Increasing Ranging Accuracy of Aluminum Nitride Pmuts by Circuit Coupling

This paper proposes a method to increase the accuracy of distance measurement for piezoelectric micromachined ultrasonic transducers (PMUTs) through introducing stable circuit coupling. The proposed method can characterize the distance through adjustable wavelength. When the ultrasonic flight distance is an odd multiple of the half wavelength, the coupling signal and the piezoelectric response signal are superimposed to produce a sharp ditch. Consequently, such ultrasonic distance measuring technique could be used for the high precision applications.