DISPERSION OF COBALT FERRITE FUNCTIONALIZED GRAPHENE NANOPLATELETS IN PLA FOR EMI SHIELDING APPLICATIONS

2021 ◽  
Author(s):  
KANAT ANURAKPARADORN ◽  
ALAN TAUB ◽  
ERIC MICHIELSSEN
Keyword(s):  
Functional Groups ◽  
Electromagnetic Interference ◽  
High Speed ◽  
Magnetic Particles ◽  
Cobalt Ferrite ◽  
Reduction Process ◽  
Cost Effective ◽  
Graphene Nanoplatelets ◽  
Angle Of Incidence ◽  
Emi Shielding

The proliferation of wireless technology calls for the development of cost-effective Electromagnetic Interference (EMI) shielding materials that reduce the susceptibility of high-speed electronic circuits to undesired incoming radiation. Ideally, such materials offer protection over wide frequency ranges and are insensitive to the polarization or angle of incidence of the impinging fields. Here, next-generation EMI shielding materials composed of polymer composites with conductive and magnetic fillers are introduced. It is shown that careful control of the concentration and dispersion of the polymers’ conductive and magnetic constituents permits tuning of the composites’ intrinsic electrical and magnetic properties. The resulting EMI shields are lightweight, cheap and offer greater protection than traditional metal gaskets and foams. In this work, cobalt ferrite magnetic nanoparticles (CoFe2O4) decorated on graphene-based material were dispersed in polylactic acid (PLA) matrix for high EM absorption level in X-band (8-12 GHz). The decoration of the magnetic particles was performed on the as-prepared conductive graphene nanoplatelets (GNP) and reduced graphene oxide (rGO). GNP composites exhibited higher DC conductivity, and permittivity than rGO composites. This is attributed to issues associated with the reduction process, including a lack of conductivity due to the insulated oxygen functional groups and the reduction in the lateral size. Compared with rGOs, the lack of out-plane functional groups causes the cobalt ferrite nanoparticles to agglomerate and not cover the entire surface of the GNPs. These morphological differences improve the magnetization and EM absorption of the composite system. The compatibilizer (pyrene-PLA-OH) was added to the composites to enhance dispersion of the GNPs in the polymer matrix which benefits in higher absorption of the shield. The influence of the compatibilizer on parameter, the reflection loss (RL) of the composite were determined from the characterized intrinsic properties

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

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 ◽  
Electromagnetic Interference ◽  
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.

scholarly journals Polyetherimide Foams Filled with Low Content of Graphene Nanoplatelets Prepared by scCO2 Dissolution

Polymers ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 328 ◽  
Author(s):  
Hooman Abbasi ◽  
Marcelo Antunes ◽  
José Velasco
Keyword(s):  
Electromagnetic Interference ◽  
Cellular Structure ◽  
Electrostatic Discharge ◽  
Graphene Nanoplatelets ◽  
Conductive Network ◽  
Emi Shielding ◽  
Melt Mixing ◽  
Degradation Behaviour ◽  
Increasing Trend ◽  
One Step

Polyetherimide (PEI) foams with graphene nanoplatelets (GnP) were prepared by supercritical carbon dioxide (scCO2) dissolution. Foam precursors were prepared by melt-mixing PEI with variable amounts of ultrasonicated GnP (0.1–2.0 wt %) and foamed by one-step scCO2 foaming. While the addition of GnP did not significantly modify the cellular structure of the foams, melt-mixing and foaming induced a better dispersion of GnP throughout the foams. There were minor changes in the degradation behaviour of the foams with adding GnP. Although the residue resulting from burning increased with augmenting the amount of GnP, foams showed a slight acceleration in their primary stages of degradation with increasing GnP content. A clear increasing trend was observed for the normalized storage modulus of the foams with incrementing density. The electrical conductivity of the foams significantly improved by approximately six orders of magnitude with only adding 1.5 wt % of GnP, related to an improved dispersion of GnP through a combination of ultrasonication, melt-mixing and one-step foaming, leading to the formation of a more effective GnP conductive network. As a result of their final combined properties, PEI-GnP foams could find use in applications such as electrostatic discharge (ESD) or electromagnetic interference (EMI) shielding.

Polarization selection characteristics of carbon fiber orientation and interweaving for electromagnetic interference shielding behaviors

2021 ◽  
pp. 004051752110342
Author(s):  
Xinghua Hong ◽  
Lulu Zhong ◽  
Junmin Wan ◽  
Yongqiang Li ◽  
Fuwang Guan ◽  
...  
Keyword(s):  
Carbon Fiber ◽  
Electromagnetic Interference ◽  
Fiber Orientation ◽  
Cost Effective ◽  
Transverse Magnetic ◽  
Woven Fabrics ◽  
Electromagnetic Properties ◽  
Emi Shielding ◽  
Spatially Distributed ◽  
The Impact

In this paper, to determine the impact of carbon fiber orientation and interweaving on electromagnetic interference (EMI) shielding behaviors, anisotropic and isotropic samples were developed by conductive/dielectric weaving of spatially distributed carbon fiber and glass fiber. Effortless and cost-effective, the electromagnetic shielding efficiency (SE) was up to 42 dB and the SE/thickness) was 41 dB/mm, which had apparent polarization selection characteristics. In addition, the angle (θ) sensitivity for the SE in transverse electric and transverse magnetic polarization modes was given in detail. SE was generally proportional to θ. Moreover, the fingerprint-like radar chart of anisotropic carbon hybrid woven fabrics in the X-band was performed, which makes polarization selection characteristics more intuitive. This paper presented an easy and effective route for assembling hybrid carbon fiber fabrics with high EMI shielding performance, which offers a clear perspective on the simulation and study of carbon fiber electromagnetic properties.

scholarly journals Recent Advancement of Electromagnetic Interference (EMI) Shielding of Two Dimensional (2D) MXene and Graphene Aerogel Composites

Nanomaterials ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 702
Author(s):  
Kanthasamy Raagulan ◽  
Bo Mi Kim ◽  
Kyu Yun Chai
Keyword(s):  
Electromagnetic Interference ◽  
Hybrid Composites ◽  
Cost Effective ◽  
Structural Features ◽  
Processing Technique ◽  
Thickness Effect ◽  
Electronic Systems ◽  
Two Dimensional ◽  
Emi Shielding

The two Dimensional (2D) materials such as MXene and graphene, are most promising materials, as they have attractive properties and attract numerous application areas like sensors, supper capacitors, displays, wearable devices, batteries, and Electromagnetic Interference (EMI) shielding. The proliferation of wireless communication and smart electronic systems urge the world to develop light weight, flexible, cost effective EMI shielding materials. The MXene and graphene mixed with polymers, nanoparticles, carbon nanomaterial, nanowires, and ions are used to create materials with different structural features under different fabrication techniques. The aerogel based hybrid composites of MXene and graphene are critically reviewed and correlate with structure, role of size, thickness, effect of processing technique, and interfacial interaction in shielding efficiency. Further, freeze drying, pyrolysis and hydrothermal treatment is a powerful tool to create excellent EMI shielding aerogels. We present here a review of MXene and graphene with various polymers and nanomaterials and their EMI shielding performances. This will help to develop a more suitable composite for modern electronic systems.

Fiber reinforced thermoplastics compounds for electromagnetic interference shielding applications

2021 ◽  
pp. 073168442110517
Author(s):  
Luís C Martins ◽  
António J Pontes
Keyword(s):  
Electromagnetic Interference ◽  
Steel Sheet ◽  
Electronic Device ◽  
Electronic Devices ◽  
Cost Effective ◽  
Second Phase ◽  
Fiber Reinforced ◽  
Shielding Effectiveness ◽  
Emi Shielding ◽  
Wide Range

Market demands for lightweight and lower cost products drive manufacturers to improve current product portfolios. In the case of electronic devices, the most significant weight originates from the enclosure, traditionally in steel or aluminum, that ensures excellent mechanical and electromagnetic shielding performance. The use of thermoplastics filled with electrically conductive fibers, such as carbon or stainless steel, was investigated as a lightweight and cost-effective alternative to steel sheet for creating electromagnetic interference (EMI) shielding enclosures for electronic devices. This paper presents an EMI shielding analysis workflow for the development of plastic enclosures for an electronic device. The workflow starts by measuring the fiber-reinforced thermoplastic compounds shielding effectiveness (SE) with an experimental method in the 30 MHz–3 GHz frequency band. This analysis helps to filter a vast list of materials with a wide range of shielding performance, 20–100 dB, and allows to obtain empirical data for the second phase of the workflow, computer simulations. Simulations with experimentally adjusted material properties were used to validate the design concept of an enclosure in its early development phase. Results from this study showed that the selected material has better EMI SE performance than a steel sheet venting grid.

Practical electromagnetic compatibility studies of a CubeSat

2016 ◽  
Vol 14 (4) ◽  
pp. 770-780
Author(s):  
Matthew Sibanda ◽  
Robert Ryk van Zyl
Keyword(s):  
Electromagnetic Interference ◽  
High Speed ◽  
Electromagnetic Compatibility ◽  
Cost Effective ◽  
Space Technology ◽  
Satellite Mission ◽  
Content Type ◽  
Design Life ◽  
Data Links ◽  
Mission Success

Purpose Incorporating electromagnetic compatibility (EMC) in the design life of traditional satellites is entrenched in the satellite industry. However, EMC treatment of CubeSats has not been widely pursued, for various possible reasons. CubeSats are a young technology platform initially intended for students and researchers at universities to create awareness and excitement amongst them for space technology. This and other factors limited the need for stringent EMC planning. As CubeSats mature in complexity, the success of future missions will rely on incorporating proper EMC designs in their development. This paper aims to address the experimental investigation of known EMC culprits within a CubeSat’s context. Design/methodology/approach Electromagnetic interference suppression effectiveness of cable trays in CubeSats, as well as crosstalk in high-speed/frequency data links, is investigated, using the PC/104 connector stack. Some recommendations for improving the EMC and, therefore, enhancing satellite mission success are provided. Findings It was found that, if physically feasible in the CubeSat, cable trays are significant radiation suppressors. A further investigation into crosstalk between pins of the PC/104 connector stack showed that grounding a pin in between two signal pins leads to a significant reduction in the coupled signal. Originality/value This paper addresses EMC within the context of a CubeSat and outlines experiments done resulting in cost-effective methods of reducing interference by using already available material (such as unused signal pins available in the PC/104 connector).

The Radio Probe™: A New Measurement Tool for High Speed Integrated Circuits

2005 ◽  
Author(s):  
Mark Kimball
Keyword(s):  
Integrated Circuits ◽  
Integrated Circuit ◽  
High Speed ◽  
Attenuation Factor ◽  
Cost Effective ◽  
Frequency Measurement ◽  
Single Frequency ◽  
Measurement Tool ◽  
Probe Design ◽  
Differential Measurement

Abstract This article presents a novel tool designed to allow circuit node measurements in a radio frequency (RF) integrated circuit. The discussion covers RF circuit problems; provides details on the Radio Probe design, which achieves an input impedance of 50Kohms and an overall attenuation factor of 0 dB; and describes signal to noise issues in the output signal, along with their improvement techniques. This cost-effective solution incorporates features that make it well suited to the task of differential measurement of circuit nodes within an RF IC. The Radio Probe concept offers a number of advantages compared to active probes. It is a single frequency measurement tool, so it complements, rather than replaces, active probes.

scholarly journals Robust, flexible, and high-performance electromagnetic interference shielding films with long-lasting service

RSC Advances ◽  
2021 ◽  
Vol 11 (30) ◽  
pp. 18476-18482
Author(s):  
Licui Wang ◽  
Zhaoxin Xie ◽  
Yanhu Zhan ◽  
Xuehui Hao ◽  
Yanyan Meng ◽  
...  
Keyword(s):  
Electromagnetic Interference ◽  
High Performance ◽  
Emi Shielding ◽  
Electromagnetic Interference Shielding

It is of great significance for electromagnetic interference (EMI) shielding materials to fulfill long-lasting service requirements.

scholarly journals 2D-3D integration of hexagonal boron nitride and a high-κ dielectric for ultrafast graphene-based electro-absorption modulators

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Hitesh Agarwal ◽  
Bernat Terrés ◽  
Lorenzo Orsini ◽  
Alberto Montanaro ◽  
Vito Sorianello ◽  
...  
Keyword(s):  
Boron Nitride ◽  
Hafnium Oxide ◽  
High Speed ◽  
Hexagonal Boron Nitride ◽  
Temperature Stability ◽  
Cost Effective ◽  
Fold Increase ◽  
Building Blocks ◽  
High Quality ◽  
New Device

AbstractElectro-absorption (EA) waveguide-coupled modulators are essential building blocks for on-chip optical communications. Compared to state-of-the-art silicon (Si) devices, graphene-based EA modulators promise smaller footprints, larger temperature stability, cost-effective integration and high speeds. However, combining high speed and large modulation efficiencies in a single graphene-based device has remained elusive so far. In this work, we overcome this fundamental trade-off by demonstrating the 2D-3D dielectric integration in a high-quality encapsulated graphene device. We integrated hafnium oxide (HfO2) and two-dimensional hexagonal boron nitride (hBN) within the insulating section of a double-layer (DL) graphene EA modulator. This combination of materials allows for a high-quality modulator device with high performances: a ~39 GHz bandwidth (BW) with a three-fold increase in modulation efficiency compared to previously reported high-speed modulators. This 2D-3D dielectric integration paves the way to a plethora of electronic and opto-electronic devices with enhanced performance and stability, while expanding the freedom for new device designs.

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