A study on performance of UHF RFID tags in a package for animal traceability application

In this paper, we study the performance of radio frequency identification (RFID) tags in ultra-high frequency (UHF) band placed in the protective package for animal traceability application. We examine the RFID tag performance by varying the air gap between the tag and the package, both on the top and bottom of the RFID tag. Two types of RFID tag antenna, dipole and meandered dipole antennas, and two types of RFID tag material, FR4 and polyester (PET), are used. The calculation results show the effects of the air gap size on the read range and resonant frequency. In all cases, the read range decrease and the resonant frequency shift to the lower one, when comparing with those of the antenna placed in free space. We use this resonant frequency shift to tune the RFID tag antenna to the desired center frequency for the certain size of the air gap between the tag and the package.