磁性基板UHF射频识别抗金属标签天线的研究

发布时间：2018-03-05 12:08

本文选题：磁性基板　切入点：UHF　出处：《电子科技大学》2014年硕士论文　论文类型：学位论文

【摘要】：随着物联网信息技术的发展普及,射频识别技术(RFID)已经在国民经济发展中起到了举重轻重的位置。UHF(Ultra High Frequency)RFID工作频段在860~960MHz,由于其工作距离通常大于1m而被广泛应用于远距离信息读写。在很多实际情况中,标签天线不可避免的被贴在金属物体上,此时普通标签受金属干扰而不能正常被读取,这是阻碍它发展的一个重要技术问题。本文详细的分析了磁性材料对偶极子天线的各项性能参数的影响,制备了3款厚度为2mm的磁性基板抗金属标签天线,同时为应用于UHF RFID抗金属标签天线的磁性材料的制备指明了研究方向。首先,介绍了UHF RFID标签天线的性能参数,分析金属环境使天线失效的机理,金属界面下,天线的方向图、阻抗、增益发生显著变化。采用HFSS软件结合理论知识,分析磁性材料对半波偶极子天线各项性能的影响,磁性材料增大了天线周围媒质的有效电磁参数,可以有效的缩短天线的物理尺寸,而电磁损耗造成天线增益的降低;不考虑损耗时,磁性材料相比介电材料更有助于提高金属环境中天线的增益;随着磁性材料厚度的增大(0~0.05λ),天线的增益逐渐增大。其次,通过分析磁性材料对天线性能的影响,结合UHF RFID标签天线本身的性能要求,确定磁性基板的电磁参数范围。磁性材料的电磁参数实部应小于10;为了减少天线的增益衰减,结合磁性材料本身的电磁特性,磁性材料的磁损耗正切应小于0.1,介电损耗正切小于0.05。高Q磁性基板利于制备小尺寸厚度薄的抗金属标签天线。采用固相反应法制备了用于抗金属标签天线的磁性基板,该磁性胶板在922 MHz的电磁参数为:μ′=2.3,ε′=6.4,tanμ=0.09,tanε=0.003,满足磁性基板的参数要求。最后,设计以磁性材料为基板的抗金属标签天线,分别对不同的磁性基板、不同的天线形状下的抗金属标签天线进行分析,成功的做出了三款厚度为2mm抗金属标签天线。当天线的长度为100mm时,可以达到最大读取距离为3m;缩小天线尺寸以降低天线的增益为代价,改变天线结构缩小天线长度尺寸为42mm、52mm时,天线的读取距离降低为1m、1.5m。复杂的天线结构在弯折线相近的区域损耗明显增大,对磁性材料的电磁损耗要求更严格。当天线形状确定时,降低磁性材料的磁导率损耗可以有效的缩短抗金属标签天线的厚度及长度。
[Abstract]:With the development of information technology in the Internet of things, RFID (Radio Frequency Identification Technology) has played a weightlifting position in the development of national economy. The working frequency band of UHF Ultra High Frequency)RFID is 860,960MHz. because its working distance is usually more than 1m, it is widely used in the reading and writing of remote information. The tag antenna is inevitably affixed to a metal object, where the ordinary label is not read properly because of metal interference. This is an important technical problem that hinders its development. In this paper, the influence of magnetic materials on the performance parameters of dipole antenna is analyzed in detail, and three kinds of magnetic substrate anti-metal label antennas with thickness of 2 mm are fabricated. At the same time, it points out the research direction for the preparation of magnetic materials used in UHF RFID anti-metal label antenna. Firstly, the performance parameters of UHF RFID tag antenna are introduced, and the mechanism of antenna invalidation under metal environment is analyzed, and the pattern of antenna under metal interface is analyzed. The influence of magnetic material on the properties of half-wave dipole antenna is analyzed by using HFSS software and theoretical knowledge. The effective electromagnetic parameters of the medium around the antenna are increased by the magnetic material. The physical size of antenna can be shortened effectively, and the gain of antenna can be reduced by electromagnetic loss. When the loss is not considered, the gain of antenna in metal environment can be improved more by magnetic material than by dielectric material. With the increase of the thickness of magnetic material, the gain of antenna increases gradually. Secondly, by analyzing the effect of magnetic material on the performance of antenna, combining with the performance requirements of UHF RFID tag antenna, Determine the range of electromagnetic parameters of the magnetic substrate. The real part of the electromagnetic parameters of the magnetic material should be less than 10. In order to reduce the gain attenuation of the antenna, combined with the electromagnetic characteristics of the magnetic material itself, The magnetic loss tangent of magnetic material should be less than 0.1 and the tangent of dielectric loss should be less than 0.05. High Q magnetic substrate is propitious to the preparation of thin anti-metal label antenna with small size. The magnetic substrate used for anti-metal label antenna is prepared by solid state reaction method. The electromagnetic parameters of the magnetic adhesive plate at 922 MHz are as follows: 渭 ~ (2. 3), 蔚 ~ (6.4N) tan 渭 ~ (0.09) tan 蔚 ~ (0.003), which meet the requirements of the magnetic substrate. Finally, an anti-metal label antenna with magnetic material as the substrate is designed, and different magnetic substrates are designed. Three anti-metal label antennas with a thickness of 2mm are successfully made by analyzing the anti-metal label antennas with different antenna shapes. When the length of the antenna is 100mm, The maximum reading distance is 3 m. When the antenna size is reduced at the cost of reducing the gain of the antenna, the length of the antenna is reduced to 42 mm or 52 mm by changing the structure of the antenna. The reading distance of the antenna is reduced to 1 ~ 1. 5 m. The loss of complex antenna structure in the area close to the bending line is obviously increased, and the electromagnetic loss of magnetic material is more strict. When the shape of antenna is determined, Reducing the permeability loss of magnetic materials can effectively shorten the thickness and length of anti-metal tag antennas.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN820;TP391.44

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