Optimized Design for Multi-Layer Absorbing Materials Based on Genetic Algorithm

2013 ◽  
Vol 681 ◽  
pp. 324-328
Author(s):  
Xin Chen ◽  
Xiang Xuan Liu ◽  
Xuan Jun Wang ◽  
Yuan Liu
Keyword(s):  
Genetic Algorithm ◽  
Electromagnetic Wave ◽  
Optimized Design ◽  
Frequency Range ◽  
Absorbing Materials ◽  
Permittivity And Permeability ◽  
Special Value ◽  
Material Choice ◽  
Optimal Material ◽  
Elitist Strategy

In order to synthesize the multi-layer radar absorbing materials (RAM) with a thin thickness and wide bandwidth, accelerating genetic algorithm (GA) with constraints and elitist strategy is employed to design the multi-layer RAM satisfied by a special value of reflection loss to electromagnetic wave. Given predefined available materials with frequency-dependent permittivity and permeability, the GA technique determines the optimal material choice for each layer and its thickness. The algorithm was successfully applied to the synthesis of double-layer to four-layers RAM coatings in the frequency range of 2-18GHz,and the optimization results was evaluated.

Electromagnetic Characteristics of Iron-Based Microwave Absorbing Materials

2011 ◽  
Vol 479 ◽  
pp. 106-111
Author(s):  
R.B. Yang ◽  
K.Y. Juan ◽  
Chien Yie Tsay ◽  
W.F. Liang ◽  
Chung Kwei Lin
Keyword(s):  
Complex Permittivity ◽  
Resonant Cavity ◽  
Electromagnetic Properties ◽  
Frequency Range ◽  
Microwave Absorbing Materials ◽  
Absorbing Materials ◽  
Permittivity And Permeability ◽  
Electromagnetic Characteristics ◽  
Iron Based ◽  
Microwave Absorbing

Nowadays human are exposed to an environment filling with electromagnetic waves over a wide frequency range. The electromagnetic properties of microwave absorbing materials plays an important role in the performance of civilian electromagnetic interference (EMI) shielding at low frequency range and military stealth technology at high frequency one. The electromagnetic properties include complex permittivity and permeability and its combination determines the electromagnetic wave absorption ability of a material. Complex permittivity and permeability can be measured by three different methods, i.e., free-space method, coaxial/waveguide method, and resonant cavity perturbation method. The first one requires a large space, expensive equipment, and not suitable for academic usage. In the present study, using coaxial/waveguide and resonant cavity perturbation methods, electromagnetic characteristics of iron-based microwave absorbing materials will be obtained and its microwave absorption performance will be investigated. In addition, a comparison between the measurements by these two methods will be addressed.

A Novel Multilayer Structure with Frequency Selected Surface for Electromagnetic Compatibility

2014 ◽  
Vol 989-994 ◽  
pp. 837-840
Author(s):  
Jie Li ◽  
Dong Lai Xu
Keyword(s):  
Electromagnetic Wave ◽  
Multilayer Structure ◽  
Electromagnetic Compatibility ◽  
Experimental Results ◽  
Frequency Range ◽  
Plastic Composites ◽  
Structure Of Metal ◽  
Absorbing Materials ◽  
Filter Characteristic ◽  
Absorption Performance

Electromagnetic wave absorbers can be widely used in Electromagnetic Compatibility (EMC). We proposed a novel multilayer structure of metal alloy-ferrite-plastic composites. A new structure with Frequency Selected Surface (FSS), which has filter characteristic, embedded in the composites was fabricated to improve the absorption performance. In bandwidth of 8.04GHz, the reflectivity was smaller than-8dB and the thickness was only 2.6mm. The reflectivity was measured using a standard NRL Arch technique in a frequency range of 3-18 GHz. The experimental results indicate that it is possible to make a desirable thin, broadband EMW absorber by the incorporation of an FSS into the magnetic absorbing materials.

Absorbing and Mechanical Properties of Cement-Based Composites with Nano-Titanic Oxide Absorbent

2010 ◽  
Vol 177 ◽  
pp. 558-561 ◽  
Author(s):  
Guo Xuan Xiong ◽  
Min Deng ◽  
Hai Qing Huang ◽  
Ming Shu Tang
Keyword(s):  
Mechanical Properties ◽  
Electromagnetic Wave ◽  
Portland Cement ◽  
Titanium Oxide ◽  
Cement Paste ◽  
Frequency Range ◽  
Absorbing Materials ◽  
Relationship Of ◽  
The Relationship

The cement-based composite absorbing materials was made of portland cement and nano-titanic oxide absorbent. The relationship of electromagnetic wave reflectivity and nanometer TiO2 contents, dispersed means, samples thickness, and effect of nanometer titanium oxide on mechanical properties of cement-based composites were discussed in details. The experiment results revealed: 1) The reflectivity of cement-based composites with nanometer titanium oxide is less than -7 dB at 8~18 GHz frequency range; 2) The least reflectivity is -16.34 dB at 16.24 GHz and the bandwidth for -10 dB is 4.5 GHz; 3) The mechanical properties of cement-based composites with nanometer titanium oxide are superior to that of cement paste.

scholarly journals Electromagnetic Wave Absorbing Materials on Radar Frequency Range

2019 ◽  
Vol 28 (1) ◽  
pp. 1
Author(s):  
Yana Taryana ◽  
Azwar Manaf ◽  
Nanang Sudrajat ◽  
Yuyu Wahyu
Keyword(s):  
Electromagnetic Wave ◽  
Frequency Range ◽  
Absorbing Materials ◽  
Radar Frequency

scholarly journals Enhanced electromagnetic wave absorption property of binary ZnO/NiCo2O4 composites

2021 ◽  
Author(s):  
Bin Du ◽  
Mei Cai ◽  
Xuan Wang ◽  
Junjie Qian ◽  
Chao He ◽  
...  
Keyword(s):  
Electromagnetic Wave ◽  
Dielectric Properties ◽  
Hydrothermal Reaction ◽  
Absorption Property ◽  
Absorption Properties ◽  
Promising Candidate ◽  
Electromagnetic Wave Absorption ◽  
Wave Absorption ◽  
Absorbing Materials ◽  
Minimum Reflection Loss

AbstractNowadays, metal oxide-based electromagnetic wave absorbing materials have aroused widely attentions in the application of telecommunication and electronics due to their selectable mechanical and outstanding dielectric properties. Herein, the binary ZnO/NiCo2O4 nanoparticles were successfully synthesized via hydrothermal reaction and the electromagnetic wave absorption properties of the composites were investigated in detail. As a result, benefiting from the dielectric loss, the as-obtained ZnO/NiCo2O4-7 samples possessed a minimum reflection loss value of −33.49 dB at 18.0 GHz with the thickness of 4.99 mm. This work indicates that ZnO/NiCo2O4 composites have the promising candidate applications in electromagnetic wave absorption materials in the future.

Electromagnetic Wave Absorbing and Mechanical Properties of Cement-Based Composite Panel with Different Nanomaterials

2017 ◽  
Vol 26 (1) ◽  
pp. 096369351702600
Author(s):  
Sun Yafei ◽  
Gao Peiwei ◽  
Peng Hailong ◽  
Liu Hongwei ◽  
Lu Xiaolin ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Electromagnetic Wave ◽  
Double Layer ◽  
Mechanical Performance ◽  
Interface Structure ◽  
Composite Panel ◽  
Effective Bandwidth ◽  
Composite Panels ◽  
Frequency Range ◽  
Triple Layer

This paper presents the microstructures and mechanical and absorbing properties of double and triple layer, cement-based, composite panels. The results obtained show that the frequency range in 2-18GHz had less than −10dB effective bandwidth, which correlates with 3.7and 10.8GHz in double and triple layer cement-based composite panels. Furthermore, the double layer panel's compressive strength at 7 and 28 days was 40.2 and 61.2MPa, respectively. For the triple layer panel, the strength values were 35.6MPa and 49.2MPa. The triple layer panel's electromagnetic wave (EMW) absorbing properties were superior compared to the properties of the double layer panel. However, the triple layer panel's mechanical performance was inferior to that of the double layer panel. This study proposes that carbon nanotubes can effectively improve the compressive strength and interface structure of cement-based composite panels.

Gradient structures of Ni – Zn ferrites for electromagnetic radiation protection devices

2021 ◽  
Vol 5 ◽  
pp. 39-46
Author(s):  
V. V. Karanskij ◽  
◽  
S. V. Smirnov ◽  
A. S. Klimov ◽  
E. V. Savruk ◽  
...  
Keyword(s):  
Electron Beam ◽  
Electromagnetic Radiation ◽  
Radiation Protection ◽  
Electromagnetic Compatibility ◽  
Protective Coatings ◽  
Frequency Range ◽  
Near Surface ◽  
Zn Ferrite ◽  
Absorbing Materials ◽  
Plasma Electronic

Increasing the reliability requirements for electromagnetic compatibility of electronic equipment requires the creation of protective coatings that absorb electromagnetic radiation or the development of new radio-absorbing materials. In the frequency range up to 1 GHz, radio-absorbing materials based on Ni – Zn ferrites are of the greatest interest. The absorption of electromagnetic radiation by ferrites occurs due to resonant phenomena at the level of domains and atoms. Improving the performance of ferrites is possible by modifying their surface properties. In this paper, gradient structures for electromagnetic radiation protection products are obtained by treating the surface of Ni – Zn ferrite samples with a low-energy electron beam. To generate the electron beam, a unique development was used — a forevacuum plasma electronic source that allows forming and transporting a beam with a power density of up to 105 W/cm2 under conditions of high pressure and high gas release. As a result of processing, gradient structures were found on the surface of ferrites. A theoretical analysis and experimental study of the obtained structures “non – magnetic conductor – ferrite”, characterized by an increased attenuation coefficient and a reduced reflection coefficient of electromagnetic radiation in the frequency range from 0.5 to 2.5 GHz. The possibility of obtaining near-surface layers depleted in zinc with increased electrical conductivity and reduced magnetic permeability is shown.

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