Electromagnetic Interference Mitigation Research Articles

Enhancing electromagnetic interference mitigation: A comprehensive study on the synthesis and shielding capabilities of polypyrrole/cobalt ferrite nanocomposites

In a society increasingly infiltrated by digital and networking technologies, designing electromagnetic interference (EMI) shielding materials is critical for safeguarding sensitive electronic equipment and ensuring the smooth functioning of essential communication networks. This study focuses on the optimization of the properties of cobalt ferrite (CoFe2O4)/polypyrrole (PPy) nanocomposites made by in-situ polymerization used for electromagnetic (EM) shielding based on their magnetic and dielectric losses. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), vibrating sample magnetometer (VSM), and vector network analyzer (VNA) were employed to study the materials' physical and chemical characteristics. The findings demonstrate that the magnetic and electric properties of the materials composed of CoFe2O4 and PPy are substantially altered by the integration of CoFe2O4 and PPy. Adding PPy to CoFe2O4 reduces the real and imaginary parts of magnetic permeability, and the conductivity, dielectric constant, and dielectric loss are increased. These effects are advantageous for EM shielding applications. The high electromagnetic shielding performance mainly results from the enhanced interfacial polarization induced by interface region among CoFe2O4 and PPy molecules. The influence of the PPy matrix in altering the dielectric and magnetic loss factors (tanδE and tanδM) of the embedded ferrite particles is pronounced. Although CoFe2O4 shows excellent attenuation characteristics, it cannot optimally match impedance with free space, particularly at higher frequencies. In addition, material thickness and shielding efficiency adjust the reflection loss (RL) performance. The prepared composites can attenuate more than 95 % of the incident electromagnetic waves. This study emphasizes the benefits of employing composite materials in EMI shielding designs and the combined advantages of conductive and magnetic materials.

Experimental validation of nonreciprocal metasurface using simple structure

AbstractThe non‐reciprocity of electromagnetic waves is a technology garnering significant attention for its applications in electromagnetic security and the mitigation of electromagnetic interference, serving to control radio waves in space. This article outlines a comprehensive design approach for a novel non‐reciprocal structure that integrates ferrite and metal patches. Additionally, it presents experimental results utilizing two types of ferrites. The experiments demonstrated the attainment of 15 dB isolation at both 6.25 GHz and 6.5 GHz.

Improving emi performance in automotive data transmission systems using spread spectrum modulation

This paper investigates the enhancement of electromagnetic interference (EMI) performance in automotive data transmission systems through the application of spread spectrum modulation techniques. The significance of this research lies in the growing complexity and density of electronic systems within modern vehicles, which increases the potential for EMI-related issues that can compromise the reliability and safety of automotive communication systems. The primary objective of this study is to evaluate the effectiveness of spread spectrum modulation in mitigating EMI and improving the overall performance of data transmission in automotive environments. To achieve this objective, the research utilizes both theoretical analysis and experimental validation. The methods include a detailed review of current EMI mitigation strategies, the design and implementation of spread spectrum modulation techniques in a controlled environment, and subsequent testing to measure the impact on EMI performance. Key metrics for evaluation include signal integrity, data transmission rate, and EMI reduction levels. The results of the study indicate a significant improvement in EMI performance when spread spectrum modulation is applied. The experimental data demonstrate a notable reduction in EMI levels, leading to enhanced signal integrity and more reliable data transmission. These findings suggest that spread spectrum modulation is a viable solution for addressing EMI challenges in automotive data transmission systems

Electromagnetic shielding material database and machine learning preparing for laser cladding FeCo-based alloy

The compilation and preprocessing of electromagnetic shielding material databases using machine learning techniques are pivotal in contemporary materials science and engineering. These materials play a crucial role in diverse applications such as electronics, telecommunications, aerospace, and automotive industries, necessitating effective attenuation of electromagnetic interference (EMI). This paper underscores the significance of comprehensive databases in organizing material properties systematically, facilitating the identification of novel materials with enhanced shielding effectiveness. It explores the role of machine learning algorithms in predictive modeling and data analysis, expediting the screening process of candidate materials and uncovering hidden correlations within complex datasets. However, the efficacy of machine learning techniques relies heavily on the quality of input data and preprocessing steps. Thus, this paper discusses methodologies for collecting material data, challenges in data curation and integration, and common preprocessing techniques such as data cleaning, feature extraction, and normalization. The integration of electromagnetic shielding material databases with machine learning preprocessing holds great promise for FeCo-based alloy laser cladding manufacturing and design, leading to innovative solutions for electromagnetic interference mitigation across various technological domains.

Optically transparent and angularly stable broad‐stopband frequency selective surface for millimeter wave electromagnetic interference mitigation

AbstractAn optically transparent and angularly stable frequency selective surface (FSS) with a broad stopband is introduced for addressing millimeter wave (mmW) electromagnetic interference. The unique FSS unit cell pattern incorporates a cross patch with Y‐shaped branches, effectively broadening the bandwidth and enhancing the angular stability. Utilizing transparent conductive indium tin oxide deposited on both sides of a glass substrate enables the FSS to reflect and absorb electromagnetic waves. Consequently, the proposed FSS exhibits an exceptionally wide stopband ranging from 18.7 to 40.2 GHz, featuring an insertion loss of 14 dB and maintaining stable angular response up to 60° for both transverse electric and transverse magnetic polarizations. Moreover, an equivalent circuit model is developed to characterize the stopband behavior of the FSS. Finally, measurements conducted on a physical prototype of the proposed FSS validate its effectiveness, showing good agreement with the simulation results.

Modulating microwave attributes of Ba1−xSrxTiO3 nanoparticles: Insights into strontium concentration, structural intricacies and electromagnetic dynamics

In this pioneering investigation, we meticulously synthesized Ba1−xSrxTiO3 nanoparticles, with Sr concentrations varying between 0.0 and 0.4 at intervals of 0.1, via a refined chemical approach. The crux of our study lies in establishing the intricate correlations between the chemical constitution (primarily Sr concentration), salient structural attributes (encompassing lattice and microstructural parameters), electrical dynamics and consequential microwave characteristics. X-ray diffraction (XRD) analyses reinforced the unity between the average ionic radii of the Ba/Sr ions and the lattice constants. Scanning electron spectroscopy (SEM) furnished insights into the microstructural intricacies, while the nominal chemical composition was ascertained via energy-dispersive X-ray (EDX) spectroscopy. A deep dive into the electrical realm revealed the temperature and field-dependent behaviors of permittivity, tangent losses and polarization. The electromagnetic traits of Ba1−xSrxTiO3 (where 0.0 < x < 0.4) were meticulously delineated by analyzing the experimentally determined S-parameters across a frequency spectrum of 6 to 18 GHz. Our findings elucidate that the predominant losses of electromagnetic wave energy are attributable to aggregated electrical losses, predominantly steered by polarization processes. Our findings demonstrate a significant attenuation in the reflected wave energy, with values spanning from − 14.3 to − 17.1 dB, highlighting the potential of these nanoparticles for cutting-edge applications in electromagnetic interference mitigation.

A novel programmed hybrid modulation for electromagnetic interference mitigation and current ripple control in miniaturised synchronous machine drives

AbstractA novel programmed hybrid spreading spectrum modulation method to mitigate electromagnetic interference (EMI) emission and bearing current in the context of miniaturised and lightweight synchronous machine drives is proposed. The proposed method adopts the combination of conventional pulsewidth modulation (PWM) and low common mode voltage PWM. The offline look‐up table for switching frequency is acquired by analysing the root mean square voltage values at different modulation indices and angles. By adjusting the switching frequency according to this table, the spectrum can be spread into the sidebands of the switching frequency, and the harmonic spike can be suppressed. To address the challenge of increased current ripple and harmonic distortion in high torque density motors under overload conditions, a motor model that considers the cross‐saturation and slotting effect is presented. This motor model is used to derive the switching frequency correction factors, aiming to mitigate the influence of saturation and slotting effect on harmonic amplification. The proposed method is well‐suited for controlling synchronous motors using three‐phase two‐level voltage source inverters. The simulation and experimental results validate the effectiveness of the proposed method, showcasing its advantages in terms of computational complexity reduction and significant attenuation of peak EMI currents.

Circularly Polarized Coaxial Horn Filtenna for Electromagnetic Interference Mitigation

Circularly Polarized Coaxial Horn Filtenna for Electromagnetic Interference Mitigation

EMI challenges in modern power electronic-based converters: recent advances and mitigation techniques

The utilization of power electronic-based converters is gaining momentum across a wide spectrum of industries. However, modern power electronic converters operate at higher frequencies compared to conventional power electronic converters, which can lead to higher rates of change in voltage and current during phase switching, and thus potentially produce more severe conducted and radiated electromagnetic interference (EMI). Their electromagnetic compatibility (EMC) has become a critical research topic, and EMI in high-frequency power electronic-based converters is more complex than that in conventional converters. This review presents a comprehensive survey of recent advancements, EMI design, and analysis of modern power electronic-based converters, focusing on the sources and mechanisms of both conducted and radiated EMI, and mitigating techniques. This review also covers the impact of topology optimization, control strategy design, and packaging design on EMC performance. Addressing emerging EMI issues in modern power electronic device-based converters is essential for ensuring safe and reliable operations. Through strategic design optimization and the implementation of EMI mitigation strategies, modern converters can seamlessly be integrated into diverse applications, offering improved EMI performance as a hallmark of their versatility.

A Review of EMI Research of High Power Density Motor Drive Systems for Electric Actuator

With the global attention given to energy issues, the electrification of aviation and the development of more electric aircraft (MEA) have become important trends in the modern aviation industry. The electric actuator plays multiple roles in aircraft such as flight control, making it a crucial technology for MEA. Given the limited space available inside an aircraft, the power density of electric actuators has become a critical design factor. However, the pursuit of high power density results in the need for larger rated power and higher switching frequency, which can lead to severe electromagnetic interference (EMI) issues. This, in turn, poses significant challenges to the overall reliability of the electric actuator. This paper provides a comprehensive review of EMI in high power density motor drive systems for electric actuator systems. Firstly, the state of the art of electric actuator systems are surveyed, pointing out the contradictory relationship between high power density and EMI. Subsequently, various EMI modeling approaches of motor control systems are reviewed. Additionally, the main EMI suppression methods are summarized. Active EMI mitigation methods are emphasized in this paper due to their advantages of higher power density compared with passive EMI filters. Finally, the paper concludes by summarizing the EMI research in motor drive systems and offering the prospects of electric actuators.

Conducted electromagnetic interference mitigation in super-lift Luo-converter for electric vehicle applications

In this article, a digital chaotic pulse width modulation (DCPWM)-dependent electromagnetic interference (EMI) noise attenuating procedure has been implemented. With the aid of a field programmable gate array (FPGA), a randomized carrier frequency modulation with a fixed duty cycle has been generated through chaotic carrier frequency, and this process is called DCPWM. Conducted EMI suppression is achieved in a 200 kHz, 40 W elementary positive output super lift Luo (EPOSLL) converter using the DCPWM technique. The results are compared and validated with periodic PWM over DCPWM in simulation and hardware with electromagnetic compatibility (EMC) standards. Besides, 9 dBV (2.81 V) of conducted EMI noise has been minimized in the DCPWM approach against periodic pulse width modulation method for the EPOSLL converter in electric vehicles applications.

AC Excitation to Mitigate Drift in AlGaN/GaN HEMT-Based Sensors

AlGaN/GaN high electron mobility transistor (HEMT) based sensors hold promise as small solid-state physical and chemical sensors because they can operate without a reference electrode and can be integrated into miniaturized sensor arrays. However, over extended time periods, low frequency noise causes anomalous variations (drift) in sensor signal, especially in liquid environments. These effects occur despite electromagnetic interference mitigation. To understand the low frequency noise, 1/ <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">f</i> noise measurements between 0.1 and 100 kHz were undertaken, in both air and water, under constant pH and normal laboratory pressure conditions. The 1/ <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">f</i> <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">γ</sup> noise for the device in water was larger in magnitude than in air, and estimates for the γ-parameter in air and water were approximately 1 and 1.5, respectively. The corner frequency was observed between 100 and 1000 Hz. Based on this analysis, AC excitation at 1 kHz was applied to the conduction channel to compare the sensor stability in de-ionized water with DC operation. In this controlled test, introduction of AC excitation resulted in a strong correlation of sensor signal with the ambient temperature variations over nearly 90 hours of testing (effectively acting as a temperature sensor with a high degree of stability) while operation in DC mode resulted in largely no correlation with temperature. This indicates that AC excitation above the corner frequency is a potentially effective method to mitigate long-term sensor instability, a critical limitation for any AlGaN/GaN transistor-based physical or chemical sensors in aqueous environments.

Deep Reinforcement Learning-Based Ground-Via Placement Optimization for EMI Mitigation

Placing ground vias plays a crucial role in mitigating electromagnetic radiation from printed circuit board (PCB) edges. Stitching dense ground vias along PCB edges is not always feasible due to limited layout areas. Finding a ground-via placement strategy to achieve the best electromagnetic interference (EMI) mitigation using a specified number of ground vias is desired in the industry. However, this process is usually tedious and labor-intensive because of the enormous search space. This article proposes an optimization algorithm based on deep reinforcement learning to adaptively seek the optimal ground-via placement strategy in complex packages. First, an evaluation module based on convolutional neural networks (CNNs) is trained to predict the EMI mitigation for any possible ground-via placement. Then, relying on the well-trained CNN, an optimization module based on dueling double deep Q network is developed to find the best ground-via placement strategy through exploration and training without prior electromagnetic knowledge. The final optimization strategy obtained by our proposed algorithm has more effective EMI mitigation than the commonly used “edge-wrapping” solution in industrial products. Our proposed algorithm also provides guidelines and insights about the design rule and the behind physics.

Flexible Ink-Minimized Screen-Printed Frequency Selective Surfaces With Increased Optical Transparency for 5G Electromagnetic Interference Mitigation

A thin, flexible and transparent polyethylene terephthalate (PET) based screen-printed band-stop Frequency Selective Surface (FSS) with ink minimization is experimentally demonstrated at 28 GHz using both planar and conformal configurations. A miniaturized conventional FSS unit cell is ink-minimized using surface meshing without compromising the angular stability of the transmission response of the surface within ±60°. This not only leads to reduced amount of expensive ink required in prototyping, thereby lowering the overall manufacturing cost, but also increases the optical transparency of the structure by a factor of 65% using an 80 μm line-width tolerance. Finally, the operation of the ink-minimized FSS is experimentally shown using a conformal geometry with two radii of curvature (60 mm and 114 mm) and a good filtering performance is confirmed. Useful for 5G electromagnetic interference (EMI) applications, these FSSs feature increased feasibility through improved transparency and reduced cost due to ink minimization.

Conducted Electromagnetic Interference Mitigation on Two-Stage Cascaded Boost (TSCB) DC-DC Converter Using FPGA Based DCPWM Technique for EV Applications

Conducted Electromagnetic Interference Mitigation on Two-Stage Cascaded Boost (TSCB) DC-DC Converter Using FPGA Based DCPWM Technique for EV Applications

Common-mode Electromagnetic Interference Mitigation for Solid-state Transformers

Solid-state transformers (SSTs) have been widely used in many areas owing to their advantages of high-frequency isolation and high power density. However, high-frequency switching causes severe electromagnetic interference (EMI) problems. Particularly, the common-mode (CM) EMI caused by the switching of the dual active bridge (DAB) converter is conducted through the parasitic capacitances in the high-frequency transformer and impacts the system reliability. With the understanding of the CM EMI model in SSTs, CM EMI mitigation methods have been studied. For passive mitigation, the coupled inductor can be integrated with the phase-shift inductor function to reduce CM EMI. For active mitigation, variations in the DAB switching frequency can help reduce the CM EMI peak. An active EMI filter can also be designed to sample and compensate for CM EMI. Using these methods, CM EMI can be reduced in SSTs.

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.

Mitigation of Electro Magnetic Interference by Using C-Shaped Composite Cylindrical Device

The extremely low-frequency (ELF) and its corresponding electromagnetic field influences the yield of CMOS processes in the foundry, especially for high-end equipment such as scanning electron microscopy (SEM) systems, transmission electron microscopy (TEM) systems, focused ion beam (FIB) systems, and electron beam lithography (E-Beam) systems. There are several techniques to mitigate electromagnetic interference (EMI), among which active shielding systems and passive shielding methods are widely used. An active shielding system is used to generate an internal electromagnetic field to reduce the detected external electromagnetic field in electric coils with the help of the current. Although the active shielding system reduces the EMI impact, it induces an internal electromagnetic field that could affect the function of nearby tools and/or high-performance probes. Therefore, in this study, we have used a C-shaped cylindrical device combined with an active shielding system and passive shielding techniques to reduce EMI for online monitoring and to overcome the aforementioned issues. In this study, the active shielding system was wrapped with a permalloy composite material (i.e., a composite of nickel and iron alloy) as a tubular device. A C-shaped opening was made on the tubular structure vertically or horizontally to guide the propagation of the electromagnetic field. This C-shaped cylindrical device further reduced electromagnetic noise up to −5.06 dB and redirected the electromagnetic field toward the opening direction on the cylindrical device. The results demonstrated a practical reduction of the electromagnetic field.

Printed Band-Stop Filter for Mitigation of Electromagnetic Interference

Printed Band-Stop Filter for Mitigation of Electromagnetic Interference

EMI Mitigation of a Ćuk-Based Power-Electronic System Using Switching-Sequence-Based Control

Switching-sequence-based control (SBC) laws when designed based on topological switching behavior can have positive effects on slow- and fast-scale dynamics of a power-electronic system (PES). The slow-scale control can encompass fast PES state regulation and tracking, based on predefined objective, while fast-scale control can address differential-mode (DM) and common-mode (CM) spectral-peak energy associated with PES switching operation. Such control laws may offer enhanced programmability to conventional PES design where bulky electromagnetic interference (EMI) filters have been traditionally used to reduce EMI of switching power converters to meet EMI regulatory standards. An EMI filter is always a less programmable solution since it is usually designed for the worst-case EMI mitigation and usually overkill for a PES operating under reduced load condition. The control scheme outlined in this article offers EMI mitigation across wide operating regions without compromising PES regulation. Moreover, it does so by use of switching sequences that guarantee the reachability of the PES dynamics using an advanced Lyapunov-function-based approach. SBC is a powerful tool to generate control actions for a PES based on multivariate PES state constraints. Hence, contemporary EMI regulatory standards are used as constraints in the SBC formulation to operate the PES under wide operating regime while autonomously mitigating the EMI levels. The work may be of paramount importance for operating the ultra-fast-transition recent wide-bandgap semiconductor devices like GaN-FET and SiC MOSFET under higher power with increasing switching frequencies, which is usually desirable for increased power density and reduced switching losses. Here, a hardware Ćuk-PES operated with GaN-FETs is fabricated and is used for case illustration. It is shown by experimental results how SBC mitigate DM and CM EMI noise of the PES while maintaining regulation even for the higher order nonminimum phase PES, while reducing sensor requirements using state observer derived from the switching model of the PES.