Field Of Electromagnetic Compatibility Research Articles

Параметрическая оптимизация асимметричных многопроводных линий передачи с учетом комбинационных импульсов

Transmission lines are significant elements and play an important role in determining the performance, reliability and functionality of radio electronics. A number of factors appearing in the use of transmission lines can lead to problems in the field of electromagnetic compatibility. One such factor is the appearance of asymmetry due to inhomogeneities, PCB manufacturing errors, dense tracing, mismatch, etc. The paper considers the effect of asymmetry on the characteristics of transmission lines with inhomogeneous dielectric filling. It is found that asymmetry of cross section and/or boundary conditions leads to the appearance of combinational pulses. Combination pulses are of interest because their arrival times do not correspond to the per-unit-length delays of the modes propagating in the transmission lines, but consist of their combinations. Their level may be comparable to the level of information signals, which may result in distortion or loss of useful information. Meanwhile, asymmetry and the resulting combinational pulses represent a new resource for improving the performance of devices based on transmission lines, which can be used to protect radio electronics from electromagnetic interference of picosecond and nanosecond duration. For the first time the optimization of parameters taking into account combinational pulses is carried out on the example of three diagrams of symmetric multiconductor transmission lines with asymmetry of termination loads: reflection symmetric and with a reference conductor in the form of side polygons. Using the genetic algorithm, the optimal parameters are obtained, which allow to reduce the value of the maximum amplitude by 1.5 times, as well as the parameters allowing to increase in 2 times the minimum value of the time interval between the decomposition pulses, on which depends the possibility of complete decomposition of the interference pulse, compared to the value obtained in the initial diagram with optimized parameters, where there are no combinational pulses at the same device dimensions. The optimization results demonstrate the efficiency of using the resource of combinational pulses to improve protective structures based on transmission lines with inhomogeneous dielectric filling.

Common mode far field radiation mechanisms and prediction of a buck converter with cables based on common mode voltage mutation method

AbstractIn the field of electromagnetic compatibility (EMC) research, the knowledge of the formation mechanism of the far field electromagnetic radiation and its prediction is essential for the electromagnetic noise suppression design of a switched mode power supply. This paper investigates the equivalent driving sources of the common mode (CM) current of a Buck converter with cables. Based on the concept of CM voltage mutation, this paper proposes two mechanism models of the same‐direction CM voltage driving mode and the opposite‐direction CM voltage driving mode and derives the approximate analytical formulas for the far field intensity estimation of the horizontal cables. To evaluate the predictive effectiveness of the CM far field radiation model, a 30 MHz very high frequency (VHF) Buck prototype with shielded cables is built and tested, and a shielding shell and low impedance ground conductor suppression designs are then verified. The CM electromagnetic radiation mechanisms of a non‐isolated power converter are demonstrated here. The proposed electromagnetic radiation models, approximate analytical formulas, and improvement design can help to advance the CM radiation analysis and optimization design.

Trends and Activities of Research in the Field of Electromagnetic Compatibility

Trends and Activities of Research in the Field of Electromagnetic Compatibility

Failure Mechanism Analysis of the Stochastic Galerkin Method in EMC Simulation Considering Geometric Randomness

By virtue of its high calculational accuracy and efficiency, the stochastic Galerkin method (SGM) has been successfully applied many times in electromagnetic compatibility (EMC) simulation in recent years. This paper proposes a calculating example taking geometric uncertainty factors into consideration. As is proved in the paper, there is a relatively large error when using the SGM to solve the example mentioned above. According to failure mechanism, the fundamental reason of the failure of the simulation lies in the additional error caused by using numerical integration to solve the inner product formula. Meanwhile, it is proved that no additional errors are introduced when using the stochastic collocation method (SCM), so the SCM is better than the SGM in stability. In the end, the paper revised the general selective strategy for uncertainty analysis methods, thus providing theoretical basis for their universal application in EMC field.

Application of the FSV Method in EMC Uncertainty Simulation Results

The uncertainty analysis method has been a research hotspot in the electromagnetic compatibility field in recent years, and its results are presented in the form of a probability density curve. Currently, there is no reasonable method to evaluate the validity of uncertain results. It is not conducive to the improvement and popularization of new uncertainty analysis methods or models. Feature selective validation method is a mature validity evaluation method for deterministic electromagnetic simulation results, and this paper extends it to electromagnetic compatibility uncertainty simulation results. On this basis, the convergence determination of the partial uncertainty analysis method is realized. The purpose is to further promote the application of the uncertainty analysis method in the electromagnetic compatibility field.

Facile fabrication of biomass chitosan-derived magnetic carbon aerogels as multifunctional and high-efficiency electromagnetic wave absorption materials

Biomass chitosan-derived porous carbon-based materials take the advantage of light weight, adjustable intrinsic conductivity, and environmental friendliness, attracting more attention in the field of electromagnetic compatibility. However, exploring a facile fabrication method to achieve rational structure design and electrical-magnetic coupling for electromagnetic absorption performance enhancement still remains challenging. Here, a unique honeycomb-like porous cobalt/carbon aerogel is fabricated through the directional freezing-drying and carbonization process, and abundant and even-distributed cobalt particles in-situ grow on the carbon skeletons. The aerogel exhibits an impressive electromagnetic wave absorption performance of a −75.8-dB absorption intensity and a −256.9-dB mm−1 specific reflection loss at a low filling content (10%), as well as an 8.53-GHz effective absorption bandwidth. Besides, the aerogel also demonstrates classy radar stealth and thermal insulation performance. The eco-friendly, easily fabricated, and high-performance cobalt/carbon aerogel suggests broad application prospects for electromagnetic compatibility and protection, thermal management, and multifarious electron devices.

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.

Enhanced the Efficiency of Electronics Circuit by using Line Impedance Stabilization Network

A Line Impedance Stabilization Network (LISN) is a crucial tool in the field of electromagnetic compatibility (EMC) testing and measurement. Its primary purpose is to ensure that conducted emissions from electrical and electronic devices are accurately measured in a controlled and standardized manner. After both circuit simulation in LTSpice firstly input noise simulation without LISN in first circuit and after that second circuit simulation in which we simulate input noise simulation with LISN we reached on the final conclusion is that by stabilizing the impedance of the power supply line, LISNs help filter out external interference and noise, allowing for precise measurements of the emissions generated by the DUT. They provide a standardized impedance interface between the device under test (DUT) and the measuring equipment, ensuring consistent and repeatable EMC testing results. We get desired result after simulation when we analysis both circuit simulation in details we get 33% improvement in frequency, noise decreases in terms of frequency and we get 3% improvement in power at output in LISN applying circuit.

Electromagnetic interference shielding performance of Ag/multi-walled carbon nanotubes-poly(methyl methacrylate) composites

An efficient strategy for synthesizing Ag/multi-walled carbon nanotubes-poly(methyl methacrylate) (Ag/MWCNT-PMMA) composites has been proposed. The synthesis concept is based on the modification of oxidized MWCNT with Ag nanoparticles and subsequent distribution of the obtained Ag/MWCNT-Ox hybrids in a PMMA matrix. Herein, Ag/MWCNT-Ox hybrids with various size and content of Ag nanoparticles serve as a tool for tuning the electrical conductivity of the two series of Ag/MWCNT-PMMA composites with MWCNT-Ox content before (4 wt%) and after (10 wt%) the percolation threshold. Adding 0.2 wt% of Ag to the first composite series with nanotubes content of 4 wt% leads to a decrease in the percolation threshold in a three-component system. In the case of the second composite series, the introduction of Ag up to 1 wt% leads to a monotonic increase in the conductivity within one order of magnitude. Ag/MWCNT-PMMA demonstrates high shielding efficiency for incident radiation in the frequency range of 26–37 GHz, most of which is absorbed due to the conductive nature of the material. The improved electromagnetic properties of the Ag/MWCNT-PMMA composites are explained by the uniform distribution of fillers in the polymer, which ensures the formation of a 3D conducting network inside the composite, and by the synergistic interaction between MWCNT and Ag. Thus, Ag/MWCNT-PMMA composites have broad application prospects in the field of electromagnetic compatibility.

Alternative Approach Leading to Reduction in Measurement Instrument Uncertainty of EMI Measurement

Abstract Even in the field of electromagnetic compatibility, low measurement uncertainty means high measurement quality. Although there are standardized procedures for obtaining the uncertainty of such a measurement, which facilitate uncertainty estimation, modern approaches show further reduction possibilities. The paper presents an alternative approach to reducing measurement instrument uncertainty in the case of electromagnetic interference measurement based on many years of our experience and a large number of measurements in this field. In the paper, two different methods of uncertainty reduction are described. The first method is based on a detailed analysis of the sources of uncertainty and the subsequent division of the analyzed frequency band into more subranges. Another method uses the choice of the antenna factor, which also contains information about the test site where the measurement is carried out. In this way, despite a lengthy analysis, it is relatively easy to achieve a measurement instrument uncertainty that is below the maximum measurement uncertainty given by the CISPR standard.

Multi-Scale Design of Ultra-Broadband Microwave Metamaterial Absorber Based on Hollow Carbon/MXene/Mo2 C Microtube.

Developing various nanocomposite microwave absorbers is a crucial means to address the issue of electromagnetic pollution, but remains a challenge in satisfying broadband absorption at low thickness with dielectric loss materials. Herein, an ultra-broadband microwave metamaterial absorber (MMA) based on hollow carbon/MXene/Mo2 C (HCMM) is fabricated by a multi-scale design strategy. The microscopic 1D hierarchical microtube structure of HCMM contributes to break through the limit of thickness, exhibiting a strong reflection loss of -66.30dB (99.99997 wave absorption) at the thinnest matching thickness of 1.0mm. Meanwhile, the strongest reflection loss of -87.28dB is reached at 1.4mm, superior to most MXene-based and Mo2 C-based microwave absorbers. Then, the macroscopic 3D structural metasurface based on the HCMM is simulated, optimized, and finally manufactured. The as-prepared flexible HCMM-based MMA realizes an ultra-broadband effective absorption in the range of 3.7-40.0GHz at a thickness of 5.0mm, revealing its potential for practical application in the electromagnetic compatibility field.

Trends and Activities of Researches in the Field of Electromagnetic Compatibility

Trends and Activities of Researches in the Field of Electromagnetic Compatibility

Lightweight Chain-Typed Magnetic Fe3O4@rGO Composites with Enhanced Microwave-Absorption Properties.

A lightweight microwave-absorbing material with a strong electromagnetic-absorption capability of practical significance in the field of electromagnetic compatibility was obtained by adjusting the ratio of Fe3O4 and rGO. A nanoparticle material with a chain-typed structure consisting of a combination of Fe3O4 and rGO was produced by a hydrothermal method under an applied magnetic field. The electromagnetic loss property of the Fe3O4@rGO composites is studied in the frequency range from 2 to 18 GHz. In addition, the reflection loss and the mechanism of microwave absorption are explored. By changing the amounts of rGO, the electromagnetic loss of the Fe3O4@rGO composites can be effectively regulated, which obtain better reflection loss. The minimum reflection loss of the Fe3O4@rGO composites is −49.4 dB at 16.2 GHz only with a thickness of 1.75 mm. Thus, the Fe3O4@rGO composites have an extremely thin thickness and a strong electromagnetic wave absorption capacity, which is a candidate for the development of lightweight magnetic absorbing materials.

Evaluation of the Effectiveness of Ferrite Characteristics Measurements Based on the CISPR 17 Standard

The requirements for limiting electromagnetic disturbances result in the need to use appropriately selected elements that suppress the disturbances in question. Therefore, detailed studies of the attenuation efficiency at the design stage should be carried out. The above approach is to ensure adaptation to the current requirements in the field of electromagnetic compatibility. Ferrite cores are the least expensive way to reduce the cost of electromagnetic interference suppression. The structure of ferrite cores is usually mixed, and the nomenclature used by manufacturers is varied. Also, the lack of detailed data on the parameters of the ferrite core may lead to incorrect design assumptions, which results with increased in design costs. Therefore, this article presents in detail the method of assessing the attenuation characteristics of ferrite depending on its parameters, based on the example of specific ferrites. Also, this article shows a methodology for defining the attenuation performance characteristics of selected ferrite cores based on experimental studies. The above-mentioned studies can be helpful by refinement of the CISPR 17 standard. The results presented in this article will indicate the possible range of impedance for the application of the analyzed methods for the evaluation of ferrite damping properties based on CISPR 17.

Application of the Multi-element Grid in EMC Uncertainty Simulation

Uncertainty analysis is a research hotspot in the field of electromagnetic compatibility (EMC) simulation. The stochastic collocation method (SCM) is considered particularly suitable for uncertainty analysis in the EMC field because it is characterized by a high level of computational efficiency and accuracy while requiring no replacement solver. However, the post-processing process of the SCM is too complex, which will seriously limit its application in many industrial environments such as real-time simulation analysis. Multi-element grid (MEG) is a novel uncertainty analysis method recently for successful application in another area. It is proved that its calculation accuracy is same as the SCM, and its post-processing process is facile. This paper introduces the MEG to the EMC field and makes a detailed comparison between it and the SCM in performance, aiming to apply uncertainty analysis to solve more practical EMC engineering problems.

Design of a lattice dielectric cylinder based on multiwalled carbon nanotube-epoxy composite for microwave absorption in the X-band

To meet the urgent electromagnetic compatibility (EMC) requirements for the electronic products, microwave absorbers with a lattice of the dielectric cylinder were investigated. The elements of the lattice have a cylindrical shape and are composites of epoxy resin filled with multi-walled carbon nanotubes (MWCNTs-EP). The relative complex permittivity of the MWCNT-EP was obtained from the S-parameters measured by the transmission-reflection method with X-band waveguide. The numerical simulation results show that the reflection coefficient of the uniform lattice of the dielectric cylinder is less than −10 dB in the entire X-band (8 GHz–12 GHz) and the reflection coefficient of the hybrid lattice of the dielectric cylinder (HLDC) is less than −15 dB in the same band. Moreover, the reflection coefficient of HLDC is less than −20 dB at normal incidence in the frequency range of 8.4 GHz–11.3 GHz. Further investigation demonstrates that the proposed HLDC could maintain good absorption performance under different incident angles and polarizations. This study suggests that HLDC with the characteristics of lightweight, excellent absorption performance, good angle, and polarization stability provide a promising prospect in the EMC field.

Data Processing Mechanism and Algorithm Optimization for Radiated Emission Measurement of Electronic and Electrical Equipment

Radiated emission is one of the most important measurement items in the field of electromagnetic compatibility. The measured value of field strength often deviates from the real value to a certain extent. According to the characteristics of typical log-periodic dipole array antenna, the relation between antenna resonance unit and frequency, as well as the position relation between phase center and calibration reference point, the calculation formula of field strength correction factor is derived. The correction factor of field strength in the 30MHz-1GHz is also calculated precisely. The data processing mechanism of radiated emission measurement is clarified. An optimization algorithm for the measurement of radiated emission is obtained eventually. After the test value is optimized by the correction factor, more accurate field strength can be obtained. The optimization interval is within (-0.348, 2.741) dB. As a data processing mechanism of the radiated disturbance, it can not only improve the accuracy of measurement, but also reduce the uncertainty and error.

Trends and Activities of Researches in the Field of Electromagnetic Compatibility

Trends and Activities of Researches in the Field of Electromagnetic Compatibility

Prediction method of Ultra-wideband electromagnetic pulse coupling in slotted cavity

With the develofpment of UWB electromagnetic pulse radiation systems, people are paying more and more attention to its serious threat to electronic equipment. The effect of UWB electromagnetic pulse has also become an important content in the field of electromagnetic compatibility. In an UWB radiation system, the distance between the device under test and the transmitting antenna is different, and the radiation field received is also different. Therefore, in actual tests, the test body is often placed at different distances from the antenna to perform multiple measurements to obtain test data as required. Based on this, this article takes the cavity as an example, and proposes a method of using the system transfer function to predict the response of the impulse field inside the cavity to simplify the test and quickly obtain the test data. Firstly, the impulse field response of a certain point with and without a cavity is measured respectively, and then the time domain response is inversely Fourier transformed to obtain the frequency domain transfer function of the test body. Finally, using the transfer function to convolute with the field to be measured, the response of the impulse field inside the cavity can be predicted under the condition of the field to be measured. It is verified by experiments that this method can better predict the response of the impulse field inside the cavity under different distance conditions, and has the characteristics of simple calculation and good prediction effect. At the same time, the transfer function obtained by this method can be used to predict the arbitrary impulse field response of the cavity in its frequency range.

Спектральний аналіз стуму живлення rl-навантаження з регулятором напруги на базі широтно-імпульсного перетворювача

Pulse-width voltage regulators are gaining increasing use in industry, especially in variable speed drives. At the same time, little research has been done in the field of electromagnetic compatibility (spectral composition of current consumption). The aim of the study is to determine, using computer simulation, the nonsinusoidality of the current consumption with an RL-load from a voltage regulator based on a pulse-width conversion. The study of the spectral composition of the supply current of an active-inductive load with a pulse-width voltage regulator was carried out using the provisions of the theory of electrical circuits of sinusoidal and non-sinusoidal periodic current using computer simulation. To analyze the spectral composition of the supply current of the RL-load with the selected voltage regulator, a simulation computer model was created, which consisted of a three-phase power supply and an RL-load, a rectifier with a transistor switch. The regulation of the applied voltage to the consumer was carried out according to the principle of a pulse-width voltage converter. As a result of studying a model of a regulated power supply based on a pulse-width converter and working on an active-inductive load, it was found that even with an initial voltage of the fundamental harmonic regulator of 34 V, the nonsinusoidality of the consumption current is 0.19%, which corresponds to the quality standard for electricity. It is advisable to use this regulator for a controlled electric drive of ventilation systems with an increased slip motor, for example, in "Climate-4M" units. Key words: semiconductor voltage converter, pulse-width converter, higher harmonics, RL-load