Energy Harvesting Transducer by Collecting Electromagnetic Energy Based on Ultrasonic Horn

This paper presents a new energy harvesting sensor by collecting electromagnetic energy based on SAW ultrasonic horn. A unidirectional transducer group and an inhomogeneous piezoelectric structure are created inside the transducer while propagating the unidirectionality required for low loss and receiving the convergent acoustic wave with higher power output. Because of using the ultrasonic horn structure, the acoustic waves may be converged by modifying the angle of the slope boundary and the wavelength of the incident wave. Almost all energy in a wave period is converged and gathered in a flash. Therefore the peak power output in receiving IDT may be much larger than that in input UDT. The electromagnetic energy collected from antenna can be gathered and accumulated ceaselessly, then burst in short time, thus the sensor can be deployed in longer distance than that of ordinary passive SAW sensors