UHF RFID temperature sensor tag using novel HDPE-BST composite material

A novel UHF RFID temperature sensor tag is designed using solid temperature-dependent material. A lightweight HDPE-BST material is first developed, whose permittivity decreases as ambient temperature increases. Using this material as the tag antenna substrate, a simple slotted patch sensor tag is then designed, fabricated, and measured. The experimental results show that an 8MHz/10°C frequency shift can be obtained. Meanwhile, the sensor tag has a narrow bandwidth of 0.6%, which is beneficial for improving tag´s sensitivity.