A Low-Cost Printed CP Patch Antenna for RFID Smart Bookshelf in Library

• Published in: IEEE transactions on industrial electronics (1982) Vol. 57; no. 5; pp. 1583 - 1589
• Main Authors: Pui-Yi Lau, Yung, Kenneth Kin-On, Yung, Edward Kai-Ning
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.05.2010; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Antenna array; Antenna feeds; Antennas; Bandwidth; Broadband antennas; circularly polarized (CP); Grounds; Industrial electronics; Integrated circuit technology; Libraries; Passive RFID tags; Patch antennas; Polarization; Radio frequency; Radio frequency identification; radio-frequency identification (RFID) antenna; Radiofrequency identification; sequentially rotated feeding; small patch antenna; wide-beamwidth antenna; Wideband
• ISSN: 0278-0046; 1557-9948
• DOI: 10.1109/TIE.2009.2035992

This paper presents a small wideband circularly polarized patch antenna printed on the low-cost FR-4 material for radio-frequency-identification smart bookshelves in libraries. The antenna is composed of four top-loaded patches sequentially rotated with a phase difference of 90° and double shorted to the ground. It operates at a center frequency of 0.915 GHz. The impedance bandwidth (SWR < 2) is 26.8%, the axial-ratio (AR) bandwidth (measured AR < 3 dB) is 11.6%, and the 3-dB beamwidth is 115°. The antenna gain is about 4 dBi, and the overall dimension is reduced by ~60% in length, in comparison with that of the conventional sequential patch antenna.