UHF RFID读写器天线设计与相控阵研究

发布时间：2018-02-16 07:52

本文关键词： 相控阵 UHF RFID 圆极化微带天线四臂螺旋天线　出处：《电子科技大学》2014年硕士论文　论文类型：学位论文

【摘要】：RFID作为一种非接触式的自动识别技术,近年来广泛应用在商品零售,交通物流,仓储管理,门禁控制等领域。UHF RFID特指800/900MHz频段的无源射频设别技术,由于其读写速率快、可识别高速运动的物体、识别目标数量多、工作距离较远、标签成本低等优点受到各国重视,正在高速发展。读写器天线作为RFID系统关键部件,将直接影响RFID系统的性能,读写器天线通常要求是圆极化的,同时根据一些应用需要,还要求做到宽频带,小型化等性能。相控阵天线具有增益高,波束扫描灵活快速的特点,因此本文将相控阵天线应用到无源UHF RFID系统中,以提高读写器对标签的识别范围和设别率等性能。本文首先阐述了相控阵天线的基本理论和UHF RFID技术的原理,提出一种可以应用于RFID的小型相控阵系统,该系统包括天线阵列,移相功分馈电网络,移相器控制电路。而本文的主要研究内容是设计圆极化的天线单元和阵列。为了满足不同应用场合需要,本文设计了两种不同类型的圆极化天线,可单独用于读写器上,并且还将这两种天线单元组合成阵列形式,用于小型的相控阵系统。第三章设计了一款宽频带高增益的圆极化天线,主要用于固定式RFID系统,该天线选择圆形微带贴片天线的类型。在对微带天线圆极化技术和宽频带技术研究的基础上,通过对圆形贴片正交双馈实现圆极化,通过增加耦合贴片和使用空气介质来拓宽频带,该天线工作频带到达860MHz-960MHz,覆盖了全球各标准划分的UHF RFID操作频带。第四章设计了一款小型化的圆极化天线,主要用于便携式读写器场合,该天线采用谐振式四臂螺旋天线结构,将天线的谐振臂改进为印制于PCB上的弯折倒F天线,以缩小尺寸和改善阻抗匹配,并通过一分四的移相功分网络馈电。该天线尺寸小,重量轻,圆极化性能强且稳定,波束宽,工作频率覆盖目前国内外应用最广泛的902MHz-928MHz频带标准。第五章分别将前面设计的两款天线单元组合成阵列天线,分为1×4线阵和2×2面阵,分析了天线阵列的性能,比如增益,波束扫描特性,并对阵列的低副瓣性能进行优化。仿真结果表明,设计的天线阵增益高,副瓣低,可实现波束扫描,为相控阵技术在RFID领域的应用奠定了良好的基础。
[Abstract]:As a non-contact automatic identification technology, RFID has been widely used in recent years in the fields of commodity retail, transportation logistics, warehouse management, access control and other fields. UHF RFID specifically refers to the passive radio frequency (RF) setting technology in 800 / 900MHz band, because of its fast reading and writing rate. As a key component of RFID system, the reader antenna, as a key component of RFID system, will directly affect the performance of RFID system, because of its advantages such as large number of targets, long working distance, low tag cost and so on, which can be used to identify objects with high speed motion. The reader antenna is usually required to be circularly polarized, at the same time according to some application needs, it is also required to achieve broadband, miniaturization, etc. The phased array antenna has the characteristics of high gain, flexible and fast beam scanning, etc. Therefore, the phased array antenna is applied to passive UHF RFID system in order to improve the performance of the reader in the identification range and the setting rate of tags. Firstly, the basic theory of phased array antenna and the principle of UHF RFID technology are described in this paper. A small phased array system, which can be applied to RFID, is proposed. The system includes antenna array, phase-shifted power division feed network. Phase shifter control circuit. The main research content of this paper is to design circularly polarized antenna elements and arrays. In order to meet the needs of different applications, this paper designs two different types of circularly polarized antennas, which can be used separately on readers and writers. In chapter 3, a circular polarization antenna with wide band and high gain is designed, which is mainly used in fixed RFID system. This antenna selects the type of circular microstrip patch antenna. On the basis of research on circular polarization technology and broadband technology of microstrip antenna, circular polarization is realized by orthogonal doubly-fed circular patch. By adding coupling patches and using air media to broaden the frequency band, the antenna operates in a frequency band up to 860MHz-960MHz, covering the global standard UHF RFID operating band. Chapter 4th designs a miniaturized circularly polarized antenna. The antenna is mainly used in portable reader. The resonant four-arm helical antenna structure is adopted in this antenna. The resonant arm of the antenna is modified into a bending inverted F antenna printed on PCB to reduce the size and improve the impedance matching. The antenna is small in size, light in weight, strong in circular polarization and stable in beam width. The operating frequency covers the 902MHz-928MHz frequency band standard, which is widely used at home and abroad. Chapter 5th combines the two antenna elements designed previously into an array antenna, which is divided into 1 脳 4 linear array and 2 脳 2 plane array. The performance of the antenna array, such as gain, is analyzed. The simulation results show that the antenna array with high gain and low sidelobe can realize beam scanning, which lays a good foundation for the application of phased array technology in the field of RFID.
【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】：TP391.44;TN820

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