适应多环境的小型化超高频RFID标签天线设计

Design of Compact UHF RFID Tag Antenna for Platform Tolerant Applications

为实现RFID标签在多种环境下正常工作,本文提出一种适应多环境的小型化超高频RFID标签天线.该天线由外层折叠贴片、中层U型贴片和T型匹配网络构成.通过折叠外层贴片实现了小型化,天线总尺寸为26mm×26mm×7mm (0.08λ×0.08λ×0.02λ).引入中层U型贴片,与折叠的外层贴片形成两个相邻谐振模式,实现了比较宽的频带效果.天线采用接近式耦合馈电和T型匹配网络,实现了与RFID芯片良好的共轭匹配.经参数分析和优化,天线在自由空间以及背面附着在水和金属环境下的-3dB带宽分别为64MHz(884～949MHz),64MHz(902～966MHz)和76MHz(902～978MHz).这表明天线在3种典型环境下都具有完全覆盖902～928MHz超高频RFID工作频带的能力,能够满足适应多环境的应用需求.

In order to achieve the normal operation of RFID tags in various environments,a miniaturized UHF RFID tag antenna that adapts to multiple environments is proposed in this article.The antenna consists of a folded patch,a U-shaped patch and a T-matching network.Benefiting from the folded structure,the antenna volume is reduced to 26 mm×26 mm×7 mm(0.08λ×0.08λ×0.02λ).In order to enhance the bandwidth,the middle U-shaped patch is introduced to form two adjacent resonant modes with the folded outer patch.The antenna uses a proximity coupled feed and a T-type matching network to achieve good conjugate matching with the RFID chip.Though Parameter analysis and optimizatio,simulation results show that the-3 dB impedance bandwidth of the proposed antenna in free space and mounted on water and metal is 79 MHz(862~941 MHz),64 MHz(902~966 MHz)and 76 MHz(902~978 MHz)respectively.This shows that the antenna has the ability to fully cover the 902~928 MHz UHF RFID operating band in all three typical environments,and can meet the needs of multi-environment applications.