基于分形结构的UHF RFID阅读器天线设计

Design of UHF RFID Reader Antenna Based on Fractal Structure

摘要: 基于分形结构设计了一种工作于UHF频段的RFID阅读器天线，其工作频段覆盖了中国的RFID标准频段(920 MHz~925 MHz)。天线结构以FR-4材料为基底，采用微带贴片化设计方案。运用常规的50 Ω同轴线对天线进行馈电，与天线形成良好的阻抗匹配。天线设计当中同时采用了闵可夫斯基和科赫两种分形结构，实现了目标天线的小型化，其尺寸为100 × 100 × 1.6 mm³。天线实测结果表明，目标天线的数值仿真分析与实测结果相吻合，实测阻抗带宽(S11 < −10 dB)为11 MHz，驻波比带宽(VSWR < 2)为13 MHz，并且覆盖了UHF RFID标准频段。

Abstract: In this paper, a kind of RFID reader antenna, which is based on the fractal structures, is designed to work in UHF band. The antenna works in China’s RFID standard frequency band (920 MHz - 925 MHz). The antenna is designed in microstrip patch, using FR-4 material as substrate, and it is fed with the commonly used 50 Ω coaxial line to form a good impedance match. Two types of the fractal structure, Minkowski and Koch, are used in the design of the antenna to achieve the miniaturization of the target antenna with the volume of 100 × 100 × 1.6 mm³. The measured results of the proposed antenna are matched very well with the numerical simulation results. The antenna’s impedance bandwidth (S11 < −10 dB) is 11 MHz and the bandwidth of the voltage standing wave ratio (VSWR < 2) is 13 MHz, which covered the UHF RFID standard band.