Design Of A Passive Rfid Yagi-Uda Sensor Tag Antenna

In this paper, a long reading range Yagi-Uda UHF RFID tag antenna with temperature sensing is proposed and demonstrated. The proposed RFID sensor tag is equipped with an RFID chip integrates temperature sensors with temperature data acquisition and processing. The alteration of the local environment may cause an impedance mismatch between the antenna and the chip and a change in the tag's gain with the consequence of bandwidth narrowing and the read range degradation. In this case, it's important to design high gain antennas to achieve long-distance sensing in high-temperature environments. The proposed antenna works at around 915MHz and the max gain reaches 5.09dBi, which maximum reading distance exceeds 10m.