Single crystal-based phased array for transoesophagial ultrasound probe

Lead-based piezoelectric single crystals such as Pb(Zn₁3/Nb₂3/)O₃-PbTiO₃ (PZN-PT) and Pb(Mg₁3/Nb₂3/)O₃-PbTiO₃ (PMN-PT) have been extensively studied during the last years as their outstanding piezoelectric properties (d₃₃ as high as 2000pC/N and k₃₃ > 90%) make them valuable for high-end ultrasound transducers. Nevertheless the specific nature of these materials, as compared with standard piezoceramics, requires to develop new transducer micro-machining and manufacturing processes to enhance the final properties of the transducers and to improve both sensitivity and bandwidth of these probes. This paper presents the acoustical design, fabrication and evaluation of a 64 elements ultrasound phased array for transoesophagial probe based on single crystal materials. The achieved phased array is a 5MHz configuration with a circular aperture. The whole transducer is included within diameter 10mm and 2mm height. Acoustical design and final results will show the improvements achieved with single crystals for this configuration by comparing these results to those obtained on standard piezoceramic phased array. Electro-acoustic characterisation is performed on the whole array and homogeneity performances will also be presented.