Effects of sample thickness and fiber aspect ratio on EMI shielding effectiveness of carbon fiber filled polychloroprene composites in the X-band frequency range

1992 ◽  
Vol 34 (4) ◽  
pp. 478-481 ◽  
Author(s):  
P.B. Jana ◽  
A.K. Mallick ◽  
S.K. De
Keyword(s):  
Carbon Fiber ◽  
Aspect Ratio ◽  
Sample Thickness ◽  
Shielding Effectiveness ◽  
Emi Shielding ◽  
Frequency Range ◽  
Band Frequency ◽  
Fiber Aspect Ratio ◽  
Emi Shielding Effectiveness ◽  
X Band

scholarly journals Nanostructured La0.7Sr0.3MnO3 compounds for effective electromagnetic interference shielding in the X-band frequency range

2015 ◽  
Vol 3 (4) ◽  
pp. 820-827 ◽  
Author(s):  
Hilal Ahmad Reshi ◽  
Avanish P. Singh ◽  
Shreeja Pillai ◽  
Rama Shankar Yadav ◽  
S. K. Dhawan ◽  
...  
Keyword(s):  
Electromagnetic Interference ◽  
Shielding Effectiveness ◽  
Emi Shielding ◽  
Frequency Range ◽  
Electromagnetic Interference Shielding ◽  
Band Frequency ◽  
Emi Shielding Effectiveness ◽  
X Band

EMI shielding effectiveness values of up to 19 dB are observed in LSMO nanomaterials.

scholarly journals Effect of granulometric distribution on electromagnetic shielding effectiveness for polymeric composite based on natural graphite

2019 ◽  
Vol 26 (1) ◽  
pp. 531-539 ◽  
Author(s):  
R. C. Portes ◽  
B. H. K. Lopes ◽  
M. A. do Amaral Junior ◽  
D. E. Florez-Vergara ◽  
S. F. Quirino ◽  
...  
Keyword(s):  
Electromagnetic Interference ◽  
Polymeric Composite ◽  
Electromagnetic Shielding ◽  
Shielding Effectiveness ◽  
Frequency Range ◽  
Natural Graphite ◽  
Band Frequency ◽  
Emi Shielding Effectiveness ◽  
Aerospace Applications ◽  
X Band

Abstract In this study, the electromagnetic interference (EMI) shielding effectiveness (SE) of polymer composites based on natural graphite in flakes (NGF) and silicone rubber was investigated with the aim to contribute to the development of the technology of electromagnetic shielding materials. This topic has attracted great attention to the aeronautical and aerospace applications, due to the serious problems that EMI can cause to the functioning of electronic devices. According to this, the present work has produced samples of composite materials with variations on the sizes of the filler particles and composition of the samples. The electromagnetic characterization of the samples is given by the Vector Network Analyzer (VNA) in the X-band frequency range (8.2 – 12.4 GHz). The results indicate that the variation of particle sizes is determinant to the SE performance along with the X-band frequency range. Furthermore, the expansion of the range of granulometry allows controlling the curves of the peaks along the X-band.

scholarly journals Ultrathin, Lightweight, and Flexible CNT Buckypaper Enhanced Using MXenes for Electromagnetic Interference Shielding

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Rongliang Yang ◽  
Xuchun Gui ◽  
Li Yao ◽  
Qingmei Hu ◽  
Leilei Yang ◽  
...  
Keyword(s):  
Electromagnetic Interference ◽  
High Performance ◽  
Electronic Devices ◽  
Deposition Process ◽  
Shielding Effectiveness ◽  
Emi Shielding ◽  
Emi Shielding Effectiveness ◽  
X Band ◽  
Wearable Electronic Devices ◽  
Emi Se

AbstractLightweight, flexibility, and low thickness are urgent requirements for next-generation high-performance electromagnetic interference (EMI) shielding materials for catering to the demand for smart and wearable electronic devices. Although several efforts have focused on constructing porous and flexible conductive films or aerogels, few studies have achieved a balance in terms of density, thickness, flexibility, and EMI shielding effectiveness (SE). Herein, an ultrathin, lightweight, and flexible carbon nanotube (CNT) buckypaper enhanced using MXenes (Ti3C2Tx) for high-performance EMI shielding is synthesized through a facile electrophoretic deposition process. The obtained Ti3C2Tx@CNT hybrid buckypaper exhibits an outstanding EMI SE of 60.5 dB in the X-band at 100 μm. The hybrid buckypaper with an MXene content of 49.4 wt% exhibits an EMI SE of 50.4 dB in the X-band with a thickness of only 15 μm, which is 105% higher than that of pristine CNT buckypaper. Furthermore, an average specific SE value of 5.7 × 104 dB cm2 g−1 is exhibited in the 5-μm hybrid buckypaper. Thus, this assembly process proves promising for the construction of ultrathin, flexible, and high-performance EMI shielding films for application in electronic devices and wireless communications.

CNT@PDMS/NW composite materials with superior electromagnetic shielding

Holzforschung ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Zi-Jing Zhou ◽  
Zhen-Xing Wang ◽  
Xiao-shuai Han ◽  
Jun-Wen Pu
Keyword(s):  
Electromagnetic Interference ◽  
Cellulose Nanofibers ◽  
Original Structure ◽  
Impregnation Method ◽  
Shielding Effectiveness ◽  
Emi Shielding ◽  
Band Frequency ◽  
Conductive Composites ◽  
Emi Shielding Effectiveness ◽  
Xrd Patterns

Abstract Lightweight materials with high electrical conductivity and hydrophobic mechanical properties are ideal materials for electromagnetic interference (EMI) shielding. Herein, the conductive composites with great EMI shielding effectiveness (SE) were successfully obtained by introducing multi-walled carbon nanotube (CNT) and polydimethylsiloxane (PDMS) based on the original structure of natural wood (NW). CNT@PDMS/NW composites were prepared via vacuum-pulse impregnation method and characterized by Fourier transform infrared (FTIR), scanning electron microscope (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) patterns, hydrophobicity analysis, and EMI shielding performance. As demonstrated, CNT nanosheets were successfully inserted into wood matrices, and hydrogen bonding between CNT nanosheets and cellulose nanofibers induced the fabrication of CNT@PDMS/NW composites. CNT@PDMS/NW composites exhibited excellent EMI SE values of 25.2 dB at the X-band frequency.

Electromagnetic shielding performance of three-dimensional woven fabrics with copper-based hybrid yarn in X-band frequency range

2018 ◽  
Vol 49 (4) ◽  
pp. 484-502 ◽  
Author(s):  
Dharmendra Nath Pandey ◽  
Arindam Basu ◽  
Pramod Kumar ◽  
Himangshu B Baskey
Keyword(s):  
Cotton Fabric ◽  
Three Dimensional ◽  
Electromagnetic Shielding ◽  
Shielding Effectiveness ◽  
Frequency Range ◽  
Structural Configuration ◽  
Band Frequency ◽  
Hybrid Yarn ◽  
X Band ◽  
Electromagnetic Shielding Effectiveness

This study involves a comprehensive evaluation of electromagnetic shielding characteristics of multilayer three-dimensional conductive fabrics by using cotton/copper wrapped hybrid yarn in X band frequency range. Five, three-dimensional fabrics with different structural configuration, such as orthogonal, angle interlock, cellular spacer, multi-tubular spacer, and contour were produced. Three different series of all five structures was also developed using pure cotton fabric, conductive hybrid yarn in weft and one-third hybrid yarn and two-third cotton yarn in warp Also, the effect of vertical and horizontal polarization of electromagnetic waves on electromagnetic shielding effectiveness was studied. The comparative analysis of reflectance transmittance and absorption behavior was also undertaken. The results indicate that pure cotton fabric (A series) does not have electromagnetic shielding capabilities. The difference between the electromagnetic shielding effectiveness values in vertical and horizontal planes of fabrics, having conductive hybrid yarn in weft direction (B series), showed significantly better results on the vertical plane in comparison to that on the horizontal plane. Fabric containing conductive hybrid yarn in both warp and weft (C series) exhibits consistent electromagnetic shielding effectiveness in both the planes. It is worth mentioning that the structural configuration in all five three-dimensional fabrics in B and C series has shown differential trends of electromagnetic shielding effectiveness in terms of reflectance, transmittance and absorption behavior. They are also found to be statistically significant. Finally, it is concluded that the conductive 3-D multilayer system develops special protective capabilities, mostly due to its larger surface area.

SiC Micro-Threads Prepared within the Carbon Fiber Felt

2008 ◽  
Vol 368-372 ◽  
pp. 843-845
Author(s):  
Feng Yuan ◽  
Hong Jie Wang ◽  
Zhi Hao Jin
Keyword(s):  
Carbon Fiber ◽  
Three Dimensional ◽  
Nitrogen Pressure ◽  
Complex Permeability ◽  
Similar Form ◽  
Frequency Range ◽  
Band Frequency ◽  
X Band ◽  
Carbon Fiber Felt ◽  
Low Nitrogen

Polyacrylonitrile (PAN) based carbon fiber felt which contains abundant various SiC microthreads and some other microstructures was prepared through sintering the pretreated felt at high temperature at low nitrogen pressure. XRD, SEM, TEM, HRTEM analyses for the sintered felt were carried out to study its components and microstructures. There are SiC nanothreads, SiC submicron threads, SiC micron threads and a few SiO2 two- or three-dimensional microstructures (possibly intermix with the similar form of SiC) existed within the inner hollow spaces of the felt. The complex permittivity, complex permeability of the sample in the X-band frequency range were obtained.

scholarly journals An Inexpensive Route to Synthesize High-Purity CrO2 for EMI Shielding in X-Band Frequencies

2012 ◽  
Vol 2012 ◽  
pp. 1-4 ◽  
Author(s):  
Vivek Verma ◽  
Shahab Ahmad ◽  
Abdullah Dar ◽  
R. Kotnala
Keyword(s):  
High Purity ◽  
Microwave Frequency ◽  
External Pressure ◽  
Shielding Effectiveness ◽  
Emi Shielding ◽  
Frequency Range ◽  
Absorption Properties ◽  
Microwave Absorption Properties ◽  
X Band ◽  
Simplified Procedure

Rod-shaped high-purity samples of CrO2 have been synthesized by an inexpensive and simplified procedure. Here, we have prepared pure CrO2 without applying any external pressure or control it during synthesis. The sample prepared exhibited an improvement in saturation magnetization values, 68 emu/g at 300 K, 136 emu/g at 80 K, and uniform grained microstructure. The complex permittivity, permeability, and microwave absorption properties of high-purity CrO2 sample were investigated in the 8.2–12.2 GHz (X-band) microwave frequency range. Microwave measurements have shown the high shielding effectiveness due to absorption (SEA) of 20.3 dB. The high value of SEA suggests that CrO2 can be used as a promising electromagnetic shielding, EMI, material in 8.2–12.2 GHz (X-band) microwave frequency range.

Electromagnetic Interference Shielding Characteristics of Carbon Nanofiber-Polymer Composites

2007 ◽  
Vol 7 (2) ◽  
pp. 549-554
Author(s):  
Yonglai Yang ◽  
Mool C. Gupta ◽  
Kenneth L. Dudley ◽  
Roland W. Lawrence
Keyword(s):  
Electromagnetic Interference ◽  
Carbon Nanofiber ◽  
Frequency Region ◽  
Shielding Effectiveness ◽  
Emi Shielding ◽  
Frequency Range ◽  
Electromagnetic Interference Shielding ◽  
Emi Shielding Effectiveness ◽  
Frequency Independent ◽  
Ku Band

Electromagnetic interference (EMI) shielding characteristics of carbon nanofiber-polystyrene composites were investigated in the frequency range of 12.4–18 GHz (Ku-band). It was observed that the shielding effectiveness of such composites was frequency independent, and increased with increasing carbon nanofiber loading within Ku-band. The experimental data exhibited that the shielding effectiveness of the polymer composite containing 20 wt% carbon nanofibers could reach more than 36 dB in the measured frequency region, indicating such composites can be applied to the potential EMI shielding materials. In addition, the results showed that the contribution of reflection to the EMI shielding effectiveness was much larger than that of absorption, implying the primary EMI shielding mechanism of such composites was reflection of electromagnetic radiation within Ku-band.

Investigation on Carbon Fiber Composites as Architectural EMI Shielding Material

2013 ◽  
Vol 748 ◽  
pp. 309-313 ◽  
Author(s):  
Mohd Shafiq Bin Ruslan ◽  
Chew Sue Ping
Keyword(s):  
Carbon Fiber ◽  
Fiber Composites ◽  
Building Construction ◽  
Carbon Fiber Composites ◽  
Shielding Effectiveness ◽  
Emi Shielding ◽  
Testing Procedures ◽  
Emi Shielding Effectiveness ◽  
Ieee Standard ◽  
Shielding Material

EMI shielding technique by using appropriate shielding material in an enclosure is commonly effective to block signal penetration. This paper presents the investigations on EMI shielding effectiveness of multilayer carbon fiber composites for architectural shielding purposes. The properties of carbon fiber such as high thermal conductivity, corrosion resistant, high tensile strength and excellent EMI shielding property make it suitable to be applied in building construction. The concrete samples with insertion of carbon fiber sheets were undergone the EMI penetration test which is based on IEEE standard testing procedures. These customized structures are proven to reduce signal penetration significantly in the high frequency range up to 2 GHz.

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