Electromagnetic Compatibility Technology Research Articles

RF Circuit EMI Suppression and EMC Analysis

The radio frequency circuit will generate strong electromagnetic interference in the process of signal transmission, and its own resistance to electromagnetic interference is weak, and the radio frequency circuits operating in the same electromagnetic environment are prone to mutual interference. Therefore, it is necessary to analyze the electromagnetic interference effect of radio frequency circuits, and then find effective suppression measures, build a good public electromagnetic environment, realize electromagnetic compatibility, and ensure the reliability of signal transmission. This research first briefly introduces electromagnetic interference and electromagnetic compatibility and then analyzes the key points of electromagnetic interference suppression in radio frequency circuits. On this basis, the specific application of electromagnetic interference suppression and electromagnetic compatibility technology of radio frequency circuit is discussed. It can serve as a guide for the design of the radio frequency circuit by analyzing the characteristics and suppression mechanism of the electromagnetic interference of the radio frequency circuit. To ensure the suppression impact of electromagnetic interference, various suppression measures are broadly implemented in accordance with the three components of electromagnetic interference. The electromagnetic compatibility-based design of RF circuits can reduce the mutual interference of RF circuits in the system and guarantee the stability and dependability of signal transmission.

Multilayered Graphene-Assisted Broadband Scattering Suppression through an Ultrathin and Ultralight Metasurface

Here, we present an ultralight multilayered graphene-based metasurface for suppressing specular reflection. With the help of a joint optimization method, dual low-reflection mechanisms including absorption and random diffusion are realized within the same structure, resulting in a remarkable decrease in the backward reflected energy in an ultrabroadband range of 7.5 to 43 GHz (a relative bandwidth of 140.6%). Experiments demonstrate that our design with a thickness of approximately 3.27 mm can maintain excellent antireflection performance over a wide angle range of 0 to 45° for both TE and TM waves. Additionally, as a result of adopting low-density substrates (polyethylene terephthalate and polymethylacrylimide foam) and multilayered graphene films, the proposed metasurface shows the advantage of ultralight weight, thus opening an avenue for a number of engineering applications such as electromagnetic shielding, information security, and electromagnetic compatibility technology. In addition, owing to the natural characteristics (corrosion resistance, bending resistance, etc.) of multilayered graphene films, the proposed metasurface shows enormous potential in some particular application scenarios with harsh conditions.

Exploration of Training Mode for EMC Technicians in Beijing Tianjin Hebei Region

Through analyzing the electromagnetic compatibility technology development level in colleges and universities, research institutes of special industry at Beijing, Tianjin and Hebei region are summarized. Combined with the joint construction by Hebei, Tianjin and Ministry of Education and first-class university building for Hebei University of Technology in Hebei province, A-list subject construction of Electronic Science and technology target is proposed. At the same time in development of an opening electromagnetic environment and electromagnetic compatibility research platform, teaching mode of practical personnel in the field of electromagnetic compatibility is explored. Through Innovation by Production, scientific research and teaching cooperation, EMC testing technical level of undergraduate is improved, EMC design rectification level of graduate is enhanced, and technical reserve and EMC talents are prepared to support the development of the industry of EMC in Beijing, Tianjin and Hebei region.

Design and Application of Insulator Detection Robot System for UHVDC Transmission Line

In recent years, with the vigorous construction of the ultra-high voltage grid, the line operating voltage level has become higher and higher. In order to ensure the safe operation of the transmission line, the line insulator string has a length of several tens of meters, and traditional manual testing has been unable to meet the requirements. With the continuous maturity of wireless communication technology, electromagnetic compatibility technology, sensor technology and other comprehensive technologies, it is necessary to develop an insulator string detection robot to replace artificial insulator detection work on UHV transmission lines. By means of wireless sensor communication technology, electromagnetic compatibility technology, video image technology and many other technologies, the insulator detection robot designed in this paper has realized automatic detection of zero resistance value of insulator of UHV transmission line. In addition, the real-time monitoring of insulator resistance value can be carried out through wireless communication to achieve the purpose of timely alarm. In addition, the robot's motion status and the insulator's field status can be observed in real time through video image acquisition. The insulator detection robot designed in this paper realizes the automatic detection of the zero value of insulator of the UHV DC transmission line. It can adapt to the UHV AC DC transmission line with different voltage levels by changing the length of the climbing arm, and at the same time adapt to the climbing detection of the string insulator of tension tower and the vertical insulator of the straight tower. The problem that the insulator string of the UHVDC transmission line can not be automatically detected by electric charge has been solved. It greatly improves the efficiency of insulator detection and the automation level of power transportation maintenance, reduces the cost of human transportation, and creates higher economic and social benefits.

Broadband microwave absorption utilizing water-based metamaterial structures.

In this paper, broadband microwave absorbers utilizing water-based metamaterial structure elements have been proposed and investigated. We employ water into the metamaterial structure unit-cell of the absorber as primary resonant elements such as the water-droplet, or water-tube structure. By investigating the resonant modes and the coupling between the water elements and the surrounding dielectrics, it is found the inherent multi-resonance of the proposed metamaterial structures could result in a broadband microwave absorption. For water-droplets design, 90% microwave absorption has been achieved from 7.5 GHz to 15 GHz, while for water-tube design, a much broader bandwidth from 5 GHz to 15 GHz is obtained for nearly 90% microwave absorption. The broadband absorption performance has been verified by both full wave simulation and experimental measurement. We believe the proposed broadband water-based absorber may find some applications in microwave stealth and electromagnetic compatibility technology.

On the interference characteristics of fully steerable radio telescope

Fully steerable radio telescope is a complex system including actuators, antenna high power driving subsystem, high sensitive receiving terminal, data transmission and control subsystem. Because of the great difference in electrical level between strong electricity subsystem and weak electricity subsystem, the very weak celestial RF signals which need to be received will be interfered by the interactive electromagnetic interferences which exist in the system, the electromagnetic emission signals generated by devices in operation and the different electromagnetic signals of environment. The electromagnetic compatibility (EMC) of radio telescopes has become the key technology of the development of and the usage of systems. In this paper, the research progresses of EMC technology of the radio telescope are summarized. From the view of system engineering, the electromagnetic interference characteristics of radio telescope system are studied, the critical control factors are determined, and an interference coupling matrix is established. Based on the electromagnetic topology theory, the EMC modeling approach to radio telescope system is presented, which provides the theoretical bases for the EMC technology researches in radio telescopes.

Prediction Model of Power Frequency Electric Field Intensity of Typical Transmission Line

The power frequency electric field and Electric radiation generated by high voltage transmission line have a great impact on the surrounding environment, which is one of the important research topic on environmental protection and electromagnetic compatibility technology field. In this paper, the information database of typical transmission line and tower established,and the prediction of power frequency electric field intensity of high voltage transmission line has been given by using the 3-D computational method.Then, the major factors affecting the calculation results of electric field is discussed based on the measured data and the error analysis is given.

Research and Design Embedded Security Computer Based on TMR for Train-Ground Communication System

Train-Ground communication system is mainly used to complete the communication between the train and the ground, the data which is produced by security computer system is vital to safe operation. The paper focus on the reliability and security technologies of embedded computer system and evaluates the reliability of TMR (Triple Modular Redundancy), which is based on the existing research of security computer and aimed on the equipment of CBTC Train-Ground communication system. The technology of CBTC Train-Ground communication is studied and the structure of the TMR for Train-Ground communication system is designed in the paper. Furthermore, the fault - safety circuits，electromagnetic compatibility technology and rail traffic-related safety standards are analyzed. Finally, the Train-Ground infrared communication security transponder system based TMR is applied to Shanghai People's Square Line 8 subway train’s double-door control system.

Research Status of Several Key Technologies for the Development of Electric Vehicles

Nowadays while the environmental protection consciousness of the people are constantly strengthening, the development and application of energy efficient vehicles, especially electric vehicles, have attracted the attention of governments and car manufacturers. Several classification approaches for electric vehicles are introduced in this paper, and the electric vehicle-related industry development goals for the next ten years in China are briefly described. Then introduced is the research status of some key technologies in the development of electric vehicles, including the battery technology, motor technology, electronic control technology and electromagnetic compatibility technology.

Research and Application of Electromagnetic Compatibility Technology

Although still in its primary phase up to now, the research about EMC science and its technological application in modern industries has become more and more noticeable. In this paper the main subjects for EMC research are introduced, then discussed briefly are some hot research topics concerning the application of EMC technology, as in such areas as military field, industrial electronics or microelectronics, power industry, onboard or airborne electronics, communications, home appliances and lighting equipments. Then the topic of complex electromagnetic environment concerning modern informationalized battlefield is emphatically addressed. At last several outstanding problems in the development of electromagnetic compatibility technology are introduced concisely.

A Technical Trend Seen in the Latest International EMC Symposia

Based on the survey of the papers and their topics presented at the latest international symposia on electromagnetic compatibility (EMC), a technical trend on EMC technology was described. The major trends include printed circuit board and integrated circuit related EMC problems, numerical modeling, statistical measurement and design, and human exposure, which should be selected as significant topics at the coming EMC international symposia.

A Globalized Trend Towards EMC Technology

The concept of electromagnetic environment and electromagnetic compatibility (EMC) is briefly described. A globalized trend in the 21th century EMC technology is reviewed from the following point of view : EMI (electromagnetic interference) reduction, immunity improvement, human safety evaluation of elecrtomagnetic fields and standardization of EMC measurement.