A New Multifunctional Sensor Using Piezoelectric Ceramic Transducers for Simultaneous Measurements of Propagation Time and Electrical Conductance

The aim of this paper is to develop a system for reconstructing an image of two parameters, e.g., temperature and body composition, in the same region of a living body. In this paper, a new multifunctional sensor for simultaneous measurements of the ultrasonic and electrical properties of an object is proposed. The proposed sensor, which uses a pair of piezoelectric ceramic transducers, measures not only the ultrasonic property of the object but also its electrical property by using the surface electrodes of each piezoelectric ceramic transducer. In the experiment, the propagation time and conductance of a simple cell model for the living body are simultaneously measured by the proposed sensor. The sodium chloride (NaCl) concentration, which is the composition that determines the conductivity of the model, and temperature are estimated from the measurements. It was found that the ultrasonic and electrical properties could simultaneously be measured. In addition, two parameters of the model could be estimated from these measured values. Therefore, it is suggested that the proposed sensor has the potential for application, although there are some problems that must be solved.