Pressure transducer, based on the phase characteristics of the GMI effect, aimed at biomedical applications

In this work it is presented the evolution of a pressure transducer aimed at biomedical applications, developed at the Laboratory of Biometrology of PUC-Rio. It uses the phenomenon of Giant Magnetoimpedance (GMI) as an intermediary block in the transduction process, which comprises the conversions of pressure in magnetic field, then this one in voltage. Among the possible biomedical applications stand out the arterial pulse wave registration and the measurement of the arterial pulse wave velocity (PWV). Throughout the text, we highlight the factors that led to the increase of sensitivity of the transducer to about 50 mV/Pa. That means an increase of 50 times in the transducer sensitivity when compared to previously developed prototypes. This improvement is due, basically, to use of the impedance phase of the GMI effect, instead of the impedance magnitude characteristics, and to the new structural configuration.