一种UHFRFID阅读器终端可调谐圆极化天线研究.PDF

Journal of Antennas 天线学报, 2015, 4, 1-8 Published Online March 2015 in Hans. /journal/ja /10.12677/ja.2015.41001 Analysis on Tunable Circularly Polarized Antenna for Applications of UHF RFID Reader Devices 1 1,2 1 1 1 Kaimin Wu , Xuefeng Zhao , Yongjun Huang , Haibin Sun , Guangjun Wen 1 Centre for RFIC and System Technology, School of Communication and Information Engineering, University of Electronic Science and Technology of China, Chengdu Sichuan 2 School of Computer Engineering, Huaihai Institute of Technology, Lianyungang Jiangsu Email: yongjunh@ th th th Received: Feb. 26 , 2015; accepted: Mar. 10 , 2015; published: Mar. 12 , 2015 Copyright © 2015 by authors and Hans Publishers Inc. This work is licensed under the Creative Commons Attribution International License (CC BY). /licenses/by/4.0/ Abstract A tunable circularly polarized (CP) patch antenna based on ferrite substrate is discussed in this paper, for universal ultra-high-frequency (UHF) RF identification (RFID) applications. Such an- tenna is composed of top dielectric layer printed with rectangular radiation patch, middle ferrite layer, and bottom dielectric layer printed with ground plane. The ferrite layer under an applied dc magnetic bias provides the CP radiation characteristic. Most importantly, ferrite layer can tune arbitrarily the operating frequency band in a wide range covering all the worldwide operating frequency bands of UHF RFID, by adjusting the dc magnetic bias. Theoretical analysis on the rea- son