NIC-based Oscillation Circuits for Self-powered Piezoelectric Ultrasonic Active Sensors

Abstract

This study aimed to develop a structurally embedded piezoelectric ultrasonic active sensor that intermittently induces ultrasonic bursts at one of the natural frequencies of the host structure, by using electric energy harvested by itself from the operational vibration of the host structure. To this end, this paper mainly focuses on how oscillation circuits to induce the ultrasonic burst coupled with the high-frequency dynamics of the host structure can be designed. A negative impedance converter (NIC)-based design of the oscillation circuit is presented, and its limit-cycle analysis is conducted by applying the describing function method to comprehend the oscillation behavior of the proposed circuit as well as its stability condition.