ANALYSIS OF MULTI-LAYERED SHIELDING DEVICE USING CU FILM AND REZIN FILM IN LOW-FREQUENCY REGION

This paper describes the shielding effectiveness (SE) of a multi-layered shielding device in low frequency region. Cu film and PET film is used for the multi-layered shielding device. The SE of the multi-layered shielding device is estimated by an electromagnetic field simulator. We were able to analyze SE in frequency range from 100 kHz to 1 GHz by using the pulse waveform. We found that the SE of Cu/Cu/Cu is nearly equal to that of Cu/PET/Cu. And we found that SE of Cu/PET/Cu/PET/Cu is 41 dB at 500 kHz

Electrically Conductive 2D Material Coatings for Flexible & Stretchable Electronics: A Comparative Review of Graphenes & MXenes

There is growing interest in transitioning electronic components and circuitry from stiff and rigid substrates to more flexible and stretchable platforms, such as thin plastics, textiles, and foams. In parallel, the push for more sustainable, biocompatible, and cost-efficient conductive inks to coat these substrates, has led to the development of formulations with novel nanomaterials. Among these, 2D materials, and particularly graphenes and MXenes, have received intense research interest due to their increasingly facile and scalable production, high electrical conductivity, and compatibility with existing manufacturing techniques. They enable a range of electronic devices, including strain and pressure sensors, supercapacitors, thermoelectric generators, and heaters. These new flexible and stretchable electronic devices developed with 2D material coatings are poised to unlock exciting applications in the wearable, healthcare and Internet of Things sectors. This review has surveyed key data from more than 200 articles published over the last 6 years, to provide a quantitative analysis of recent progress in the field and shade light on future directions and prospects of this technology. We find that despite the different chemical origins of graphenes and MXenes, their shared electrical properties and 2D morphology, guarantee intriguing performance in end applications, leaving plenty of space for shared progress and advancements in the future

Conductive textiles for signal sensing and technical applications

Conductive textiles have found notable applications as electrodes and sensors capable of detecting biosignals like the electrocardiogram (ECG), electrogastrogram (EGG), electroencephalogram (EEG), and electromyogram (EMG), etc; other applications include electromagnetic shielding, supercapacitors, and soft robotics. There are several classes of materials that impart conductivity, including polymers, metals, and non-metals. The most significant materials are Polypyrrole (PPy), Polyaniline (PANI), Poly(3,4-ethylenedioxythiophene) (PEDOT), carbon, and metallic nanoparticles. The processes of making conductive textiles include various deposition methods, polymerization, coating, and printing. The parameters, such as conductivity and electromagnetic shielding, are prerequisites that set the benchmark for the performance of conductive textile materials. This review paper focuses on the raw materials that are used for conductive textiles, various approaches that impart conductivity, the fabrication of conductive materials, testing methods of electrical parameters, and key technical applications, challenges, and future potential

Manipulating Light at Micro- and Nano-Scale: Enable Photonic Structures Toward Real-World Applications

Recent advances in fabrication and processing methods have spurred many breakthroughs in the field of nano- and micro-structures that provide novel ways of manipulating light interaction in a well controllable manner, thereby enabling various innovative applications. In this dissertation, new photonic design concepts and materials featuring high performance and long-term stability are investigated for bridging the gap between the research and the real-world applications. Firstly, angle-insensitive and high-purity structural color filters based on one-dimensional layered structures that are suitable for mass-production are studied. Various scenarios including reducing the layer number and depositing the whole device via an all-solution process have been proposed to simplify the fabrication, thereby lowering the manufacturing cost. The proposed structures offer significant advantages over existing colorant-based filters in terms of high efficiency, slim dimension, and being free from photobleaching. They have been successfully adapted into practical applications including decorative paints, visibly-opaque but near-infrared-transmitting camouflage coatings, and highly-efficient colored photovoltaics. As a special color, ‘black’ has been studied separately based on ultrabroadband absorbers that are achieved by simultaneously exciting multiple absorption resonances. It can significantly enhance the efficiency of energy harvesting and conversion in various applications. In addition, optical designs are incorporated into vehicle interiors, opening up a new path to the extensive use of optics in automobiles: Anti-glare colored dashboard with the potential for high-resolution dashboard displays are demonstrated with micro-scale lenticular lenses; Invisible vehicle pillars for safe driving are realized with compact optical cloaks using different optical components, including polarizers and mirrors. The next part is the research into a cost-effective and easy-to-fabricate method for flexible transparent electrodes employing ultrathin (thickness < 10 nm), ultra-smooth (roughness < 1 nm), and low-loss copper-doped silver. This novel silver alloy requires only room-temperature deposition and presents outstanding optical and electrical properties, mechanical flexibility, and environmental stability, which are greatly desired in potential high-performance flexible optoelectronic devices. Lastly, other optical structures inspired by methods employed in above researches that have impactful applications, including retro-reflective particles that can be embedded in transparent glasses for light detection and ranging and omnidirectional planar solar concentrators based on curved micro-reflectors, are briefly discussed. All the strategies and methodologies proposed here could bring optical researches out of the labs and open up more opportunities for further advancement.PHDElectrical EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttps://deepblue.lib.umich.edu/bitstream/2027.42/149791/1/jichg_1.pd

Electromagnetic Interference Shielding Effectiveness of Interlayered Systems Containing Metal-Oxide, Conducting Polymer and Carbon Nanotube Reinforced Polymeric Composites

The Electromagnetic Interference (EMI) Shielding Effectiveness (SE) has become one of the important requirements for the devices associated with telecommunication systems consisting of large frequency bands. The degradation of the quality of transmitting signal influenced by frequencies emitting from external sources can be reduced by covering the circuits of the devices by EMI Shielding materials like polymer composites, metal-based nanofiber mats, the metal of oxide films, etc. The investigation strives for the attenuation of EMI by introducing two composite mats from conducting polymer-based, multiwalled carbon nanotubes (MWCNTs) coated Nylon 6 nanofiber composites. Two other composite mats are also developed by the Forcespinning® method using sol solution of functionalized multiwalled carbon nanotubes (f-MWCNTs) and magnetite (Fe3O4) into as-prepared polyacrylonitrile (PAN) which is then carbonized at elevated temperature to convert it into carbon nanofiber (CNF). A total of four layers of mats are stacked and compression molded together to develop one multilayered composite (MLC 1). The Fe3O4 has higher magnetic properties which may provide a good magnetic loss effect. The focus is to investigate the synergistic effects between higher magnetic Fe3O4, conductive MWCNTs nanofillers with the dielectric CNF, conducting polymer, and functionalized MWCNTs coated nanofiber composite which can provide information about the dominating mechanism. (Absorption, reflection, or multiple reflections) for EMI SE. The multilayered composite (MLC 2) consisting 8 layers (repeating the stacking sequence again) has given the highest obtained value more than 40 dB EMI SE in the frequency range from 300–500 MHz. The results will bring some findings of optimized materials yielding good EMI SE in lightweight applications

Optically transparent UWB antenna for wireless application & energy harvesting

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.Transparent UWB antennas have been the focus of this PhD research. The use of transparent UWB antennas for stealth and energy harvesting has been the underlying applications that have given impetus to this research. Such transparent antennas being built on materials that are discreet, flexible, conformal, conductive and having the ability to provide good antenna performance on glass to serve as the ‘last mile’ link in subsequent generation communications after 4G have been the basis for this contention. UWB in this regard is able to provide the transmission and reception of high data rates and fast video transmission that is an elementary demand of even a 4G wireless communications system. The integration of UWB antennas with photovoltaic to provide integral energy harvesting solutions that will further enhance the value of the UWB system in terms of cost effectiveness and performance are thus the basis of this work. This work hence starts with the study of a transparent conductive oxide polymer, AgHT and its properties, and culminates in the development of a transparent UWB antenna, which can be integrated with photovoltaic for window glass applications on homes and buildings. Other applications such transparent antennas can find use for like on-body wireless communications in healthcare monitoring was also analysed and presented. The radar absorbing material (RAM) property of the AgHT was investigated and highlighted using CST simulation software, as no measurement facilities were available. The transparent UWB antenna in lieu of the inherent absorbent property of the AgHT material is thus able to exhibit stealth characteristics, a feature that would be much desired in military communications. Introduction of a novel method of connecting the co-axial connector to the feed of the antenna to improve gain and efficiency of transparent polymer based antennas and the development of a UWB antenna that maintains its Omni-directional characteristic instead of becoming directional on an amorphous silicon solar cell are presented as some of the contributions for this research work. Some preliminary analysis on the impact of glass on UWB antennas for video transmission and how to improve transmission is presented. The ability of the conductive part of the antenna radiator to be used as a RF and microwave harvester and how it can further add value to a transparent UWB antenna is presented by way of experimental data. Finally yet importantly, this thesis presents some insight into how transparent antennas may be used in Green Technology Buildings to provide an integrated solution for both wireless communications and energy harvesting as part of the future work. Improvement to the aesthetics of the external appearance of residential buildings through the integration of transparent satellite dish onto solar panels on rooftops is also discussed and illustrated as part of this future work

Polypropylene melt-blown for electromagnetic shielding purposes

Protože se elektrické a elektronické přístroje a příslušenství rychle vyvíjejí, je důležité přenášet elektromagnetickou energii prostřednictvím různých frekvenčních pásem používaných na trzích, omezovat a zabránit elektronickým zařízením ze všech zdrojů rušení. Štíty se často používají k izolaci z místnosti, zařízení, obvodu atd. Zdroje elektromagnetického záření externě nebo k zamezení škodlivých vnitřních emisí elektromagnetické energie. Jedním z hlavních problémů se zavedením elektrické a elektronické technologie ve světě je elektromagnetické rušení mezi zařízeními. Různí vědci a průmyslové podniky se intenzivně zajímali o řešení tohoto problému. Tabule jsou tradičně považovány za nejlepší elektromagnetický stínící materiál, ale jsou drahé, těžké, flexibilní a tepelně expandované. Používání elektronických a elektrických zařízení textilních předmětů je však vhodné, protože jsou lehké, univerzální a levnější. Vědci upozornili na různá řešení, včetně textilních výrobků a kompozitních textilií, které tyto textilní struktury zahrnují flexibilitu a shodu. Nežádoucí elektromagnetická emise v kombinaci se specifickým zdrojem záření EMI nebo přenos do okolního elektrického systému jsou elektrické signály. Tento šum, části cívek, digitální zařízení a dlouhé kabely stejnosměrného nebo střídavého proudu mohou být způsobeny elektromagnety. Při frekvencích, které mohou vysílat energii na rádiové frekvenci [1]. Feromagnetické materiály ve směsi s vlákny a textiliemi jsou nakonec elektricky vodivé a účinné při ochraně před elektromagnetickým zářením. Pro elektromagnetické stínění se stříbro, měď nebo nerezová ocel nejlépe kombinují se střižovými nebo filamentovými vlákny. Pro různé elektromagnetické stínění tkaniny kompozitní příze vyrobené ze směšování kovových a textilních vláken. Tkaní kovových přízí je více obtížné než kompozitních přízí. Vedení polymerních kompozitů může vytvořit lepší funkčnost. Navíc je kovové potahování netkaných textilií pro komerční použití nákladově efektivní. Tato práce popisuje studii vývoje kovového povlaku na netkané textilii pro účely elektromagnetického stínění.As electric and electronic devices and accessories are increasing rapidly, transmitting electromagnetic power through the different frequency bands used on the markets, restricting and preventing electronic equipment from all sources of interference has become important. Shields are often used for insulation from a room, equipment, circuit, etc. Electromagnetic radiation sources externally or to avoid harmful internal electromagnetic energy emissions. One of the main issues with the introduction of electrical and electronic technology in the world is electromagnetic interference between devices. Different scientists and industrial enterprises were keenly interested in seeking solutions to this problem. Table sheets are traditionally considered to be the best electromagnetic shielding material, but they are expensive, heavy, flexible, and thermally expanded. However, the use of electronic and electrical equipment of textile items is appropriate because they are lightweight, versatile, and cheaper. Researchers have drawn attention to various solutions, including textile products and composite textiles these textile structures include flexibility and conformity. Face Unwanted electromagnetic emission in combination with the specific EMI source radiation or transmittal to the surrounding electrical system is electrical signals. This noise, coil parts, digital devices and long DC or AC cables can be caused by Electromagnets. At frequencies that can emit energy on radio frequency [1]. Ferromagnetic materials in mix with fibres and textiles end up being electrically conducive and effective in protecting from electromagnetic radiation. For electromagnetic shielding silver, Copper or stainless steel are best combined with staple or filament fibres. For different electromagnetic shielding fabric composite yarns made from mixing metal and textile fibres. It's difficult to weave metallic yarns than the composite yarn. Conducting polymer composites can create better functionality. Moreover, metallic coating over nonwoven fabrics is cost-efficient for commercial use. This paper describes the study on developing metal coating over nonwoven fabric for electromagnetic shielding purposes