Patent ID: 8129886

Claim:
An acoustical stack for use within an ultrasound transducer that has a center frequency, comprising: a poled piezoelectric material layer comprising poled piezoelectric material having a first acoustic impedance, the poled piezoelectric material layer having top and bottom sides and a first thickness, the acoustical stack having an output electrical impedance based on the first thickness; and a first impedance matching layer configured to be attached to one of the top and bottom sides of the poled piezoelectric material layer, the first impedance matching layer having a second thickness, the first impedance matching layer formed of a material having an acoustic impedance that is substantially similar to the first acoustic impedance, the poled piezoelectric material layer and the first impedance matching layer forming an acoustic resonance thickness, the center frequency of the transducer based on the acoustic resonance thickness; a second impedance matching layer configured to be attached to an opposite side of the poled piezoelectric material layer than the first impedance matching layer, wherein the poled piezoelectric material layer and the first and second impedance matching layers having a non-descending acoustic impedance.