On the Use of 3D-printed Ultrasonic Horns to Tune the Frequency Response of Airborne MEMS Transducers

This paper shows how mm-sized 3D-printed ultrasonic horns can be employed to tune the frequency response of airborne MEMS ultrasonic transducers. We present a system integration approach, which we conceptualized with the help of a physics-based compact model for the prediction of the full-system behavior. Simulation results are compared to dynamic optical measurements for three exemplary horn geometries of same length. We demonstrate how small differences in the mouth size of the ultrasonic horn influence substantially the frequency response of a membrane-based piezoelectric transducer operated in transmitting mode, that is the position and peak height of its resonant frequencies. This work lays the foundation for the development of airborne ultrasonic transceivers with tailored acoustic characteristics by means of properly designed ultrasonic horns of dedicated shape and length.