Improving the radiation properties of a piezoceramic air ultrasound transducer by adding a ceramic membrane

Ultrasound systems based on piezoceramic transducers have the disadvantageous property of poor acoustical impedance matching to air leading to relative low ultrasound pressure output in spite of high driving voltages. In order to increase the output of the transducer a thin ceramic membrane (LTCC Low Temperature Cofired Ceramic) is mounted on the piezoceramic material. With the mounted membrane, the measured ultrasound pressure is more than three times as high as without the membrane at the same driving voltage. First results of this new type of transducer will be presented in this work.