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International Journal of Antennas and Propagation
Volume 2013 (2013), Article ID 194145, 9 pages
http://dx.doi.org/10.1155/2013/194145
Research Article

Dual-Dipole UHF RFID Tag Antenna with Quasi-Isotropic Patterns Based on Four-Axis Reflection Symmetry

1State Key Laboratory of Industrial Control Technology, Department of Control Science and Engineering, Zhejiang University, Hangzhou 310027, China
2College of Information Science and Engineering, Guangxi University for Nationalities, Nanning 530006, China
3School of Instrument Science and Engineering, Southeast University, Nanjing 210096, China

Received 30 January 2013; Revised 3 April 2013; Accepted 7 April 2013

Academic Editor: Guo-Ping Gao

Copyright © 2013 Chunfang Qin 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

In many RFID practical applications, it is required that reader can effectively read tags which are placed in radiation covering area randomly. In this paper, a passive UHF dual-dipole tag antenna with quasi-isotropic patterns is designed, which can reduce the sensibility of tag read-orientation in a long distance. Two dipoles with four-axis reflection symmetric structure are used, and the two arms of the dipole are bent to fill the space of the antenna. In this way, a quasi-isotropic tag is easier to be obtained. The test results show that the gain deviation of the proposed antenna was less than 3.25 dB, and the maximum reading range in different directions was from 6.9 m to 10.0 m, with better quasi-isotropic performance and reading range than other commercial tags.