Effects Of Electromagnetic Interference Research Articles

Multifunctional Textiles Enabled by Simultaneous Interaction with Infrared and Microwave Electromagnetic Waves

AbstractConventional textiles keep the body warm and provide an aesthetic appearance for human beings, while they are insufficient for military and civil applications in harsh environments. Multifunctional textiles that are capable of creating infrared (IR) camouflage, electromagnetic interference (EMI) shielding, and personal warming by interacting with both IR and microwave electromagnetic waves (EMWs) are developed. The inorganic–organic polytetrafluoroethylene (PTFE)/Ag/PTFE (IO‐PAP) building blocks are deposited on the polyurethane (PU)‐coated textiles using an eco‐friendly magnetron sputtering technique, where a smooth and durable Ag layer is grown, circumventing the large roughness and less connection between fibers in conventional textiles. Using the IO‐PAP building blocks, the ultralow IR emissivity and the ultrahigh microwave reflectance are achieved for effective IR camouflage and EMI shielding, respectively, together with satisfactory mechanical robustness. The EMI shielding effectiveness is further improved to 73 dB through employing a Fabry–Pérot‐based double‐sided PAP (D‐PAP) architecture. The D‐PAP‐coated textiles also exhibit personal warming, increasing the skin temperature by 2.7 °C compared with conventional cotton through reflecting thermal radiation of human bodies and mitigating radiative heat loss from textiles. This work will inspire the ultra‐band EMW engineering of textiles for realizing advanced functionalities in a way of eco‐friendly and scalable manufacture.

Broadband millimeter-wave absorbers: a review

AbstractThis paper reports an exhaustive review of recent research progress in the development of millimeter-wave absorbers. With the advancement in technologies, microwave absorbers have shown their evolution in several applications such as defense, security identification, stealth technology, and several more. The importance of these absorbers is increasing due to electromagnetic interference (EMI) effects. Primarily, an abundant amount of absorbers has been developed in lower frequency bands and with the increasing demand for 5G technology, the usage of millimeter-wave bands has gained attention. This in turn requires the development of millimeter-wave absorbers to provide EMI shielding in several applications. Out of several materials, polymers have grabbed attention in the mitigation of EMI. An absorber that combines carbonaceous elements with polymers offers large design flexibility and tunability per the filler concentration. This paper focuses on the classification of these absorbers based on geometry as well as that by using polymers with their design challenges, merits, and demerits with their industrial applications. Comparative studies of geometrically based absorbers and polymeric-based absorbers are also shown.

Effective electromagnetic interference shielding properties of micro-truss structured CNT/Epoxy composites fabricated based on visible light processing

In this work, a novel self-writing visible light processing method is employed to fabricate self-propagating polymer waveguide based porous epoxy matrix, which subsequently turns into micro-truss structured carbon nanotube (CNT)/epoxy conductive composites through CNT dip-coating. It is discovered that, by illuminating a photosensitive epoxy pre-polymer with intersecting blue LED beams simultaneously for only 15 min, 3D micro-truss structured epoxy matrix with thickness of ∼1.8 mm is obtained. When incorporating CNTs with a low content of 1.20 vol%, the micro-truss structured CNT/epoxy composites exhibit high electrical conductivity of 62.93 S/m. These composites show absorption-dominated shielding mechanism, and high electromagnetic interference (EMI) shielding efficiency (SE) of 34.5 dB is obtained in the X band with 1.20 vol% of CNT. The specific shielding efficiency (SSE) of the CNT/epoxy composites is up to 100 dB cm3 g−1, and the corresponding SSE/t eliminating the effect of thickness is up to 535 dB cm2 g−1, which is much higher than that reported in other studies with the same CNT contents. This work provides a quick and scalable technique to prepare polymer matrix with ordered porous structures, and would also inspire and guide the fabrication of well-ordered porous conductive polymer composites with superior EMI shielding performances.

Microwave scattering behaviour of carbon black/ molybdenum di sulphide /cobalt composite for electromagnetic interference shielding application

Erasing signature of an object from an enemy's radar is, tactically, disruptive move achieved by the effective electromagnetic interference (EMI) shield. We report on the microwave scattering (2–18 GHz) behaviour of the nano-composite for architecting efficient shield composed of carbon black (CB), molybdenum di sulphide (MoS2) and cobalt (Co). Nano-composite, prepared by a facile, solid state synthesis route, are characterized using infrared, x-ray diffractometry, UV–visible, energy dispersive x-ray spectroscopic techniques including scanning electron microscopy. In infrared and Rayleigh analysis, formation of -C-Mo-C, OSO, Mo–O, and Co–O phases generated asymmetric polarization at low % CB content that gets transformed into a symmetric mode due to formation of Co–O and Co–S–C radicals at high CB % to cause maximum power losses. Possible polarization mechanism is discussed. In constitutive analysis, two-fold increase in the dielectric function, the dual behaviour (Debye and Jonscher) of the ac conductivity, and the synergistic magneto-dielectric coupling factor influenced the scattering performance of the composite. Broadly, at 18% composition, the shielding effectiveness is recorded to be > 97@14 GHz with 7.7 GHz of the bandwidth and the thickness ∼2.5 mm. The Dallenbach return loss is almost 75% revealing a high-performance shield design @18% CB/MoS2/Co nano-composite.

Predictive Modeling for Detection of Source of Electromagnetic Disturbances in Inductive Wireless Charging of Electric Vehicles

The effects of Electromagnetic Interference (EMI) in Inductive Power Transfer (IPT) for electric vehicle charging circuits are elaborated with Common Mode (CM) emission. Electromagnetic Compatibility (EMC) has to be sustained in the circuits such that it is prone to the effects of interferences, noises and disturbances. These issues can be addressed at the initial product development stage, with accurate identification of the parameters that influence the CM emission in the circuit. The analysis of EMI focuses on three features, namely Source of EMI, Coupling path and Receptor. In the IPT model, the primary source of the EMI is the power converter used for high-frequency supply to the inductive coils. The power converter switches and the heat sink with its Printed Circuit Board (PCB) design are predominant in power electronic circuits. This paper facilitates the reduction of EMI without including complex filters. The system is tested for the violated standard SAEJ2954. In addition, the article corroborates precognitive modeling by implementing compensation networks used in IPT applications and their effectiveness in reducing the leakage current caused by the converters and the coils. The paper insights the air gap variation of the coil with the power transfer efficiency and its influence on electromagnetic interferences. The Fast Fourier Transform (FFT) analysis used in PSIM shows leakage current and harmonic reduction with the compensation network and Pulse Width Modulation (PWM) technique. The fabrication model for the front end power supply to the IPT is tested. The electrical noise emission is estimated using predictive modeling.

Analysis of Electromagnetic Interference Effect of the Pulse Interference on the Navigation Receiver

Aiming at the problem that satellite navigation signals are easily interfered by the radio frequency (RF) pulse signal, the electromagnetic interference effect of RF pulse on the navigation receiver is studied in this paper. A mathematical model of the pulse interference signal is established, and we choose the bit error rate (BER) as an indicator of the quality of the BDS signal. It is found that the BER is proportional to the duty cycle of the pulse signal and inversely proportional to the equivalent carrier-to-noise ratio (C/N0) through simulation. Then, an experiment of electromagnetic injection on the BDS receiver has been carried out, which studied the influence of the pulse interference parameters, such as repetition frequency and duty cycle on the C/N0 of the BDS signal and the electromagnetic sensitivity threshold of the receiver. The comparative experiment between the pulse interference and the single-frequency continuous wave (CW) interference was also carried out, and we found that the effect of the pulse interference is better than that of single-frequency CW interference. The former is the correlation interference, and the latter is the blocking interference. Combined with the experiment phenomenon, the interference mechanism was further analyzed according to the relationship between the pulse period and the ranging code period of the navigation signal.

Wireless Communication in Modular Multilevel Converters and Electromagnetic Interference Characterization

The wireless control of modular multilevel converter (MMC) submodules was recently proposed. The success of the control depends on specialized control methods suitable for wireless communication and a properly designed wireless communication network in the MMC valve hall while aiming for low latency and high reliability. The wireless communication in the hall can be affected by the electromagnetic interference (EMI) of MMC submodules, voltage and current transients. In this article, firstly, a wireless communication network based on 5G New Radio is designed for an example full-scale MMC valve hall. After that, the radiated EMI characteristics of the MMC submodules with different voltage and current ratings and two dc circuit breakers are measured. The effects of EMI on wireless communication in the multi-GHz frequency band are tested. The interference from the components is confined below <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mathrm {500 \text {M} \text {Hz} }$ </tex-math></inline-formula> , and the wireless communication with <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mathrm {5825 \text {M} \text {Hz} }$ </tex-math></inline-formula> center frequency is not affected by the interference.

Emerging Intelligent Bidirectional Charging Strategy Based on Recurrent Neural Network Accosting EMI and Temperature Effects for Electric Vehicle

Transportation is currently advancing towards Electric Vehicle (EV) technology. This paper presents a brief and systematic analysis of the real-time issues obtained in Electric Vehicles (EVs) due to the various ranges of energy storage devices. In general, EV energy management system is integrated with power electronic circuits for effective power conversion and reliable operation. Some issues are addressed while using the batteries in EV systems such as charging time, efficiency of battery, and raw materials. Not only battery issues but also real-time non-technical issues and operational issues are also discussed in this paper. During energy conversion with power electronic circuits, the system attains extreme temperature levels which in turn reduces the performance of the system. To maintain an optimum temperature level, it is important to study the temperature effect of the system at the most prior levels. Due to the adaption of power electronic components, some extent of noise is generated, technically treated as Electromagnetic Interference (EMI), as system capacity increases the EMI content also improved proportionately. Therefore, to mitigate the EMI effect, the low pass filter-based EMI filter is introduced in the system such that the noise level is suppressed. Bidirectional Charging System (BCS) is one of the emerging technologies in EV to obtain autonomous power supply systems in the form of Vehicle to Grid (V2G), Grid to Vehicle (G2V), and Vehicle to Load (V2L). To know the behaviour of BCS the proposed RNN controller is employed and is compared with ANN bidirectional charging model. BCS charging system with RNN controller has better dynamic response to exchange the power via DC/DC converter and AC/DC converter as compared to ANN controller.

Combined effects of electrostatic and electromagnetic interferences of high voltage overhead power lines on aerial metallic pipeline

The main purpose of this paper is to model and analyze the electrostatic and electromagnetic interferences between a HV overhead power line and an aerial metallic pipeline situated parallel at a close distance. The modelling of these interferences is typically done for safety reasons, to ensure that the induced voltage does not pose any risk to the operating and maintenance personnel and to the integrity of the pipeline. The adopted methodologies respectively for electrostatic and electromagnetic interferences are based on the charge and current simulation methods combined with the Teaching learning based optimization (TLBO) algorithm. The Friedman test analysis indicate that teaching learning based optimization (TLBO) algorithm can be used for parameters optimization, it showed better results. In the case where the induced currents and voltages values exceed the limit authorized values by the international CIGRE standard, mitigation measures become necessary. The simulation results obtained were compared with those provided respectively by the admittance matrix analysis and Carson's method, good agreement was obtained.

Research and Prospect on Key Technologies of Indoor Positioning Based on Visible Light Communication

Indoor positioning has become a research hotspot because of its important application value in industrial production and daily life. Traditional wireless positioning technologies such as Wi Fi and Bluetooth are difficult to achieve high-precision indoor positioning due to electromagnetic interference and multipath effect. The modulated white LED can not only meet the needs of lighting, but also transmit the location information to achieve high-precision indoor positioning. This paper first introduces several modulation methods commonly used in visible light positioning system, compares the characteristics of different modulation methods, and proposes a modulation method suitable for visible light positioning; Then, two demodulation methods of the visible light positioning system are introduced and discussed; After that, several visible light location algorithms are introduced, and the performance of each algorithm is analyzed in detail; Finally, the problems in visible light positioning are discussed and prospected.

Reduced Graphene Oxide-Ti3c2tx Composite Papers with the Ingenious Combination of Fire-Resistant Skeleton Structure and Porous Conductive Framework for Effective Electromagnetic Interference Shielding

Reduced Graphene Oxide-Ti3c2tx Composite Papers with the Ingenious Combination of Fire-Resistant Skeleton Structure and Porous Conductive Framework for Effective Electromagnetic Interference Shielding

Microwave scattering parameters of ferro–nanocarbon composites for tracking range countermeasures

Manipulating radar signatures by designing and architecting effective electromagnetic interference shield.

Light-weight carbon fiber/silver-coated hollow glass spheres/epoxy composites as highly effective electromagnetic interference shielding material

Highly effective electromagnetic interference shielding materials with light-weight feature are urgently demanded for releasing electromagnetic pollution. In this study, the hollow glass spheres were coated with silver particles to produce electrically conductive microspheres. The Carbon fiber/silver-coated hollow glass spheres (Ag@HGMs)/epoxy composites were manufactured by composites liquid molding process. The electromagnetic interference shielding properties of the composites were investigated in the X-band (8.2–12.4 GHz) range. The Ag@HGMs play a role in filling up the vacancy of the conductive network of carbon fibers in the composites, which not only form new conductive pathways but also act as bridges to connect CFs and provide additional channels for the electron transfer within the composites thus improving the electrical conductivity. The total shielding effectiveness (SET) increases with increasing Ag@HGMs loadings and the maximum SET is high as 88.1 dB. The increased SET dominated by absorption loss SEA is attributed to the high conductivity and multilayer construction of carbon fiber veil. The maximum specific SE of the carbon fiber/Ag@HGMs/epoxy composites can achieve 128.8 dB cm3/g, simultaneously the tensile strength and modulus can reach 95.6 MPa and 2.71 GPa, which provides a facile and promising strategy for designing and developing light-weight and high performance electromagnetic interference shielding materials.

Interfacing MXene Flakes on a Magnetic Fiber Network as a Stretchable, Flexible, Electromagnetic Shielding Fabric.

A unique self-standing membrane composed of hierarchical thermoplastic polyurethane (TPU)/polyacrylonitrile (PAN) fibers is prepared by the electrospinning technique, followed by a simple dip-coating process. Fe3O4 nanoparticles are uniformly anchored on TPU/PAN fibers during the electrospinning process, enabling the membrane to achieve effective electromagnetic interference shielding (EMI SE) performance. Such a hybrid membrane has a high magnetization of 18.9 emu/g. When MXene (Ti3C2Tx) layers are further loaded on the TPU/PAN/Fe3O4NPs hybrid membrane, its EMI SE performance in the X band can exceed 30 dB due to the hydrogen bonds generated between the macromolecular chain of PAN and the functional group (Tx) on the surface of MXene. Simultaneously, the interfacial attraction between MXene and the TPU/PAN/Fe3O4NPs substrate is enhanced. The EMI SE mechanism of the hybrid membrane indicates that this film has great potential in the fields of wearable devices and flexible materials

MXene-Coated Wrinkled Fabrics for Stretchable and Multifunctional Electromagnetic Interference Shielding and Electro/Photo-Thermal Conversion Applications.

Stretchability and multifunctional heating abilities are highly desired for wearable electromagnetic interference (EMI) shielding fabrics to tackle the growing electromagnetic pollution for special crowd, such as pregnant women. Herein, we fabricated stretchable MXene-coated thermoplastic polyurethane (TPU) fabrics by simple uniaxial prestretching and spraying methods. The obtained unique wrinkled structure endowed the film with effective strain-invariant electrical conductivity and EMI shielding properties. Specifically, the prepared stretchable film with an extremely low MXene loading (0.417 mg cm-2) exhibited a stable EMI shielding effectiveness of approximately 30 dB under 50% tensile strain and durability during stretching and bending cycles. More importantly, owing to the high electrical conductivity and localized surface plasmon resonance (LSPR) effect of the MXene layer, the stretchable fabrics exhibited excellent Joule heating (up to 104 °C at a voltage of 5 V) and superior photothermal conversion abilities. Moreover, the unique wrinkled MXene-coating layer not only endows the fabrics with stretchable heat abilities but also enhances the photothermal conversion performance by increasing the light absorption area and travel path. We believe that this study offers a novel strategy for the versatile design of stretchable and multifunctional wearable shielding fabrics.

Diglycidyl ether of bisphenol – A functionalized graphene/copper foam composite with enhanced thermal conductivity and effective electromagnetic interference shielding

Due to development of electronic devices, thermal management and electromagnetic interference (EMI) problems in electronic devices are becoming crucial issues. In the present work, a novel method is proposed for the synthesis of thermally- and electrically-conductive graphene-copper/polymer composites. The graphene surface is grafted with the diglycidyl ether of bisphenol-A (DGEBA), and the graphene-copper double 3D network structure is fabricated via a freeze drying method. The double structure is then pressed and wetted with epoxy to create a polymer-based composite. The as-prepared interconnected conductive network structure forms a continuous thermally and electrically conductive pathway, while the thermal conductivity and mechanical properties are further enhanced by the decreased interfacial resistance between the filler and matrix. In detail, the composite is shown to exhibit a high EMI shielding efficiency of 38.16 dB and a thermal conductivity of 1.20 W/mK. In addition, the composite exhibits a tensile modulus of 48.86 MPa, and an elongation at breaking point of 10.72%. The present authors believe that this approach holds great promise for the development of EMI shielding and thermally conductive materials.

An EMI-Immune PAM-4 Transmitter With Input Level Shifter in 130-nm BiCMOS Technology

This work presents a design of an electromagnetic interference (EMI)-immune pulse amplitude modulation-4 (PAM-4) transmitter. The traditional PAM-4 transmitters are prone to failing in the presence of EMI, which is experimentally verified. The proposed PAM-4 shows superior performance over the traditional PAM-4 transmitter, in the presence of EMI, by using an Input Level Shifter (ILS). ILS minimises the effect of EMI on a PAM-4 signal by reducing the input commonmode level of the transmitter and renders it compatible with the previous logic state. The proposed PAM-4 transmitter is fabricated in 130-nm BiCMOS technology with a chip area of 580mum×915 mum. EMI-immunity measurements are aligned with the IEC 62132-2 standard by using a transverse electromagnetic (TEM) cell for radiated EMI-immunity. In the presence of a wide range of EMIs, the proposed PAM-4 transmitter operates at a data rate of 6.5 Gbps and maintains the minimum required eye-opening of 70mV as per the standard IEEE 802.2bs. The proposed EMI-immune transmitter can withstand EMI powers of 0-16dBm in frequencies ranging from 1MHz to 1.5 GHz.

Flexible, stretchable and electrically conductive PDMS decorated with polypyrrole/manganese-iron oxide nanocomposite as a multifunctional material for high performance EMI shielding applications

Rapid growth in portable and wearable electronics requires high performance electromagnetic shielding materials that are lightweight, flexible, stretchable and electrically conductive to counter the problems of increasing electromagnetic pollutions. Absorption dominant microwave wrap-on shielding materials are in great demand for mitigating the effect of electromagnetic interference on devices and the environment. In this work we report preparation of a multifunctional composite that effectively combines the outstanding EMI shielding, electrical conductivity mechanical flexibility and magnetic properties of hybrid polymer nanocomposite systems for wearable electronics. Highly conductive Polypyrrole (PPy)/Manganese-Iron oxide (MnFe2O4) nanocomposites treated with para toluene sulphonic acid (PTSA) were incorporated into polydimethylsiloxane (PDMS) matrix to obtain a multifunctional hybrid structure. The incorporation of PTSA treated PPy- MnFe2O4 nanoparticles forms excellent conductive network and improves the electrical and magnetic properties of the composites. The PDMS based nanocomposite exhibit superior conductivity of 24.03 S/cm with robust mechanical properties such as Young’s modulus (0.93 MPa) and tensile strength (2.62 MPa). Due to improved conductivity and magnetic attributes this PDMS based nanocomposite with 0.5 mm thickness shows absorption dominated superior electromagnetic shielding performance (EMI-SE of −21 dB corresponds to 99.21% of shielding efficiency) in X-band microwave frequencies. Further, these nanocomposite shields exhibit excellent stability in conductivity and EMI-SE values under mechanical stretching and bending. Apart from being an excellent shielding material, this PDMS based nanocomposite serves as a superior strain sensor, indicates multifunctional dimensions of this material. Owing to the features such as light weight, flexibility, stretchability, high conductivity, excellent EMI-SE as and superior strain sensing performance, these composites can be used in flexible and foldable devices as smart wrap-on shield.

Absorption-dominant microwave shielding properties of Sn0.2Fe2.8O4-graphite-PVDF ternary nanocomposite films

Absorption-dominant microwave shields are in high demand for mitigating the effect of electromagnetic interference (EMI) on devices and the environment. In this paper, we describe the development of absorption enhanced ternary nanocomposites and their EMI shielding capability. Polymer based shields have been fabricated by dispersing conducting graphite and magnetic spinel ferrite Sn0.2Fe2.8O4 nanoparticles in electroactive polymer polyvinylidene fluoride. Shielding effectiveness (SE) values in the expected range of 10–30 dB in the X-band region, were achieved with as low as 30–50 wt% of pristine graphite and 1–10 wt% of Sn0.2Fe2.8O4. The industrial standard of 99% shielding (SE ⩾ 20 dB) was obtained with 50 wt% of graphite. The composites exhibit absorption as the dominant mechanism of shielding. The percentage SE due to absorption is about 70% and is tuned upwards by the increase in ferrite concentration. The composites were characterized by x-ray diffraction and vibrating sample magnetometry; thermal analysis confirms their stability. The thin, flexible films fabricated by the simple and cost-efficient technique of solution casting will be extremely valuable as wrap-on shields for X-band microwave attenuation.

A Regulated Pulse Current Driver with Spread Spectrum Clock Generator

This paper presents a regulated pulse current driver with a spread spectrum clock generator (SSCG) to lower the electromagnetic interference (EMI) effect. An SSCG is used and implemented by applying a triangular wave to modulate a voltage-controlled oscillator (VCO). The results show a 7 dBm reduction in the peak power level with a frequency deviation of 10%, demonstrating that the dominate harmonic is spread and distributed to adjacent frequencies, and the magnitude of harmonics is significantly reduced. The results demonstrate that the driver with a spread spectrum clock generator would help to reduce interference in sensitive electronic components and be suitable for portable consumer electronics applications.