Electromagnetic Compatibility Laboratory Research Articles

On the electromagnetic shielding properties of carbon fiber materials

Introduction. Due to the good electrical and thermal properties of carbon, carbon-based materials represent a major trend is various applications, including electromagnetic compatibility. Among carbon-based materials, graphite-impregnated woven fabrics represent a new trend in the field of electromagnetic shielding, with the perspective of being used for protective clothing. The novelty of the proposed work consists in the exhaustive comparative analysis of various carbon-based sample shields by employing both simulation and experimental methods. The selected configurations included a simple graphite plate, a graphite powder strip network, and a graphite-impregnated fabric with 2´2 twill weave. Purpose. The main scope of the analysis is to prove the efficiency of the graphite-impregnated twill woven fabric in the field of electromagnetic shielding. Methods. Two main research methods were employed: simulation and experiment, both following the same protocol: the shield placed in the middle, with the excitation (transmitting antenna) on one side and the measurement / receiving antenna on the other. The experimental stage was thorough, being performed in two different laboratories and by applying the double transverse electromagnetic (TEM) cell method and the shielded box method. Results. A significant difference yielded from the comparison of the simulation and experimental results for the shielding effectiveness, probably due to the fact that the virtual model is an idealized version of the physical one, not taking into account its imperfections. The virtual analysis yielded the graphite plate shield as the most efficient, followed closely by the twill fabric. The graphite strip network had significantly poorer performance compared to the other two shields, probably due to the electrical contact imperfections between the graphite strips and the optical transparency of the shield. The main focus of the analysis was the twill woven graphite-impregnated fabric; therefore, its shielding effectiveness was determined through simulation and experiment. The experimental analysis was performed in two stages in two different electromagnetic compatibility laboratories, by employing the double TEM cell method and the shielded box method, respectively, both methods providing similar results and classifying the shielding performance as good. Practical value. The paper provides an accurate analysis of the graphite-impregnated 2´2 twill woven fabric in terms of electromagnetic shielding effectiveness, by employing both simulation and experimental methods, and comparing its performance to the one other graphite-based shields.

Simulation of the Immunity Test of a Photovoltaic System Disturbed by Electromagnetic Voltage Surge

This paper presents a computer simulation model (in the MATLAB/Simulink environment) of a photovoltaic system disturbed by a 1.2/50 µs voltage surge pulse, while operating as part of the fixed system of an intelligent building. The tested part of the system consisted of a single PV module and a single-phase DC/AC voltage source converter provided with a maximum power point tracking system. The simulation of the test performed in accordance with the IEC 61000-4-5 standard required the development of a model of a surge waveform generator and a model of a coupling/decoupling network. The 1.2/50 μs voltage surge pulse was introduced into the system from the power grid side. During the test significant changes in the value of the AC voltage and current were found in the DC/AC converter system. The results of the computer simulation tests were verified with measurements performed in an accredited electromagnetic compatibility laboratory using the instructions specified in IEC 61000-4-5. The MATLAB/Simulink environment was proved as a useful tool of the assessment of effects of conducted electromagnetic disturbances on electronic/electric devices.

Preface

It was a great pleasure to welcome all the participants from different countries to the 2020 3rd International Symposium on Power Electronics and Control Engineering (ISPECE 2020) was be held on November 26-28, 2020 in Chongqing, China. ISPECE 2020 is to bring together innovative academics and industrial experts in the field of Power Electronics and Control Engineering to a common forum. The primary goal of the conference is to promote research and developmental activities in Power Electronics and Control Engineering and another goal is to promote scientific information interchange between researchers, developers, engineers, students, and practitioners working all around the world. The conference will be held every year to make it an ideal platform for people to share views and experiences in Power Electronics and Control Engineering and related areas.The conference model was divided into two sessions, including oral presentations and keynote speeches. In the first part, some scholars, whose submissions were selected as the excellent papers, were given 15 minutes to perform their oral presentations one by one. Then in the second part, keynote speakers were each allocated 30-45 minutes to hold their speeches. In this conference, we were greatly honor to invited Prof. Yuanchang Zhong from Chongqing University, China to serve as our Conference Chairman. There were over 180 experts and scholars representing different famous universities and institutes around the globe to attend the conference.During the conference, we invited seven industry elites to present their insightful speeches. The first keynote speaker, Prof. Goh Hui Hwang, from Department of Electrical Engineering, Guangxi University, China. His technical interests and expertise include electrical engineering, power systems, renewable and sustainable energy, embedded power generation, wavelet analysis, load shedding, and data mining. Prof. Junhua Xiong, North China University of Water Resources and Electric Power, China, shared a speech: Control method for improving power quality of high-permeability photovoltaics connected to low-voltage distribution network. Her method has been applied to the project of Xuji Group Co., Ltd. in Australia, and the operation results show that the method has good effect on power quality improvement. The third keynote speakers, Assoc. Prof. GHAMGEEN IZAT RASHED, from Wuhan University-School of Electrical Engineering and Automation, China. His special research of interest in AI and its application to the power system, FACTS devices specially TCSC and its control. Prof. Long Li, School of Electronic Engineering, IEEE Senior Member. His main research directions include electromagnetic metamaterials and metasurfaces, new antennas and microwave circuits, electromagnetic compatibility, wireless power transfer and energy harvesting, and so on. Prof. Ke Jin, from Nanjing University of Aeronautics and Astronautic. His main research includes power electronic topology and control, power electronic system integration, wireless power transmission, etc. Prof. YinQuan Yu, from East China Jiaotong University. His research activities are design and analysis Smart Permanent Magnet Synchronous Motor (PMSM), Machine Health Monitoring and Fault Diagnosis, Mechatronics and Robotics, Shock Absorption and Noise Reduction of High-speed and Highprecision Equipment, Intelligent Manufacturing and Precision Machining. The finale keynote speaker, Prof. Long Xiao, from Electromagnetic Compatibility Laboratory at China Ship Development and Design Center. He was mainly engaged in the research of far-field high-power microwave wireless energy transmission technology.We are glad to share with you that we received lots of submissions from the conference and we selected a bunch of high-quality papers and compiled them into the proceedings after rigorously reviewed them. These papers feature following topics but are not limited to: Power Electronics, Control Engineering, Mechanical Engineering and other related topics. All the papers have been through rigorous review and process to meet the requirements of International publication standard.We are really grateful to the International/National advisory committee, keynote speakers, session chairs, organizing committee members, student volunteers and administrative assistance of the management section of University, including accounts section, digital media and publication house. Also, we are thankful to all the authors for contributing a large number of papers in the conference, because of which the conference became a story of success. It was the quality of their presentations and their passion to communicate with the other participants that really make this conference series a great success.The Organizing Committee of ISPECE 2020List of Committee member, Conference Chair, Organizing Committees Chairman, Organizing Committees are available in this pdf.

Effectiveness of Noise Suppressing Sheet Material for Mitigation of Automotive Radiated Emissions

Integrated circuit (IC) and printed circuit board (PCB) electromagnetic (EM) modeling methods are becoming essential during the development of automotive electronic control units. Academic and industrial efforts focus on radiated and conducted emissions caused by flaws in PCB design from EM compatibility (EMC)/electrostatic discharge (ESD) point of view, including improper placement, grounding, and shielding of ICs. In this article, the effectiveness of noise suppressing sheet material for the mitigation of radiated emission at global positioning system (GPS) and Global'naya Navigatsionnaya Sputnikovaya Sistema (GLONASS) bands according to U.S. automotive original equipment manufacturer (OEM) requirements is investigated. A few test scenarios that include the NSS material are explored to gauge its performance in near-, intermediate-, and far-field regions, using 3-D full-wave numerical simulations and EMC laboratory experiments.

Design and Research on Integrated Platform of EMC Laboratory

The electromagnetic compatibility (EMC) laboratory plans to implement a proprietary EMC testing platform, which is customized according to the professional perspective of EMC testing. The integrated platform will fully utilize the overall advantages of knowledge resources from various angles to realize the automatic operation of various functions. The simple and tedious work of the engineers during the inspection process will be completed automatically, reducing the burden and devoting more time to creative and high-value work. At the same time, the platform will integrate higher-level related management systems and all EMC testing equipment to achieve overall data interaction among the testing department, design department and higher-level management agencies during the EMC testing process.

5 GHz Band LTE-LAA Signal Selection for Use as the Unintended Signal in ANSI C63.27 Wireless Coexistence Testing.

This article details the experimental work conducted at the Electromagnetic Compatibility and Wireless Laboratory, U.S. Food and Drug Administration, to investigate the use of LAA signals for wireless coexistence testing. A software defined radio platform was deployed to generate realistic LAA signals and measure the wireless coexistence impact on the LAA communication link. The equipment under test (EUT) used IEEE 802.11ac as an example incumbent technology in the 5 GHz band. The standardized radiated anechoic chamber method was used for testing. Results highlight the mutual coexistence impact of LAA in the 5 GHz band and suggest that selecting an LAA signal with the maximum possible channel time occupancy and the highest possible modulation and coding scheme (MCS) yields the most impactful coexistence situation on both the EUT and the LAA system. Additionally, an analysis of the internal LAA system states during coexistence testing is presented to document the inverse relationship between LAA transmit and wait times during coexistence and the adverse impact of challenging coexistence scenarios on successful channel access. Finally, the risk management process of wireless coexistence for medical devices is summarized and associated with coexistence testing.

Design and development of harmonics and flicker generator (HFG) for electromagnetic compatibility (EMC) application

It is observed that the standards IEC 61000-3-2 and IEC 61000-3-3 do not discuss the calibration methods required to evaluate the performance of a Harmonics and Flicker emission test setup, used for Electromagnetic Compatibility (EMC) measurements. When the instrument does not have a direct standard procedure, reference data for comparison analysis is required to calibrate/verify any equipment or system. In particular, emission measurement systems in EMC laboratories necessarily require a reference source value to check the performance of the test system periodically. This necessitates the design and development of a Harmonics and Flicker Generator to not only identify a known repeatable Harmonics and Flicker value but also to find out the deviation of the test setup. The proposed Harmonics and Flicker Generator is intended to be used for the calibration of Harmonics and Flicker emission test setup and for Inter Laboratory Comparison analysis (ILC) to evaluate the performance capabilities of the EMC test laboratories. This paper discusses the Harmonics and Flicker generator design techniques, schematic circuit, functional description, performance analysis and results.

Evaluation of radiated immunity tests using adjusted pulse modulated signals

The main goals of an engineering test are reproducing a real scenario in a controlled environment and monitoring a device under validation when exposed to such condition. In this context, some recent studies have indicated misalignments between the waveforms suggested by the Radiated Immunity standards and the real telecommunication signals. Reproducing an actual signal in an electromagnetic compatibility laboratory might, however, be an expensive task, since it demands more sophisticated hardware. In this study, a simple solution for this problem is proposed based on adjustments applied to the standardised pulse modulated waveform. The objective is to develop an alternative to the traditional procedures, in an attempt to provide the manufacturers a more realistic test environment for their products. Mathematical manipulations indicate that a good agreement between the adjusted waveforms and a digital television signal cannot be simultaneously achieved in both time and frequency domains. Multiple trade-off solutions are then generated and analysed through electromagnetic simulations. Results show that, in the 210-216 MHz frequency range, the pulse modulated signals model the digital television interference capability better than the classical continuous wave does.

Wireless Coexistence Testing in the 5 GHz Band with LTE-LAA Signals.

Exploiting unlicensed spectrum bands for cellular communication is a rapidly embraced trend by industry stakeholders. Accordingly, the specifications of Long Term Evolution (LTE) were extended in Release 13 to allow unlicensed spectrum operation, also known as LTE-Licensed Assisted Access (LAA). LTE is widely adopted, and there is a potential for significant coexistence impact of LTE-LAA on users of unlicensed spectrum including wireless medical devices, whether adopters of the new technology or incumbents. Therefore, work was initiated to revise and update the American National Standards Institute (ANSI) C63.27 standard for evaluation of wireless coexistence. This paper details the experimental work conducted at the Electromagnetic Compatibility and Wireless Laboratory, U.S. Food and Drug Administration, to investigate the use of LAA signals for wireless coexistence testing. A software defined radio platform was deployed to generate realistic LAA signals and measure the wireless coexistence impact on the LAA communication link. The equipment under test (EUT) used IEEE 802.11ac as an example incumbent technology in the 5 GHz band. The standardized radiated anechoic chamber method was used for testing. Results highlight the mutual coexistence impact of LAA in the 5 GHz band and suggest that selecting an LAA signal with the maximum possible channel time occupancy and the highest possible modulation and coding scheme (MCS) yields the most impactful coexistence situation on both the EUT and the LAA system.

Electromagnetic Characteristics Measurement of Organic Material Absorber

Electro Magnetic Compatibility (EMC) Chamber requires high performance absorber material to assure the quality of EMC chamber related to Radio Frequency (RF) shielding effectiveness of the corresponding chamber. RF shielding effectiveness is measured following EN 50147-1 testing method. EMC laboratory of BPPT (Indonesian Agency for the Assessment and Application of Technology uses polyurethane absorber material which absorbs the carbon-neoprene mixture to maintain consistent RF performance over a broad frequency band, especially in the frequency range of CISPR 22 radiated emission test between 30 MHz to 6 GHz, limits in CISPR 22 (Information technology equipment-radio disturbance characteristics-limits and methods of measurement). This paper proposes alternative absorber materials based on organic materials: rice husk, coconut husk, cotton and sawn wood crumbs. In the early phase of this research, the frequency under consideration are 900 MHz and 1800 MHz. These frequencies are mostly used by mobile phone devices, therefore at this phase the resulted organic material absorber may be used for alternative mobile phone casing before to be used as absorber material for EMC laboratory in a broader frequency band. The organic materials are produced by mixing them with cement, carbon, and resin. Free space testing method is used in the measurements. Results has shown a mixture of 50% coconut husk with resin absorb the most radiated emission in 900 MHz, while 30% of coconut husk will absorb the most radiated emission in 1800 MHz.

Proficiency Testing in EMC Radiated Immunity

Electromagnetic compatibility (EMC) testing is a complex activity that requires adequate infrastructure, skilled personal, and correct working procedures. One of the most efficient ways to validate the testing capabilities of a laboratory is the proficiency testing or interlaboratory comparison. In contrast to proficiency testing in EMC emission, which can be realized, for example, by using a comb generator with an antenna as test object, proficiency testing in EMC immunity is not very common today, mainly because there is no device that is specially designed for this purpose. In this contribution, we present a proficiency testing performed with a device that is specially developed to assess the field immunity testing capabilities of EMC laboratories according to IEC 61000-4-3. We also propose a method for the evaluation of this comparison. Improvements for the next implementations are finally discussed.

Electromagnetic radiation and behavioural response of ticks: an experimental test

Factors associated with the increased usage of electronic devices, wireless technologies and mobile phones nowadays are present in increasing amounts in our environment. All living organisms are constantly affected by electromagnetic radiation which causes serious environmental pollution. The distribution and density of ticks in natural habitats is influenced by a complex of abiotic and biotic factors. Exposure to radio-frequency electromagnetic field (RF-EMF) constitutes a potential cause altering the presence and distribution of ticks in the environment. Our main objective was to determine the affinity of Dermacentor reticulatus ticks towards RF-EMF exposure. Originally designed and constructed radiation-shielded tube (RST) test was used to test the affinity of ticks under controlled laboratory conditions. All test were performed in an electromagnetic compatibility laboratory in an anechoic chamber. Ticks were irradiated using a Double-Ridged Waveguide Horn Antenna to RF-EMF at 900 and 5000MHz, 0MHz was used as control. The RF-EMF exposure to 900MHz induced a higher concentration of ticks on irradiated arm of RST as opposed to the RF-EMF at 5000MHz, which caused an escape of ticks to the shielded arm. This study represents the first experimental evidence of RF-EMF preference in D. reticulatus. The projection of obtained results to the natural environment could help assess the risk of tick borne diseases and could be a tool of preventive medicine.

Electromagnetic compatibility of PLC adapters for in-home/domestic networks

Abstract The use of programable logic controllers (PLC) technology in electrical networks 230 V causes electromagnetic radiation that interferes with other electrical equipment connected to the network [1–4]. Therefore, this article describes the issues of electromagnetic compatibility (EMC) of new PLC adapters used in IP broadband services in a multi-user environment. The measurements of disturbing electromagnetic field originated in PLC adapters were made in a certified laboratory EMC (laboratory of electromagnetic compatibility) in the Institute of Electrical Engineering at Faculty of Electrical Engineering and Information Technology of the Slovak University of Technology in Bratislava. The measured spectra of the radiated electromagnetic field will be compared with the results obtained when testing older PLC modems [5].

Immunity test of the lighting installation for electromagnetic surge disturbances

The paper presents the results of computer simulation of the operation of a lighting installation disturbed by a voltage surge of 1.2 / 50 μs. The components included in the model of the system were: voltage surge generator (accordance with the PN-EN 61000-4-5 Standard), coupling - decoupling system, over-current circuit breaker, iluminance level controller and incandescent lamp. The results of simulation tests with the results of tests carried out in an accredited electromagnetic compatibility laboratory were compared.

An alternative method for conducting immunity tests in the industrial environment

For studying the electromagnetic compatibility (EMC) of any device, measuring the devices' immunity is very important. At present, most of the standards relating to immunity are designed for laboratories, and the immunity tests are always conducted by using coupling-decoupling networks (CDN) in laboratories, in accordance with the standard EN61000-4-6. However, these methods are not always feasible because of some limitations. If the equipment under test (EUT) has large dimensions or high currents, as in the case of most of the industrial equipment, it is not possible to send it to the EMC laboratory or to use CDNs for testing. To overcome this problem, an alternative method is proposed for conducting immunity tests in the industrial environment. In this paper, the test methods for the laboratory and for the industrial environment, the former with CDNs and the latter with current probes, are described first. From these tests, correction factors (CF) are extracted, based on the analysis of the loop impedances in the laboratory and the injected loop currents in the industrial environment. Finally, a link is established between the laboratory and the industrial environment, and then, the equalization between the two is realized by using these correction factors.

Ticks and radio-frequency signals: behavioural response of ticks (Dermacentor reticulatus) in a 900 MHz electromagnetic field

The electromagnetic field (EMF) is present in the environment throughout the world and encompasses both natural and human-made sources of electromagnetic fields. It has been shown that EMF influences a variety of biological systems, including the behavioural responses of both vertebrates and invertebrates. As such, determining the effects of the EMF on the ecosystem in detail may be important for understanding the ecology and biology of organisms, particularly those, such as ticks, that are important in disease transmission. Our main goal was to determine if the tick, Dermacentor reticulatus, interacts with the EMF. An experimental behavioural test of tick sensitivity to radio frequency power radiation was performed under laboratory conditions. Tests were performed in an electromagnetic compatibility laboratory in a radio frequency electromagnetic field (RF-EMF) anechoic chamber. Ticks were irradiated using a Double-Ridged Waveguide Horn Antenna with 900 MHz RF-EMF. The applied radio-frequency power was tuned below the proposed limit for public exposure to mobile phone base stations. We found that exposure induces an immediate tick locomotor response manifested either in a previously unreported jerking movement of the whole body or in jerking of the first pair of legs. Overall, ticks exhibited significantly greater movement in the presence of the RF-EMF. Significant sex differences relative to RF-EMF exposure were observed in both response variables. In the presence of RF-EMF, body jerking by females was greater than in males and vice versa for leg jerks. This study represents the first experimental evidence of a behavioural response of D. reticulatus ticks to exposure to RF-EMF.

Guest Editorial

Guest Editorial

Shielded Design of Screen-Printed EEG Electrode Set Reduces Interference Pick-Up

Thick-film technologies, such as screen printing, are becoming more popular in the manufacturing of bioelectrodes due to their simplicity, low cost, high reproducibility, and efficiency in large-scale production. Since electroencephalography (EEG) is a method for measuring potential differences in the microvolt scale, it is important to minimize all electromagnetic interferences. However, protecting screen-printed electrodes and their conduction traces from electromagnetic interferences has not been adequately investigated. We hypothesized that interference pick-up could be effectively reduced by an optimized silver or graphite shielded construction. The interference pick-up of the electrodes was technically evaluated in an electromagnetic compatibility laboratory and with EEG recordings of healthy volunteers. The grounding layer significantly (p<; 0.001) reduced radio frequency (RF) interference in the standardized laboratory tests and the shielded electrodes exhibited significantly better power-line interference immunity in the EEG recordings (p<; 0.05). The silver layer achieved better shielding in the RF tests than the graphite layer (p= 0.029). Since the silver layer is straightforward and cheap to produce with the screen printing technique, it could be advantageously used to shield, e.g., in emergency rooms where many interfering electronic devices are close to patient.

Quantitative Evaluation of Laboratory Testing Capability

In view of the differences and errors existed between traditional EMC(electromagnetic compatibility) laboratory and standard laboratory, we introduce the concept of laboratory proficiency testing, and presents the evaluation parameter related to laboratory proficiency testing, such as, correlation coefficient, peak retention rate, connection degree, finally comprehensive similar reached for the laboratory testing capability. We also verified the evaluation parameters proposed in this paper.

Electromagnetic Field Coupling to a Thin Wire Located Symmetrically Inside a Rectangular Enclosure

This paper calculates the current in a conductor inside a cavity, which is induced by lumped and distributed sources. The current is obtained both analytically (Green's function method) and numerically (multilevel fast multipole method). A long parallel wire is chosen that connects two opposite walls of a rectangular resonator. Since the conductor preserves the translational symmetry of the resonator in one principal direction, the current and the total exciting electrical field can be derived from spatial Fourier series formulations. The obtained results clearly show the influence of the walls on the induced current. Resonance peaks of the resonator, which do not arise in normal electromagnetic compatibility laboratory tests, occurred in the current spectra. The numerical results agree very well with the analytical ones; however, the results are obtained much faster using the analytical formulae (by a factor of 1000).