scholarly journals Broadband Bi-Directional Polarization-Insensitive Metamaterial Absorber

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7339
Author(s):  
Feng Tian ◽  
Xia Ma ◽  
Han Hao ◽  
Xuewen Li ◽  
Jingdao Fan ◽  
...  

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.

2019 ◽  
Vol 6 ◽  
pp. 1 ◽  
Author(s):  
Ke Chen ◽  
Xinyao Luo ◽  
Guowen Ding ◽  
Junming Zhao ◽  
Yijun Feng ◽  
...  

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.


Nanomaterials ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 2636
Author(s):  
Fenghui Cao ◽  
Jia Xu ◽  
Xinci Zhang ◽  
Bei Li ◽  
Xiao Zhang ◽  
...  

We developed a simple method to fabricate SiO2-sphere-supported N-doped CNTs (NCNTs) for electromagnetic wave (EMW) absorption. EMW absorption was tuned by adsorption of the organic agent on the precursor of the catalysts. The experimental results show that the conductivity loss and polarization loss of the sample are improved. Meanwhile, the impedance matching characteristics can also be adjusted. When the matching thickness was only 1.5 mm, the optimal 3D structure shows excellent EMW absorption performance, which is better than most magnetic carbon matrix composites. Our current approach opens up an effective way to develop low-cost, high-performance EMW absorbers.


2019 ◽  
Vol 1 (9) ◽  
pp. 3621-3625 ◽  
Author(s):  
Ben-Xin Wang ◽  
Chao Tang ◽  
Qingshan Niu ◽  
Yuanhao He ◽  
Runye Chen

Broadband metamaterial absorbers are of critical importance in practical applications, but their obtainment approaches are quite complex at present.


Photonics ◽  
2021 ◽  
Vol 8 (12) ◽  
pp. 574
Author(s):  
Duong Thi Ha ◽  
Bui Son Tung ◽  
Bui Xuan Khuyen ◽  
Thanh Son Pham ◽  
Nguyen Thanh Tung ◽  
...  

We demonstrate a dual-band, polarization-insensitive, ultrathin and flexible metamaterial absorber (MA), based on high-order magnetic resonance. By exploiting a flexible polyimide substrate, the thickness of MA came to be 1/148 of the working wavelength. The absorption performance of the proposed structure was investigated for both planar and bending models. In the case of the planar model, a single peak was achieved at a frequency of 4.3 GHz, with an absorption of 98%. Furthermore, additional high-order absorption peaks were obtained by the bending structure on a cylindrical surface, while the fundamental peak with a high absorption was maintained well. Our work might be useful for the realization and the development of future devices, such as emitters, detectors, sensors, and energy converters.


2019 ◽  
Vol 10 (3) ◽  
pp. 233-241
Author(s):  
Salman Daniel ◽  
Prince Bawuah

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.


Author(s):  
Shuguang Fang ◽  
Lianwen Deng ◽  
Pin Zhang ◽  
Lei-Lei Qiu ◽  
Haipeng Xie ◽  
...  

Abstract In this paper, two kinds of dual-band metamaterial absorbers (MMAs) with stable absorption performance based on fractal structures are proposed. As the key feature, with the increase in fractal order, the fractal MMAs can reduce the weight while keeping the absorption performance. The multi-band absorption property is analyzed by multiple L-C resonances generated by the fractal structure. By virtue of good impedance matching characteristics and the synergy of the circuit and electromagnetic resonance, effective and stable microwave absorption is readily achieved. Finally, two prototypes are fabricated for demonstration, and the measurement result is consistent well with the simulation one. As expected, the proposed fractal MMAs have the advantage of low-cost, light-weight, and dual-effective absorption bands, and have great potential in the application of multi-band radar stealth.


Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2145 ◽  
Author(s):  
Youwei Zhang ◽  
Hui-Ling Ma ◽  
Ke Cao ◽  
Liancai Wang ◽  
Xinmiao Zeng ◽  
...  

A facile and environmentally friendly method is proposed to prepare reduced graphene oxide–nickel (RGO–Ni) nanocomposites using γ-ray irradiation. Graphene oxide (GO) and Ni2+ are reduced by the electrons which originated from the gamma radiolysis of H2O. The structure and morphology of the obtained RGO–Ni nanocomposites were analyzed using X-ray diffraction (XRD) and Raman spectroscopy. The results show that Ni nanoparticles were dispersed uniformly on the surface of the RGO nanosheets. As expected, the combination of RGO nanosheets and Ni nanoparticles improved the electromagnetic wave absorption because of the better impedance matching. RGO–Ni nanocomposites exhibited efficient electromagnetic wave absorption performance. The minimum reflection loss (RL) of RGO–Ni reached −24.8 dB, and the highest effective absorption bandwidth was up to 6.9 GHz (RL < −10 dB) with a layer thickness of 9 mm.


Nanomaterials ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 833 ◽  
Author(s):  
Zhi Zhang ◽  
Qi Lv ◽  
Yiwang Chen ◽  
Haitao Yu ◽  
Hui Liu ◽  
...  

To reduce electromagnetic pollution as well as increase the accuracy of high-precision electronic equipment, more attention has been paid to new electromagnetic wave (EMW) absorbing materials, which have the advantages of strong absorption, wide absorption bands, and a narrow thickness. In this study, a novel ternary type of the NiS2@rGO/polypyrrole (PPy) sandwich-like structured composites was synthesized via a facile two-step method, in which the hydrothermal method was used to prepare NiS2@rGO binary composites and then the in situ polymerization method was used to synthesize the PPy, which acted as the outer layer of the sandwich-like structure. The morphologies and electromagnetic absorption performance of the NiS2@rGO/PPy were measured and investigated. A sample with 6 wt% NiS2@rGO/PPy loading paraffin-composite obtained an outstanding reflection loss (RL) of −58.7 dB at 16.44 GHz under a thickness of 2.03 mm. Simultaneously, the effective electromagnetic wave absorption bandwidth for RL < −10 dB, which covered 7.04 to 18.00 GHz (10.96 GHz), was achieved by changing the thickness of the absorber from 2.0 to 3.5 mm. The results not only suggest that the NiS2@rGO/PPy composite has excellent performance in the field of EMW absorption but also prove that the novel sandwich-like structure can contribute to appropriate impedance matching through multiple relaxation and interfacial polarization processes.


2020 ◽  
Vol 8 (30) ◽  
pp. 10204-10212
Author(s):  
Chen Wu ◽  
Kai Bi ◽  
Mi Yan

Scalable self-supported FeNi3/Mo2C flexible paper with satisfactory impedance matching and multiple loss mechanisms to allow excellent wave absorption performance.


2020 ◽  
Vol 30 (4) ◽  
pp. 311
Author(s):  
Van Huynh Tran ◽  
Thanh Tung Nguyen ◽  
Xuan Khuyen Bui ◽  
Dinh Lam Vu ◽  
Son Tung Bui ◽  
...  

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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