In-nostrils antennas for temperature-based breath monitoring

Conventional diagnostic monitoring of human breathing involve cumbersome and wired equipment, that is uncomfortable for the user and that, most of the times, do not consider the breathing asymmetries between the two nostrils. This paper presents a fully miniaturized two-channel flexible and epidermal antenna sensor for the passive wireless bilateral monitoring of nasal breathing based on temperature measurement. The device fits the nose as a septum ring and is made of highly flexible and soft biocompatible materials. It comprises two coupled loop antennas whose Ultra-High Frequency (UHF) Radio Frequency IDentification (RFID) temperature-sensing microchips are placed just inside the nostrils to implement both sensing and transmission of the breath data. Parametric electromagnetic design and experimental evaluation of the device are both presented in the paper, providing a maximum reading distance above 50 cm.