Patent ID: 7716986

Claim:
An acoustic wave sensing device, comprising: a piezoelectric substrate having a thicker portion and a thinner portion with a thickness smaller than a wavelength of a propagated acoustic wave and meeting a requirement for producing a flexural plate wave (FPW), wherein the thinner portion is formed via a micromachining process or a chemical process; an inter-digital transducer disposed on an upper side or a lower side of the thinner portion of the piezoelectric substrate, the inter-digital transducer having a first electrode and a second electrode, wherein a propagation path located between the first electrode and the second electrode is coated with a sensing material capable of sensing liquid or gas particles and provides a sensing area; a protective layer coated on the first electrode and the second electrode; and a micro-channel that receives gas or liquid, the micro-channel being formed on the sensing area via the micromachining process or the chemical process.