Dual-band metamaterial absorber with stable absorption performance based on fractal structure

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.

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.


2018 ◽  
Vol 7 (2) ◽  
pp. 68-75 ◽  
Author(s):  
P. N. Vummadisetty ◽  
A. Kumar

This research article presents, a compact 0.19 λ x 0.32 λ size ACS fed printed monopole wideband antenna loaded with multiple radiating branches suitable for LTE2300/WiBro, 5 GHz WLAN and WiMAX applications. The proposed triple band uniplanar antenna encompasses of C shaped strip, L shaped strip, rectangular shaped strip and a lateral ground plane. All the radiating strips and ground plane are etched on the 26 × 15 m size low cost FR4 epoxy substrate. This designed geometry evoked three independent reonances at 2.3 GHz, 3.5 GHz and 5.5 GHz with precise impedance matching over each operating band. The reflection coefficient ( ) response of the presented antenna demonstrates three distinct resonant modes associated with -10 dB bandwidths are about 2.24-2.40 GHz, 3.38-3.83 GHz and 5.0-6.25 GHz respectively. From the study, it is also observed that the proposed design works perfect with microstrip as well as CPW feedings. Hence the designed Multi Feed Multi Band (MFMB) antenna can be easily deployed in to any portable wireless device that works for 2.3/3.5/ 5 GHz frequency bands.


2011 ◽  
Vol 239-242 ◽  
pp. 1260-1264
Author(s):  
Wei Wei Ji ◽  
Tao Wang ◽  
Yan Nie ◽  
Rong Zhou Gong

Based on the impedance matching and electromagnetic resonant characteristic of composite materials, we present a single-layer metamaterial absorber consisting of arch copper loop and substrate FR-4, of which the resonant frequency depended on the loop’s geometry perimeter. By combining resonant loops with different dimensions together, we can achieve multi-band absorption. The standard finite difference time domain method was used to calculate the magnitudes of reflectance, and then the induced surface current and power loss distributions were demonstrated to analyze the insight physical picture of the multi-band resonant feature. By optimizing the simulation results, the absorptivities of two absorption peaks are all above 98% when the number of copper loops is two, 95% for three absorption peaks of three loops, and 87% for four absorption peaks of four loops.


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.


Crystals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 415
Author(s):  
Bui Xuan Khuyen ◽  
Vu Thi Hong Hanh ◽  
Bui Son Tung ◽  
Vu Dinh Lam ◽  
Young Ju Kim ◽  
...  

In this work, the possibility of a switchable metamaterial absorber is proposed to control absorption bandwidth in the WiMAX/LTE (worldwide interoperability for microwave access/long term evolution) band, by taking advantage of the low cost and myriad structural configurations afforded by water-based metamaterials. By exploiting truncated cone-type resonators, the fractional bandwidth of 27.6% of absorption spectrum can be adjusted flexibly to be 7.4% of the narrow-band absorption depending on the volume of injected water, in both simulation and experiment at room temperature. In particular, this control method can be applied stably for different temperature of injected water. We describe a dynamic mechanism for broadband MA, as well as a principle for controlling the absorption characteristics utilizing a combination of magnetic resonance and perfect impedance matching. These results are a stepping-stone towards the realization of smart electronics integrated with multi-functional metamaterials in military, biomedical, communication and other fields.


2018 ◽  
Vol 7 (4) ◽  
pp. 71-77 ◽  
Author(s):  
K. P. Kaur ◽  
T. Upadhyaya

A novel dual-band wide-angle ultra-thin absorber composed of dual closed-concentric ten-point stars with polarization independence is presented in this article. The ten-point stars formed resonators are engraved on low cost FR4 substrate. The EM absorber performance is studied in terms of electrical and physical parameters. The polarization independence is practically demonstrated using waveguide measurement method. The measured results are in good agreement with simulated results. The absorbance values of 99.37% and 97.18% are achieved at 2.13 GHz and 2.52 GHz, respectively. The presented absorber design is wide-angle RF absorber with high absorbance values of about 80% up to 60° under TE mode and 87% up to 75° of oblique incidence angle for TM mode excitations. The experimental results demonstrate the absorption effectiveness of the proposed design to be utilized in RF energy harvester modules for capturing ambient UMTS band signals and in RF absorber applications for S band radar systems. The presented absorber unit cell is ultrathin and compact with the thickness and size less than λ/56 mm and λ/5 mm, respectively, at lowest absorption frequency.


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.


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.


Sensors ◽  
2018 ◽  
Vol 18 (12) ◽  
pp. 4209 ◽  
Author(s):  
Ahasanul Hoque ◽  
Mohammad Tariqul Islam ◽  
Ali Almutairi ◽  
Touhidul Alam ◽  
Mandeep Jit Singh ◽  
...  

In this paper, a dual-band metamaterial absorber (MMA) ring with a mirror reflexed C-shape is introduced for X and Ku band sensing applications. The proposed metamaterial consists of two square ring resonators and a mirror reflexed C-shape, which reveals two distinctive absorption bands in the electromagnetic wave spectrum. The mechanism of the two-band absorber particularly demonstrates two resonance frequencies and absorption was analyzed using a quasi-TEM field distribution. The absorption can be tunable by changing the size of the metallic ring in the frequency spectrum. Design and analysis of the proposed meta-absorber was performed using the finite-integration technique (FIT)-based CST microwave studio simulation software. Two specific absorption peaks value of 99.6% and 99.14% are achieved at 13.78 GHz and 15.3 GHz, respectively. The absorption results have been measured and compared with computational results. The proposed dual-band absorber has potential applications in sensing techniques for satellite communication and radar systems.


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