Research And Design Of UHF Reader

Radio Frequency Identification (RFID) is a kind of non-contact automatic identification technology begins in 1980's, which has advantages of high security, high reliability and high anti-interference ability. It not only can identify several tags at the same time, but also can identify with rapid moving objects. So that RFID is widely used in the field of Service trade, Physical distribution management, Commodity production and Transportation and so on in recent year. RFID system can be divided into Active systems and Passive systems, or Low-frequency (LF), High-frequency (HF), Ultra-high frequency (UHF) and Microwave systems, according with the operating frequency. The UHF, however, with the features of longer identification distance, higher speed and non-metallic materials penetrating and so on, becoming the focus of current research.The paper introduces a design of UHF reader based on EPC Gen2 standard protocol, the main tasks involved:First, simply introduces the development of RFID and the component of RFID systems and the use of different systems.Second, deeply analyses the EPC Gen2 standard protocol and its technical characteristics, including the data encoding, modulation, demodulation and tag selection, inventory and access commands etc.Third, analyses the frame and function of C8051F340 and AS3991, simulates the critical path of the interrogator, designs the hardware circuits of the system and completes the testing of it.Fourth, programs the software of firmware for the reader and researches the algorithm of anti-collision defined in the protocol of Gen2.Fifth, designs the control windows, which can be used to control the work of Reader.Through actual test, it is proved that the system which is controlled by the host can work steadily and effectively, all that accord with expected goals. Reader not only can operate Gen2 tag, but also can identify tags at a time.