An Ultra-Low-Power High-Precision Temperature Sensor Using Nonlinear Calibration with an Inaccuracy of +0.6/-1 °C...

Area of Science:

• Electrical Engineering
• Sensor Technology
• Metrology

Background:

• Ultra-low-power temperature sensors in Radio-Frequency Identification (RFID) systems often exhibit significant temperature errors exceeding ±1 °C.
• Nonlinear output characteristics of these sensors complicate accurate temperature measurement.
• Existing calibration methods may be costly or insufficient for high-precision requirements.

Purpose of the Study:

• To develop and validate a three-point nonlinear calibration scheme for ultra-low-power, high-precision temperature sensors.
• To address and mitigate the temperature error issue in RFID temperature measurement systems.
• To propose a cost-effective calibration solution integrated into the reader system.

Main Methods:

• A three-point nonlinear calibration scheme incorporating a temperature-dependent nonlinearity coefficient was proposed.
• The calibration algorithm was embedded into the RFID reader for reduced cost.
• A dichotomy-based approach was employed for efficient temperature calibration.
• The sensor's nonlinear output characteristics were compensated.

Main Results:

• The proposed calibration scheme effectively compensated for sensor nonlinearity.
• Temperature errors for five sensor samples were reduced from ±8 °C to within -1 °C to 0.6 °C.
• The calibration was validated across a temperature range of -30 °C to 90 °C.

Conclusions:

• The three-point nonlinear calibration scheme offers a highly accurate solution for ultra-low-power temperature sensors in RFID systems.
• Integrating the calibration algorithm into the reader provides a cost-effective and efficient method for high-precision temperature measurement.
• The successful implementation in mass production demonstrates the practical viability of the proposed solution.