Theory, modeling and characterization of PZT-on-alumina resonant piezo-layers as acoustic-wave mass sensors

Abstract Lead zirconate titanate (PZT) films screen-printed on alumina substrate form composite piezoelectric resonators that can be exploited as acoustic-wave mass sensors. The paper presents a theoretical treatment of such layered resonators based on the use of the Mason’s model to derive the expression of the distributed-parameter electric impedance, followed by an approximation yielding a lumped-element equivalent circuit valid around the sensor fundamental resonance. Expressions for the resonant frequency and mass sensitivity are obtained, which are validated by experimental results relative to PZT thick-film sensors. The model is of general applicability, provided that the PZT and substrate operate close to their quarter-wave resonance.