Single-Feed Wideband Circularly Polarized Antenna for UHF RFID Reader
In this paper, a single-feed wideband circularly polarized antenna has been proposed for UHF RFID reader. This antenna is designed to cover the frequency range from 860 to 960 MHz. In this antenna, the main patch is a modified form of the conventional E-shaped patch to obtain a circular polarization. A parasite patch is placed at the same layer of main patch to enhance axial ratio bandwidth. A short-circuited cylinder is also added in main patch to broaden the impedance bandwidth. The 3 dB axial ratio bandwidth is over 11 %, from 850 to 960 MHz. The impedance bandwidth is of 17 % (850–1000 MHz). Thus, The impedance bandwidth and 3 dB axial ratio bandwidth totally covers the universal UHF RFID band (860–960 MHz). The simulated and measured results indicate that the proposed antenna will be a good candidate for UHF RFID reader system.
KeywordsWideband UHF RFID Circularly polarized antenna LHCP
The authors would like to thank Advantech Jsc Company for their support of Ansoft Designer HFSS used as simulation tool to obtain these results in this paper.
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