Articoli di riviste: "METAMATERIAL ABSORBER"

1

Tran, Van Huynh, Thanh Tung Nguyen, Xuan Khuyen Bui, Dinh Lam Vu, Son Tung Bui e Thi Hong Hiep Le. "Experimental Verification of a TH\(\text{z}\) Multi-band Metamaterial Absorber". Communications in Physics 30, n. 4 (20 ottobre 2020): 311. http://dx.doi.org/10.15625/0868-3166/30/4/15081.

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Multi-band metamaterial absorbers have been of great interest owing to their potentials for a wide range of communicating, sensing, imaging, and energy harvesting applications. In this work, we experimentally investigate a four-band metamaterial absorber operating at THz frequencies. The metamaterials are fabricated using the maskless UV photolithography and e-beam evaporation techniques. The absorption spectra of the proposed absorber are measured using the micro-Fourier transformed infrared spectroscopy. It was demonstrated that multi-band absorption behavior originates from different individual metamaterial resonators. The thickness of the dielectric spacer plays a key role in optimizing the absorption performance, in line with the predicted results on single-band THz absorbers.

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Li, Xin, Qiushi Li, Liang Wu, Zongcheng Xu e Jianquan Yao. "Focusing on the Development and Current Status of Metamaterial Absorber by Bibliometric Analysis". Materials 16, n. 6 (12 marzo 2023): 2286. http://dx.doi.org/10.3390/ma16062286.

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In this paper, a total of 4770 effective documents about metamaterial absorbers were retrieved from the Web of Science Core Collection database. We scientifically analyzed the co-occurrence network of co-citation analysis by author, country/region, institutional, document, keywords co-occurrence, and the timeline of the clusters in the field of metamaterial absorber. Landy N. I.’s, with his cooperator et al., first experiment demonstrated a perfect metamaterial absorber microwave to absorb all incidents of radiation. From then on, a single-band absorber, dual-band absorber, triple-band absorber, multi-band absorber and broad-band absorber have been proposed and investigated widely. By integrating graphene and vanadium dioxide to the metamaterial absorber, the frequency-agile functionality can be realized. Tunable absorption will be very important in the future, especially metamaterial absorbers based on all-silicon. This paper provides a new research method to study and evaluate the performance of metamaterial absorbers. It can also help new researchers in the field of metamaterial absorbers to achieve the development of research content and to understand the recent progress.

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Neil, Thomas R., Zhiyuan Shen, Daniel Robert, Bruce W. Drinkwater e Marc W. Holderied. "Moth wings are acoustic metamaterials". Proceedings of the National Academy of Sciences 117, n. 49 (23 novembre 2020): 31134–41. http://dx.doi.org/10.1073/pnas.2014531117.

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Metamaterials assemble multiple subwavelength elements to create structures with extraordinary physical properties (1–4). Optical metamaterials are rare in nature and no natural acoustic metamaterials are known. Here, we reveal that the intricate scale layer on moth wings forms a metamaterial ultrasound absorber (peak absorption = 72% of sound intensity at 78 kHz) that is 111 times thinner than the longest absorbed wavelength. Individual scales act as resonant (5) unit cells that are linked via a shared wing membrane to form this metamaterial, and collectively they generate hard-to-attain broadband deep-subwavelength absorption. Their collective absorption exceeds the sum of their individual contributions. This sound absorber provides moth wings with acoustic camouflage (6) against echolocating bats. It combines broadband absorption of all frequencies used by bats with light and ultrathin structures that meet aerodynamic constraints on wing weight and thickness. The morphological implementation seen in this evolved acoustic metamaterial reveals enticing ways to design high-performance noise mitigation devices.

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Gu, Leilei, Hongzhan Liu, Zhongchao Wei, Ruihuan Wu e Jianping Guo. "Optimized Design of Plasma Metamaterial Absorber Based on Machine Learning". Photonics 10, n. 8 (27 luglio 2023): 874. http://dx.doi.org/10.3390/photonics10080874.

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Metamaterial absorbers have become a popular research direction due to their broad application prospects, such as in radar, infrared imaging, and solar cell fields. Usually, nanostructured metamaterials are associated with a large number of geometric parameters, and traditional simulation designs are time consuming. In this paper, we propose a framework for designing plasma metamaterial absorbers in both a forward prediction and inverse design composed of a primary prediction network (PPN) and an auxiliary prediction network (APN). The framework can build the relationship between the geometric parameters of metamaterials and their optical response (reflection spectra, absorption spectra) from a large number of training samples, thus solving the problem of time-consuming and case-by-case numerical simulations in traditional metamaterial design. This framework can not only improve forward prediction more accurately and efficiently but also inverse design metamaterial absorbers from a given required optical response. It was verified that it is also applicable to absorbers of different structures and materials. Our results show that it can be used in metamaterial absorbers, chiral metamaterials, metamaterial filters, and other fields.

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Yang, Guishuang, Fengping Yan, Xuemei Du, Ting Li, Wei Wang, Yuling Lv, Hong Zhou e Yafei Hou. "Tunable broadband terahertz metamaterial absorber based on vanadium dioxide". AIP Advances 12, n. 4 (1 aprile 2022): 045219. http://dx.doi.org/10.1063/5.0082295.

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The special electromagnetic properties of metamaterials have contributed to the development of terahertz technology, and terahertz broadband absorbers for various applications have been investigated. The design of metamaterial absorbers with tunability is in a particularly attractive position. In this work, a tunable broadband terahertz metamaterial absorber is proposed based on the phase transition material vanadium dioxide (VO2). The simulation results show that an excellent absorption bandwidth reaches 3.78 THz with the absorptivity over 90% under normal incidence. The absorptivity of the proposed structure can be dynamically tuned from 2.7% to 98.9% by changing the conductivity of VO2, which changes the structure from a perfect reflector to an absorber. An excellent amplitude modulation with the absorptivity is realized. The mechanism of broadband absorption is explored by analyzing the electric field distribution of the absorber based on impedance matching theory. In addition, it also has the advantage of polarization and incident angle insensitivity. The proposed absorber may have a wide range of promising applications in areas such as terahertz imaging, sensing, and detection.

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Li, Xiu, Chang Jun Hu e Yang Wang. "Design of Metamaterial Absorber with Ultra-broadband and High Absorption". Journal of Physics: Conference Series 2557, n. 1 (1 luglio 2023): 012077. http://dx.doi.org/10.1088/1742-6596/2557/1/012077.

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Abstract Metamaterial absorbers with perfect absorption properties are essential in various fields. A multilayer metamaterial disc absorber has been designed and analyzed using a finite-difference time-domain method. In the wavelength range from 300 nm to 3000 nm, this metamaterial absorber absorbs more than 90%. The metamaterial absorber is polarisation-insensitive due to its symmetric structure. On the other hand, the designed absorber still provides a high absorbance (>80%) at an incidence angle of 60°. Surface plasmon resonance (SPR), cavity resonance, local surface plasmon resonance (LSPR), and inter-resonance interactions dominate the absorber for efficient absorption and extended absorption bandwidth.

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Liu, Xiajun, Feng Xia, Mei Wang, Jian Liang e Maojin Yun. "Working Mechanism and Progress of Electromagnetic Metamaterial Perfect Absorber". Photonics 10, n. 2 (14 febbraio 2023): 205. http://dx.doi.org/10.3390/photonics10020205.

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Electromagnetic metamaterials are artificial subwavelength composites with periodic structures, which can interact strongly with the incident light to achieve effective control of the light field. Metamaterial absorbers can achieve nearly 100% perfect absorption of incident light at a specific frequency, so they are widely used in sensors, optical switches, communication, and other fields. Based on the development history of metamaterials, this paper discusses the research background and significance of metamaterial perfect absorbers. Some perfect absorption mechanisms, such as impedance matching and coherent perfect absorption, are discussed. According to the functional division, the narrowband, dual frequency, multi-frequency, broadband, and tunable metamaterial perfect absorbers are briefly described.

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Peng, Mengyue, Faxiang Qin, Liping Zhou, Huijie Wei, Zihao Zhu e Xiaopeng Shen. "Material–structure integrated design for ultra-broadband all-dielectric metamaterial absorber". Journal of Physics: Condensed Matter 34, n. 11 (28 dicembre 2021): 115701. http://dx.doi.org/10.1088/1361-648x/ac431e.

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Abstract Material and structure are the essential elements of all-dielectric metamaterials. Structure design for specific dielectric materials has been studied while the contribution of material and synergistic effect of material and structure have been overlooked in the past years. Herein, we propose a material–structure integrated design (MSID) methodology for all-dielectric metamaterials, increasing the degree of freedom in the metamaterial design, to comprehensively optimize microwave absorption performance and further investigate the contribution of material and structure to absorption. A dielectric metamaterial absorber with an ultra-broadband absorption from 5.3 to 18.0 GHz is realized. Theoretical calculation and numerical simulation demonstrate that the symphony of material and structure excites multiple resonance modes encompassing quarter-wavelength interference cancellation, spoof surface plasmon polariton mode, dielectric resonance mode and grating mode, which is essential to afford the desirable absorption performance. This work highlights the superiority of coupling of material and structure and provides an effective design and optimization strategy for all-dielectric metamaterial absorbers.

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Ge, Tingting, Zhijin Li, Wei Song e Xinqing Sheng. "Design and Simulation of Photo-excited Tunable Perfect Absorber Based on Semiconductor-incorporated Metamaterial Structure". Journal of Physics: Conference Series 2219, n. 1 (1 aprile 2022): 012030. http://dx.doi.org/10.1088/1742-6596/2219/1/012030.

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Abstract The perfect metamaterial absorber with sandwich structure is capable to realize nearly 100% microwave absorption. We designed and simulated a photo-excited tunable perfect absorber based on semiconductor-incorporated metamaterials using HFSS (Ansoft). This absorber composes of semiconductor Ge in designed pattern in the unit cell. Under different pump power of the incident laser light, the conductivity of Ge on the metamaterial varies. In this way, the absorption frequency of the absorber can be tuned. Simulation results showed that, under the two pump light conditions, the absorber is with maximum absorbances of over 97% in both cases. We also analyzed the loss in the absorber through numerical experiments.

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Ali, Hema Omer, e Asaad M. Al-Hindawi. "A Ultra-broadband Thin Metamaterial Absorber for Ku and K Bands Applications". Journal of Engineering 27, n. 5 (28 aprile 2021): 1–16. http://dx.doi.org/10.31026/j.eng.2021.05.01.

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In this paper, a design of the broadband thin metamaterial absorber (MMA) is presented. Compared with the previously reported metamaterial absorbers, the proposed structure provides a wide bandwidth with a compatible overall size. The designed absorber consists of a combination of octagon disk and split octagon resonator to provide a wide bandwidth over the Ku and K bands' frequency range. Cheap FR-4 material is chosen to be a substate of the proposed absorber with 1.6 thicknesses and 6.5×6.5 overall unit cell size. CST Studio Suite was used for the simulation of the proposed absorber. The proposed absorber provides a wide absorption bandwidth of 14.4 GHz over a frequency range of 12.8-27.5 GHz with more than %90 absorptions. To analyze the proposed design, electromagnetic parameters such as permittivity permeability reflective index , and impedance were extracted and presented. The structure's working principle is analyzed and illustrated through input impedance, surface current, and the electric field of the structure. The proposed absorber compared with the recent MMA presented in the literature. The obtained results indicated that the proposed absorber has the widest bandwidth with the highest absorption value. According to these results, the proposed metamaterials absorber is a good candidate for RADAR applications.

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Murakami, Kenki, e Wakana Kubo. "Optimizing broadband metamaterial absorber using deep reinforcement learning". Applied Physics Express 16, n. 8 (1 agosto 2023): 082007. http://dx.doi.org/10.35848/1882-0786/acf094.

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Abstract Optimization of the geometry of broadband metamaterial absorbers is crucial for improving the performance of optoelectronic devices. However, a large number of geometric parameters should be considered to achieve broad absorption, which is time-consuming. Herein, we propose a rapid and simple method for optimizing metamaterial absorbers dedicated to thermal radiation absorption using deep reinforcement learning. Deep reinforcement learning generated an ideal geometry for a broadband metamaterial absorber after 4 h, demonstrating the effectiveness of this technique for the rapid and effective optimization of metamaterial absorbers.

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Guo, Tian-Long, Fangfang Li e Matthieu Roussey. "Dielectric Cavity-Insulator-Metal (DCIM) Metamaterial Absorber in Visible Range". Nanomaterials 13, n. 8 (18 aprile 2023): 1401. http://dx.doi.org/10.3390/nano13081401.

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For many years, metamaterial absorbers have received much attention in a wide range of application fields. There is an increasing need to search for new design approaches that fulfill more and more complex tasks. According to the specific application requirements, design strategy can vary from structure configurations to material selections. A new combination of a dielectric cavity array, dielectric spacer, and gold reflector as a metamaterial absorber is proposed and theoretically studied in this work. The complexity of the dielectric cavities leads to a more flexible optical response than traditional metamaterial absorbers. It gives a new dimension of freedom for a real three-dimensional metamaterial absorber design.

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Jiang, Haoqing, Yue Wang, Zijian Cui, Xiaoju Zhang, Yongqiang Zhu e Kuang Zhang. "Vanadium Dioxide-Based Terahertz Metamaterial Devices Switchable between Transmission and Absorption". Micromachines 13, n. 5 (30 aprile 2022): 715. http://dx.doi.org/10.3390/mi13050715.

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Terahertz metamaterial plays a significant role in the development of imaging, sensing, and communications. The function of conventional terahertz metamaterials was fixed after fabrication. They can only achieve a single function and do not have adjustable characteristics, which greatly limits the scalability and practical application of metamaterial. Here, we propose a vanadium dioxide-based terahertz metamaterial device, which is switchable between being a transmitter and an absorber. The transmission and absorption characteristics and temperature tunable properties of phase change metamaterials in the terahertz band were investigated. As the temperature of vanadium dioxide is varied between 20 °C and 80 °C, the device can switch between transmission and quad-band resonance absorption at the terahertz frequency range, with a high transmission rate of over 80% and a peak absorbance of 98.3%, respectively. In addition, when the device acts as an absorber, the proposed metamaterial device is tunable, and the modulation amplitude can reach 94.3%; while the device is used as a transmissive device, the modulation amplitude of the transmission peak at 81%. The results indicate that the proposed metamaterial device can promote the applications of terahertz devices, such as switching, modulation, and sensing.

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Chen, Ke, Xinyao Luo, Guowen Ding, Junming Zhao, Yijun Feng e Tian Jiang. "Broadband microwave metamaterial absorber with lumped resistor loading". EPJ Applied Metamaterials 6 (2019): 1. http://dx.doi.org/10.1051/epjam/2018011.

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Narrow absorption bandwidth has been a fundamental drawback hindering many metamaterial absorbers for practical applications. In this paper, by loading lumped resistors, we have successfully designed a microwave metamaterial absorber with multioctave wide absorption bandwidth covering the entire X- and Ku-bands, while keeping the thickness of the absorber less than 1/10 of the working wavelength. The polarization-insensitive absorber shows a good angular stability for both transverse electric (TE) and transverse magnetic (TM) incidences. Prototype has been fabricated and measured to validate the design principle and the simulated results, and good agreements are observed between simulated and measured results. The proposed metamaterial absorber offers an efficient way to realize broadband microwave absorption with stable angular performance, which may find potential uses in many applications, for example, electromagnetic compatibility.

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Abdalla, M. A., e Z. Hu. "On The Study of Development of X Band Metamaterial Radar Absorber". Advanced Electromagnetics 1, n. 3 (8 dicembre 2012): 94. http://dx.doi.org/10.7716/aem.v1i3.25.

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A new development of metamaterial applications in radar absorbers for X band is introduced. Two modifications were suggested based on two different approaches which are a new called fan shaped resonator absorber and a modified high impedance metamaterial absorber. Both approaches introduce thin radar absorber (5.3% at centre frequency) with wide bandwidth and high absorption level. The theoretical concepts of each design are explained and validated using full wave simulation. Results illustrate that the new development can achieve wider bandwidth, multiple operating bands; the increase in bandwidth is up to 8 times the conventional one. Moreover, the reported absorbers have capability to operate with different polarizations.

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KAJIKAWA, Kotaro. "Metamaterial Light Absorber". Review of Laser Engineering 44, n. 1 (2016): 27. http://dx.doi.org/10.2184/lsj.44.1_27.

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Grant, J., I. J. H. McCrindle, C. Li e D. R. S. Cumming. "Multispectral metamaterial absorber". Optics Letters 39, n. 5 (24 febbraio 2014): 1227. http://dx.doi.org/10.1364/ol.39.001227.

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Huang, Xiaojun, Ziliang Zhou, Miao Cao, Rong Li, Cuizhen Sun e Xiaoyan Li. "Ultra-Broadband Mid-Infrared Metamaterial Absorber Based on Multi-Sized Resonators". Materials 15, n. 15 (5 agosto 2022): 5411. http://dx.doi.org/10.3390/ma15155411.

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Mid-infrared metamaterial absorbers have many applications in the field of infrared detection, infrared thermal energy utilization, radiation refrigeration, invisible camouflage, etc. In this study, we designed an ultra-broadband mid-infrared metamaterial absorber based on multi-sized resonators. The structure of the absorber consisted of a gold substrate and nine resonators. The simulated results showed that the absorptivity of the absorber was higher than 90% in the 8.33–15.09 μm waveband with an average absorptivity of 95.17%. The energy distributions of the electric and magnetic fields were introduced to investigate the physics of broadband absorption. Moreover, we combined the multi-layer structure with the plane random arrangement structure to achieve a balance between thickness and width. Our study further illustrates the potential application of multi-sized resonators in metamaterial absorbers to realize high absorptivity and ultra-broadband to improve the performance of devices applied in infrared detection, radiation refrigeration, and other fields.

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Tian, Feng, Xia Ma, Han Hao, Xuewen Li, Jingdao Fan, Liang Guo e Xiaojun Huang. "Broadband Bi-Directional Polarization-Insensitive Metamaterial Absorber". Materials 14, n. 23 (30 novembre 2021): 7339. http://dx.doi.org/10.3390/ma14237339.

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Conventional metamaterial absorbers eliminate the transmitted electromagnetic wave by attaching the metal plate with the unidirectional absorption performance; these absorbers limit the practical applications to a large extent. In this paper, we present a broadband bi-directional metamaterial absorber by etching chip resistors on the resonators for expanding the bandwidth, and two orthogonal I-shaped structures are pasted on the both sides of the ultra-thin substrate (FR-4) instead of the metal plate for enhancing absorptance of the absorber. Simulated results show that absorptance of the designed absorber is larger than 0.9 in 1.43–2.51 GHz along the forward and backward directions under both TE and TM polarizations. Microwave experiments in the chamber are performed to verify the simulations, and the experimental results exhibit the excellent agreement with the simulations. Additionally, two I-shaped structures are orthogonally pasted on an ultrathin substrate, leading to the impedance-matching of both forward and backward directions, and the absorptance can be tailed dynamically via the middle layer of the substrate. The physics of the absorption are visualized by using a transmission line based on equivalent circuits. We claim that the designed bi-directional metamaterial absorber can be a good candidate for electromagnetic stealth and energy harvesting.

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Song, Zijun, Guolu Ma, Zao Yi, Jianguo Zhang e Yong Zhao. "Metamaterial Solar Absorber Based on Refractory Metal Titanium and Its Compound". Coatings 12, n. 7 (30 giugno 2022): 929. http://dx.doi.org/10.3390/coatings12070929.

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Metamaterials refers to a class of artificial materials with special properties. Through its unique geometry and the small size of each unit, the material can acquire unique electromagnetic field properties that conventional materials do not have. Based on these factors, we put forward a kind of high absorption near-ultraviolet to near-infrared electromagnetic wave absorber of the solar energy. The surface structure of the designed absorber is composed of TiN-TiO2-Al2O3 with rectangles and disks, and the substrate is Ti-Al2O3-Ti layer. In the study band range (0.1–3.0 μm), the solar absorber’s average absorption is up to 96.32%, and the designed absorber absorbs more than 90% of the electromagnetic wave with a wavelength width of 2.577 μm (0.413–2.990 μm). Meanwhile, the designed solar absorber has good performance under different angles of oblique incident light. Ultra-wideband solar absorbers have great potential in light absorption related applicaitions because of their wide spectrum high absorption properites.

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A., Elakkiya, Radha Sankararajan, Sreeja B.S. e Manikandan E. "Modified I-shaped hexa-band near perfect terahertz metamaterial absorber". Circuit World 46, n. 4 (16 luglio 2020): 281–84. http://dx.doi.org/10.1108/cw-11-2019-0155.

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Purpose A novel and simple six-band metamaterial absorber is proposed in the terahertz region, which is composed of an I-shaped absorber and circular ring with four gaps and a continuous metal ground plane separated by only 0.125 mm polyimide dielectric substrate. Initially, I-shaped resonator gives three bands at 0.4, 0.468 and 0.4928 THz with the absorptivity of 99.3%, 97.9% and 99.1%, respectively. The purpose of this paper is to improve the number of bands, for which the authors added the circular ring with four gaps, so the simulated metamaterial absorber exhibited six absorption peaks at 0.3392, 0.3528, 0.3968, 0.4676, 0.4768 and 0.492 THz, with the absorption rate of 91.4%, 94.2%, 94.9%, 90.3%, 77.5% and 97.4%, respectively. The surface current distribution and angle independence are explained for all the six frequencies which are used to analyze the absorption mechanism clearly. Structure maximum uses the squares and circles, so it will make the fabrication easy. The multiband absorbers obtained here have potential applications in many engineering technology, thermal radiation, material detection and imaging and optoelectronic areas. Design/methodology/approach This paper presents the design of the six-band metamaterial absorber which is from the I-shaped resonator and circular ring with four gaps and the metallic ground plane separated by the 0.125 polyimide dielectric substrate. The absorber exhibited six absorption peaks at 0.3392, 0.3528, 0.3968, 0.4676, 0.4768 and 0.492 THz, with the absorption rate of 91.4%, 94.2%, 94.9%, 90.3%, 77.5% and 97.4%, respectively. From the fabrication point of view, the proposed six-band metamaterial absorber has a very simple geometrical structure, and it is very easy to be fabricated. Findings The authors present a new and simple design of six-band absorber based on an I-shaped absorber and circular ring with four gaps and a metallic ground plane separated by a polyimide layer having the thickness of 0.125 mm. Six different resonance absorption peaks are found at 0.3392, 0.3528, 0.3968, 0.4676 , 0.4768 and 0.492 THz. Surface current distribution and angle independence plot have been studied to understand the absorption behavior of the designed terahertz metamaterial absorber. Originality/value The multiband absorbers obtained here have potential applications in many engineering technology, thermal radiation, material detection, security, sensors, imaging and optoelectronic areas.

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Han, Chen, Renbin Zhong, Zekun Liang, Long Yang, Zheng Fang, Yiqing Wang, Anchen Ma et al. "Independently Tunable Multipurpose Absorber with Single Layer of Metal-Graphene Metamaterials". Materials 14, n. 2 (8 gennaio 2021): 284. http://dx.doi.org/10.3390/ma14020284.

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This paper reports an independently tunable graphene-based metamaterial absorber (GMA) designed by etching two cascaded resonators with dissimilar sizes in the unit cell. Two perfect absorption peaks were obtained at 6.94 and 10.68 μm with simple single-layer metal-graphene metamaterials; the peaks show absorption values higher than 99%. The mechanism of absorption was analyzed theoretically. The independent tunability of the metamaterial absorber (MA) was realized by varying the Fermi level of graphene under a set of resonators. Furthermore, multi-band and wide-band absorption were observed by the proposed structure upon increasing the number of resonators and resizing them in the unit cell. The obtained results demonstrate the multipurpose performance of this type of absorber and indicate its potential application in diverse applications, such as solar energy harvesting and thermal absorbing.

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Han, Chen, Renbin Zhong, Zekun Liang, Long Yang, Zheng Fang, Yiqing Wang, Anchen Ma et al. "Independently Tunable Multipurpose Absorber with Single Layer of Metal-Graphene Metamaterials". Materials 14, n. 2 (8 gennaio 2021): 284. http://dx.doi.org/10.3390/ma14020284.

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This paper reports an independently tunable graphene-based metamaterial absorber (GMA) designed by etching two cascaded resonators with dissimilar sizes in the unit cell. Two perfect absorption peaks were obtained at 6.94 and 10.68 μm with simple single-layer metal-graphene metamaterials; the peaks show absorption values higher than 99%. The mechanism of absorption was analyzed theoretically. The independent tunability of the metamaterial absorber (MA) was realized by varying the Fermi level of graphene under a set of resonators. Furthermore, multi-band and wide-band absorption were observed by the proposed structure upon increasing the number of resonators and resizing them in the unit cell. The obtained results demonstrate the multipurpose performance of this type of absorber and indicate its potential application in diverse applications, such as solar energy harvesting and thermal absorbing.

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El Assal, Aicha, Hanadi Breiss, Ratiba Benzerga, Ala Sharaiha, Akil Jrad e Ali Harmouch. "Toward an Ultra-Wideband Hybrid Metamaterial Based Microwave Absorber". Micromachines 11, n. 10 (13 ottobre 2020): 930. http://dx.doi.org/10.3390/mi11100930.

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In this paper, we propose a novel design of an ultra-wideband hybrid microwave absorber operating in the frequency range between 2 GHz and 18 GHz. This proposed hybrid absorber is composed of two different layers that integrate a multiband metamaterial absorber and a lossy dielectric layer. The metamaterial absorber consists of a periodic pattern that is composed of an arrangement of different scales of coupled resonators and a metallic ground plane, and the dielectric layer is made of epoxy foam composite loaded with low weight percentage (0.075 wt.%) of 12 mm length carbon fibers. The numerical results show a largely expanded absorption bandwidth that ranges from 2.6 GHz to 18 GHz with incident angles between 0° and 45° and for both transverse electric and transverse magnetic waves. The measurements confirm that absorption of this hybrid based metamaterial absorber exceeds 90% within the above-mentioned frequency range and it may reach an absorption rate of 99% for certain frequency ranges. The proposed idea offers a further step in developing new electromagnetic absorbers, which will impact a broad range of applications.

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Alsaif, Haitham, Jonas Muheki, Naim Ben Ali, Kaouther Ghachem, Jaymit Surve e Shobhit K. Patel. "Thin-Film Solar Energy Absorber Structure for Window Coatings for Self-Sufficient Futuristic Buildings". Micromachines 14, n. 8 (17 agosto 2023): 1628. http://dx.doi.org/10.3390/mi14081628.

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Energy-efficient buildings are a new demand in the current era. In this paper, we present a novel metamaterial design aimed at achieving efficient solar energy absorption through a periodic MMA structure composed of a W-GaAs-W. The proposed structure can be implemented as the window coating and in turn it can absorb the incident solar energy and, then, this energy can be used to fulfill the energy demand of the building. Our results reveal significant improvements, achieving an average absorptance of 96.94% in the spectral range. Furthermore, we explore the influence of the angle of incidence on the absorber’s response, demonstrating its angle-insensitive behavior with high absorption levels (above 90%) for incidence angles up to 60° for TE polarization and 40° for TM polarization. The proposed structure presents a significant advancement in metamaterial-based solar energy absorption. By exploring the effects of structural parameters and incident angles, we have demonstrated the optimized version of our proposed absorber. The potential applications of this metamaterial absorber in self-sufficient futuristic building technologies and self-sustaining systems offer new opportunities for harnessing solar energy and are a valuable contribution to future developments in the fields of metamaterials and renewable energy.

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Anjali, M., Kumaran Rengaswamy, Abhishek Ukey, Lincy Stephen, C. V. Krishnamurthy e V. Subramanian. "Flexible metamaterial based microwave absorber with epoxy/graphene nanoplatelets composite as substrate". Journal of Applied Physics 133, n. 6 (14 febbraio 2023): 063105. http://dx.doi.org/10.1063/5.0138171.

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Customization of substrates for the design of metamaterial absorbers gives the user a wide choice of parameters like flexibility, thickness, dielectric constant, etc. Polymer composites are attractive in this regard as they provide a variety of options to fabricate substrates with desirable properties depending on the matrix and filler materials. In this work, flexible polymer nanocomposites with different weight percentages of graphene nanoplatelets (GnP) in epoxy were fabricated and the dielectric characterization was performed. The presence of GnP increased the real part of the dielectric constant from 2.5 for 0 wt. % to 14.7 for 9 wt. % of the epoxy-GnP composites measured in X-band frequency. The substrate with 5 wt. % of GnP in epoxy having a relative permittivity of 7.3–j0.25 is chosen to design a metamaterial absorber, and the absorption studies are carried out numerically. The proposed absorber having a thickness of λ/22 is shown to have a maximum absorption of 99.8% at the frequency 9.88 GHz. Furthermore, an equivalent circuit model of the absorber is proposed and the analytical values of the circuit elements are determined. The metamaterial prototype is fabricated by coating metallic resonating structures on top of the flexible E-GnP5 substrate of thickness 1.4 mm by thermal evaporation. The performance of the fabricated absorber agrees well with the simulation results. These polymer nanocomposites with good flexibility, thermal stability, and optimum dielectric properties would be the future materials for developing conformal metamaterial absorbers for microwave applications.

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27

Cao, Miao, Xiaojun Huang, Lina Gao, Xiaoyan Li, Linyan Guo e Helin Yang. "Broadband Bi-Directional All-Dielectric Transparent Metamaterial Absorber". Nanomaterials 12, n. 23 (22 novembre 2022): 4124. http://dx.doi.org/10.3390/nano12234124.

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Water-based absorbers have shown great development potential in the past few years. In this paper, an all-dielectric transparent bi-directional water-based broadband metamaterial absorber is designed. The simulation results indicate that absorptance of the absorber is over 90% in 5.7–41.6 GHz, and its fraction bandwidth is 151.8%. The experimental results are greatly consistent with the simulations. The designed absorber has excellent performances of polarization insensitivity, oblique incidence stability and thermal stability. When the absorptance is more than 0.8, the maximum incident angle reaches 40° in TE mode and is over 60° in TM mode. In 0–80 °C, absorptance of the absorber is hardly changed. Because of the optical transparency of the designed absorber, it can be extensively used in stealth window weapons and electromagnetic compatibility equipment.

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28

Sabluk, A. V., e A. A. Basharin. "Terahertz radiation converter based on metamaterial". Izvestiya Vysshikh Uchebnykh Zavedenii. Materialy Elektronnoi Tekhniki = Materials of Electronics Engineering 26, n. 1 (14 aprile 2023): 56–65. http://dx.doi.org/10.17073/1609-3577-2023-1-56-65.

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Since the early 1980s, the terahertz range (from 0.1 to 10 THz) attracts constant attention of both fundamental and applied physics. Due to its unique properties, terahertz radiation finds it’s applications in spectroscopy, defectoscopy, and security systems. The construction of efficient absorbers and converters in terahertz range is crucial for further development of terahertz technologies. In this work, we use a frequency-selective high-Q metamaterial to construct a converter of terahertz radiation into the infrared radiation. The converter consists of a metamaterial absorber of terahertz radiation covered with a micrometer thick layer of graphite, which emits in the infrared range the energy absorbed by the metamaterial. We have made a numerical electrodynamic and associated thermal simulation of the radiation converter. The metamaterial simulation at 96 GHz (low opacity window of the atmosphere) shows the electromagnetic radiation absorption coefficient of 99.998%, and the analytically calculated converter efficiency of 93.8%. Concluding the above our terahertz radiation converter may contribute to security systems and defectoscopy setups.

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29

Sabluk, Andrey V., e Alexey A. Basharin. "Metamaterial-based terahertz converter". Modern Electronic Materials 8, n. 4 (19 dicembre 2022): 149–55. http://dx.doi.org/10.3897/j.moem.8.4.98919.

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Abstract (sommario):

Since the early 1980s the terahertz range (0.1 to 10 THz) attracts permanent attention of fundamental and applied science. Due to its unique properties terahertz radiation is used in a wide range of applications such as spectroscopy, non-destructive defectoscopy and security systems. The design of high-efficiency terahertz absorbers and converters is currently the main task in the development of terahertz technologies. In this work a frequency selective high-Q metamaterial is used for the fabrication of a terahertz-to-infrared converter. The converter consists of a metamaterial-based terahertz absorber coated with a micrometer-thick graphite layer that reemits the absorbed energy in the infrared range. We have carried out electrodynamic and the related thermodynamic calculations of the suggested radiation converter. Numerical simulations yield an electromagnetic radiation absorption coefficient of 99.998% and an analytically calculated converter efficiency of 93.8%. Thanks to these advanced parameters suggested terahertz converter can find it’s applications in a wide range of transportation security inspection and defectoscopy tasks.

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30

Lu, Taiguo, Dawei Zhang, Peizhen Qiu, Jiqing Lian, Ming Jing, Binbin Yu e Jing Wen. "Ultrathin Terahertz Dual-Band Perfect Metamaterial Absorber Using Asymmetric Double-Split Rings Resonator". Symmetry 10, n. 7 (20 luglio 2018): 293. http://dx.doi.org/10.3390/sym10070293.

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In this article, an ultrathin terahertz dual band metamaterial absorber made up of patterned asymmetrical double-split rings and a continuous metal layer separated by a thin FR-4 layer is designed. Simulation results show that two almost identical strong absorption peaks appear in the terahertz band. When the incident electric field is perpendicular to the ring gaps located at 11 μm asymmetrically, the absorptivity of 98.6% at 4.48 THz and 98.5% at 4.76 THz can be obtained. The absorption frequency and the absorptivity of the absorber can be modulated by the asymmetric distribution of the gaps. The perfect metamaterial absorber is expected to provide important reference for the design of terahertz modulator, filters, absorbers, and polarizers.

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31

Kim, Young Ju, Young Joon Yoo, Ki Won Kim, Joo Yull Rhee, Yong Hwan Kim e YoungPak Lee. "Dual broadband metamaterial absorber". Optics Express 23, n. 4 (9 febbraio 2015): 3861. http://dx.doi.org/10.1364/oe.23.003861.

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32

Gu, Chao, Shao-Bo Qu, Zhi-Bin Pei, Zhuo Xu, Jia Liu e Wei Gu. "Multiband terahertz metamaterial absorber". Chinese Physics B 20, n. 1 (gennaio 2011): 017801. http://dx.doi.org/10.1088/1674-1056/20/1/017801.

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33

Yang, Quanlong, Xieyu Chen, Yanfeng Li, Xueqian Zhang, Yuehong Xu, Zhen Tian, Chunmei Ouyang, Jianqiang Gu, Jiaguang Han e Weili Zhang. "Aperiodic-metamaterial-based absorber". APL Materials 5, n. 9 (settembre 2017): 096107. http://dx.doi.org/10.1063/1.4996112.

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34

Dayal, Govind, e S. Anantha Ramakrishna. "Metamaterial saturable absorber mirror". Optics Letters 38, n. 3 (16 gennaio 2013): 272. http://dx.doi.org/10.1364/ol.38.000272.

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35

Yudistira, Hadi Teguh, e Kiki Kananda. "The Preliminary Microwave Metamaterial Absorber Based on Ring-Shaped for Stealth Technology". IOP Conference Series: Earth and Environmental Science 1209, n. 1 (1 luglio 2023): 012028. http://dx.doi.org/10.1088/1755-1315/1209/1/012028.

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Abstract (sommario):

Abstract Controlling electromagnetic waves on the material is needed by several applications such as sensors, stealth technology, and energy harvesting. An artificial material that could control electromagnetic waves is called metamaterial. Meanwhile, a metamaterial absorber can absorb the electromagnetic wave. Two concepts can be used to explain the absorbing phenomena on metamaterial absorber: the matching impedance of the air and the part of the imaginary that is high of the index of refractive collectively or the theory of interference that is destructive. The correlation of matching air impedance with destructive interference theory has been found by Yudistira in his previous works. In this study, the preliminary research of metamaterial absorbers based on ring shape is presented. The 40 mm, 35 mm, 30 mm, and 25 mm ring-shaped widths are applied to this work. We used numerical simulation work to understand the performance of metamaterial absorbers based on ring-shaped. CST microwave studio was used for numerical simulation work. The absorbance peak results for w=20, w=17.5, w=15, and w=12.5 mm are 0.92 at 3.43 GHz, 0.95 at 3.7 GHz, 0.95 at 4.04 GHz and 0.99 at 4.47 GHz, severally. The maximum absorbance is yielded to 0.99 absorbances for 25 mm of the width of the ring-shaped.

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36

Jeong, Heijun, Manos M. Tentzeris e Sungjoon Lim. "Optically Transparent Metamaterial Absorber Using Inkjet Printing Technology". Materials 12, n. 20 (17 ottobre 2019): 3406. http://dx.doi.org/10.3390/ma12203406.

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Abstract (sommario):

An optically transparent metamaterial absorber that can be obtained using inkjet printing technology is proposed. In order to make the metamaterial absorber optically transparent, an inkjet printer was used to fabricate a thin conductive loop pattern. The loop pattern had a width of 0.2 mm and was located on the top surface of the metamaterial absorber, and polyethylene terephthalate films were used for fabricating the substrate. An optically transparent conductive indium tin oxide film was introduced in the bottom ground plane. Therefore, the proposed metamaterial absorber was optically transparent. The metamaterial absorber was demonstrated by performing a full-wave electromagnetic simulation and measured in free space. In the simulation, the 90% absorption bandwidth ranged from 26.6 to 28.8 GHz, while the measured 90% absorption bandwidth was 26.8–28.2 GHz. Therefore, it is successfully demonstrated by electromagnetic simulation and measurement results.

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37

Jiang, Zhaoxia, Jin Leng, Jin Li, Jianfei Li, Boyang Li, Mao Yang, Xiaolian Wang e Qiwu Shi. "Flexible Terahertz Metamaterials Absorber based on VO2". Photonics 10, n. 6 (28 maggio 2023): 621. http://dx.doi.org/10.3390/photonics10060621.

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Terahertz (THz) metamaterials have attracted great attention due to their widely application potential in smart THz devices; however, most of them are fabricated on rigid substrate and thus limit the exploration of flexible THz electronics. In this paper, a flexible THz metamaterial absorber (MMA) incorporated with phase change material vanadium dioxide (VO2) is proposed. The simulation results indicate that two absorption peaks at around 0.24 THz (marked as A) and 0.46 THz (marked as B) can be observed by designing a I-shaped metamaterial combined with split ring structure. The strong absorption over 92% at 0.24 THz is bending-insensitive, but the absorption at 0.46 THz is bending-sensitive, across the bending angle in the range of 0–50 degrees. Moreover, dynamic modulation of the absorption can be achieved across the insulator-metal phase transition of VO2. Particularly, the absorption of the A-peak can be tuned from 99.4% to 46.9%, while the absorption of the B-peak can be tuned from 39.6% to 99.3%. This work would provide significance for the design of flexible THz smart devices.

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38

Daniel, Salman, e Prince Bawuah. "Right-Angle Shaped Elements as Dual-Band Metamaterial Absorber in Terahertz". Photonic Sensors 10, n. 3 (27 dicembre 2019): 233–41. http://dx.doi.org/10.1007/s13320-019-0573-6.

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Abstract (sommario):

AbstractMetamaterial absorbers display potential applications in the field of photonics and have been investigated extensively during the last decade. We propose a dual-band resonant metamaterial absorber with right-angle shaped elements (RAEs) in the terahertz range based on numerical simulations. The absorber remains insensitive to a wide range of incidence angles (0°–70°) by showing a minimum absorbance of ~80% at 70°. Furthermore, the proposed absorber is highly independent on any state of polarization of the incidence electromagnetic wave due to the high absorbance, i.e., greater than 80%, recorded for the considered polarization states. To further comprehend the slight variations in absorbance as a function of change in the angle of incidence, the impedance of the structure has been critically examined. The metamaterial absorber is simple in design, and we provide a possible path of fabrication.

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39

Hassan, H., e M. Abu. "Ultra Thin Flexible Octagonal Metamaterials Absorber". Indonesian Journal of Electrical Engineering and Computer Science 10, n. 3 (1 giugno 2018): 833. http://dx.doi.org/10.11591/ijeecs.v10.i3.pp833-839.

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<span lang="IN">An ultra thin flexible octagonal metamaterial absorber on 0.13 mm fastFilm D27 material has been presented in this paper. CST microwave studio was used in designing and simulating the octagonal metamaterial absorber. The flexible octagonal metamaterial absorber was resonated at 10 GHz with highly perfect absorbance of 99.98%. However, Full Width Half Maximum (FWHM) of the absorbance was relatively small 135 MHz affected from the ultra thin substrate used. By using triangular lattice arrangement of the unit cell, the FWHM could be increased to 171 MHz. Besides that, combination of resonating frequencies technique also had increased the FWHM more than 74% increment from basic unit cell with one resonance frequency. The flexibleness of the metamaterial absorber could increase the functionality of the metamaterial absorber to be used in any application especially in reducing radar cross section for stealth application.</span>

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40

R.O. Ryazantsev, Y.P. Salomatov e S.V. Polenga. "Metamaterial absorber and antenna ground plane". Technical Physics Letters 48, n. 15 (2022): 18. http://dx.doi.org/10.21883/tpl.2022.15.53812.18947.

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Metamaterial absorber located near solid metal surface was investigated and antenna design was developed for receiving satellite navigation signals using absorptive ground plane comprises proposed material. The metamaterial structure has been developed, frequency characteristics have been analyzed by finite element method in frequency domain, operating dimensions of elements have been established. Modeling and analysis of radiation pattern for antenna with absorptive ground plane versus the antenna with the classic high impedance ground plane were carried out. Conclusions were drawn on the applicability of the proposed metamaterial structure. Keywords: GNSS Antenna, metamaterial absorber, high impedance ground plane.

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41

Yuan, Yujiao, Yunping Qi, Baohe Zhang, Jinghui Ding, Weiming Liu, Haowen Chen e Xiangxian Wang. "A polarization-insensitive, wide-angle dual-band tunable graphene metamaterial perfect absorber with T-shaped strips and square ring". Physica Scripta 97, n. 2 (31 gennaio 2022): 025507. http://dx.doi.org/10.1088/1402-4896/ac4cfc.

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Abstract Metamaterial perfect absorbers play an essential role in many optoelectronic devices. In this paper, a dual-band tunable metamaterial perfect absorber based on graphene is proposed. The simulation results present that under normal incidence two absorption peaks of 99.9% and 99.9% occur at the frequencies 1.69 THz and 4.30 THz, respectively. Impedance matching theory is employed to elaborate this dual-band perfect absorption phenomenon. While at oblique incidence, the absorption of the absorber remains more than 90% over a wide incident angle from 0° to 75° for the transverse electric (TE) polarization and 60° for the transverse magnetic (TM) polarization separately. Furthermore, it is also independent to the polarization angles. In addition, the effects of different geometrical parameters and the chemical potential of graphene on the resonant frequencies are investigated in detail. The two peaks of the absorber can be dynamically tuned by the variation of the chemical potential of graphene. Due to its good performances, the designed metamaterial perfect system has great potential applications in biosensing, photodetectors, stealth, and imaging devices.

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42

Venneri, Francesca, Sandra Costanzo e Antonio Borgia. "A Dual-Band Compact Metamaterial Absorber with Fractal Geometry". Electronics 8, n. 8 (8 agosto 2019): 879. http://dx.doi.org/10.3390/electronics8080879.

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A fractal absorber based on a metamaterial configuration is proposed for dual-frequency operation within the UHF band. The miniaturization skills of the proposed fractal shape are used to design a dual-band metamaterial absorber cell with reduced size (<λ/2 at the two operating frequencies) and a very thin substrate thickness (≅λ/100). A metamaterial absorber panel is realized and experimentally validated. Good agreements between full-wave simulations and measurement results are demonstrated.

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43

Wang, Jinfeng, Tingting Lang, Tingting Shen, Changyu Shen, Zhi Hong e Congcong Lu. "Numerical Study of an Ultra-Broadband All-Silicon Terahertz Absorber". Applied Sciences 10, n. 2 (7 gennaio 2020): 436. http://dx.doi.org/10.3390/app10020436.

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In this article we present and numerically investigate a broadband all-silicon terahertz (THz) absorber which consists of a single-layer periodic array of a diamond metamaterial layer placed on a silicon substrate. We simulated the absorption spectra of the absorber under different structural parameters using the commercial software Lumerical FDTD solutions, and analyzed the absorption mechanism from the distribution of the electromagnetic fields. Finally, the absorption for both transverse electric (TE) and transverse magnetic (TM) polarizations under different incident angles from 0 to 70° were investigated. Herein, electric and magnetic resonances are proposed that result in perfect broadband absorption. When the absorber meets the impedance matching principle in accordance with the loss mechanism, it can achieve a nearly perfect absorption response. The diamond absorber exhibits an absorption of ~100% at 1 THz and achieves an absorption efficiency >90% within a bandwidth of 1.3 THz. In addition, owing to the highly structural symmetry, the absorber has a polarization-independent characteristic. Compared with previous metal–dielectric–metal sandwiched absorbers, the all-silicon metamaterial absorbers can avoid the disadvantages of high ohmic losses, low melting points, and high thermal conductivity of the metal, which ensure a promising future for optical applications, including sensors, modulators, and photoelectric detection devices.

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44

Liu, Xiao Ming, Chu Wen Lan, Qian Zhao e Ji Zhou. "Perfect Absorber Based on Mie Dielectric Metamaterials". Advanced Materials Research 873 (dicembre 2013): 456–64. http://dx.doi.org/10.4028/www.scientific.net/amr.873.456.

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An isotropic Mie resonance-based metamaterial perfect absorber with near unity absorbance is experimentally and numerically demonstrated. The metamaterial is constructed with an array of dielectric cubes and a metallic ground plane. A good agreement between experimental and simulated result at X band absorption is achieved, the absorptivities are 97% and 98% at 9.96 GHz, separately. The absorption peak of the metamaterial perfect absorber is dependent on the permittivity, the size and the array pattern of the dielectric particles. The Mie resonance of dielectric particles provides a novel mechanism for creating the electric and magnetic resonances and offers a simpler route for the isotropic metamaterial perfect absorber with near unity absorbance.

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45

Tang, Yibo, Longhui He, Jianming Xu, Hailang He, Yuhan Li e Anfeng Liu. "Single-peak-regulation and wide-angle dual-band metamaterial absorber based on hollow-cross and solid-cross resonators". European Physical Journal Applied Physics 91, n. 3 (settembre 2020): 30901. http://dx.doi.org/10.1051/epjap/2020200145.

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Abstract (sommario):

A dual-band microwave metamaterial absorber with single-peak regulation and wide-angle absorption has been proposed and illustrated. The designed metamaterial absorber is consisted of hollow-cross resonators, solid-cross resonators, dielectric substrate and metallic background plane. Strong absorption peak coefficients of 99.92% and 99.55% are achieved at 8.42 and 11.31 GHz, respectively, which is basically consistent with the experimental results. Surface current density and changing material properties are employed to illustrate the absorptive mechanism. More importantly, the proposed dual-band metamaterial absorber has the adjustable property of single absorption peak and could operate well at wide incidence angles for both transverse electric (TE) and transverse magnetic (TM) waves. Research results could provide and enrich instructive guidances for realizing a single-peak-regulation and wide-angle dual-band metamaterial absorber.

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46

John Paul, John Bosco, e Aruldas Shobha Rekh. "Circular ring shaped ultra-wideband metamaterial absorber with polarization insensitivity for energy harvesting". International Journal of Electrical and Computer Engineering (IJECE) 12, n. 2 (1 aprile 2022): 1243. http://dx.doi.org/10.11591/ijece.v12i2.pp1243-1250.

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<span>A circular ring-shaped metamaterial (CRM) absorber was designed to harvest radio frequency (RF) energy in the ultra-wideband (UWB) frequency band applications. The proposed metamaterial unit cell features a circular shaped structure, with rectangular strip lines connected in the form of a cross leaving a square shaped slot at center. The unit cell dimensions are 15×15×1.6 mm. The absorber was etched on a low cost FR4 substrate having a dielectric constant of 4.4. Ansys high frequency structure simulator (HFSS) software was used for simulation and the analysis were carried out for unit cell, 2×2, 3×3, and 4×4 array structures. The absorber parameters plotted are absorption characteristics and reflection characteristics. Also, the metamaterial parameters (μeff) and (εeff) are also retrieved from the absorber parameters and analyzed. From the analysis, the values (μeff) and (εeff) were found to be negative, leaving refractive index also negative (n<0), which proved the metamaterial property. The proposed CRM absorber showed good absorption characteristics of more than 80% and also metamaterial property in the entire UWB band (4-13 GHz). Hence the absorber proves to be a good candidate in powering low power sensors/microcontrollers for internet of things (IoT) applications.</span>

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47

Tung, Nguyen Thanh, e Le Hong Phuc. "Lithographic fabrication and spectroscopic characterization of a THz metamaterial absorber". Vietnam Journal of Science and Technology 59, n. 1 (15 gennaio 2021): 40. http://dx.doi.org/10.15625/2525-2518/59/1/15415.

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Abstract (sommario):

THz metamaterial absorbers are often studied by computational techniques, where the influence of actual material parameters and fabricating limitation has not been completely understood. Here we present an experimental investigation on a far-infrared metamaterial absorber composed of a gold disk-shaped resonator, a silicon oxide spacer, and a gold film. The samples are fabricated using the UV laser lithography technique in combination with the electron-beam evaporation. The absorption feature of fabricated samples is examined by Fourier-transformed infrared spectroscopy and supported by finite integration simulations.

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48

Wang, Pu, Ziang Gao, Zhengshan Xu e Tonggang Zhao. "Perfect Solar Absorber Based on Four-Step Stacked Metamaterial". Photonics 10, n. 10 (27 settembre 2023): 1082. http://dx.doi.org/10.3390/photonics10101082.

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Solar absorbers are of great significance in the development of new energy technologies. However, the current approaches are mostly complex and fail to achieve high absorption rates across a wide range of wavelengths. Here, we propose a four-step stacked metamaterial solar absorber that achieves near-perfect absorption. Our four-step stacked absorber (FSSA) boasts an average absorption rate of 96.32% from 499 nm to 2348.3 nm, and a high average absorption rate of 94.96% from 300 nm to 2500 nm. Electromagnetic mode analysis and the impedance matching theory were employed to analyze the designed FSSA, which revealed that the high absorption rates are due to the propagating surface plasmon resonance (PSPR) and localized surface plasmon resonance (LSPR) modes. The FSSA offers broadband, high absorption rates, and high spectrum selectivity. Additionally, the structural parameters are adjusted to optimize the proposed perfect solar absorber. This proposed absorber can have promising applications in the renewable energy industry.

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49

Hou, Xin Fu, Yao Yao Li, Xiao Jing Wu, Guang Yu He e Ming Wei Wang. "A thermal tunable terahertz metamaterial absorber based on strontium titanate". Physica Scripta 97, n. 8 (21 luglio 2022): 085507. http://dx.doi.org/10.1088/1402-4896/ac8079.

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Abstract At present, the development of metamaterials is abundant. Scientists have developed plenty of metamaterials to meet the rich needs in medicine, military and so on. A temperature sensitive dual-band absorber made of strontium titanate(SrTiO3, STO) with stacked structure is designed, and the absorbance of double modes in the range of 0–0.25 THz exceeds 99%. The absorber is insensitive to polarization and could maintain good absorption efficiency at large angle incidence. As the temperature changes from 200 K to 400 K, the resonant frequency changes significantly, and the modulation depth exceeds 40%. The proposed thermal tunable absorber can be used in radiative heat measurement, biomedical and chemical sensing, photoelectric detection and other fields. It also can be used to make thermal tunable sensors, light modulators, Terahertz absorbers and other novel devices.

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50

Pushpakaran, Sarin Valiyaveettil, Jayakrishnan M. Purushothama, Manoj Mani, Aanandan Chandroth, Mohanan Pezholil e Vasudevan Kesavath. "A metamaterial absorber based high gain directional dipole antenna". International Journal of Microwave and Wireless Technologies 10, n. 4 (3 aprile 2018): 430–36. http://dx.doi.org/10.1017/s1759078718000454.

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AbstractA novel idea for generating directional electromagnetic beam using a metamaterial absorber for enhancing radiation from a microwave antenna in the S-band is presented herewith. The metamaterial structure constitutes the well-known stacked dogbone doublet working in the absorption mode. The reflection property of the dogbone metamaterial absorber, for the non-propagating reactive near-field, is utilized for achieving highly enhanced and directional radiation characteristics. The metamaterial absorber converts the high-spatial reactive spectrum in the near-field into propagating low-spatial spectrum resulting in enhanced radiation efficiency and gain. The gain of a printed standard half-wave dipole is enhanced to 10 dBi from 2.3 dBi with highly directional radiation characteristics at resonance.

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