Metamaterial Microwave Absorber (MMA) for Electromagnetic Interference (EMI) Shielding in X-Band

Rotational Symmetry ◽

Unit Cell ◽

Microwave Absorber ◽

Light Weight ◽

Emi Shielding ◽

S Parameter ◽

X Band ◽

Planar Array ◽

High Absorption

Abstract The present paper is aimed at investigating application of planar Metamaterial (MM) structures for effective EMI Shielding and Stealth applications in X-Band. Various MM structures using FR4 substrate and Copper conductors were conceived and designed followed by simulations carried out using CST MWS Suite software. As a first step, the de- signs were aimed at achieving extremely high absorption for normal incidence, polarisation independence and maintaining high absorption in wide angle performance while keeping the requirement of light weight, flexibility and environmental ruggedness in mind for deployability on platforms to achieve effective stealth against Radars and for other EMI shielding applications. Circularly symmetric, single layer Metamaterial Microwave Absorber (MMA) design over thin FR4 substrate in spokes and wheel structural arrangement provided these desired features. The thin FR4 substrate of 0.6 mm provides the light weight and flexibility while absorbing the EM waves. Rotational symmetry of the spoke and cut-wheel design gives it polarisation independence and 4 ring planar array concept with rings scaled to different sizes in the same plane in the unit cell provided the increase in bandwidth. Reduction in received signal level of the echo is depicted by the S-Parameter at the input port. Getting values of this S-Parameter less than -60dB at resonant frequency for MMAs is highly encouraging and is not reported much in literature. Enhancement of nearly 3-8 times in operating bandwidth was achieved by changing size of rings in each quadrant in the co-planar array having four resonant rings in each unit cell.

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

Nano-Micro Letters ◽

10.1007/s40820-021-00597-4 ◽

2021 ◽

Vol 13 (1) ◽

Author(s):

Rongliang Yang ◽

Xuchun Gui ◽

Li Yao ◽

Qingmei Hu ◽

Leilei Yang ◽

...

Keyword(s):

High Performance ◽

Electronic Devices ◽

Deposition Process ◽

Shielding Effectiveness ◽

Emi Shielding ◽

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.

Multilayered salt water with high optical transparency for EMI shielding applications

Scientific Reports ◽

10.1038/s41598-020-78717-0 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Duy Tung Phan ◽

Chang Won Jung

Keyword(s):

Light Transmission ◽

Salt Water ◽

Water Layer ◽

Visual Observation ◽

Optical Transparency ◽

Shielding Effectiveness ◽

Emi Shielding ◽

Multilayered Structures ◽

X Band

AbstractElectromagnetic interference (EMI) shielding for visual observation applications, such as windows utilized in military or aerospace, is important but difficult to realize due to conventional materials having difficulty in achieving sufficient transparency and EMI shielding simultaneously. In this paper, we present multilayered structures based on salt water for simultaneous highly optical transparency (OT) and EM shielding effectiveness (SE) performance. In the proposed structures, planar acrylic and glass were used as two types of clear substrates to hold salt water. The measured OT of both acrylic/salt water/acrylic and glass/salt water/glass structures was higher than 90% with a nearly uniform light transmission, which introduced a negligible impact on optical observation. Furthermore, both simulations and experimental results demonstrated that the SE of the multilayer structure was higher than 20 dB in the X-band from 7.5 to 8.5 GHz. Moreover, the SE was significantly enhanced by increasing the thickness of the salt water layer. Especially, both OT and SE of the multilayered structures were improved simultaneously by increasing the salinity of the salt water. These proposed structures demonstrate great potential in EMI shielding observation applications.

Flexible few-layered graphene/poly vinyl alcohol composite sheets: synthesis, characterization and EMI shielding in X-band through the absorption mechanism

RSC Advances ◽

10.1039/c5ra04038h ◽

2015 ◽

Vol 5 (46) ◽

pp. 36498-36506 ◽

Cited By ~ 20

Author(s):

Sandeep K. Marka ◽

Bashaiah Sindam ◽

K. C. James Raju ◽

Vadali V. S. S. Srikanth

Keyword(s):

Vinyl Alcohol ◽

Poly Vinyl Alcohol ◽

Shielding Effectiveness ◽

Emi Shielding ◽

Electromagnetic Interference Shielding Effectiveness

Composite Sheet ◽

Absorption Mechanism ◽

X Band ◽

An excellent electromagnetic interference shielding effectiveness of ∼19.5 dB was measured for a 1 mm thick flexible few-layered graphene (FLG)/PVA composite sheet owing to the formation of network-like features by FLG in the PVA matrix.

Synthesis of reduced graphene oxide paper for EMI shielding by a multi-step process

Functional Materials Letters ◽

10.1142/s1793604720510248 ◽

2020 ◽

Vol 13 (05) ◽

pp. 2051024

Author(s):

Yangyang Lin ◽

Genliang Hou ◽

Song Bi ◽

Xunjia Su ◽

Hao Li

Keyword(s):

Graphene Oxide ◽

Reduced Graphene Oxide ◽

Functional Groups ◽

Reduction Process ◽

Emi Shielding ◽

Hydroiodic Acid ◽

X Band ◽

Reduced Graphene ◽

Graphene Oxide Paper

A multi-step reduction process was developed to produce reduced graphene oxide (rGO) paper for electromagnetic interference (EMI) shielding. First step reduction was achieved by hydroiodic acid to remove most of the oxygen-containing functional groups, and sodium borohydride was used in the second step reduction to reduce carbonyl group which is the most difficult functional group to remove. In the last step reduction, hydroiodic acid was used as reducing agent again to remove the remaining oxygen-containing functional groups. The results show that this method can greatly improve the conductivity and EMI shielding performance of rGO paper. The resulting rGO paper with a C/O ratio of 19.38 and a thickness of 9.1[Formula: see text][Formula: see text]m exhibited high conductivity of 1084[Formula: see text]S/cm and excellent average EMI shielding efficiency of 45.84[Formula: see text]dB in the X-band, better than that reduction by other chemical methods.

Layer-structured silver nanowire/polyaniline composite film as a high performance X-band EMI shielding material

Journal of Materials Chemistry C ◽

10.1039/c5tc04406e ◽

2016 ◽

Vol 4 (19) ◽

pp. 4193-4203 ◽

Cited By ~ 64

Author(s):

Fang Fang ◽

Yuan-Qing Li ◽

Hong-Mei Xiao ◽

Ning Hu ◽

Shao-Yun Fu

Keyword(s):

Electrical Conductivity ◽

High Performance ◽

Composite Films ◽

Silver Nanowire ◽

Emi Shielding ◽

X Band ◽

Pani Composite ◽

Shielding Material

The superiority of layer-structured Ag-NW/PANI composite films over the plain-structured in electrical conductivity and electromagnetic interference shielding.

Researching on X-Band Electromagnetic Interference Shielding Efficiency of MWCNTs Buckypapers Inserted with Mn Nanopowder

NANO ◽

10.1142/s1793292018500613 ◽

2018 ◽

Vol 13 (06) ◽

pp. 1850061 ◽

Cited By ~ 1

Author(s):

Shaowei Lu ◽

Yaoyao Bai ◽

Jijie Wang ◽

Chenxu Zhao ◽

Wei Li ◽

...

Keyword(s):

Energy Dispersive Spectrometer ◽

Composite Films ◽

Resin Matrix ◽

Manufacturing Cost ◽

Shielding Effectiveness ◽

Emi Shielding ◽

Filtration Method ◽

X Band

Ultrathin multi-walled carbon nanotubes (MWCNTs) buckypapers inserted with Mn nanopowder were fabricated via vacuum filtration method, at a lower manufacturing cost and easier operation. The buckypapers were characterized structurally using scanning electron microscopy, energy-dispersive spectrometer and X-ray diffraction. Electromagnetic interference (EMI) shielding effectiveness (SE) of MWCNTs buckypapers inserted with Mn nanopowder (0–30[Formula: see text]wt.%) were tested in X-band (8.2–12.4[Formula: see text]GHz). When the blended Mn nanopowder content is 20[Formula: see text]wt.%, the buckypaper exhibits much higher EMI SE of average value up to 42[Formula: see text]dB with the thickness of only 0.11[Formula: see text]mm. Further, this buckypaper is flexible and lightweight, and can be integrated with resin matrix composites. Thus, the results and techniques promise a simple and effective approach to achieve lightweight and ultrathin composite films for a wide application prospect in the field of EMI shielding and microwave absorption.

Flexible GnPs/EPDM with Excellent Thermal Conductivity and Electromagnetic Interference Shielding Properties

NANO ◽

10.1142/s1793292019500759 ◽

2019 ◽

Vol 14 (06) ◽

pp. 1950075 ◽

Cited By ~ 2

Author(s):

Shaowei Lu ◽

Yaoyao Bai ◽

Jijie Wang ◽

Dandan Chen ◽

Keming Ma ◽

...

Keyword(s):

Thermal Conductivity ◽

Rubber Matrix ◽

Shielding Effectiveness ◽

Emi Shielding ◽

X Band ◽

Cost Efficient ◽

Emi Se ◽

Shielding Material

As the portable device hardware has been increasing at a noticeable rate, ultrathin flexible materials with the combination of high thermal conductivity and excellent electromagnetic interference (EMI) shielding performance are urgently needed. Here, we fabricated ethylene propylene diene monomer rubber with different loading graphene nanoplatelets (GnPs/EPDM) by a cost-efficient approach, which combines mixing, ultrasonication and compression. Further investigation demonstrates that the 8[Formula: see text]wt.% GnPs/EPDM with only 0.3[Formula: see text]mm in thickness shows excellent electrical conductivity (28.3[Formula: see text]S/m), thermal conductivity (0.79[Formula: see text]W/m[Formula: see text]K) and good mechanical properties. Besides, the 8[Formula: see text]wt.% GnPs/EPDM exhibits an EMI shielding effectiveness (SE) up to 33[Formula: see text]dB in the X-band (8.2–12.4[Formula: see text]GHz) and 35[Formula: see text]dB in the Ku-band (12.4–18[Formula: see text]GHz), superior to most of the reported rubber matrix. Additionally, the GnPs/EPDM shows excellent flexibility and stability with 95% and 94% retention of EMI SE even after repeated bending for 5000 times and corrosion (under 5% NaCl environment) for a week. Our flexible EMI shielding material will benefit the fast-growing next-generation commercial portable flexible electrons.

Outstanding electromagnetic interference shielding effectiveness of polyvinylbutyral–polyaniline nanocomposite film

RSC Advances ◽

10.1039/c6ra14277j ◽

2016 ◽

Vol 6 (82) ◽

pp. 79058-79065 ◽

Cited By ~ 25

Author(s):

Pritom J. Bora ◽

Gaurav Lakhani ◽

Praveen C. Ramamurthy ◽

Giridhar Madras

Keyword(s):

Nanocomposite Film ◽

Shielding Effectiveness ◽

Emi Shielding ◽

Solution Processed ◽

X Band ◽

Electromagnetic Interference Shielding Effectiveness ◽

Polyaniline Nanocomposite ◽

Ku Band

In this study, we studied the electromagnetic interference (EMI) shielding property of a solution processed polyvinylbutyral–polyaniline nanocomposite (PVBPN) film in the X-band (8.2–12.4 GHz) and Ku-band (12.4–18 GHz) frequency.

A multi-dimensional and level-by-level assembly strategy for constructing flexible and sandwich-type nanoheterostructures for high-performance electromagnetic interference shielding

Nanoscale ◽

10.1039/c9nr09087h ◽

2020 ◽

Vol 12 (5) ◽

pp. 3308-3316 ◽

Cited By ~ 8

Author(s):

Caichao Wan ◽

Yue Jiao ◽

Xianjun Li ◽

Wenyan Tian ◽

Jian Li ◽

...

Keyword(s):

High Performance ◽

Shielding Effectiveness ◽

Emi Shielding ◽

Free Standing ◽

Assembly Strategy ◽

X Band ◽

Sandwich Type

A multi-dimensional and level-by-level assembly strategy is developed to construct free-standing and sandwich-type nanoheterostructures achieving an outstanding EMI shielding effectiveness of ∼50.6 dB in the X-band.