Fabrication and modeling of broadband ultrasonic transducers using partial composites

Broadband ultrasound imaging is capable of achieving superior resolution in clinical applications. An effective and easy way of manufacturing broadband transducers is desired for these applications. In this work, a partial composite in which the piezoelectric plate is mechanically graded with a number of rectangular grooves is introduced. Finite element analysis (FEA) demonstrated that the partial composite could easily obtain multiple resonant modes, resulting in a broadband time domain response. Experimental tests were carried out to validate the theoretical results. Based upon the FEA designs, several single-element transducers were fabricated using either a non-diced ceramic or a diced partial composite. A superior bandwidth of 92% was achieved by the partial composite transducer when compared to a bandwidth of 56% produced by the non-diced ceramic transducer.