無線射頻辨識讀取器之天線設計及研製

Design and Implementation of RFID Reader Antenna

李造端(Tsao-Duan Li)

指導教授 ： 林怡成

國立臺灣大學/電機資訊學院/電信工程學研究所/碩士(2008年)

https://doi.org/10.6342/NTU.2008.00026

摘要

摘要

本論文主要在探討無線射頻辨識系統之讀取器天線(RFID reader antenna)之設計與研製，內容將以平面開槽迴路式圓極化天線為主，操作頻率在2.45GHz，並對此平面開槽迴路式天線的圓極化原理研究與討論，根據電磁模擬與物理特性來提出個人的看法與解釋此類型天線的圓極化方向(左手圓極化/右手圓極化)。文中提出一「雙T迴路型」之平面開槽迴路式天線來縮小至原來的平面開槽迴路式天線的70%左右；另ㄧ架構為在天線下方加一反射器來提升正Z方向的圓極化增益至5~6dBic左右；最後提出一1×2循序旋轉陣列(sequential rotated array)架構套用在此天線上來改善3dB軸長比頻寬至10%左右。本文對此類型天線的縮小化、增益的提升，及對3dB軸長比頻寬的改善提出了設計架構及實作成果，且作表分析比較各種天線改良前後的表現，以達到無線射頻辨識系統讀取器之需求。

關鍵字

無線射頻辨識系統 ； 平面開槽迴路式天線 ； 圓極化 ； 軸長比值 ； 反射器 ； 循序旋轉陣列

並列摘要

Abstract

This thesis presents the design and implementation of RFID reader antennas. Using a slot loop with perturbed meander line section, the proposed antenna may successfully achieve the circular polarization requirements, operating at 2.45 GHz. The proposed double-T slot may reduce the antenna area by 30%. Using a reflector ground underneath the antenna, the circularly polarized gain may be raised up to 5~6 dBic. Moreover, a 10% 3-dB axial ratio bandwidth is obtained by using a sequential rotated feed network and 1x2 arrays. The features of the designed antenna include the size reduction, gain improvement, and axial ratio bandwidth enhancement. An electromagnetic simulation and physical explanation is also provided in this thesis to interpret the working principle of circular polarization of the proposed antennas.

並列關鍵字

RFID ； Printed Slot Loop CP Antenna ； circular polarization ； axial ratio ； reflector ； sequential rotated array

參考文獻

[1]R.Want, “An Introduction to RFID Technology”, IEEE Pervasive Computing, vol. 5, no.1, pp. 25-33, Jan.-Mar.2006.

[2]Xianming Qing and Ning Yang, “2.45GHz Circularly Polarized RFID Antenna”, The Ninth International Conference on Communications Systems, 2004. ICCS 2004, pp. 612-615, Sep. 2004.

[3]Leena Ukkonen, Lauri Sydänheimo, and Markku Kivikoski, “Read Range Performance Comparison of Compact Reader Antennas for A Handheld UHF RFID Reader－Supplement, Applications & Practice”, IEEE Communication Magazine, vol. 45, no. 4, pp. 24-31, April 2007.

[6]Jia-Yi Sze, Kin-Lu Wong, and Chieh-Chin Huang, “Coplanar Waveguide-Fed Square Slot Antenna for Broadband Circularly Polarized Radiation”, IEEE Trans on Antennas and Propagation, vol.51, no.8,pp. 2141-2144, August 2003.

[7]Kin-Lu Wong, Chien-Chin Huang, and Wen-Shan Chen, “Printed Ring Slot Antenna for Circular Polarization”, IEEE Trans on Antennas and Propagation, vol. 50, no. 1, pp. 75-77, January 2002.