Tonpilz transducer head mass selection based on excitation signal type

The head mass as front-end material is an essential component of Tonpilz transducers. The transmission mechanism of head mass under excitations of continuous wave and short pulse are investigated in order to maximize the transducer acoustic radiation power. In the case of continuous wave excitation, it was found that the role of the head mass is to change the effective vibration velocity, and the transmitting voltage response is proportional to the characteristic impedance of the head mass. In the case of short pulse excitation, the head mass acts as a medium layer, and the highest acoustic radiation power appears when the characteristic acoustic impedance of head mass matches that of water medium. Our results provide deeper insight on the Tonpilz transducer design mechanism, and useful selection rules for the front-end material under different types of excitation signals.