Physiotherapy ultrasonic transducers are mainly composed by a piezoelectric ceramic bonded to a metallic thin membrane. These transducers vibrate at the thickness fundamental mode. The acoustic efficiency depends on the vibration pattern of the transducer face in contact with the human skin. Radial modes excited by the piezoceramic disc introduce a distribution of amplitude and phase that penalizes both the efficiency and the acoustic field distribution.
In this work, different designs have been studied to decrease the influence of the radial modes on the vibration pattern. For this end, both the metallic membrane and the piezoceramic have been modified in shape.
Funding
CICYT DPI2013-46915-C2-1-R and MAT2013-48009-C4-3-P grants are acknowledged.
