The Design and Preparation of Foam Concrete Absorber for WLAN Anti-Jamming EMW-Absorber

2013 ◽  
Vol 785-786 ◽  
pp. 300-304 ◽  
Author(s):  
Fan Wu ◽  
Wan Jun Hao ◽  
Yue Fang Zhang ◽  
Ming Ming Wang ◽  
Dong Wei Chen ◽  
...  
Keyword(s):  
Pollution Control ◽  
Electromagnetic Interference ◽  
Maximum Absorption ◽  
Specimen Thickness ◽  
New Materials ◽  
Foam Concrete ◽  
Absorption Properties ◽  
Thermal Insulating ◽  
Film Specimen ◽  
Properties Of Composites

This paper reports that according to the principle of EMW-absorption, thermal insulating EMW-absorber for building was designed and theoretically simulated of the λ/4 type. The EMW-absorption properties of composites in the band of 2-4 GHz were examined, A maximum absorption of-20 dB at 3 GHz and 80% of bandwidth below-10 dB was achieved under following conditions: using 380Ω/□ resistive film, specimen thickness of 2 cm. Similarly, absorbing materials for 2.45 GHz have successfully designed and prepared,a maximum absorption of-17 dB at 2.45 GHz, and 65% of bandwidth below-10 dB can be reached. New materials can be used for electromagnetic interference protection for WLAN and indoor electromagnetic radiation pollution control.

The Design and Preparation of Composite Gypsum Boards Absorber Based on Phase Modulation Membrane

2014 ◽  
Vol 881-883 ◽  
pp. 1216-1220
Author(s):  
Ying Ying Yi ◽  
Wan Jun Hao ◽  
Hui Chao Zhao ◽  
Yi Feng Dong ◽  
Fan Wu ◽  
...  
Keyword(s):  
Electromagnetic Wave ◽  
Pollution Control ◽  
Electromagnetic Interference ◽  
Phase Modulation ◽  
Maximum Absorption ◽  
Specimen Thickness ◽  
Electromagnetic Wave Absorption ◽  
Wave Absorption ◽  
Thermal Insulating ◽  
Film Specimen

According to the principle of electromagnetic wave absorption, functionally reforming thermal insulating materials for building, through designing and theoretically simulating of the λ/4 model, the article has successfully prepared EPS composite gypsum boards for electromagnetic wave absorption. The result shows that, a maximum absorption of-18.7dB at 3GHz and 85% of bandwidth below-10dB was achieved under following conditions: using 380Ω/□ resistive film, specimen thickness of 1.50cm. However, by using phase modulation membrane (PMM),it achieved a maximum absorption of-20dB and 100% of bandwidth below-10dB. This new composite materials can be used for electromagnetic interference protection for WLAN and indoor electromagnetic radiation pollution control.

The Design and Preparation of X Band Absorbing Insulation Coatings

2014 ◽  
Vol 881-883 ◽  
pp. 1065-1069
Author(s):  
Dong Wei Chen ◽  
Fan Wu ◽  
Xue Hong Yu ◽  
Chang Jun Liao ◽  
Wan Jun Hao ◽  
...  
Keyword(s):  
Electromagnetic Wave ◽  
Carbon Fiber ◽  
Thermal Insulation ◽  
Electromagnetic Interference ◽  
New Materials ◽  
Insulating Materials ◽  
Electromagnetic Wave Absorption ◽  
Wave Absorption ◽  
Thermal Insulating ◽  
X Band

According to the principle of electromagnetic wave absorption, functionally reforming thermal insulating materials for building, through designing and theoretically simulating of the λ/4 model, using carbon fiber film, the article has successfully prepared insulation coatings for X-band electromagnetic wave absorption. Result shows, with the thickness of 3.0 mm in 8 ~ 12 GHz band, 100% of bandwidth below-10 dB can be reached. New materials can be used such as the surface of the thermal insulation of buildings and X-band electromagnetic interference protection.

scholarly journals Reduction of Electromagnetic Interference Using ZnO-PCL Nanocomposites at Microwave Frequency

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Abubakar Yakubu ◽  
Zulkifly Abbas ◽  
Nor Azowa Ibrahim ◽  
Ahmad Fahad
Keyword(s):  
Electromagnetic Interference ◽  
Electromagnetic Compatibility ◽  
Environmentally Friendly ◽  
Microwave Frequency ◽  
Absorption Properties ◽  
Radio Emissions ◽  
Surface Areas ◽  
Home Appliance ◽  
Coaxial Probe ◽  
Very High

In industrial equipment and home appliance applications, the electromagnetic compatibility compliance directive (ECCD) demands that electromagnetic interference side effects be eliminated or marginally minimized. The equipment must not disturb radio and telecommunication as well as other appliances. Additionally the ECCD also governs the immunity of such equipment to interference and seeks to ensure that this equipment is not disturbed by radio emissions when used as intended. Many types of absorbing materials are commercially available. However, many are expensive and not environmentally friendly. It is in the light of the above that we studied the electromagnetic absorption properties of ZnO-PCL nanocomposites prepared from cheap and abundant resources which are environmentally friendly (zinc and polycaprolactone). The test was carried out using a microstrip, open ended coaxial probe, and vector network analyzer. Amongst other findings, result showed that the ZnO-PCL nanocomposite has the capability of attenuating microwave frequency up to −18.2 dB due to their very high specific surface areas attributed to the nanofillers at 12 GHz.

scholarly journals Effect of Glycidyl Methacrylate on Water Absorption Properties of Sago Hampas Biocomposite

2015 ◽  
Vol 6 (2) ◽  
pp. 34-38
Author(s):  
M. S. Jamaludin ◽  
A. Zulkharnain ◽  
A. A. Khan ◽  
N. Wagiman
Keyword(s):  
Water Absorption ◽  
Glycidyl Methacrylate ◽  
Standard Test ◽  
Test Method ◽  
Matrix Composites ◽  
Hot Press ◽  
Absorption Properties ◽  
Average Water ◽  
Absorption Percentage ◽  
Properties Of Composites

 This study examines the water absorption of sago hampas biocomposite utilizing glycidyl methacrylate as its matrix. Composites were fabricated with 25, 30, 40 wt% sago hampas content and another sample of pure sago hampas using hydraulics hot press machine. The water absorption properties of composites with different sago hampas composition were investigated according to Standard Test Method for Tensile Properties of Polymer Matrix Composite Materials of ASTM D570. Water absorption of pure sago hampas composite have the highest average water absorption percentage with 59.1 wt% as compared to the lowest average water absorption percentage recorded for 30 wt% sago hampas content biocomposite with 16.8%. However sago hampas loading was increased resulting in the increased in average water absorption on biocomposite for 40 wt% sago hampas content which is 33.1%.

Thermal Insulating and Constructive Foamed Concrete on a Composite Gypsum Binder

2019 ◽  
Vol 974 ◽  
pp. 125-130 ◽  
Author(s):  
Natalia V. Chernyisheva ◽  
Svetlana V. Shatalova ◽  
Maria Yu. Drebezgova ◽  
Evgeniy N. Lesnichenko
Keyword(s):  
Concrete Mixture ◽  
Foam Concrete ◽  
Thermal Insulating ◽  
Mineral Addition ◽  
Foamed Concrete ◽  
Stepwise Loading ◽  
Cellular Concrete ◽  
Loading Scheme

The article discusses the possibility of obtaining the effective thermal insulating and constructive foamed concrete on a composite gypsum binder. The composition was selected, the stepwise loading scheme of the foam concrete mixture components was proposed, the properties and microstructure of cellular concrete based on a composite gypsum binder with mineral addition of finely-dispersed concrete scrap were studied.

Magnetic and Microwave Absorption Properties of Magnetite-Durian Shell Nanocomposite Sheet in Gigahertz Range

2018 ◽  
Vol 775 ◽  
pp. 217-223
Author(s):  
Afraha Baiti Arif ◽  
Rose Farahiyan Munawar ◽  
Qumrul Ahsan ◽  
Maisarah Abu
Keyword(s):  
Microwave Absorption ◽  
Electromagnetic Interference ◽  
Filler Content ◽  
Spherical Shape ◽  
Constant Thickness ◽  
Frequency Range ◽  
Absorption Properties ◽  
Microwave Absorption Properties ◽  
Weight Percentage ◽  
Durio Zibethinus

In this paper, a novel microwave absorber of thin, light weight, flexible, green and low cost magnetic nanocomposite sheet that can work in high frequency range is fabricated. The vast and increasing numbers in electronic and telecommunication devices has create electromagnetic interference (EMI) in which may lead to application disturbance. Therefore, electromagnetic (EM) wave absorber with the ability of high absorption rate is strongly demanded. Here, durian shell (Durio zibethinus Murray) embedded magnetite (Fe3O4) nanocomposite sheets were prepared via pulping and lumen loading technique. The nanocomposite sheets were fabricated by varying the weight percentage of the filler content (2-10 wt% of Fe3O4) at constant thickness and varying the thickness of the sheets (0.1-1.0 mm) at constant filler content. FESEM micrograph shows that the Fe3O4 nanoparticles are in cubical and spherical shape with the 20–50 nm of size range. The microwave absorption properties of the sheets were tested by a vector network analyze (VNA) in the frequency range of 4-18 GHz. The samples were also tested using vibrating sample magnetometer (VSM) in order to study the magnetic properties. The absorption or maximum reflection loss (RL) of the samples increases continually and the increase of both filler content and sample thickness has led to the shift of dip to lower frequency region.

scholarly journals The effect of modification of binders on technological and operational properties of composite construction materials

2018 ◽  
Vol 245 ◽  
pp. 03017 ◽  
Author(s):  
Lyubov Zakrevskaya ◽  
Igor Handelsman ◽  
Galina Provatorova
Keyword(s):  
Positive Impact ◽  
Construction Materials ◽  
New Materials ◽  
Composite Construction ◽  
Recycled Pet ◽  
Main Method ◽  
Basic Properties ◽  
Laboratory Technology ◽  
Properties Of Composites

The object of the study includes modified road bitumen and geotextile materials, for the synthesis of which recycled PET and CNT were used. The production of new materials is caused by the need to improve their technical characteristics, which, in the end, should have a positive impact on the properties of composites based on them. The main method of research is an experiment. During the experiment, a grid of compositions of new materials and laboratory technology for their production were developed, their basic properties were studied. According to the results of the study of the basic properties of new materials there is an improvement of their basic properties up to 10% compared to the original ones.

The Research of the Absorption and Angle Characteristics of Honeycomb Hexagon Phase Modulation Membrane

2014 ◽  
Vol 1035 ◽  
pp. 254-258
Author(s):  
Ying Ying Yi ◽  
Wan Jun Hao ◽  
Hui Chao Zhao ◽  
Yi Feng Dong ◽  
Xin Dan Yu
Keyword(s):  
Electromagnetic Wave ◽  
Composite Materials ◽  
Electromagnetic Radiation ◽  
Pollution Control ◽  
Electromagnetic Interference ◽  
Phase Modulation ◽  
Membrane Structure ◽  
Hexagonal Phase ◽  
Line Length ◽  
Absorption Peak

According to the honeycomb hexagonal phase modulation membrane, this paper designed and prepared λ/4 electromagnetic wave absorber. Studies have shown that the honeycomb hexagonal phase modulation membrane structure can realize the absorber width. Experiments have shown that 65% of bandwidth below-10 dB was achieved under following conditions: line length a = 4 cm, line weight b = 6 mm. For line length a = 4 cm, line weight b = 6 mm, the angle characteristics of phase modulation membrane was studied. The study of angle characteristics have shown that, absorption peak moved backward with the angles increasing. This new composite materials can be used for electromagnetic interference protection for WLAN and indoor electromagnetic radiation pollution control.

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