Design of a Resistant Circularly Polarized Tag Antenna with high performances in the EU UHF RFID band

In this study, a novel resistant Radio Frequency IDentification (RFID) tag with high performances is presented. The proposed tag consists of two antennas. The first one is an inductive antenna used for matching the imaginary part of the chip impedance at the target frequency. The second antenna is coupled with the first one in order to increase the gain and improve the tag performances. The tag antennas are designed to operate in the EU Ultra-High Frequency (UHF) RFID band. The crossed dipole antennas technique is used to achieve the Circular Polarization (CP) in the operating band. Many prototypes have been manufactured, and good agreement between simulations and measurements has been achieved. The band covered for an Axial Ratio (AR) < 3 dB is from 863 to 869 MHz. The Read Range (RR) of the tag has been measured in a standard anechoic chamber. From the measured results in EU RFID band, the tag has a maximum RR of about 16.35 m at 868 MHz.