Design And Research Of RFID Antennas For Coal Mine Monitoring Systems

With the constant development of wireless communication, RFID technology has been widely used in all kinds of specific application areas. Currently, all kinds of coal mine accidents have occurred. Due to the unique environment and the continuous accident of the mine, there is a major problem that plagued the people about the safety production, managing and rescuing miners under the mine. Therefore, to research a new type of RFID system for coal mine is very important so as to keep an accurate record of the number of miners, to protect the safety of miners and to ensure the rescue measures to be carried out successfully. As a vital and integral part of the system, RFID antennas have attracted much attention, and the design is very urgent and significant. In fact, the development of RFID antennas is of theoretical significance and practical value to the RFID system.Firstly, a brief introduction to the RFID technology is given, the operating principle of RFID system and the hotspot of research are described, and meanwhile the technical specifications and investigating status of antenna in RFID system are analyzed and discussed. And then, according to the environment of the underground coal mine and the working characteristics of RFID system, suitable fractal structures are chosen for designing the tag and the reader antennas. Finally, the simulations, optimizations, fabrications and experimental measurements of the RFID antennas are done. The author's contributions in this thesis include following aspects.1. According to the analysis and research of the attenuation of the electromagnetic waves in the mine tunnel as well as the requirement of no explosion with equipment, we choose 2.4GHz as the system frequency.2. In order to improve the performance and achieve miniaturization, a Minkowski fractal structure is given. By using coaxial and fractal technology in simulation. In order to improve bandwidth, two -layer structure is used, and it is found that the later antenna is more suitable for the personnel position system on the bandwidth requirement.3. The structure designed for tag antenna is obtained through the simulations of several antenna conductions. Finish the design of the radio frequency module with its matching circuits. Through the bending technology and the structure of the mirror compensation, the antenna can achieve miniaturization and wide bandwidth characteristics.4. The experimental samples are manufactured, and the resonant characteristics and gain of the above samples are also tested. The experimental results meet the practical requirements and the measured data agree with the calculated results.5. Analyze the the error between the simulation results and the test results.In this dissertation, the RFID fractal tag antenna for small coal mine monitoring systems has been analyzed and designed. Due to its compact structure, small size, predominant performance and low cost, it is not only suitable for coal mine applications but also applications which need lots of tags, such as container automatic identification system and no stop toll collection system.