由于在密集布放时, 超高频(ultra high frequency, UHF)射频识别(radio frequency identification, RFID)标签不仅存在算法上的碰撞问题, 而且标签之间存在电磁耦合, 会造成系统性能下降. 首先从理论上分别推导出前、后向链路的标签最小读取功率与天线增益的关系, 然后通过仿真得出小间距下的标签天线增益. 对比实验中测得的小间距下标签最小读取功率的变化, 得出如下结论: 多标签在密集布放环境下的瓶颈链路为前向链路; 标签天线增益和功率传输系数是影响群读性能的关键因素. 分析和测试结果可以为设计群读性能优异的标签提供参考.
Radio frequency identification (RFID) tags produce electromagnetic (EM) coupling when stacked together, causing performance degradation of RFID systems. This problem is different from the well-known RFID collision problem. This paper first obtains the connection between the tag’s reading power and antenna gain of both forward link and reverse link by theoretical derivation. The tag antenna gain is simulated when two tags are close to each other. By comparing with the reading power of two tags measured in the experiment, the following conclusions are made. Performance of RFID systems is limited by the forward link when tags are stacked. Antenna gain and power transmission coefficient of stacked tags are key factors that influence tags reading rate. Conclusions can provide a reference for developing high performance tags in dense tag environment.
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