Design And Simulation Of UHF RFID System Based On The Protocol Of EPC C1G2

Radio frequency identification (RFID) is contactless automatic identification technology based on radio frequency signal. A typical RFID system consists of three main components-a reader, a tag and an antenna. RFID systems use low frequency, high frequency, ultra high frequency or microwave. With the development of LF and HF RFID, they have got a great progress and have been applied widely in recent years. People in RFID area pay more attention to the UHF RFID recently, which is still at the initial stage. UHF RFID is one of the most promising technologies in the 21st century and is particularly suitable for application in logistics industry because of its advantages, such as faster speed and higher range. This thesis focuses on the UHF RFID system.At first, this thesis introduces the basic concepts and principles of RFID system briefly and analyzes the development status at home and aboard. Secondly, the thesis analyzes the characters of EPC C1G2 protocol and gives a specific introduction to the encoding and modulation technology. Thirdly, conventional design schemes of the reader are researched and a UHF RFID reader is designed based on the analysis of protocol. The reader can be divided into two parts: a transceiver and a receiver. The transceiver is on quadrature zero-IF topology, which is flexible for multi-modulation types. The out band spurious is limited by raised cosine filter in transceiver. The receiver is on quadrature zero-IF topology as well and the zero-point effect is removed by combining the signal of IQ branches. In the part of baseband demodulation for data recovery, the thesis researches the optimum-receiver scheme based on the principle of correlation matching and the waveform recognition scheme based on the information of waveform. According to the characteristic of the receiver, which is that the data rate of the receiving signal is controlled by the reader, a simplified optimum-receiver scheme is proposed. The simplified optimum-receiver scheme could be used in the low-cost reader. Finally, a power distribution model is researched in the system link analysis and it concludes that the maximum operation range is decided by the power consumption of tag and the sensitivity of reader. Meanwhile, forward link and backward link of the designed reader are modeled in Matlab/Simulink respectively based on the theoretical research and the BER performance of designed RFID system is simulated and analyzed.