic invisibility cloaking and radiation force cancellation." Journal of Quantitative Spectroscopy and Radiative Transfer 207 (March 2018): 48–53. http://dx.doi.org/10.1016/j.jqsrt.2017.12.021.

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3

Weder, Ricardo. "The boundary conditions for point transformed electromagnetic invisibility cloaks." Journal of Physics A: Mathematical and Theoretical 41, no. 41 (September 15, 2008): 415401. http://dx.doi.org/10.1088/1751-8113/41/41/415401.

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4

Weder, Ricardo. "A rigorous analysis of high-order electromagnetic invisibility cloaks." Journal of Physics A: Mathematical and Theoretical 41, no. 6 (January 29, 2008): 065207. http://dx.doi.org/10.1088/1751-8113/41/6/065207.

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5

Kaproulias, S., and M. M. Sigalas. "On the sensitivity of the 2D electromagnetic invisibility cloak." Physica B: Condensed Matter 407, no. 20 (October 2012): 4078–80. http://dx.doi.org/10.1016/j.physb.2012.02.017.

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6

Guo, Zhong Wei, Wen Tao Xu, Hong Feng Li, and Wang Yang Hu. "The Visualization of Electromagnetic Environment for Weapon Equipments." Advanced Materials Research 466-467 (February 2012): 1191–96. http://dx.doi.org/10.4028/www.scientific.net/amr.466-467.1191.

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Aiming at the invisibility of the electromagnetic environment (EME), this paper presents the method to visualize the weapon equipments EME. The visualization can be divided into two steps. Firstly, we can model the weapon equipments EME to get the electromagnetic data by the finite difference time domain(FDTD) and the transformation from the near field to the far field. Secondly, we can render the electromagnetic data by the data field visualization. The experiment shows that this way is feasible and effective.

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7

Zolla, Frédéric, Sébastien Guenneau, André Nicolet, and J. B. Pendry. "Electromagnetic analysis of cylindrical invisibility cloaks and the mirage effect." Optics Letters 32, no. 9 (April 3, 2007): 1069. http://dx.doi.org/10.1364/ol.32.001069.

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8

Meng, Fan-Yi, Ying Liang, Qun Wu, and Le-Wei Li. "Invisibility of a metamaterial cloak illuminated by spherical electromagnetic wave." Applied Physics A 95, no. 3 (January 27, 2009): 881–88. http://dx.doi.org/10.1007/s00339-009-5092-7.

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9

Sarin, V. P., M. P. Jayakrishnan, P. V. Vinesh, C. K. Aanandan, P. Mohanan, and K. Vasudevan. "An experimental realization of cylindrical cloaking using dogbone metamaterials." Canadian Journal of Physics 95, no. 10 (October 2017): 927–32. http://dx.doi.org/10.1139/cjp-2016-0876.

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The quest for invisibility has inspired a deep ardour in the research community over the past decade. The invention of metamaterials has boosted the research on electromagnetic cloaking due to its unusual electromagnetic parameters under plane wave incidence. In this study, we propose a novel cloaking scheme, using dogbone metamaterials, for effectively routing the incident electromagnetic fields around a target metal cylinder under consideration. Notable reduction in the scattered power is observed from the target in comparison to an uncloaked target. Experiments and simulations validate an effective reduction in the scattering cross section of the target and effective guiding of the incident plane wave around the target.

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10

Brosa, Ulrich. "Electromagnetic Waves in Variable Media." Zeitschrift für Naturforschung A 67, no. 3-4 (April 1, 2012): 111–31. http://dx.doi.org/10.5560/zna.2011-0069.

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Two methods are explained to exactly solve Maxwell’s equations where permittivity, permeability, and conductivity may vary in space. In the constitutive relations, retardation is regarded. If the material properties depend but on one coordinate, general solutions are derived. If the properties depend on two coordinates, geometrically restricted solutions are obtained. Applications to graded reflectors, especially to dielectric mirrors, to filters, polarizers, and to waveguides, plain and cylindrical, are indicated. New foundations for the design of optical instruments, which are centered around an axis, and for the design of invisibility cloaks, plain and spherical, are proposed. The variability of material properties makes possible effects which cannot happen in constant media, e.g. stopping the flux of electromagnetic energy without loss. As a consequence, spherical devices can be constructed which bind electromagnetic waves

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11

Islam, Sikder, Mohammad Faruque, and Mohammad Islam. "A Near Zero Refractive Index Metamaterial for Electromagnetic Invisibility Cloaking Operation." Materials 8, no. 8 (July 29, 2015): 4790–804. http://dx.doi.org/10.3390/ma8084790.

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12

Monticone, Francesco, and Andrea Alù. "Physical bounds on electromagnetic invisibility and the potential of superconducting cloaks." Photonics and Nanostructures - Fundamentals and Applications 12, no. 4 (August 2014): 330–39. http://dx.doi.org/10.1016/j.photonics.2014.05.008.

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13

Kemp, B. A., and C. J. Sheppard. "Electromagnetic and material contributions to stress, energy, and momentum in metamaterials." Advanced Electromagnetics 6, no. 1 (January 9, 2017): 11. http://dx.doi.org/10.7716/aem.v6i1.430.

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We demonstrate modeling of the field-kinetic and material response subsystem for various media and extend the models to dispersive negative index metamaterials. It is shown that neither the Minkowski or Abraham models are universally correct, as demonstrated to describe metamaterials under both the field-kinetic and wave SEM models for various applications such as negative refraction, perfect lensing, and invisibility cloaking.

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14

Yang, Zhiguo, and Li-Lian Wang. "Accurate Simulation of Circular and Elliptic Cylindrical Invisibility Cloaks." Communications in Computational Physics 17, no. 3 (March 2015): 822–49. http://dx.doi.org/10.4208/cicp.280514.131014a.

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AbstractThe coordinate transformation offers a remarkable way to design cloaks that can steer electromagnetic fields so as to prevent waves from penetrating into thecloaked region(denoted by Ω0, where the objects inside are invisible to observers outside). The ideal circular and elliptic cylindrical cloaked regions are blown up from a point and a line segment, respectively so the transformed material parameters and the corresponding coefficients of the resulted equations are highly singular at the cloaking boundary ∂Ω0. The electric field or magnetic field is not continuous across ∂Ω0. The imposition of appropriatecloaking boundary conditions(CBCs) to achieve perfect concealment is a crucial but challenging issue.Based upon the principle that a well-behaved electromagnetic field in the original space must be well-behaved in the transformed space as well, we obtain CBCs that intrinsically relate to the essential “pole” conditions of a singular transformation. We also find that for the elliptic cylindrical cloak, the CBCs should be imposed differently for the cosine-elliptic and sine-elliptic components of the decomposed fields. With these at our disposal, we can rigorously show that the governing equation in Ω0can be decoupled from the exterior region, and the total fields in the cloaked region vanish under mild conditions. We emphasize that our proposal of CBCs is different from any existing ones.Using the exact circular (resp., elliptic) Dirichlet-to-Neumann (DtN) non-reflecting boundary conditions to reduce the unbounded domainto a bounded domain, we introduce an accurate and efficient Fourier-Legendre spectral-element method (FLSEM) (resp., Mathieu-Legendre spectral-element method (MLSEM)) to simulate the circular cylindrical cloak (resp., elliptic cylindrical cloak). We provide ample numerical results to demonstrate that the perfect concealment of waves can be achieved for the ideal circular/elliptic cylindrical cloaks under our proposed CBCs and accurate numerical solvers.

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15

Li, Xiaofei, Jingzhi Li, Hongyu Liu, and Yuliang Wang. "Electromagnetic interior transmission eigenvalue problem for inhomogeneous media containing obstacles and its applications to near cloaking." IMA Journal of Applied Mathematics 82, no. 5 (July 5, 2017): 1013–42. http://dx.doi.org/10.1093/imamat/hxx022.

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Abstract This article is concerned with the invisibility cloaking in electromagnetic wave scattering from a new perspective. We are especially interested in achieving the invisibility cloaking by completely regular and isotropic mediums. Our study is based on an interior transmission eigenvalue problem. We propose a cloaking scheme that takes a three-layer structure including a cloaked region, a lossy layer and a cloaking shell. The target medium in the cloaked region can be arbitrary but regular, whereas the mediums in the lossy layer and the cloaking shell are both regular and isotropic. We establish that there exists an infinite set of incident waves such that the cloaking device is nearly invisible under the corresponding wave interrogation. The set of waves is generated from the Maxwell–Herglotz approximation of the associated interior transmission eigenfunctions. We provide the mathematical design of the cloaking device and sharply quantify the cloaking performance.

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16

Xu, He-Xiu, Mingzhao Wang, Guangwei Hu, Shaojie Wang, Yanzhao Wang, Chaohui Wang, Yixuan Zeng, Jiafang Li, Shuang Zhang, and Wei Huang. "Adaptable Invisibility Management Using Kirigami-Inspired Transformable Metamaterials." Research 2021 (September 10, 2021): 1–11. http://dx.doi.org/10.34133/2021/9806789.

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Many real-world applications, including adaptive radar scanning and smart stealth, require reconfigurable multifunctional devices to simultaneously manipulate multiple degrees of freedom of electromagnetic (EM) waves in an on-demand manner. Recently, kirigami technique, affording versatile and unconventional structural transformation, has been introduced to endow metamaterials with the capability of controlling EM waves in a reconfigurable manner. Here, we report for a kirigami-inspired sparse meta-architecture, with structural density of 1.5% in terms of the occupation space, for adaptive invisibility based on independent operations of frequency, bandwidth, and amplitude. Based on the general principle of dipolar management via structural reconstruction of kirigami-inspired meta-architectures, we demonstrate reconfigurable invisibility management with abundant EM functions and a wide tuning range using three enantiomers (A, B, and C) of different geometries characterized by the folding angle β. Our strategy circumvents issues of limited abilities, narrow tuning range, extreme condition, and high cost raised by available reconfigurable metamaterials, providing a new avenue toward multifunctional smart devices.

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17

Kozar, A. I. "ELECTROMAGNETIC LATTICE "INVISIBILITY" OF THE RESONANCE CUBIC CRYSTAL MADE OF MAGNETODIELECTRIC SPHERES." Telecommunications and Radio Engineering 77, no. 2 (2018): 155–60. http://dx.doi.org/10.1615/telecomradeng.v77.i2.60.

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18

Ming-Ji, Chen, Pei Yong-Mao, and Fang Dai-Ning. "An Improved Method of Designing Isotropic Multilayered Spherical Cloak for Electromagnetic Invisibility." Chinese Physics Letters 27, no. 3 (March 2010): 034102. http://dx.doi.org/10.1088/0256-307x/27/3/034102.

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19

Xu, Su, Hongyi Xu, Hanhong Gao, Yuyu Jiang, Faxin Yu, John D. Joannopoulos, Marin Soljačić, Hongsheng Chen, Handong Sun, and Baile Zhang. "Broadband surface-wave transformation cloak." Proceedings of the National Academy of Sciences 112, no. 25 (June 8, 2015): 7635–38. http://dx.doi.org/10.1073/pnas.1508777112.

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Guiding surface electromagnetic waves around disorder without disturbing the wave amplitude or phase is in great demand for modern photonic and plasmonic devices, but is fundamentally difficult to realize because light momentum must be conserved in a scattering event. A partial realization has been achieved by exploiting topological electromagnetic surface states, but this approach is limited to narrow-band light transmission and subject to phase disturbances in the presence of disorder. Recent advances in transformation optics apply principles of general relativity to curve the space for light, allowing one to match the momentum and phase of light around any disorder as if that disorder were not there. This feature has been exploited in the development of invisibility cloaks. An ideal invisibility cloak, however, would require the phase velocity of light being guided around the cloaked object to exceed the vacuum speed of light—a feat potentially achievable only over an extremely narrow band. In this work, we theoretically and experimentally show that the bottlenecks encountered in previous studies can be overcome. We introduce a class of cloaks capable of remarkable broadband surface electromagnetic waves guidance around ultrasharp corners and bumps with no perceptible changes in amplitude and phase. These cloaks consist of specifically designed nonmagnetic metamaterials and achieve nearly ideal transmission efficiency over a broadband frequency range from 0+ to 6 GHz. This work provides strong support for the application of transformation optics to plasmonic circuits and could pave the way toward high-performance, large-scale integrated photonic circuits.

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20

Ye, Dexin, Ling Lu, John D. Joannopoulos, Marin Soljačić, and Lixin Ran. "Invisible metallic mesh." Proceedings of the National Academy of Sciences 113, no. 10 (February 16, 2016): 2568–72. http://dx.doi.org/10.1073/pnas.1600521113.

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A solid material possessing identical electromagnetic properties as air has yet to be found in nature. Such a medium of arbitrary shape would neither reflect nor refract light at any angle of incidence in free space. Here, we introduce nonscattering corrugated metallic wires to construct such a medium. This was accomplished by aligning the dark-state frequencies in multiple scattering channels of a single wire. Analytical solutions, full-wave simulations, and microwave measurement results on 3D printed samples show omnidirectional invisibility in any configuration. This invisible metallic mesh can improve mechanical stability, electrical conduction, and heat dissipation of a system, without disturbing the electromagnetic design. Our approach is simple, robust, and scalable to higher frequencies.

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21

Zhan, Junjie, Yujian Mei, Kai Li, Yi Zhou, Jian Chen, and Yungui Ma. "Conformal metamaterial coats for underwater magnetic-acoustic bi-invisibility." Applied Physics Letters 120, no. 9 (February 28, 2022): 094104. http://dx.doi.org/10.1063/5.0066328.

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Invisible coats inspired by metamaterials have been widely explored for different physical quantities and even with multifunctional response capabilities. In particular, a magnetic cloak has gained special attention for high practicability when compared with its electromagnetic counterparts. In this work, we report a bi-physical metamaterial invisible coating technique that could effectively hide underwater objects from being detected via both magnetic fields and acoustic waves. An ultra-thin coat could work for objects having irregular shapes like squares, greatly broadening potential practical applications. The bilayer magnetic cloaking technique is fully exploited to cast a spatially dependent permeability profile, which could quasi-statically balance out the diamagnetic response of irregular-shaped metals based on field “scattering” cancellation. Integrated with this magnetic cloak, an ultrathin acoustic metasurface made of periodic microbubbles is developed to achieve broadband acoustic absorption for acoustic stealth. This integrated magnetic-acoustic bi-physical conformal coat may lead to important applications not only for military purposes but also for civilian apparatus in shielding the field and wave disturbances, for example, in medical scanning.

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22

Vellucci, Stefano, Alessio Monti, Mirko Barbuto, Alessandro Toscano, and Filiberto Bilotti. "Progress and perspective on advanced cloaking metasurfaces: from invisibility to intelligent antennas." EPJ Applied Metamaterials 8 (2021): 7. http://dx.doi.org/10.1051/epjam/2020013.

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Among the different cloaking applications proposed in the literature, the antenna framework has emerged as one of the most fruitful and mature field. In particular, mantle cloaking approach has proven to be a powerful tool for enabling unprecedented possibilities in antenna design. Here, we provide a review of the most significant works in the field of electromagnetic invisibility for antenna applications, demonstrating the versatility of cloaking metasurfaces in antenna scenarios. We also discuss our recent results and investigations on the design of advanced cloaking metasurfaces equipped with electronic components and circuits and able enriching the antenna intelligence.

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23

Alekseev, Gennady, Olga Dyakonova, Alexey Lobanov, and Andrey Yu. Fershalov. "2D Electromagnetic Wave Scattering Problem for Cylindrical Cloak Incorporating PEMC-Layer." Key Engineering Materials 685 (February 2016): 75–79. http://dx.doi.org/10.4028/www.scientific.net/kem.685.75.

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The 2D scattering problem is studied for the case of a two-dimensional cylindrical invisibility cloak, incorporating a tiny layer of perfect electromagnetic conductor (PEMC). The solution of the corresponding Helmholtz equation with variable coefficients is seeked as cylindrical functions Fourier series. The coefficients of these series are determined by solving the system of four linear algebraic equations with respect to four unknown coefficients with badly-conditioned matrix. The Singular Value Decomposition (SVD) method is applied for solving the system. Based on this idea the efficient numerical method is developed for solving the cloaking problem under study. The properties of this algorithm are studied and some results of numerical experiments are discussed.

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24

Lassas, Matti, and Ting Zhou. "The Blow-up of Electromagnetic Fields in 3-Dimensional Invisibility Cloaking for Maxwell's Equations." SIAM Journal on Applied Mathematics 76, no. 2 (January 2016): 457–78. http://dx.doi.org/10.1137/15m103964x.

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25

Lyu, Zhou, Binzhen Zhang, Junping Duan, Yuhua Yang, Rui Liu, Yiqing Wei, and Jingwen Liu. "Transparent ultra-broadband absorber based on a tree seedling composite structure." Journal of Physics D: Applied Physics 55, no. 9 (November 19, 2021): 095104. http://dx.doi.org/10.1088/1361-6463/ac3350.

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Abstract In this work, we design, analyze and process an ultra-broadband absorption optical transparent metamaterials absorbing device. The simulation results show that within the 13.68–71.6 GHz frequency range, the devicereaches more than 90% absorptivity, and that transverse magnetic waves and transverse waves under a large angle of polarization and incident angle can obtain high absorption performance. Therefore the device has the perfect performance of polarization insensitivity and wide angle of incidence. The absorbing mechanism is analyzed by using the equivalent medium theory, and the theoretical results are in good agreement with the simulation results. Because of its advantages of wideband absorption, high transparency, lightweight, and easy availability, the deive has important application value in practical civil and military fields, such as electromagnetic interference, electromagnetic compatibility, super lens, invisibility cloak, solar cell device design and so on.

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26

Li, Hongjie, Shanqiang Li, Hongyu Liu, and Xianchao Wang. "Analysis of electromagnetic scattering from plasmonic inclusions beyond the quasi-static approximation and applications." ESAIM: Mathematical Modelling and Numerical Analysis 53, no. 4 (July 2019): 1351–71. http://dx.doi.org/10.1051/m2an/2019004.

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This paper is concerned with the analysis of time-harmonic electromagnetic scattering from plasmonic inclusions in the finite frequency regime beyond the quasi-static approximation. The electric permittivity and magnetic permeability in the inclusions are allowed to be negative-valued. Using layer potential techniques for the full Maxwell system, the scattering problem is reformulated into a system of integral equations. We derive the complete eigensystem of the involved matrix-valued integral operator within spherical geometry. As applications, we construct two types of plasmonic structures such that one can induce surface plasmon resonances within finite frequencies and the other one can produce invisibility cloaking. It is particularly noted that the cloaking effect is a newly found phenomenon and is of different nature from those existing ones for plasmonic structures in the literature. The surface plasmon resonance result may find applications in electromagnetic imaging.

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27

Lončar, Josip, Josip Vuković, Igor Krois, and Silvio Hrabar. "Stability Constraints on Practical Implementation of Parity-Time-Symmetric Electromagnetic Systems." Photonics 8, no. 2 (February 18, 2021): 56. http://dx.doi.org/10.3390/photonics8020056.

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Recently, several applications leveraging unconventional manipulation of electromagnetic radiation based on parity-time symmetry have been proposed in the literature. Typical examples include systems with unidirectional invisibility and asymmetric refraction. Such applications assume an inherent system stability and no occurrence of unbounded signal growth or unwanted self-oscillations. Here, a general instability issue of parity-time-symmetric systems is investigated, with particular emphasis on a recently proposed system based on resistive metasurfaces. Explicit closed-form stability criterion is derived, crosschecked and verified by both time-domain transient simulations and the measurements on an experimental demonstrator operating in a lower radiofrequency range. Results of this study lead to the conclusion that any parity-time-symmetric system is necessarily marginally stable. Finally, it is shown that such a marginally stable system may easily become unstable if not designed carefully.

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28

Loran, Farhang, and Ali Mostafazadeh. "Transfer-matrix formulation of the scattering of electromagnetic waves and broadband invisibility in three dimensions." Journal of Physics A: Mathematical and Theoretical 53, no. 16 (March 31, 2020): 165302. http://dx.doi.org/10.1088/1751-8121/ab7669.

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29

Valagiannopoulos, Constantinos, and Sergei A. Tretyakov. "Stability of active photonic metasurface pairs." New Journal of Physics 23, no. 11 (November 1, 2021): 113045. http://dx.doi.org/10.1088/1367-2630/ac37ac.

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Abstract Adding active components to a photonic device may dramatically enrich and improve its performance but, at the same time, creates the risk of instability, namely, occurrence of unwanted self-oscillations. Stability considerations are not always given the attention they deserve when setups employing gain media are investigated; thus, the desired effects or reported regimes may not be achievable. In this work, a generic electromagnetic configuration comprising a pair of planar impedance metasurfaces is examined and analytical stability conditions for its operation are derived. The obtained results for the analyzed basic module can shed light on the stability conditions of more complex active systems that incorporate such components and serve a broad range of applications from imaging and polarization engineering to invisibility cloaking and wavefront transformations.

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30

Ginis, Vincent, and Philippe Tassin. "Transformation optics beyond the manipulation of light trajectories." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 373, no. 2049 (August 28, 2015): 20140361. http://dx.doi.org/10.1098/rsta.2014.0361.

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Since its inception in 2006, transformation optics has become an established tool to understand and design electromagnetic systems. It provides a geometrical perspective into the properties of light waves without the need for a ray approximation. Most studies have focused on modifying the trajectories of light rays, e.g. beam benders, lenses, invisibility cloaks, etc. In this contribution, we explore transformation optics beyond the manipulation of light trajectories. With a few well-chosen examples, we demonstrate that transformation optics can be used to manipulate electromagnetic fields up to an unprecedented level. In the first example, we introduce an electromagnetic cavity that allows for deep subwavelength confinement of light. The cavity is designed with transformation optics even though the concept of trajectory ceases to have any meaning in a structure as small as this cavity. In the second example, we show that the properties of Cherenkov light emitted in a transformation-optical material can be understood and modified from simple geometric considerations. Finally, we show that optical forces—a quadratic function of the fields—follow the rules of transformation optics too. By applying a folded coordinate transformation to a pair of waveguides, optical forces can be enhanced just as if the waveguides were closer together. With these examples, we open up an entirely new spectrum of devices that can be conceived using transformation optics.

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31

Kim, Yongjune, Ilsung Seo, Il-Suek Koh, and Yongshik Lee. "Design method for broadband free-space electromagnetic cloak based on isotropic material for size reduction and enhanced invisibility." Optics Express 24, no. 20 (September 21, 2016): 22708. http://dx.doi.org/10.1364/oe.24.022708.

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32

Xu, Rui-Jia, and Yu-Sheng Lin. "Actively MEMS-Based Tunable Metamaterials for Advanced and Emerging Applications." Electronics 11, no. 2 (January 13, 2022): 243. http://dx.doi.org/10.3390/electronics11020243.

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In recent years, tunable metamaterials have attracted intensive research interest due to their outstanding characteristics, which are dependent on the geometrical dimensions rather than the material composition of the nanostructure. Among tuning approaches, micro-electro-mechanical systems (MEMS) is a well-known technology that mechanically reconfigures the metamaterial unit cells. In this study, the development of MEMS-based metamaterial is reviewed and analyzed based on several types of actuators, including electrothermal, electrostatic, electromagnetic, and stretching actuation mechanisms. The moveable displacement and driving power are the key factors in evaluating the performance of actuators. Therefore, a comparison of actuating methods is offered as a basic guideline for selecting micro-actuators integrated with metamaterial. Additionally, by exploiting electro-mechanical inputs, MEMS-based metamaterials make possible the manipulation of incident electromagnetic waves, including amplitude, frequency, phase, and the polarization state, which enables many implementations of potential applications in optics. In particular, two typical applications of MEMS-based tunable metamaterials are reviewed, i.e., logic operation and sensing. These integrations of MEMS with metamaterial provide a novel route for the enhancement of conventional optical devices and exhibit great potentials in innovative applications, such as intelligent optical networks, invisibility cloaks, photonic signal processing, and so on.

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33

Zheng, Bin, Yihao Yang, Zheping Shao, Qinghui Yan, Nian-Hai Shen, Lian Shen, Huaping Wang, Erping Li, Costas M. Soukoulis, and Hongsheng Chen. "Experimental Realization of an Extreme-Parameter Omnidirectional Cloak." Research 2019 (August 18, 2019): 1–8. http://dx.doi.org/10.34133/2019/8282641.

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An ideal transformation-based omnidirectional cloak always relies on metamaterials with extreme parameters, which were previously thought to be too difficult to realize. For such a reason, in previous experimental proposals of invisibility cloaks, the extreme parameters requirements are usually abandoned, leading to inherent scattering. Here, we report on the first experimental demonstration of an omnidirectional cloak that satisfies the extreme parameters requirement, which can hide objects in a homogenous background. Instead of using resonant metamaterials that usually involve unavoidable absorptive loss, the extreme parameters are achieved using a nonresonant metamaterial comprising arrays of subwavelength metallic channels manufactured with 3D metal printing technology. A high level transmission of electromagnetic wave propagating through the present omnidirectional cloak, as well as significant reduction of scattering field, is demonstrated both numerically and experimentally. Our work may also inspire experimental realizations of the other full-parameter omnidirectional optical devices such as concentrator, rotators, and optical illusion apparatuses.

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34

Wright, Derek W., and Richard S. C. Cobbold. "The Characteristics and Applications of Metamaterials." Ultrasound 17, no. 2 (May 1, 2009): 68–73. http://dx.doi.org/10.1179/174313409x415639.

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The past 10 years have seen remarkable developments in microwave, optical and acoustic methods that make use of the unique wave transmission properties of a class of ordered composites known as metamaterials. These materials differ from regular materials in that wave propagation is dramatically affected by the size and arrangement of their small-scale structure, and not just by the choice of constituent materials. Their characteristic feature sizes can be much less than, or on the same order as a wavelength. They have a variety of potential applications ranging from super-lenses, to enabling subwavelength imaging resolution, to the creation of a Harry Potter-like ‘invisibility cloak’. In this review we provide an overview of some of these achievements, much of which has been proposed and demonstrated with optical and electromagnetic waves. However, more recently these ideas have been extended to acoustic waves, offering the opportunity of controlling ultrasound wave propagation in a unique manner.

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35

Derevianko, S., A. Vasylchenko, O. Yekimov, R. Oliynik, and O. Yermolenko. "ABSORPTION OF ELECTROMAGNETIC WAVES WITH VARIOUS WAVELENGTH BY NANOPARTICLES." Наукові праці Державного науково-дослідного інституту випробувань і сертифікації озброєння та військової техніки, no. 10 (December 30, 2021): 40–44. http://dx.doi.org/10.37701/dndivsovt.10.2021.04.

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An aim of the article is to review the potential of nanotechnology in military for the development of stealth technologies. Methods. Analysis of information, synthesis, generalization and comparison. Results. An overview of nanoparticles use in the development of stealth technologies has been made. Foreign and Ukrainian publications were analyzed. The possibility of using nanoparticles of metals like iron, cobalt, nickel, zinc, manganese and other metals and composite nanomaterials for absorption, refraction and scattering of waves of different lengths and frequencies, which can be used in the development of coatings for military equipment to reduce visibility and counter targeting systems has been shown. The possibility of using nanoparticles of nonmetals to absorb infrared radiation, which is important for masking equipment, military facilities and personnel, has been highlighted. High-tech weapons, technical means of detection and guidance are constantly being modernized and improved. One of the most important conditions for tactical superiority over the enemy is camouflage and counteraction to these systems. One of the ways to increase the resistance to detection and guidance systems is the development of stealth technologies based on nanoparticles of metals and non-metals. In the long run, nanotechnology and stealth coating should ensure the invisibility of objects in a wide frequency band of electromagnetic waves, which can reach two to three orders of magnitude. These are ambitious tasks, however, they are real. Foreign and domestic scientists have proven the possibility of using nanoparticles of metals and composite materials to develop coatings with the ability to absorb electromagnetic waves in a wide range, which can be used in the development of coatings to counter radar stations and other detection systems. Given the significant scientific potential of Ukrainian scientists, presence of technologies needed for the synthesis of nanoparticles of metals and nonmetals of various shapes and sizes, based on previous research on the ability of nanoparticles to absorb waves of different lengths and frequencies, we see high prospects for stealth technologies for the Military Forces of Ukraine.

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36

Moghbeli, Ebrahim, Hassan Ranjbar Askari, and Mohammad Reza Forouzeshfard. "The effect of geometric parameters of a single-gap SRR metamaterial on its electromagnetic properties as a unit cell of interior invisibility cloak in the microwave regime." Optics & Laser Technology 108 (December 2018): 626–33. http://dx.doi.org/10.1016/j.optlastec.2018.07.025.

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37

KUSHWAHA, MANVIR S., and BAHRAM DJAFARI-ROUHANI. "SURFACE PLASMONS IN COAXIAL METAMATERIAL CABLES." Modern Physics Letters B 27, no. 17 (June 17, 2013): 1330013. http://dx.doi.org/10.1142/s0217984913300135.

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Thanks to Victor Veselago for his hypothesis of negative index of refraction, meta-materials — engineered composites — can be designed to have properties difficult or impossible to find in nature: they can have both electrical permittivity (ϵ) and magnetic permeability (μ) simultaneously negative. The metamaterials — henceforth negative-index materials (NIMs) — owe their properties to subwavelength structure rather than to their chemical composition. The tailored electromagnetic response of the NIMs has had a dramatic impact on classical optics: they are becoming known to have changed many basic notions related with electromagnetism. The present article is focused on gathering and reviewing fundamental characteristics of plasmon propagation in coaxial cables fabricated of the right-handed medium (RHM) (with ϵ > 0, μ > 0) and the left-handed medium (LHM) (with ϵ < 0, μ < 0) in alternate shells starting from the innermost cable. Such structures as conceived here may pave the way to some interesting effects in relation to, for example, optical science exploiting the cylindrical symmetry of coaxial waveguides that make it possible to perform all major functions of an optical fiber communication system in which the light is born, manipulated, and transmitted without ever leaving the fiber environment, with precise control over the polarization rotation and pulse broadening. This review also covers briefly the nomenclature, classification, potential applications, and the limitations (related, for example, to the inherent losses) of the NIMs and their impact on classical electrodynamics in general, and in designing the cloaking devices in particular. A recent surge in efforts on invisibility and the cloaking devices seems to have spoiled the researchers worldwide: proposals include not only a way to hide an object without having to wrap the cloak around it, but also to replace a given object with another, thus adding to the deception even further! All this is attributed as much to the fundamental as to the practical advances made in the fabrication and characterization of NIMs. The article concludes briefly addressing the anticipated implications of plasmon observation in the multicoaxial cables and suggesting future dimensions worth adding to the problem. The background provided is believed to make less formidable the task of future writers of reviews in this field.

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38

Nicolet, A., F. Zolla, Y. Ould Agha, and S. Guenneau. "Geometrical transformations and equivalent materials in computational electromagnetism." COMPEL - The international journal for computation and mathematics in electrical and electronic engineering 27, no. 4 (July 11, 2008): 806–19. http://dx.doi.org/10.1108/03321640810878216.

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PurposeThis paper aims to review various techniques used in computational electromagnetism such as the treatment of open problems, helicoidal geometries and the design of arbitrarily shaped invisibility cloaks. This seemingly heterogeneous list is unified by the concept of geometrical transformation that leads to equivalent materials. The practical set‐up is conveniently effected via the finite element method.Design/methodology/approachThe change of coordinates is completely encapsulated in the material properties.FindingsThe most significant examples are the simple 2D treatment of helicoidal geometries and the design of arbitrarily shaped invisibility cloaks.Originality/valueThe paper provides a unifying point of view, bridging several techniques in electromagnetism.

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39

Gallina, Ilaria, Giuseppe Castaldi, Vincenzo Galdi, Andrea Alù, and Nader Engheta. "Selected Applications of Transformation Electromagnetics." Advances in Science and Technology 75 (October 2010): 246–55. http://dx.doi.org/10.4028/www.scientific.net/ast.75.246.

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In this paper, we present a concise summary of selected results from our recent and ongoing studies on transformation electromagnetics. Specifically, we focus on cloak/anti-cloak interactions (with possible application to sensor invisibility), and on some general classes of metamaterial slabs (made of double positive, double negative or single negative media) with interesting image displacing/reconstruction capabilities.

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40

Alekseev, G., A. Tokhtina, and O. Soboleva. "Invisibility problem in acoustics, electromagnetism and heat transfer. Inverse design method." Journal of Physics: Conference Series 894 (October 2017): 012004. http://dx.doi.org/10.1088/1742-6596/894/1/012004.

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41

Misseroni, D., A. B. Movchan, and D. Bigoni. "Omnidirectional flexural invisibility of multiple interacting voids in vibrating elastic plates." Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 475, no. 2229 (September 2019): 20190283. http://dx.doi.org/10.1098/rspa.2019.0283.

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In elasticity, the design of a cloaking for an inclusion or a void to leave a vibrational field unperturbed by its presence, so to achieve its invisibility, is a thoroughly analysed, but still unchallenged, mechanical problem. The ‘cloaking transformation’ concept, originally developed in electromagnetism and optics, is not directly applicable to elastic waves, displaying a complex vectorial nature. Consequently, all examples of elastic cloaking presented so far involve complex design and thick coating skins. These cloakings often work only for problems of unidirectional propagation, within narrow ranges of frequency, and considering only one cloaked object. Here, a new method based on the concept of reinforcement, achieved via elastic stiffening and mass redistribution, is introduced to cloak multiple voids in an elastic plate. This simple technique produces invisibility of the voids to flexural waves within an extremely broad range of frequencies and thus surpassing in many aspects all existing cloaking techniques. The proposed design principle is applicable in mechanical problems ranging from the micro-scale to the scale of civil engineering. For instance, our results show how to design a perforated load-bearing building wall, vibrating during an earthquake exactly as the same wall, but unperforated, a new finding for seismic protection.

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42

Yue, Xiuli, Junyi Nangong, Peiyan Chen, and Tiancheng Han. "Thermal Cloak: Theory, Experiment and Application." Materials 14, no. 24 (December 17, 2021): 7835. http://dx.doi.org/10.3390/ma14247835.

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In the past two decades, owing to the development of metamaterials and the theoretical tools of transformation optics and the scattering cancellation method, a plethora of unprecedented functional devices, especially invisibility cloaks, have been experimentally demonstrated in various fields, e.g., electromagnetics, acoustics, and thermodynamics. Since the first thermal cloak was theoretically reported in 2008 and experimentally demonstrated in 2012, great progress has been made in both theory and experiment. In this review, we report the recent advances in thermal cloaks, including the theoretical designs, experimental realizations, and potential applications. The three areas are classified according to the different mechanisms of heat transfer, namely, thermal conduction, thermal convection, and thermal radiation. We also provide an outlook toward the challenges and future directions in this fascinating area.

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Islam, Sikder Sunbeam, Mohammad Rashed Iqbal Faruque, Mohammad Jakir Hossain, and Mohammad Tariqul Islam. "LIMITATIONS OF METAMATERIALS FOR INVISIBILITY CLOAKING." Jurnal Teknologi 78, no. 6-9 (June 21, 2016). http://dx.doi.org/10.11113/jt.v78.9138.

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Electromagnetic invisibility cloak (hide) has begun a new period in the scientific community. With the advent of metamaterials and its recent developments, researchers have now turned their faces to invisibility cloak. Metamaterials are man-made materials that have surprising electromagnetic property and it may show the characteristics of negative refractive index in materials that are normally not found in nature in any material. These exotic properties of metamaterial have opened up new possibilities for invisibility and other electromechanical fields. However, although metamaterials have created the field for invisibility cloaking but it has some limitations as well. Specially, constructing a perfect invisibility cloak in the visible range using metamaterials is still a big issue. In this paper, we have focused the limitations of metamaterial for invisibility cloaking beside basic principle of metamaterials and contributions in cloaking.

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44

Tadi, Saeed Hasanpour, and Babak Shokri. "Multi-cloak invisibility, a new strategy for simultaneous acoustic and electromagnetic invisibility." Waves in Random and Complex Media, February 23, 2021, 1–9. http://dx.doi.org/10.1080/17455030.2021.1885765.

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45

Klotz, Geoffroy, Nicolas Malléjac, Sebastien Guenneau, and Stefan Enoch. "Controlling frequency dispersion in electromagnetic invisibility cloaks." Scientific Reports 9, no. 1 (April 15, 2019). http://dx.doi.org/10.1038/s41598-019-42481-7.

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46

Serna, Alberto, Luis J. Molina, Javier Rivero, Luis Landesa, and José M. Taboada. "Multilayer homogeneous dielectric filler for electromagnetic invisibility." Scientific Reports 8, no. 1 (September 17, 2018). http://dx.doi.org/10.1038/s41598-018-32070-5.

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47

Zhang, Baile, and Bae-Ian Wu. "Electromagnetic Detection of a Perfect Invisibility Cloak." Physical Review Letters 103, no. 24 (December 7, 2009). http://dx.doi.org/10.1103/physrevlett.103.243901.

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48

Zhang, Baile, Hongsheng Chen, Bae-Ian Wu, Yu Luo, Lixin Ran, and Jin Au Kong. "Response of a cylindrical invisibility cloak to electromagnetic waves." Physical Review B 76, no. 12 (September 4, 2007). http://dx.doi.org/10.1103/physrevb.76.121101.

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Rahmani, Adel, M. J. Steel, and Patrick C. Chaumet. "Invisibility and supervisibility: Radiation dynamics in a discrete electromagnetic cloak." Physical Review B 87, no. 4 (January 30, 2013). http://dx.doi.org/10.1103/physrevb.87.045430.

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50

Chaumet, Patrick C., Adel Rahmani, Frédéric Zolla, and André Nicolet. "Electromagnetic forces on a discrete spherical invisibility cloak under time-harmonic illumination." Physical Review E 85, no. 5 (May 8, 2012). http://dx.doi.org/10.1103/physreve.85.056602.

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