Dual-chip RFID on-skin tag for bilateral breath monitoring

Breath monitoring is critical for multiple applications, ranging from monitoring patients in Intensive Care Units (ICUs) to the design of optimized physical training. Recently proposed Radiofrequency Identification (RFID) tags and systems for breath monitoring only return integrated information on breathing, whereas the air flow through each nostril can provide more useful information. In this paper, a dual-tag temperature-sensing RFID device is introduced for the simultaneous bilateral monitoring of the nostrils' breath. The device comprises two coupled tapered loops each closed to a transmission line probe excited by a smaller loop hosting the Integrated Circuit (IC). The resulting two-ports tag is such that each temperature-sensing IC is placed just below a nostril. Numerical and preliminary experimentations with epidermal prototypes suggest that the two sensors can be simultaneously read along the nose septum's direction up to a distance of 50 cm.