| 摘要: |
| 超高频(Ultra high Frequency,UHF)射频识别（Radio Frequency Identification,RFID）阅读器射频前端的自干扰信号会降低接收信噪比，造成标签的误读和漏读。针对目前有源干扰对消技术存在的抑制效果和实时性较差的缺点，在分析有源干扰对消原理的基础上，提出了基于改进Powell搜索算法的自适应射频干扰对消方案。设计了有源对消电路，通过改进的Powell最优值搜索算法实现电路控制参数的自适应调节，使电路工作在最优的抑制状态。测试结果表明，在840~ 960 MHz 的RFID频段内，达到了 37 dB 以上的抑制效果，从而使RFID阅读器收发端之间的隔离度提高至 62 dB 以上，最高可达到 70 dB 。电路上电的首次自动调节过程耗时大约为 31.7 ms ，之后的自适应过程可在 3.9 ms 左右完成参数调节。此电路可有效提高射频识别系统的识别正确率，为提升国产RFID读写器芯片的整体性能提供了新的技术方案。 |
| 关键词: UHF RFID 自干扰信号抵消 有源干扰抵消电路 Powell搜索算法 |
| DOI： |
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| 基金项目:国家自然科学基金资助项目（61671315） |
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| An adaptive RF self-interference cancellation technology for UHF RFID |
| YU Xu,SONG Guodong,LIU Xueguan,ZHOU Minglai |
| (School of Electronic and Information Engineering,Soochow University) |
| Abstract: |
| The self interference signal of the radio frequency(RF) front end of the ultra high frequency RF identification(UHF RFID) reader will reduce the received signal to noise ratio,causing misreading and leakage reading of the label.For the disadvantages of current active interference cancellation technology,such as poor suppression effect and real time performance,an adaptive RF interference cancellation scheme based on the improved Powell search algorithm is proposed according to the analysis of the principle of active interference cancellation.With the improved Powell search algorithm for optimal value,the active cancellation circuit designed in the scheme mentioned above can realize the automatic adjustment of circuit control parameters,thus making the circuit work under optimal suppression state.The test results show that the adaptive RF self interference cancellation circuit designed achieves a suppression effect of more than 37 dB in the RFID frequency band between 840 MHz and 960 MHz,so that the isolation between the receiving end and transmitting end of the RFID reader can be increased to more than 62 dB,and the maximum can reach 70 dB.The first automatic adjustment process when the circuit is powered on takes about 31.7 ms,and the subsequent adaptive process can complete parameter adjustment in about 3.9 ms.This circuit can effectively improve the recognition accuracy of the RFID system,and provides a new technical solution for improving the overall performance of the domestic RFID reader chips. |
| Key words: UHF RFID self interference signal cancellation active interference cancellation circuit Powell search algorithm |
