高频RFID密集标签系统频率偏移预估研究
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摘要
针对标签密集放置导致系统工作频率偏移问题,传统的频率偏移预估方法,如叠加法认为标签间的耦合作用可累加,但误差较大,提出了一种基于电感耦合矩阵特征值的系统频率预估方法。首先通过对密集标签系统建立耦合模型,提取密集标签间的互感;然后,基于二端口网络,推导出密集标签系统的电感耦合矩阵,提取电感耦合矩阵的特征值代入汤姆逊公式计算;最后,在室内环境中测试了各种标签密集场景。实验结果表明,对于高频射频识别(HF RFID)密集标签系统,所提出特征值法在标签数量大于7时,误差小于9.8%,与叠加法相比,预估精确性更高。
Traditional estimation methods of frequency offset, such as the superposition method, consider that the coupling effect between tags can be accumulated, but the error is large. Aiming at the system operation frequency shift due to dense tag placement, an estimation methods based on the characteristic value of inductive coupling matrix of high frequency(HF) systems is proposed. Firstly, the coupling model for the dense tag system is established and the mutual inductance between the dense tags are extracted. Then, based on the two-port network, the inductive coupling matrix of the dense label system is obtained. The characteristic value of the inductive coupling matrix are extracted into the Thompson formula. Finally, various dense tag scenes were tested in the indoor environment. The experimental results show that for the HF RFID dense tag system, the proposed characteristic value method has an error of less than 9.8% when the number of tags is greater than 7, and the prediction accuracy is higher than that of the superposition method.
Traditional estimation methods of frequency offset, such as the superposition method, consider that the coupling effect between tags can be accumulated, but the error is large. Aiming at the system operation frequency shift due to dense tag placement, an estimation methods based on the characteristic value of inductive coupling matrix of high frequency(HF) systems is proposed. Firstly, the coupling model for the dense tag system is established and the mutual inductance between the dense tags are extracted. Then, based on the two-port network, the inductive coupling matrix of the dense label system is obtained. The characteristic value of the inductive coupling matrix are extracted into the Thompson formula. Finally, various dense tag scenes were tested in the indoor environment. The experimental results show that for the HF RFID dense tag system, the proposed characteristic value method has an error of less than 9.8% when the number of tags is greater than 7, and the prediction accuracy is higher than that of the superposition method.
引文
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[13] SOODMAND S, BROWN T W C. Inductively coupled small self resonant coil (SSRC) reader antennas for HF RFID applications[J]. AEU-International Journal of Electronics and Communications, 2017(78):32-40.
[14] 佘开, 何怡刚, 李兵,等. 基于场景几何特征的ETC识别范围预测方法[J]. 仪器仪表学报, 2017, 38(2):295-303.SHE K, HE Y G, LI B, et al. Prediction method of identification zone for ETC based on scenario geometric features[J]. Chinese Journal of Scientific Instrument, 2017,38 (2): 295-303.
[15] 苏圆圆, 何怡刚, 邓芳明,等. 绝缘子温湿度在线监测技术研究[J]. 电子测量与仪器学报, 2016,30(7):1098-1106.SU Y Y, HE Y G, DENG F M, et al. Research on online monitoring technology for temperature and humidityof insulator[J]. Journal of Electronic Measurement and Instrumentation, 2016, 30(7):1098-1106.
[2] CHEN X, LU F, YE T T. The “weak spots” in stacked UHF RFID tags in NFC applications[C]. IEEE International Conference on Rfid, 2010:181-186.
[3] SUNNY A I, TIAN G Y, ZHANG J, et al. Low frequency (LF) RFID sensors and selective transient feature extraction for corrosion characterisation[J]. Sensors & Actuators A Physical, 2016(241):34-43.
[4] HAN J, QIAN C, WANG X, et al. Twins:Device-free object tracking using passive tags[J]. IEEE Transactions on Networking, 2016,24(3):1605-1617.
[5] 徐计荣, 钱松荣. 高频 RFID 重叠标签载波变频读写器设计[J]. 计算机工程, 2014, 40(2):317-320.XU J R, QIAN S R.The design of high frequency RFID overlapping label carrier frequency conversion device [J]. Computer Engineering, 2014, 40(2):317-320.
[6] LU F, CHEN X S, YE T T. Performance analysis of stacked RFID tags[C]. IEEE International Conference on RFID, 2009:330-337.
[7] 彭章友, 任秀方, 孟春阳,等. UHF RFID密集标签互耦效应的频移特性研究[J]. 电子测量技术, 2015,38(6):11-15.PENG ZH Y, REN X F, MENG CH Y, et al. Study on frequency shift characteristics of mutual coupling between UHF RFID tags in dense environment[J]. Electronic Measurement Technology, 2015,38(6):11-15.
[8] 彭章友, 孟春阳, 任秀方,等. 密集布放环境下的标签互阻设计方法[J]. 电子与信息学报, 2015,37(6):1304-1309.PENG ZH Y, MENG CH Y, REN X F, et al. Design method of tag mutual resistance in dense environment[J].Journal of Electronics & Information, 2015,37(6):1304-1309.
[9] 朱海龙, 赖晓铮, 戴宏跃,等. 金属环境对HF频段RFID系统的影响[J]. 华南理工大学学报 (自然科学版), 2008, 36(5):84-88.ZHU H L, LAI X ZH, DAI H Y, et al. Effects of metal environment on HF frequency band RFID system [J]. Journal of south China University of Technology (Natural Science Edition), 2008, 36(5):84-88.
[10] QING X, CHEN Z N. Proximity effects of metallic environments on high frequency RFID reader antenna: Study and applications[J]. IEEE Transactions on Antennas & Propagation, 2007, 55(11):3105-3111.
[11] JIANG B, SMITH J R, PHILIPOSE M, et al. Energy scavenging for inductively coupled passive RFID systems[J]. IEEE Transactions on Instrumentation & Measurement, 2007,56(1):118-125.
[12] CAIZZONE S, MARROCCO G. RFID Grids: Part II—Experimentations[J]. IEEE Transactions on Antennas & Propagation, 2011,59(8):2896-2904.
[13] SOODMAND S, BROWN T W C. Inductively coupled small self resonant coil (SSRC) reader antennas for HF RFID applications[J]. AEU-International Journal of Electronics and Communications, 2017(78):32-40.
[14] 佘开, 何怡刚, 李兵,等. 基于场景几何特征的ETC识别范围预测方法[J]. 仪器仪表学报, 2017, 38(2):295-303.SHE K, HE Y G, LI B, et al. Prediction method of identification zone for ETC based on scenario geometric features[J]. Chinese Journal of Scientific Instrument, 2017,38 (2): 295-303.
[15] 苏圆圆, 何怡刚, 邓芳明,等. 绝缘子温湿度在线监测技术研究[J]. 电子测量与仪器学报, 2016,30(7):1098-1106.SU Y Y, HE Y G, DENG F M, et al. Research on online monitoring technology for temperature and humidityof insulator[J]. Journal of Electronic Measurement and Instrumentation, 2016, 30(7):1098-1106.