超高频(UHF)射频识别(RFID)系统的性能受到多径信道的制约，为提高 UHFRFID 系统的可靠性，文中针对前向信道和后向信道都为莱斯分布的 UHF RFID 系统，给出了最大比合并(MRC)准则下系统信噪比的概率分布，导出了系统中断概率和误码率的理论表达式，并开发了多天线 UHF RFID 读写器的原型机，通过数值仿真和实际测试考察接收天线数、莱斯因子对系统性能的影响． 实验结果表明，多天线技术能够有效地提高UHF RFID 系统的性能，并且接收天线越多，系统的中断概率和误码率越低．

The performances of UHF (Ultra-High Frequency) RFID (Radio Frequency Identification) systems are affected by multi-path channels． In order to improve the reliability of UHF RFID systems，this paper gives the probability distribution of SNR (Signal-to-Noise Ratio) under the MRC (Maximal Ratio Combining) combiner for the UHF RFID system with Rician distribution in both forward and backward channels，and presents the theoretical descriptions of both outage probability and bit error rate． Then，a prototype of multi-antenna UHF RFID reader is developed，and the system performance affected by receiving antenna number and Ｒician factor is investigated through numerical simulation and practical test． Experimental results show that multi-antenna technology improves the performance of UHF RFID systems effectively，and that the outage probability and bit error rate of UHF RFID systems both decrease as the receiving antenna number increases．