Simulation and measurement of low permittivity media with LiNbO3 and LiTaO3 LFE resonators

The focus of this work is the measurement of viscous liquids with lateral field excited (LFE) resonators. Since a large electromechanical coupling factor k is supposed to be favourable for decreased sensitivity to the adjacent media´s viscosity, different materials (LiNbO₃, LiTaO₃ and quartz) having larger electromechanical coupling factors have been applied and compared. Additionally, an electrode configuration different to the standard coplanar LFE pattern has been investigated. Simulations have been performed concerning changes in mechanical and electrical properties of quartz crystals with the variation of the permittivity of the surrounding media. Corresponding electronic circuits for impedance analysis has been developed.