Electromagnetic Interference Control Research Articles

Electromagnetic Disturbance Source Modeling Scheme and its Interference Estimation of Medium–Low-Speed Maglev Train Interior

Magnetic fields from the linear motor, suspended electromagnet, and collector shoe arcing are the three main electromagnetic interference (EMI) sources for the medium–low-speed maglev train interior. Under their collective influence, the field intensity may exceed the standard threshold, consequently affecting the operational reliability of the train system. However, in previous studies, the EMI sources were analyzed separately, and studies regarding the influence of factors such as the motor states and the train body (TB) shielding against arcing EMI were lacking. Therefore, in this paper, all three EMI source are considered, and an EM disturbance source modeling scheme is proposed using the COMSOL software platform. Its effectiveness is demonstrated and the train interior magnetic field is analyzed, primarily with respect to prior simulations and tests. Subsequent analyses enable a comparative assessment of the individual contributions of each EMI source to the overall interference, considering the EMI control standards. The influence of other EMI source parameters, such as different motor states, is analyzed, and the potential for modifying the material composition and structural thickness of the TB is explored to determine the appropriate EMI inhibition strategy.

Metaheuristic aided structural topology optimization method for heat sink design with low electromagnetic interference

This study investigates the application of the Metaheuristic Aided Structural Topology Optimization (MASTO) method as a novel approach to address the multiphysics design challenge of creating a heat sink with both high heat conductivity and minimal Electromagnetic Interference (EMI). A distinctive 2D layout with elongated fins is examined for electromagnetic traits, highlighting resonance-related EMI concerns. MASTO proves to be a valuable tool for navigating the complex design space, yielding thoughtfully optimized solutions that harmonize efficient heat dissipation with effective EMI control. By merging simulation findings with practical observations, this study underscores the potential of the MASTO method in achieving effective designs for intricate multiphysics optimization problems. Specifically, the method's capacity to address the complex interplay of heat transfer with convection and the suppression of electromagnetic emissions is showcased. Moreover, the study demonstrates the feasibility of translating these solutions into tangible outcomes through manufacturing processes.

ANALYSIS OF STANDARDS REQUIREMENTS FOR AIRCRAFT BONDING

In the design, modernization and further aircraft operation, the issue of bonding as a means of electromagnetic interference control from equipment and static electricity, lightning protection is given much attention.
 The relevance of this article lies in the need to understand and comply with the requirements of the standards of all parts of the research and production cycle of modernization of aircraft from enterprises that develop devices and equipment for aircraft to the design bureaus of aircraft repair plants.
 To ensure the normal operation of radio technical apparatus on aircraft, protection against interference is applied, that caused by electrostatic charges due to voltage ripples on the generator commutator and engine manifold or at the output of rectifiers, as well as due to magnetic fields generated by various electrical facilities and wires.
 Interference protection of aircraft onboard equipment from electromagnetic interference is achieved by carrying out special measures, including screening of conductors, harnesses of the aircraft electrical system and ignition system of power drive units, bonding of shielding coatings of conductors and harnesses, structural elements and aircraft units. Bonding is also carried out to protect against lightning strikes.
 The article analyzes the requirements of state and industry standards for bonding, as the main technical measure of lightning protection and electromagnetic interference control on aircraft. Careful selection of the requirements of the standards allows to properly conduct and control the bonding of aircraft. It helps to determine the division of responsibilities in the design, execution and control of the state of bonding.

Biomimetic Porous MXene Sediment-Based Hydrogel for High-Performance and Multifunctional Electromagnetic Interference Shielding.

Developing high-performance and functional hydrogels that mimic biological materials in nature is promising yet remains highly challenging. Through a facile, scalable unidirectional freezing followed by a salting-out approach, a type of hydrogels composed of "trashed" MXene sediment (MS) and biomimetic pores is manufactured. By integrating the honeycomb-like ordered porous structure, highly conductive MS, and water, the electromagnetic interference (EMI) shielding effectiveness is up to 90 dB in the X band and can reach more than 40 dB in the ultrabroadband gigahertz band (8.2-40 GHz) for the highly flexible hydrogel, outperforming previously reported porous EMI shields. Moreover, thanks to the stable framework of the MS-based hydrogel, the influences of water on shielding performance are quantitatively identified. Furthermore, the extremely low content of silver nanowire is embedded into the biomimetic hydrogels, leading to the significantly improved multiple reflection-induced microwave loss and thus EMI shielding performance. Last, the MS-based hydrogels allow sensitive and reliable detection of human motions and smart coding. This work thus not only achieves the control of EMI shielding performance via the interior porous structure of hydrogels, but also demonstrates a waste-free, low-cost, and scalable strategy to prepare multifunctional, high-performance MS-based biomimetic hydrogels.

Control of EMI in High-Technology Nano Fab by Exploitation Power Transmission Method with Ideal Permutation

There are many high-power electrical cables around and within semiconductor foundries. These cables are the source of extremely low-frequency (ELF < 300 Hz) magnetic fields that affect the tools which operate by the function of electronic beams. Miss operation (MO) happens because the ELF magnetic fields induce beam shift during the measurement or process for cutting-edge chips below 40 nm. We present the optimal permutation of power transmission lines to reduce electromagnetic influence in high-technology nano fabs. In this study, the magnetic field was reduced using a mirror array power cable system, and simulation results predicted the best permutations to decrease the electromagnetic interference (EMI) value to below 0.4 mG in a working space without any shielding. Furthermore, this innovative method will lower the cost of high-technology nano fabs, especially for the 28 nm process. The motivation behind this paper is to find the ideal permutation of power transmission lines with a three-phase, four-cable framework to decrease the EMI in high-technology nano fabs. In this study, the electromagnetic interference was diminished using the ideal-permutation methodology without investing or using additional energy, labor, or apparatus. Moreover, this advanced methodology will help increase the effectiveness and reduce the costs of nano fabs. The mathematical and experimental results of the study are presented with analysis.

Semi-Crystalline Polyaniline with an Enhanced Conductivity Synthesized with a Novel Binary Dopant Sulfonic Acid-Surfactant: Mechanical, Electrical and Shielding Performances of Nylon/PANI Conductive Fabrics at 9.45 GHz

Aniline was doped by a novel binary dopant agent, sulfonic acid-surfactant. Naphthalene disulfonic acid (NDSA) and an anionic surfactant (sodium dodecyl sulfate, SDS) were used to form the binary dopant agent; synthesis of the doped PANI was accomplished by using ammonium peroxydisulfate (APS) as the oxidant via a hybrid microemulsion polymerization at various temperatures (–10, 0, 20, and 40 °C). The synthesized polyaniline (PANI-NDSA-SDS) salts were characterized by Fourier transform infrared, UV-visible and Raman spectroscopy, X-ray diffraction, scanning electron microscopy (SEM), the electrical properties were determined using a four-point probe method, and the mechanical properties of the fabric samples were also studied. The PANI-NDSA-SDS salts showed a semi-crystalline structure with nanostructure morphology. Among the four polyaniline salts, the PANI-NDSA-SDS prepared at 20 °C showed higher values of conductivity and polymerization yield. In this study, this polyaniline salt was used as coating materials for preparation of conductive Nylon fabrics. As a result, the tensile strength increased by 15%, from 27.21 to 31.42 MPa. Higher electrical performance was obtained for the Nylon/polyaniline composites, 128–724 ohm/square; thus, for electromagnetic shielding applications, the conducting polyaniline coated Nylon fabrics can be used as a shield material for the control of electromagnetic interference at 9.45 GHz, the frequency of the instrument used for the measurements. The conducting fabrics showed an electromagnetic interference value between 20.09 and 34.44 dB.

Dynamical Networks Modelling Applied to Low Voltage Lines with Nonlinear Filters

The nonlinear dynamical behaviour of a network that is submitted to disturbances is the starting point of this work, where we consider a low voltage line (the network) with nonlinear varistor filters responding, dynamically, to those disturbances. Network models consider static measurements, and here we develop an iterative model to deal with dynamical measurements. We begin with the one-dimensional communication line model using reflected and incident signals, which are dependent on the node parameters, proceeding a time-step computation. Each node is a space representation that consolidates parameters for a specific vertex and its edges. Nonlinear functions are applied within the node and will contribute to the general process running on the structure. The idea of a structure and its related processes leads to a new concept of sustainability and system robustness. This concludes the work, along with several experimental and simulation results, with direct advantages to electromagnetic interference control and mitigation.

Active Electromagnetic Interference Control in Time Domain: Application to Software Correction of Defective Lossy Transmission-Line Networks

This paper introduces a generalized approach of the linear combination of configuration field (LCCF) method. The technique developed in this paper provides a way to identify the temporal profile of electromagnetic sources satisfying particular properties for a given target (fields, voltage, or current). Here, we focus on identifying voltage signals that would lead to a specified voltage over a time interval at some points of a network. To experimentally apply the same idea, we propose two possibilities to decrease the maximum frequencies of the voltage signals. The LCCF method is then applied to bring a software correction to a lossy transmission-line network presenting soft or hard defects.

Reinforcement of Electromagnetic Wave Absorption Characteristics in PVDF-PMMA Nanocomposite by Intercalation of Carbon Nanofibers

With the recent developments in the millimeter and sub-millimeter wave instruments and devices, there is a need to develop electromagnetic (EM) wave absorbing materials in these frequency bands for applications like electromagnetic interference control, electromagnetic compatibility, etc. In this work, carbon nanofibers (CNF) were uniformly dispersed in a blend of poly(methyl methacrylate), polyvinylidene fluoride and cyanoacrylate for air spray coating a film on the cellulosic substrates. The samples were characterized for evaluation of their structure, morphology, electrical and EM absorption properties in 0.15–1.2 THz range by X-ray diffraction, field emission electron microscopy, I–V measurements and terahertz time domain spectroscopy. These coatings can conveniently be applied to the material surfaces by conventional air spray painting method, which makes this technique cost-effective as well as easy to deploy in various applications. The electrical conductivity enhancement in the samples has been attributed to the formation of conducting network by uniform distribution of CNFs in the insulating polymer matrix. As a result, the shielding effectiveness (SE) has been observed to improve with the increase in CNF’s loading in the polymer matrix. The SE is also a function of frequency, which is attributed to the increase in the skin depth. A SE of 20 dB has been estimated in these samples for the frequencies 1 THz and higher, which is of significant importance for the use of this technique in practical applications.

Multilayered Electromagnetic Interference Shielding Structures for Suppressing Magnetic Field Coupling

Control of electromagnetic interference (EMI) represents a major challenge for emerging consumer electronics, the Internet of Things, automotive electronics, and wireless communication systems. This paper discusses innovative EMI shielding materials and structures that offer higher shielding effectiveness compared with copper. To create high shielding effectiveness in the frequency range of 1 MHz to 100 MHz, multilayered shielding topologies with electrically conductive and nanomagnetic materials were modeled, designed, fabricated, and characterized. In addition, suppression of out-of-plane and in-plane magnetic-field coupling noise with these structures is compared with that of traditional single-layer copper or nickel–iron films. Compared with single-layered copper shields, multilayered structures consisting of copper, nickel–iron, and titanium showed a 3.9 times increase in shielding effectiveness in suppressing out-of-plane or vertically coupled noise and 1.3 times increase in lateral coupling. The superiority of multilayered thin-film shields over conventional shielding enables greater design flexibility, higher shielding effectiveness, and further miniaturization of emerging radiofrequency (RF) and power modules.

Investigation of electromagnetic shielding properties of boron, carbon and boron–carbon fibre hybrid woven fabrics and their polymer composites

The growth of the electronic industry and the widespread use of electronic equipment in communications, computations, automations, biomedicine, space and other purposes have led to many electromagnetic interference (EMI) problems as systems operate in close proximity. It is likely to become more severe in the future, unless proper EMI control methodology and techniques are used to meet the electromagnetic compatibility requirements. In recent years, electromagnetic (EM) waves in the 1–10 GHz range are broadly used in wireless communication tools and local area networks. In the future, the usable range of EM waves will tend to shift further to higher frequency regions with the development of information technology as well as electronic devices. As a consequence, the seriousness of problems such as EMI of electronic devices and health issues is ever rising. In this study, electromagnetic shielding effectiveness, absorbance and reflectance properties of the boron, carbon and boron–carbon plain woven fabrics and boron/polyester, carbon/polyester, and boron–carbon/polyester hybrid composites were investigated. Using a coaxial transmission line holder set-up, the (EMSE), reflectance and absorbance of various fabrics and composites were carried out in the frequency range from 15 to 3000 MHz.

A Resonator-Based Suppressor for Mitigating the Noise Transfer on Metal Plates for Control of Electromagnetic Interference

This letter introduces a novel resonator-based suppressor to mitigate the noise transfer on the metal plates inside electronic devices. Compared with the traditional method using ferrite-based absorbers, which is inadequate to fully eliminate gigahertz (GHz) noise, the proposed solution can achieve a high-level noise rejection within the desired frequency band in GHz range. The unit cell of the suppressor is composed of multiple quarter-wavelength ( $\lambda /4$ ) strip resonators. By simply cascading unit cells in series, a higher-order suppressor can be implemented with wider bandwidth and deeper suppression level. In this letter, a third-order example is demonstrated with the center frequency at 2.48 GHz. Its ability to reduce the amount of noise transfer is experimentally verified, where the maximum suppression level is about 20 dB. Lastly, for a complete demonstration of noise mitigation, the near-field intensity on the test board attached with the noise suppressor is measured.

Angular independent frequency selective surfaces for interference control in indoor wireless environments

A study of electromagnetic wave propagation in buildings using a finite-difference time-domain algorithm has demonstrated that waves are incident on walls over a wide range of angles. If wall mounted frequency selective shielding is desired, it is argued that this behaviour requires shielding solutions that are angle insensitive. A simple single-layer annular ring frequency selective surface (which is relatively economic to fabricate) is shown to offer adequate angular stability of the transmission response, and is thus suitable for electromagnetic interference control in indoor wireless environments.

English

This paper discusses the procedure adapted after carrying out several iterations for selecting an ideal location to introduce a high power high frequency (HF) transmitter-receiver in a tactical combat vehicle from electromagnetic compatibility view. This radio set contributes for very high field strength to neighbouring electronic devices and other very high frequency (VHF) Tx-Rx situated in the same vehicular platform. An integrated approach was followed in deciding the optimum solution to locate the HF radio set. Leakage from HF radio set is to be minimised within the vehicle to reduce the field coupling level to neighbouring equipment. Radiation from HF antenna was maximised by careful installation of antenna, outside the vehicle environment to ensure optimum radiation of intended signal. Voltage standing wave ratio (VSWR) measurement was carried out to verify this. Four different locations experimented have been reported in this paper. The vehicle penetration loss (VPL) can reveal the amount of leakage from external field generated by antennas to field inside the turret. The HF, being a congested operating spectrum, due care was taken in electromagnetic interference control of HF-VHF radios and other tank electronic subsystems. High RF power of HF transmitter and very high sensitivity of HF receiver could affect systems either way. Hence, electromagnetic compatibility (EMC) measures and optimum location of HF radio set are important from MIL-STD461 C, MIL6051-D/MIL-STD464A point of view.Defence Science Journal, 2010, 60(3), pp.302-306, DOI:http://dx.doi.org/10.14429/dsj.60.357

Electromagnetic Shielding Effectiveness of Multifunctional Metal Composite Fabrics

The growth of the electronic industry and the widespread use of electronic equipment in communications, computations, automations, bio-medicine, space, and other purposes have led to many electromagnetic interference (EMI) problems as systems operate in close proximity. It is likely to become more severe in the future, unless proper EMI control methodology and techniques are used to meet the electromagnetic compatibility requirements. This article presents a comprehensive review of EMI shielding theory and materials. Furthermore, a method for fabricating a multifunctional metal composite fabric with electromagnetic (EM) shielding characteristics was successfully developed. The parameters influencing EM shielding properties of the metal composite fabrics were investigated. It was shown that the EM shielding effectiveness of the metal composite fabrics could be tailored by modifying the metal grid size and geometry.

A simple impulsiveness correction factor for control of electromagnetic interference in dynamic wireless applications

The emerging software defined radio technologies will be an enabler for a new generation of dynamic wireless systems. It will also open up the possibility of allocating frequencies in a, more dynamic way than today. From an intersystem-interference point of view, this can cause unforeseen problems to occur due to the increased complexity in such applications. In such applications, a measure indicating whether or not a frequency band is possible to use from an electromagnetic interference point of view, must be found. A simple approach is to use the measured total average interference power within the receiver band. Since the interference impact on modern digital communication systems from an interference signal does not only depend on the power but also on the actual waveform of the interference signal, some kind of quality measure of the average-power approach would be convenient to use. In this paper, we introduce a simple quality measure of the average-power approach so that a rough adjustment for the interference-waveform properties can be done.

EMEC—An EM Simulator Based on Topology

For the control of electromagnetic interference a topological approach is strongly recommended. It allows for a complex system to be structured into a feasible number of zones, each having certain levels of energy density, transient amplitudes, background noise, etc. Electromagnetic compatibility (EMC) is reached by making sure that all system elements comply with those levels. In this paper, a simulation program is described that facilitates the EMC specification. The user interface forces the user to adapt to the topological approach. Sources, zone properties, cables, and other coupling path etc., are specified and disturbances in arbitrary locations are computed. By comparing computed results for varying system properties with known emission and immunity properties of system elements, different ways to reach EMC can be evaluated. Including actual external threats among the sources, EMC compliance means that the system is immune to intentional electromagnetic interference, high-power electromagnetics, electromagnetic pulse, lightning, etc.

Variability studies on EMI data for electronic, telecommunication and information technology equipment

Data variability has long been a problem for radiated emission testings of electronic, telecommunication and information technology equipment. When a piece of electronic equipment undergoes electromagnetic interference (EMI) test, the inherent data variability is inevitable even with known test facility uncertainties. This study presents a methodology for analyzing this variability based on a modified analysis of variances (ANOVA), with polynomial regression analyses. The data variability is estimated after the prototype has been built in a design laboratory. The analytical analysis results can also be used to provide confidence limits for internal in-process EMI control when the equipment is mass-produced.

Shielding effectiveness of conducting polyaniline coated fabrics at 101 GHz

Conducting polyaniline coated fabrics can be used as a shield material for the control of electromagnetic interference at 101 GHz. The conducting fabrics can also be used for the dissipation of electrostatic charge. The conducting fabric shows a shielding effectiveness of 35.61 dB. The characterization of the conducting polymer polyaniline and conducting fabrics was carried by spectroscopic techniques and thermogravimetric analysis. Static charge measurements of the conducting fabrics show a complete removal of static charge.

Hybrid moment-method physical-optics formulation for modeling the electromagnetic behavior of on-board antennas

On-board antenna design involves aspects such as optimization of radiation patterns, control of electromagnetic interference and disturbance (EMC/EMI), the assessment of radiation hazards, etc. This paper describes a hybrid moment-method physical-optics (MM–PO) approach that has been shown to be an efficient and accurate tool to predict the above-mentioned electromagnetic aspects concerning antennas installed on board. Some numerical results are presented and compared with a reference MM solution in order to illustrate the accuracy and efficiency of the proposed approach. © 2000 John Wiley & Sons, Inc. Microwave Opt Technol Lett 27: 88–93, 2000.