Research On The EMC Of RFID Application In Automobile Production Line

RFID (Radio Frequency Identification) technology, known as radio frequency identification, is a non-contact automatic identification technology which flourishes at the beginning of the nineties of the twentieth century.However, the automobile production line is an open metal complex environment, and UHF band RFID systems are extremely sensitive to metal, RFID antenna easily affected by metal and at the same time the radiation characteristic changes which affect the normal operation of the system consequently. Therefore, subsequent EMC (Electromagnetic Compatibility, EMC) issues could not be overlooked. RFID system is a complex, open electromagnetic environment, with the RFID technology, RFID reader antennas and antenna of the electromagnetic radiation will become a new focus of research. Therefore, this paper deals with the vehicle and spare parts for production line application of RFID systems, the research of electromagnetic compatibility was carried out.This paper is based on the theory of electromagnetic field, from the radiation, receiving and scattering of the antenna, discusses the antenna radiation field produced by its distance field theory and various characteristics. This paper discusses electromagnetic energy transformation of the RFID system, testing electromagnetic interference of electrical equipment which run on the automobile production line, setting up electromagnetic environment model of automobile production line, analyzing metal environment of the automobile production line. At first, this paper tests the read rate of readers and tags under metal environment based on influence of reflective and shielding from metal on RFID system. Experiments show that the UHF RFID system is affected by the environment, especially metal. The effect of metal on the reader could be divided into reflecting and shielding. Reflecting provides reading holes and shielding would reduce the reading rate but not to zero. The tag would be hard to receive energy from the reader when put near metal, resulting in the original electromagnetic field in the metal surface deformation field distribution, and then give rise to antenna mismatch.Using the electromagnetic field simulation software Ansoft HFSS, this paper simulates the common antenna of UHF RFID system. The patch shape of microstrip patch antenna is the important factor which affects the performance of antenna. Under metal environment, general dipole antennas are very poor, which even can not work normally in UHF band. But through optimization, the square dipole antennas not only can achieve directional but also can improve radiation gain. Comparison has been made between the rectangular microstrip patch antenna and the circular one. The simulation result shows that the bandwidth of two microstrip patch antenna is too narrow. By comprehensive consideration of each performance index, the rectangular microchip antenna is better than the circular one based on the metal environment.This study is expected to improve RFID system in the automobile production line application of electromagnetic compatibility, to enhance the accuracy and reliability of RFID systems, to provide scientific basis for the popularization and application of the RFID system in the automobile production line. This will have important theoretical and practical significance for raising the level of our theory and application of RFID.