Title :
Full Passive UHF Tag With a Temperature Sensor Suitable for Human Body Temperature Monitoring
Author :
Vaz, A. ; Ubarretxena, A. ; Zalbide, I. ; Pardo, D. ; Solar, H. ; García-Alonso, A. ; Berenguer, R.
Author_Institution :
Dept. of Electron. & Commun., Univ. of Navarra (Tecnun), San Sebastian, Spain
Abstract :
A long-range UHF RF identification (RFID) sensor has been designed using a 0.35- ??m CMOS standard process. The power-optimized tag, combined with the ultralow-power temperature sensor, allows an ID and a temperature reading range of 2 m from a 2-W effective radiated power output power reader. The temperature sensor is based on a ring oscillator, where the temperature dependence of the oscillation frequency is used for thermal sensing. The temperature sensor exhibits a resolution of 0.035??C and an inaccuracy value lower than 0.1??C in the range from 35??C to 45??C after two-point calibration. The average power consumption of the temperature sensor is only 110 nW at ten conversions per second while keeping a high resolution and accuracy. These properties allow the use of the RFID as a batteryless sensor in a wireless human body temperature monitoring system.
Keywords :
CMOS analogue integrated circuits; UHF integrated circuits; biomedical telemetry; calibration; low-power electronics; oscillators; patient monitoring; radiofrequency identification; temperature sensors; CMOS standard process; RFID; batteryless sensor; full passive UHF tag; long-range UHF RF identification sensor; oscillation frequency; power 110 nW; power 2 W; radiated power output power reader; ring oscillator; temperature 35 degC to 45 degC; two-point calibration; ultralow-power temperature sensor; wireless human body temperature monitoring system; CMOS analog front end; RF identification (RFID); digital core; high accuracy; low power; temperature sensor; ultrahigh frequency (UHF);
Journal_Title :
Circuits and Systems II: Express Briefs, IEEE Transactions on
DOI :
10.1109/TCSII.2010.2040314
