Abstract: This paper introduced the design and implementation of UHF (Ultra High Frequency) RFID (Radio Frequency Identification) reader system, which took ARM9 microprocessor as the controller, and used austria microsystems' UHF RFID reader IC AS3992 for RF processing. With the design of the external power amplifier circuit, the external RF power detection circuit and the reader antenna impedance matching digital tuning circuit, the transmitter output power was up to +33dBm and the receiver Signal-to-Noise Ratio (SNR) had got improved. The reader system achieved high-speed identification of ISO/IEC 18000-6C 900MHz RFID tags. Besides, it transplanted the embedded Linux operating system based on ARM9 hardware system and developed the embedded Web firmware control system to realize tags operations and reader device network configuration, which also provided a platform for data communication between readers and secondary development. The UHF RFID reader system has been applied effectively in the RFID management system of a certain power plant vehicles, the operation result shows that it has successfully realized the purpose to identify and process the information of vehicles' tag in the distance of 10m with stable performance, which satisfies the engineering requirements.

Key words: Radio Frequency Identification (RFID), Ultra High Frequency (UHF) reader, RF impedance matching, power detection, Web server

摘要： 采用ARM9微处理器为主控制器，射频处理采用奥地利微电子公司的AS3992芯片为核心，设计开发了超高频RFID读写器系统。系统设计了外置功率放大电路、功率探测电路和天线端阻抗匹配调谐电路，使发射机输出功率达到+33dBm，并有效地提高了接收机信噪比，实现了对符合ISO/IEC 18000-6C 900MHz RFID协议的多标签的稳定高速读写;同时在ARM9硬件平台上移植了嵌入式Linux系统，并设计了读写器Web固件控制系统，以实现多标签盘存和读写器的网络配置等操作,为读卡器之间数据通信和二次开发提供平台。该系统已搭建运行于某电厂运煤车辆出入RFID管理控制系统中，运行结果表明，系统最大稳定读取距离达到10m，满足了工程需求。

关键词: 无线射频识别, 超高频读写器, 射频阻抗匹配, 功率探测, Web服务器