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International Journal of Antennas and Propagation
Volume 2013 (2013), Article ID 961042, 5 pages
http://dx.doi.org/10.1155/2013/961042
Research Article

A Compact RFID Reader Antenna for UHF Near-Field and Far-Field Operations

1School of Computer Science & Engineering, South China University of Technology, Guangzhou 510006, China
2School of Electronic & Information, South China University of Technology, Guangzhou 510641, China

Received 17 February 2013; Revised 8 July 2013; Accepted 9 July 2013

Academic Editor: Yuan Yao

Copyright © 2013 Lai Xiao zheng et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

A compact loop antenna is presented for mobile ultrahigh frequency (UHF) radio frequency identification (RFID) application. This antenna, printed on a 0.8 mm thick FR4 substrate with a small size of 31 mm × 31 mm, achieves good impedance bandwidth from 897 to 928 MHz, which covers USA RFID Band (902–928 MHz). The proposed loop configuration, with a split-ring resonator (SRR) coupled inside it, demonstrates strong and uniform magnetic field distribution in the near-field antenna region. Its linearly polarized radiation pattern provides available far-field gain. Finally, the reading capabilities of antenna are up to 56 mm for near-field and 1.05 m for far-field UHF RFID operations, respectively.