US Patent 7288878 Piezoelectric transducer assembly

A transducer assembly may comprise a thickness-mode piezoelectric ceramic body, a pair of foil conductors with mesh end portions, and a coupling medium used to fill in the interstices in the meshes. The foil conductors are held in contact with the electrode layers by a selected combination of adhesive mechanical clamping forces. One of the conductors is placed between one face of the ceramic body and a window that separates the transducer assembly from a fluid to be measured. The other conductor is held between the other face of the ceramic body and a backing body, which may be an acoustic isolator or a resonant isolating structure comprising a resonant body and an acoustic mass that is substantially heavier than the ceramic element. The structure may additionally comprise isolating sheets of material, which may be polymeric, that are positioned on either side of the resonator so that one of them is between the resonator and the backing body and the other is between the resonator and the surface with the foil conductor.