BAE Systems PLC
Transducer

Abstract:

An electroacoustic transducer, comprising a piezoelectric part comprising a piezoelectric material having a first acoustical impedance and an acoustical thickness, a substrate part comprising a material having a second acoustical impedance, and an intermediate part comprising a material having a third acoustical impedance and at least partially sandwiched between the piezoelectric part and the substrate part for acoustical communication therewith. The first acoustical impedance and the second acoustical impedance each has a respective value within a range of values for which the value of third acoustical impedance: is an upper limit if said acoustical thickness is less than 0.4.LAMBDA., or is a lower limit if said acoustical thickness is greater than 0.4.LAMBDA. where .LAMBDA. is an acoustical wavelength in the material of the piezoelectric part.