Effects Of Electromagnetic Interference Research Articles

General issues of ensuring electromagnetic compatibility of aircraft on-board equipment

The article examines the effect of electromagnetic interference on the electrical components of the aircraft from the point of view of external and internal electromagnetic environments. The external electromagnetic environment consists of high-intensity radiated fields and lightning strikes. Internal threats can be divided into four types: intersystem, intra-system, induced radiated fields of high intensity and internal transients during a lightning strike. On the basis of the considered impact, the article defines the directions of development in the field of providing electromagnetic compatibility for an all-electric aircraft.

Crucial role of structural design on performance of cryogel-based EMI shields: an experimental review.

In the field of electromagnetic interference (EMI) shielding with materials based on highly porous constructs, such as foams, cryogels, aerogels and xerogels, a significant challenge lies in designing structures that primarily absorb rather than reflect incident electromagnetic waves (EMWs). This goal necessitates a dual focus on the electrical conductivity and the internal porosity of the given porous material. To explore these issues, we fabricated various graphene oxide (GO)-based cryogels by molding, emulsion templating, chemically-induced gelation, freeze-casting, and liquid-in-liquid streaming. Following thermal annealing to enhance electrical conductivity for effective EMI shielding, we assessed the physicochemical, mechanical and structural characteristics of these cryogels. Notably, the cryogels exhibited distinct EMI shielding behaviors, varying significantly in terms of primary shielding mechanisms and overall shielding effectiveness (SET). For example, chemically-crosslinked cryogels, which showed the highest electrical conductivity, predominantly reflected EMWs, achieving a reflectance of approximately 70% and a SET of 43.2 dB. In contrast, worm-like cryogels, despite having a similar SET of 42.9 dB, displayed a unique absorption-dominant shielding mechanism. This was attributed to their multi-scale porosities and numerous internal interfaces, which significantly enhanced their ability to absorb EMWs, reflected in an absorbance of 54.7%. Through these experiments, our aim is to provide key heuristic rules for the structural design of EMI shields.

Highly effective EMI shielding composites for 5G Ka-band frequencies

Reliable electromagnetic interference (EMI) shielding is essential to secure communications, protect components, and ensure efficient 5G network operation as these technologies expand. In this investigation, we propose a composite material that demonstrates remarkable EMI shielding efficacy, particularly within the Ka-band frequency range (26–40 GHz). This material is practical for industrial fabrication because it can be readily produced by integrating carbonyl iron powder (CIP) and carbon fabric (CF) into a polydimethylsiloxane matrix. It achieves a high shielding effectiveness of at least 120 dB within the Ka-band range, which can be further increased to an ultra-high level of 160 dB by adjusting the CF content. Electromagnetic analyses reveal that this enhanced shielding efficiency is due to the synergistic interplay between multiple reflections of incident EM waves within the CF structure and the excellent EM wave absorption properties of CIP. This composite material not only enhances EM shielding efficiency but also provides enhanced mechanical strength and thermal conductivity, rendering it a practical choice for EM shielding applications in the 5G Ka-band frequency range.

Investigation on high EMI shielding effectiveness and shielding mechanism of spherical Ti3C2Tx microfilm prepared by spray-freezing

Due to the explosive growth of the number of miniature electronic devices in the 5 G era, higher requirements have been raised for electromagnetic pollution protection materials. The production of effective electromagnetic (EM) interference (EMI) shielding materials is still challenging. In this research, Ti3C2Tx microspheres were successfully synthesized by the self-developed spray freezing technology and 43 µm-thick spherical Ti3C2Tx microfilm was prepared by vacuum filtration. The spherical film can block 5 G communication signals and its EMI shielding effectiveness (SE) is 51 dB, which is 50% higher than that of the 2D Ti3C2Tx film of approximately the same thickness. Additionally, the effects of transmitting X-band EM waves through a 43 µm-thick spherical Ti3C2Tx sheet were simulated employing Comsol Multiphsics. It is found that an annular current traveling perpendicular to the direction of electromagnetic wave propagation will be induced in the spherical Ti3C2Tx, which leads an extra larger EM loss. This discovery provides a novel avenue for the structural design of EMI shielding materials.

Analysis of Electromagnetic Interference Effect on Semiconductor Scanning Electron Microscope Image Distortion

Most electronic devices are susceptible to electromagnetic interference (EMI); thus, it is necessary to recognize and identify the cause and effect of EMI as it can corrupt electronic signals and degrade equipment performance. Particularly, in semiconductor manufacturing, the equipment used for image capturing is subject to various noises induced by EMI, causing the image analysis to be unreliable during the image recognition and digitization process. Thus, in this research, we aim to detect and quantify the influence of EMI on semiconductor SEM (scanning electron microscope) images. For this, we apply several useful denoising and edge detection techniques to find a clearer distorted shape from EMI-generated images and then compute five shape-related measures to evaluate the distortion. From a comprehensive experimental analysis and statistical tests, it is found that the medians of all the extracted shape-related measures of high-EMI SEM images are higher than those of both medium- and weak-EMI SEM images, and also all the p-values of the statistical tests are close to 0, and thus we can conclude that all the measures are good quantification metrics for assessing the impact of EMI on semiconductor SEM images.

Conductive polymer nanocomposite incorporated with carbon nanotubes for effective electromagnetic interference shielding: A numerical study

AbstractThis study presents a comprehensive numerical investigation of the electromagnetic interference (EMI) shielding capabilities of a conductive polymer nanocomposite incorporated with carbon nanotubes (CPNC) in the X‐band. The investigation is conducted using a commercial finite element simulation package, Ansys HFSS. The study focuses on analyzing the EMI shielding effectiveness (SE) of CPNC by varying the weight percent (wt%) of carbon nanotubes (CNTs), thickness, and shape of the shielding material. Our outcomes show that the EMI SE of CPNC increases with the wt% of CNTs. Notably, a maximum EMI SE is observed around ~90 dB due to absorption (SEA) at a 4 mm pallet‐shaped CPNC and ~180 dB for a hollow cylindrical CPNC (22.86 mm outer diameter and 3 mm thickness) with 2 wt% of CNT. The EMI SE due to absorption (SEA) at a pallet thickness of 4 mm exhibits a significant improvement of ~107% compared to the SEA observed at a thickness of 1 mm. These findings highlight the exceptional absorption capabilities and lightweight nature of CPNC, rendering it a promising shielding material for aerospace and satellite communication applications.Highlights EMI SE of CPNC increases with the wt% of CNT in the polypyrrole (PPy) matrix. The percolation threshold is observed at a low 2 wt% concentration of CNT. Thickness of the shielding material influences the EMI SE of CPNC. CPNC provides absorption‐dominated shielding.

Improvement in the structural, magnetic and electromagnetic behaviour of barium hexaferrites with yttrium doping for EMI shielding

Electromagnetic interference (EMI) shielding is critical for protecting electronic devices from interference generated by various sources such as power lines, radio waves, microwaves, and electronic devices. In this current study, we present a thorough investigation of the structural, magnetic, and electromagnetic properties of Y3+ doped M-type barium nano hexaferrites. Polycrystalline BaFe12−xYxO19 (x = 0.0, 0.3, 0.5, 0.7, and 0.9) hexaferrites are prepared using the citrate precursor method. The results of X-ray diffraction (XRD), Rietveld refinement and Raman spectroscopy confirmed that all samples have a single-phase, and pure hexagonal crystalline structure with space group P69/mmc. This result is consistent for all the prepared compositions. The structure and dopant materials in different chemical states of the sample are determined based on the X-ray photoelectron spectroscopy (XPS) spectrum. Field emission scanning electron microscopy (FESEM) analysis showed that the particles had a distinct hexagonal morphology. The chemical composition of the prepared hexaferrites is investigated using energy dispersive X-ray analysis (EDAX). UV spectroscopy showed an inverse relationship between the molar ratio of yttrium and the band gap. Vibrating sample magnetometer (VSM) results showed a decrease in saturation magnetization (Ms) and coercivity (Hc) with increasing fraction of yttrium ions. The shielding efficiency (SE) of the synthesized hexa materials against EMI is evaluated using a vector network analyser (VNA). In particular, effective EMI shielding was observed in the frequency spectra of 8–12 GHz (X-band region). Among the tested compositions, BaFe12–0.7Y0.7O19 with a thickness of 3 mm exhibited highest SE of 80.07 dB in the X-band region. The proposed yttrium-substituted barium M-type hexagonal ferrites exhibit significant reflection loss with enhanced absorption spectrum even when applied to an extremely thin 3 mm material, making it a possible preference as the radar-absorbed compound for EMI attenuators for weather monitoring, radar tracking, air traffic management, and gigahertz antennas. Furthermore, commercial applications including long-term magnetic media for recording, storing information, etc. are possible uses of the synthesised magnetic yttrium-doped barium M-type hexagonal ferrites.

Hydrophobic Composite Foams with Asymmetric Gradient Sandwich Structure for Excellent Electromagnetic Interference Shielding and Photothermal Response.

The evolution of contemporary electronics urgently requires the use of versatile electromagnetic interference (EMI) shielding materials in complex environments. Interlayer polydimethylsiloxane (PDMS)/Fe3O4@multiwalled carbon nanotubes (MWCNTs) foams were prepared by a simple physical foaming method with excellent flexibility and electromagnetic wave absorption. The bottom nickel aramid paper (NiP) layer creates a dense conductive network by chemical plating technology, which ensures excellent EMI effectiveness. The upper carbon black (CB)/Fe3O4 layer further improves the absorption performance via conductive loss and magnetic loss. With the effective layout of the impedance matching layer, absorbing layer, and conductive shielding layer, the CB/Fe3O4-PDMS/Fe3O4@MWCNTs-NiP composite material achieves an EMI shielding effectiveness (EMI SE) of 61.7 dB and an absorption coefficient of 0.58 at X-band. In addition, the composite foam provides photothermal conversion and hydrophobicity due to the effective stacking of PDMS and CB/Fe3O4. Thus, the multifunctional composite foam presents a broad range of possible applications, benefiting EMI shielding as well as other specific areas.

Synthesis of ionic liquid modified 1‐D nanomaterial and its strategical distribution into the biodegradable binary polymer matrix to get reduced electrical percolation threshold and electromagnetic interference shielding effectiveness

AbstractIonic liquid is increasingly being used as a chemical modulator of multi‐walled carbon nanotubes (MWCNT). Here, we report the practical method for producing biodegradable electromagnetic interference (EMI) shield films made of thermoplastic polyurethane (TPU), polybutylene adipate‐co‐terephthalate (PBAT), and 1‐(2‐aminoethyl)‐3‐methyl‐1H‐imidazol‐3‐ium modified MWCNT (MIL). The field emission scanning electron microscopy study of cryo‐fractured 50:50 PBAT/TPU blend giving co‐continuous morphology and subsequent polymer EMI shield nanocomposite material had shown the co‐continuous nanofiller distribution. The nanoparticles were chosen to be distributed in the PBAT portion, according to subsequent research employing HRTEM and DMA. The electrical percolation threshold (EPT) is determined to be situated within 1–3 wt% of nanoparticles loading as the remarkable shift in total EMI shielding efficiency from −14.6 dB (for 1 wt%) to −28.6 dB (for 3 wt%) of nanoparticle‐loaded film at 10 GHz (in X‐band region) for a 0.8 mm thick film reveals that the EPT is approximately at 2 wt% of nanoparticle loading. The effective EMI shielding of −37.3 dB was achieved by 10 wt% of MIL loading.

3D printing of carbon fiber powder/polylactic acid with enhanced electromagnetic interference shielding

The construction of segregated structures within conductive polymer composites (CPCs) is a promising strategy for enhancing the effectiveness of electromagnetic interference (EMI) shielding. Herein, three-dimensional (3D) printed carbon fiber powder (CF)/polylactic acid (PLA) composites were prepared with various filling ratio, filling pattern, thickness and CF contents. The results showed that CF was uniformly dispersed in the PLA. Additionally, the modulus of the printed CF/PLA composite displayed an improvement in comparation to injected composite, despite a decrease of the strength. Within the final printed CF/PLA composite, CF integrated into 3D printed PLA formed an interconnected conductive network based on 3D printing technology. The performances of 3D printed CF/PLA composite exhibited superior comprehensive performance when the filling ratio was 50 %, combined with a grid filling pattern, a thickness of 5 mm, and CF content of 20 %, and its shielding efficiency could reach 99.67 %. Meanwhile, the EMI shielding mechanism of 3D printed CF/PLA composite was dominantly of absorption loss. This work suggests that 3D printing technology provides a simple and effective method for developing 3D printed CF/PLA composite with excellent EMI performance, suitable for different electronic devices and radiation source fields.

Anisotropic high-strength polyimide-based electromagnetic interference shielding foam based on cation-π interaction

Effective electromagnetic interference (EMI) shielding plays a vital role in numerous applications by mitigating the detrimental impacts of electromagnetic waves. In this study, we developed a novel anisotropic MXene@PI hybrid foam for efficient EMI shielding using a synergistic approach involving directional freezing, freeze-drying, thermal imidization, and a subsequent dip-coating step. The cation-π interaction was harnessed to create a crosslinked structure for enhancing the mechanical properties of the polyimide (PI) foam and also to improve the interfacial interaction between MXene and the inner wall of the foam. The foam exhibited a tubular structure in a vertical frozen direction while adopting a honeycomb-like structure in a parallel freezing direction. The anisotropic MXene@PI-5 hybrid foam demonstrated remarkable EMI shielding effectiveness of up to 62.7 dB in the vertical freezing direction, 158.02 % higher than that observed in the parallel direction, and 109.70 % higher than that in the isotropic foam with the same loading of MXene. This anisotropic MXene@PI hybrid foam offers great potential for applications requiring efficient EMI shielding, such as aerospace, electronics, telecommunications, etc. The unique combination of the cation-π interaction and anisotropic structure provides enhanced EMI shielding properties, making it a promising candidate for future EMI shielding materials.

Research on simulation method for nonlinear effects of airborne SAR electromagnetic interference

In order to simulate the nonlinear interference effect of high-power electromagnetic signals on airborne Synthetic Aperture Radar (SAR) imaging, the walk–stop geometric modeling of airborne SAR was established, and the range time-domain pulse coherence method was used to simulate SAR echo. By establishing a SAR receiver RF channel model, the interference mechanism of high-power electromagnetic signals is combined on RF front-end devices, the nonlinear effects on the echo signal when high-power electromagnetic signals enter the receiver are simulated, and finally the range Doppler algorithm is used to image the echo signal and the interference signal. A method for evaluating the interference effect of high-power electromagnetic signals on airborne SAR imaging using the correlation coefficient of images was proposed. The results showed that the change in the correlation coefficient of images before and after interference relative to the interference signal ratio was consistent with the image interference effect. The correlation coefficient showed a stepped trend with the change in the interference signal ratio, and there was a saturation effect after the interference effect reached a certain level.

Analysis Of Power Quality Parameters and Devices for Their Measurement

Purpose. The main objective of this study is to assess the phenomena that affect the parameters of power quality, to consider ways to counteract the deterioration of power quality, to assess the effect of electromagnetic interference on the human body, and to review the available devices for measuring the parameters of electric energy. Methodology. To obtain relevant data, the authors conducted a literature review on the topic of the work using full-text and abstract databases. The main causes of electromagnetic compatibility (EMC) violations and ways to counteract these violations are considered. The main parameters of electricity quality, conditions for their measurement and permissible ranges according to the State Standards of Ukraine (SSU) are highlighted. A review of devices for measuring the parameters of electricity quality and the search for a suitable one that meets Ukrainian standards was carried out. Findings. The authors have proved: 1) the problem of measuring electricity quality parameters is relevant and important for its accurate accounting; 2) control of electricity quality parameters and compliance with state standards allows avoiding negative impact on the electricity supply system; 3) the use of modern digital measuring devices provides greater measurement accuracy than analog ones, and they are able to take into account more parameters in one measurement. Originality. The authors conducted a study in the field of electromagnetic compatibility in the field of electromagnetic compatibility using a digital device that gives more accurate and reliable results of power quality parameters. Practical value. Based on the results obtained, it is possible both to correct the personal research of individual scientists or teams of scientists and to predict further prospects for the development of the subject area «Electromagnetic Compatibility» in traction power supply systems in railway transport. The research can also be useful in the study of the disciplines «Electromagnetic Compatibility of Railway Automation Systems» and «Electrical Circuits and Lines of Railway Automation», organization of scientific and practical seminars, advanced training courses, etc.

Effective electromagnetic interference shields based on cellulose nanofibers-carbon nanotubes layered composites

The rapid development of electronic devices and communication technologies has inadvertently led to the production of significant amounts of Electromagnetic Interference (EMI) and radiation, necessitating the development of sustainable, low-density, affordable, and high-performance EMI shielding materials. The present study involves fabricating a layered composite material comprising alternating substrate and conducting layer made primarily of TEMPO-mediated oxidized cellulose nanofibers (TCNF) and carbon nanotubes (CNT). For the substrate layer, TCNF is modified with optimized polydopamine and Fe3+ concentrations to produce mechanically strong film with a tensile modulus of 12.3 GPa. Furthermore, two CNT/TCNF ratios are used in the conducting film: 60% and 80%. In addition to absorption and reflection, the presence of TCNF in the conducting layer creates an impedance mismatch, resulting in a zigzag reflection mechanism for EMI losses. For a thickness of 212 μm, the 5-layered composite exhibited a notable tensile strength of 58 MPa and an efficient EMI shielding effectiveness (EMI SE) of 39 dB in X-band. The prepared composites meet the requirements for a commercial EMI shielding material, namely >20 dB, and outperform the mechanical strength of many other EMI shielding materials.

Lightweight and flexible Ag-wrapped polyimide aerogel fabrics for electromagnetic interference shielding

Lightweight, flexible and highly effective electromagnetic interference (EMI) shielding fabrics are urgent demanded to protect the human body from harmful electromagnetic radiation. However, the design of fiber microstructures for achieving high-performance EMI shielding still remains significant challenges. Herein, novel EMI shielding fabrics have been designed based on polydopamine-assisted Ag deposition on polyimide (Ag@PI) aerogel fabrics. The Ag@PI aerogel fabric integrates highly conductive Ag and leverages the three-dimensional porous structure of aerogel to facilitate multiple reflections and interface polarization of electromagnetic waves. The Ag@PI aerogel fabrics exhibit ultra-high electromagnetic interference shielding performance of 89.4 dB owing to their unique porous structure, while the Ag@PI fabric without porous structure is only 65.1 dB. The normalized specific shielding effectiveness (SSE) of the Ag@PI aerogel fabrics is up to 812.7 dB cm3 g−1, significantly exceeding that of other EMI shielding textiles reported so far.

A novel multisource energy harvester with enhanced thermal conductivity for efficient energy harvesting and superior EMI shielding

With the rapid growth of industries, renewable energy sources like wind and solar have emerged as prominent alternatives. However, their inherent intermittency demands the development of efficient energy harvester technologies. Conventional energy harvesters are limited to capturing a single energy type, resulting in compromised storage capabilities. Moreover, the detrimental effects of electromagnetic interference (EMI) on equipment necessitate immediate attention. To address these challenges, we present the development of a novel phase change composite, CMW@PEG, which possesses remarkable enhancements in thermal conductivity (1.26 W/m∙K), electrical conductivity (71.9 S/cm), and UV absorption capacity (close to 1). Notably, this composite exhibits an outstanding EMI shielding capability of 49.36 dB, safeguarding equipment operations effectively. Furthermore, it showcases impressive solar-thermal (87.9 %) and electric-thermal (93.3 %) conversion efficiencies. The unique properties of CMW@PEG offer a pioneering strategy for harnessing and utilizing renewable energy efficiently and hold tremendous promise in advancing the sustainable energy landscape.

Phase separation-regulated fabrication of MXene/PVA cryogel sensor with effective electromagnetic interference shielding

Multifunctional hydrogels with desirable mechanical properties have attracted extensive attention in flexible electronic devices. Herein, tough and robust Ti3C2Tx MXene/polyvinyl alcohol (PVA) composite cryogel with excellent flexibility is prepared via a cyclic freeze–thaw (F-T) method. The morphological and crystalline structure of the composite cryogel is regulated by the phase separation process during fabrication, which greatly contributes to the enhanced mechanical properties. The highly flexible and stretchable MXene/PVA cryogel exhibits sensitive and reliable responses to deformations, demonstrating promising application in the detection of human motions and smart coding. Furthermore, the composite cryogel presents a high absorption-dominated electromagnetic interference (EMI) shielding effectiveness of 25 dB at an ultralow MXene loading of 0.04 wt%, which is ascribed to the synergetic effect of its tunable porous structure and water-rich environment. These findings provide valuable insights into the design and fabrication of high-performance multifunctional hydrogels.

Fabrication of PVC-based composite films with controlled electrical conductivity via delayed phase separation-induced directional distribution of CNT for effective electromagnetic interference shielding

Fabrication of PVC-based composite films with controlled electrical conductivity via delayed phase separation-induced directional distribution of CNT for effective electromagnetic interference shielding

A shield of defense: Developing ballistic composite panels with effective electromagnetic interference shielding absorption

The primary goal of this study is to develop cost-effective shield materials that offer effective protection against high-velocity ballistic impact and electromagnetic interference (EMI) shielding capabilities through absorption. Six fiber-reinforced epoxy composite panels, each with a different fabric material and stacking sequence, have been fabricated using a hand-layup vacuum bagging process. Two panels made of Kevlar and glass fibers, referred to as (K-NIJ) and (G-NIJ), have been tested according to the National Institute of Justice ballistic resistance protective materials test NIJ 0108.01 Standard-Level IIIA (9 mm × 19 mm FMJ 124 g) test. Three panels, namely, a hybrid of Kevlar and glass (H–S), glass with ceramic particles (C–S), and glass with recycled rubber (R–S) have been impacted by the bullet at the center, while the fourth panel made of glass fiber (G-S) has been impacted at the side. EMI shielding properties have been measured in the X-band frequency range via the reflection-transmission method. Results indicate that four panels (K-NIJ, G-NIJ, H–S, and G-S) are capable of withstanding high-velocity impact by stopping the bullet from penetrating through the panels while maintaining their structural integrity. However, under such conditions, these panels may experience localized delamination with variable severity. The EMI measurements reveal that the highest absorptivity observed is 88% for the K-NIJ panel at 10.8 GHz, while all panels maintain an average absorptivity above 65%. All panels act as a lossy medium with a peak absorptivity at different frequencies, with K-NIJ and H–S panels demonstrating the highest absorptivity. In summary, the study results in the development of a novel, cost-effective, multifunctional glass fiber epoxy composite that combines ballistic and electromagnetic interference shielding properties. The material has been developed using a simple manufacturing method and exhibits remarkable ballistic protection that outperforms Kevlar in terms of shielding efficiency; no bullet penetration or back face signature is observed, and it also demonstrates high EMI shielding absorption. Overall, the materials developed show great promise for various applications, including the military and defense.

Hyperelastic, Robust, Fire‐Safe Multifunctional MXene Aerogels with Unprecedented Electromagnetic Interference Shielding Efficiency

AbstractMXene aerogels have shown great potential for many important functional applications, in particular electromagnetic interference (EMI) shielding. However, it has been a grand challenge to create mechanically hyperelastic, air‐stable, and durable MXene aerogels for enabling effective EMI protection at low concentrations due to the difficulties in achieving tailorable porous structures, excellent mechanical elasticity, and desired antioxidation capabilities of MXene in air. Here, a facile strategy for fabricating MXene composite aerogels by co‐assembling MXene and cellulose nanofibers during freeze‐drying followed by surface encapsulation with fire‐retardant thermoplastic polyurethane (TPU) is reported. Because of the maximum utilization of pore structures of MXene, and conductive loss enhanced by multiple internal reflections, as‐prepared aerogel with 3.14 wt% of MXene exhibits an exceptionally high EMI shielding effectiveness of 93.5 dB, and an ultra‐high MXene utilization efficiency of 2977.71 dB g g−1, tripling the values in previous works. Owing to the presence of multiple hydrogen bonding and the TPU elastomer, the aerogel exhibits a hyperelastic feature with additional strength, excellent stability, superior durability, and high fire safety. This study provides a facile strategy for creating multifunctional aerogels with great potential for applications in EMI protection, wearable devices, thermal management, pressure sensing, and intelligent fire monitoring.