Anti-Corrosion and Long Communication Range RFID Tags Based on Graphene-Assembled Films for Underground Wireless Temperature Sensing.

Soil temperature monitoring constitutes a critical component of modern agricultural production systems. Conventional detection methods are typically labor-intensive, exhibit low operational efficiency, and demonstrate poor adaptability to soil-buried environments. In this study, a passive radio-frequency identification (RFID)-based temperature sensing system is proposed, in which the antenna and AMC structures are fabricated from graphene-assembled films (GAF) and the temperature detection is enabled by an integrated commercial RFID chip. The system offers favorable corrosion resistance and extended-range wireless communication capability. To further enhance the wireless communication distance, a GAF artificial magnetic conductor (AMC) is specifically designed and integrated with the sensor. Consequently, the maximum free-space communication range of the GAF RFID sensing system increases from 10.1 to 16.8 m. The test results show that the GAF temperature sensor has a maximum temperature deviation of 1.2 °C and a mean absolute error of 0.366 °C with calibrated mercury thermometer in the soil. Moreover, real-time wireless data acquisition and display of GAF temperature system are successfully demonstrated. The proposed GAF RFID sensing system effectively addresses key limitations of conventional sensing techniques and demonstrates initial feasibility for soil-buried temperature monitoring applications.