The multi-layered effective permittivity function applied to the mass loading and viscous coupling in shear horizontal-acoustic plate modes

It is now well known that acoustic plate wave devices are very promising as gravimetric sensors in liquid phase as well as liquid properties sensors. Here, a model based on the effective permittivity function is developed to take into account the multi-layered configuration of these devices operatin g in liquid phase. Indeed, for gravimetric applications, a three-layered co nfiguration is implemented: the piezoelectric plate, the elastic solid film and the semi-infinite liquid medium. The predictions of the model for an i ncreasing solid film thickness are compared with experimental measurements obtained by electrodeposition. For the determination of liquid properties, a two-layered configuration is appropriate: the piezoelectric plate loaded by the liquid medium. Here, particular attention is paid to the effect of t he density and the viscosity of the liquid medium on the device response. T he theoretical results are compared with measurements performed with aqueou s glycerol solutions, whose density and viscosity increase with concentrati on of glycerol. For high concentrations, the Maxwellian behavior of the aqu eous glycerol solutions allows to determine the shear rigidity modulus of g lycerol. (C) 1999 Elsevier Science S.A. All rights reserved.