Practical design of Love wave viscosity sensors using the eighth dimensional matrix formulation

There are increasing research activities on Love wave devices in biochemical sensing application due to its high sensitivity and low acoustic damping. This paper aims at practical design of Love wave devices for liquid viscosity sensing based on effective permittivity approach and eighth dimension matrix formulation. First, we adopted the effective permittivity approach to calculate and discuss electromechanical coupling coefficient and temperature dependence of the 0th-order Love wave in ZnO/quartz layered structures. Besides, since the measured targets are liquid, reducing wave attenuation and increasing sensitivity become two important issues for the optimum design of a Love wave sensor. To take into account the effect of liquid viscosity on the device sensitivity, we adopted the eighth dimension matrix formulation to calculate phase velocity dispersion and wave attenuation of Love wave devices loaded with water. Finally, we also compared the calculated sensitivity with the existing experimental results. Results show that the proposed approach provided a satisfactory prediction of the device sensitivity of a Love wave liquid sensor.