An experimental study of the insertion loss changes with mass and viscous liquid loading has been carried out for the first, second and third order modes of a polymer coated Love wave acoustic sensor. Devices were fabricated on ST-cut Quartz, coated with various thickness of polymer and operated at a fundamental frequency of 110 MHz. The effect of increasing the over-layer thickness was investigated and higher order Love wave modes were observed. A systematic study of insertion loss changes as a function of deposited mass was carried out for devices incorporating guiding layers of thickness up to 12 micron by depositing thin films of gold and tin on the propagation path. In addition, sensitivity to viscous loading was investigated on the first, second and third Love modes by applying solutions of poly(ethylene glycol) with increasing densities. The change in insertion loss of the higher order modes for both experiments is shown to be of the same order of magnitude as the first Love wave mode.
- Love wave