The Research On RFID Technique

The development of computer, semiconductor, micro_electronics and RF technology promote the Radio-Frequency Identification technique. With the support of government and less standard obstacle, it grows rapidly and extends from military products to civil products, from close systems to open systems. RFID has great power in objects tracking, identifying, supervision and management, and RFID systems have been used in many areas and bring great impact to these areas. RFID has become a common and important research and development area all over the world.This paper introduces a read-only 125 KHz low frequency RFID reader used in close systems. It uses EM4095, At89S52 and integrated loop. This design can fetch the transponder's message correctly and send to the PC terminal. It realizes the core function of Non-Touch management systems. The limit distance is around 17 cm. The shape can be designed with the customer's demand. Compared with other products, this design overcomes their weaknesses, such as high cost, short distance, fixed shape and less research effort. We offer a high price verse performance ration solution to such kind of system. Meanwhile, this paper introduces the research and development on 900MHz UHF read-only passive transponder. Considering the current situation in domestic market, we have designed and realized the RF-DC module. It can get voltage 1 V@ -10dBm. Based on the EITS board with SpartanII100E, we have used FPGA and realized the data-store and data-send function.Concretely, this dissertation briefly introduces basic concept of RFID system and explains the function and related theory, then combined with the low frequency reader characteristics gives the design process of the low frequency reader circuit and PCB. After that, it introduces the whole software design with assembly language about AT89S52, followed with hardware PCB beta version. Later, this dissertation discusses basic knowledge of UHF transponder design, describes the RF-DC module. We choose the schottky diode HSMS2855, do the simulation with ADS and check and re-design with Vector Network Analyzer, then discuss various experiment results and design methods with different RF-DC architectures. The equivalent diode impedance varies with different input power, and the load value affects the RF-DC converter efficiency. The two features instruct the operation. At the end of this paper, we give the FPGA method used to store and send data in logic block segment.