A 22-m Operation Range Semi-Passive UHF RFID Sensor Tag With Flexible Thermoelectric Energy Harvester

• Published in: IEEE sensors journal Vol. 22; no. 20; pp. 19797 - 19808
• Main Authors: Solar, Hector, Beriain, Andoni, Rezola, Ainhoa, del Rio, David, Berenguer, Roc
• Format: Journal Article
• Language: English
• Published: New York IEEE 15.10.2022; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Biomedical materials; Effective radiated power; Electric potential; Energy harvesting; integrated circuit (IC); Integrated circuits; Internet of Things (IoT); Low temperature; Microcontrollers; Radio frequency identification; radio frequency identification (RFID); Radiofrequency identification; Sensor phenomena and characterization; Sensors; Temperature sensors; thermoelectric generator (TEG); Thermoelectric generators; Thermoelectricity; Ultrahigh frequencies; Voltage; Wireless communication; Wireless sensor networks
• ISSN: 1530-437X; 1558-1748
• DOI: 10.1109/JSEN.2022.3202634

This article presents a wireless temperature sensor tag able to work in both fully passive mode and in semi-passive mode when assisted by a flexible thermoelectric generator (TEG). The sensor tag consists of an EPC C1G2/ISO 18000-6C ultrahigh-frequency (UHF) radio frequency identification (RFID) integrated circuit (IC) connected to a low-power microcontroller unit (MCU) that samples and collects the temperature from a digital temperature sensor. With a temperature gradient as low as 2.5 °C, the test results show that the TEG provides an output power of 400 <inline-formula> <tex-math notation="LaTeX">\mu </tex-math></inline-formula>W with an output voltage of 40mV. Bymeans of an up-converter in order to boost the TEG output voltage, this harvester supplies the power required to the sensor tag for a 2-conv/s data rate in semi-passive mode. Moreover, when the tag operates in semi-passive mode, a communication range of 22.2 m is measured for a 2-W effective radiated power (ERP) reader. To the best of our knowledge, the proposed TEG-assisted sensor tag shows the longest communication range and the only one that provides stable external power at low-temperature gradients. The measured performance and the chosen architecture allow using the wireless sensor in multiple industrial or biomedical applications.