The purpose of this paper is to demonstrate the possibility of implementing folded dipole antennas operative at two closely spaced frequencies of interest, for instance, in ultra-high-frequency radio frequency identification (UHF-RFID) applications. The dual-band functionality is achieved by coupling a spiral resonator to the antenna, which operates as an unbalanced transmission line. This modifies the impedance of the antenna and dual-band functionality can be achieved by virtue of the conjugate matching between the antenna and the chip at the frequencies of interest. Two prototype devices have been designed and fabricated: a mono-band folded dipole UHF-RFID tag, and a dual-band UHF-RFID tag based on a spiral resonator coupled to a folded dipole antenna. The measured read ranges at the operating frequencies are in the vicinity of 6 m. The read ranges of the designed tags have been also measured by attaching them to different objects (a CD-ROM box and a plastic ID card). A certain frequency shift is obtained, but this shift can be corrected by merely modifying the distance between the resonator and the antenna.
Palabras clave: Dipole antenna, sRadio frequency identification (RFID), Radio navigation, Resonators
International Workshop on Antenna Technology - iWAT 2012, Tucson, Arizona (Estados Unidos de América). 05-07 Marzo 2012
Fecha de publicación: marzo 2012.
F. Paredes, G. Zamora, F.J. Herraiz-Martínez, F. Martín, J. Bonache, Dual-band RFID tags based on folded dipole antennas loaded with spiral resonators, International Workshop on Antenna Technology - iWAT 2012. ISBN: 978-1-4673-0036-0, pp. 136-139, Tucson, Estados Unidos de América, 05-07 Marzo 2012