Self-powered piezoelectric wireless micro-sensors by absorbing electromagnetic energy

This paper presents a new scheme of self-powered micro-sensor by absorbing electromagnetic energy. A unidirectional transducer group and a resonant acoustic cavity are created inside the transducer while keeping the unidirectionality required for. low loss. As a result, the electromagnetic energy collected from antenna can. be converted into acoustic energy and stored in the resonant cavity The energy output in another path is controlled by a specific circuit. Therefore the electromagnetic energy. can be gathered and accumulated ceaselessly, and the collecting energy can be released and produce a high power in very short term. Measurement on a 70MHz device demonstrates that the resonant frequency in resonator is related to the measured parameter and the sensor can be deployed in long distance detection.