Table 5.

Body temperature monitoring systems.

Ref.	Proposed Device	Principle	Measured Parameters	Used Device for Measurement	Location	Wireless Connectivity	Performance Evaluation	Accuracy
[66]	Kalman filter based body temp. estimation model	Temperature variation with HR	HR, skin temperature	Ag/AgCl gel electrodes	Chest	-	Compared with data from ingestible temperature capsule	RMSE: 0.40 °C
[68]	Wireless, dual channel body temp measurement system	Mean of measurements from two ear canals	Core body temp	Digital temp sensor DS18B20	Ear canal	Bluetooth		±0.1 °C
[69]	Wearable wireless temperature monitoring	Two-point calibration	Circadian rhythms, Skin temp	MF51E NTC thermistor	Skin	RF (Tyndall node) over Body sensor network (BSN)	Compared with data from a thermometer	0.02 °C
[71]	Embedded NTC temperature sensor and conductive textile wires in a belt made with soft bamboo		ECG, skin temperate	NTC Mon-A-Therm 90045 and Shieldex® Silver Plated Nylon yarn	Skin	-	Compared with data from the NICU sensor connected to the Solar® 8000M patient monitor	±0.1 °C
[72]	Wireless body temperature monitoring		Skin temperature	LM35	Hand	ZigBbee and WLAN		±0.25 °C
[75]	RFID sensor chip in 0.35-μm CMOS standard process	Temperature dependence of the frequency of ring oscillator				Tag and reader communicate at 868 MHz	Measurement was performed in a climate chamber	~±0.1°C Resolution: 0.035°C
[76]	Epidermal-like RFID tag made on a Poli-caprolactone membrane	Re-tunable epidermal tag	Skin temperature	EM4325	Abdomen	Tag and reader communicate within a band of 780–950 MHz	Compared with data from PT104 thermocouple	±0.25 °C
[77]	Deep body temperature measurement system embedded in a neck pillow	Embedding 1 Dual-heat-flux, 2 double-sensor in neck pillow	Core body temperature		Around neck	-	Compared with data from infrared thermometer (thermoscan IRT 4520)	-
[79]	Heater-less deep body temperature probe	Dual-heat-flux method	Core body temperature		Forehead	-	Compared with data from zero-heat-flow thermometers	Correlation: 97%