scholarly journals Improved impedance matching by multi-componential metal-hybridized rGO toward high performance of microwave absorption

2021 ◽  
Vol 10 (1) ◽  
pp. 1-9
Author(s):  
Jinlong Xie ◽  
Hunan Jiang ◽  
Jinyang Li ◽  
Fei Huang ◽  
Ahsan Zaman ◽  
...  
Keyword(s):  
Microwave Absorption ◽  
High Performance ◽  
Impedance Matching ◽  
Design And Synthesis ◽  
Microwave Absorbing Materials ◽  
Reduced Graphene ◽  
Military Applications ◽  
Absorption Performance ◽  
Microwave Absorption Performance ◽  
Minimum Reflection Loss

Abstract Microwave-absorbing materials with good microwave absorption performance are of great interest for military applications and human health, which is threatened by electromagnetic radiation pollution. Herein, the design and synthesis of multi-componential metal-hybridized graphene composites via freeze drying and pyrolysis of ferrocene hydrazone complex precursor are reported. Various magnetic nanoparticles are loaded on reduced graphene oxide (rGO) via controlling their pyrolysis temperature. The complex electromagnetic parameters of these hybrids are therefore regulated by the hybrid components. Among them, rGO hybridized by the sea-island-like Fe2O3/Fe3O4/FeNi3 multi-componential metals shows a good balance of dielectric and magnetic constants. Thus, the improved impedance matching with free space brings about a superior electromagnetic wave absorption performance, especially on the effective absorption bandwidth. The minimum reflection loss (RL) of the hybrids is as low as −40.3 dB at 11 GHz with the RL bandwidth of −10 dB being 4.55 GHz (from 9.25 to 13.8 GHz).

scholarly journals High-efficiency and ultra-thin electromagnetic wave absorption xAl2O3-(1-x)Sr0.85Gd0.15TiO3 ceramics in X-band

2020 ◽  
Author(s):  
Hui Xie ◽  
Chaoqun Yang ◽  
Yingying Zhou ◽  
Zhaowen Ren ◽  
Ping Liu
Keyword(s):  
Microwave Absorption ◽  
Reflection Loss ◽  
High Efficiency ◽  
Impedance Matching ◽  
Frequency Dispersion ◽  
Interfacial Polarization ◽  
Peak Frequency ◽  
Microwave Absorbing Materials ◽  
Absorption Performance ◽  
Microwave Absorption Performance

Abstract xAl2O3-(1-x)Sr0.85Gd0.15TiO3(x=0.2, 0.3, 0.4, 0.5) ceramics were fabricated by hot-press sintering. Their morphology, phase composition, conductivity, dielectric properties as well as microwave absorption performance were examined by scanning electron microscopy (SEM), X-ray diffraction (XRD), multifunction digital four-probe meter and vector network analysis, respectively. The microwave absorption of as-prepared xAl2O3-(1-x)Sr0.85Gd0.15TiO3 ceramics demonstrates excellent microwave absorbability. It is unexpectedly found that with a thickness of only 0.346 mm, xAl2O3-(1-x)Sr0.85Gd0.15TiO3 (x=0.2) ceramic exhibits an absorption bandwidth of 3.7 GHz (8.7-12.4 GHz), being consequential to reflection loss less than -10 dB (over 90% of microwave absorption). It is as well discovered that the minimum reflection loss and absorption peak frequency of xAl2O3-(1-x)Sr0.85Gd0.15TiO3 (x=0.3) with a thickness of 0.436 mm were -45.43 dB and 11.3 GHz, respectively. The prominent microwave absorption performance of the ceramic with such a thin thickness can be attributed to strong interfacial polarization, dielectric frequency dispersion, and good electromagnetic impedance matching. It indicates that the xAl2O3-(1-x)Sr0.85Gd0.15TiO3 ceramics with appropriate Al2O3 mass fraction and thickness showing good potential for effective microwave absorbing materials.

scholarly journals An Easy Method of Synthesis CoxOy@C Composite with Enhanced Microwave Absorption Performance

Nanomaterials ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 902
Author(s):  
Wenli Bao ◽  
Cong Chen ◽  
Zhenjun Si
Keyword(s):  
Microwave Absorption ◽  
Impedance Matching ◽  
Interfacial Polarization ◽  
Magnetic Composite ◽  
Easy Method ◽  
Electromagnetic Absorption ◽  
Absorption Performance ◽  
Matched Impedance ◽  
Microwave Absorption Performance ◽  
Minimum Reflection Loss

Design of interface-controllable magnetic composite towards the wideband microwave absorber is greatly significance, however, it still remains challenging. Herein, we designed a spherical-like hybrids, using the Co3O4 and amorphous carbon as the core and shell, respectively. Then, the existed Co3O4 core could be totally reduced by the carbon shell, thus in CoxOy core (composed by Co and Co3O4). Of particular note, the ratios of Co and Co3O4 can be linearly tuned, suggesting the controlled interfaces, which greatly influences the interface loss behavior and electromagnetic absorption performance. The results revealed that the minimum reflection loss value (RLmin) of −39.4 dB could be achieved for the optimal CoxOy@C sample under a thin thickness of 1.4 mm. More importantly, the frequency region with RL < −10 dB was estimated to be 4.3 GHz, ranging from 13.7 to 18.0 GHz. The superior wideband microwave absorption performance was primarily attributed to the multiple interfacial polarization and matched impedance matching ability.

Efficient microwave traps with markedly enhanced interfacial polarization and impedance matching enabled by dual-shelled, dual-cavity magnetic@dielectric hollow nanospheres

2020 ◽  
Vol 8 (46) ◽  
pp. 16489-16497
Author(s):  
Jiasong Hua ◽  
Wenjun Ma ◽  
Xiaoyun Liu ◽  
Qixin Zhuang ◽  
Zeyang Wu ◽  
...  
Keyword(s):  
Microwave Absorption ◽  
Reflection Loss ◽  
Impedance Matching ◽  
Interfacial Polarization ◽  
Hollow Nanospheres ◽  
Absorption Performance ◽  
Microwave Absorption Performance ◽  
Magnetic Dielectric ◽  
Minimum Reflection Loss

Dual-shelled, dual-cavity Fe3O4@TiO2 hollow nanospheres exhibit an outstanding microwave absorption performance with a minimum reflection loss of −60.17 dB.

scholarly journals Excellent microwave absorption properties by tuned electromagnetic parameters in polyaniline-coated Ba0.9La0.1Fe11.9Ni0.1O19/reduced graphene oxide nanocomposites

RSC Advances ◽  
2017 ◽  
Vol 7 (58) ◽  
pp. 36433-36443 ◽  
Author(s):  
Juhua Luo ◽  
Yue Zuo ◽  
Pan Shen ◽  
Zhu Yan ◽  
Kang Zhang
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Microwave Absorption ◽  
Reflection Loss ◽  
Absorption Properties ◽  
Microwave Absorption Properties ◽  
Reduced Graphene ◽  
Absorption Performance ◽  
Microwave Absorption Performance ◽  
Minimum Reflection Loss

The obvious enhancement of microwave absorption performance of Ba0.9La0.1Fe11.9Ni0.1O19/reduced graphene oxide/polyaniline ternary nanocomposites in 2–18 GHz was observed. The minimum reflection loss can reach −49.1 dB with thickness of 1.9 mm.

scholarly journals Effect of Reaction Time on Microwave Absorption Properties of Fe3O4 Hollow Spheres Synthesized via Ostwald Ripening

Materials ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 2921 ◽  
Author(s):  
Wei Huang ◽  
Yujiang Wang ◽  
Shicheng Wei ◽  
Bo Wang ◽  
Yi Liang ◽  
...  
Keyword(s):  
Reaction Time ◽  
Microwave Absorption ◽  
Ostwald Ripening ◽  
Impedance Matching ◽  
Hollow Spheres ◽  
Absorption Properties ◽  
Microwave Absorption Properties ◽  
Magnetic Structures ◽  
Absorption Performance ◽  
Microwave Absorption Performance

Hollow magnetic structures have great potential to be used in the microwave absorbing field. Herein, Fe3O4 hollow spheres with different levels of hollowness were synthesized by the hydrothermal method under Ostwald ripening effect. In addition to their microstructures, the microwave absorption properties of such spheres were investigated. The results show that the grain size and hollowness of Fe3O4 hollow spheres both increase as the reaction time increases. With increasing hollowness, the attenuation ability of electromagnetic wave of Fe3O4 spheres increases first and then decreases, finally increases sharply after the spheres break down. Samples with strong attenuation ability can achieve good impedance matching, which it does preferentially as the absorber thickness increases. Fe3O4 hollow spheres show the best microwave absorption performance when the reaction time is 24 h. The minimum reflection loss (RL (min)) can reach −40 dB, while the thickness is only 3.2 mm.

scholarly journals Reduced graphene oxide decorated with octahedral NiS2/NiS nanocrystals: facile synthesis and tunable high frequency attenuation

RSC Advances ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 5550-5556 ◽  
Author(s):  
Min Lu ◽  
Na Gao ◽  
Xiao-Juan Zhang ◽  
Guang-Sheng Wang
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Microwave Absorption ◽  
High Frequency ◽  
High Frequency Range ◽  
Frequency Range ◽  
Facile Synthesis ◽  
Reduced Graphene ◽  
Absorption Performance ◽  
Microwave Absorption Performance

Reduced graphene oxide (RGO) decorated with octahedral NiS2/NiS nanocrystals were fabricated and they possessed an excellent microwave absorption performance in the high frequency range.

scholarly journals Broadband microwave absorber constructed by reduced graphene oxide/La0.7Sr0.3MnO3 composites

RSC Advances ◽  
2019 ◽  
Vol 9 (71) ◽  
pp. 41817-41823 ◽  
Author(s):  
Kelan Yan ◽  
Feng Yin ◽  
Chao Pang ◽  
Xiuhui Zuo ◽  
Qitu Zhang ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
High Performance ◽  
Magnetic Loss ◽  
Impedance Matching ◽  
High Attenuation ◽  
Microwave Absorbing Materials ◽  
Reduced Graphene ◽  
Absorbing Materials ◽  
Electric Loss

High-performance microwave absorbing materials require optimized impedance matching and high attenuation ability. To meet these requirements, rGO/LSMO composites were prepared thereby incorporating electric loss with magnetic loss materials.

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