On the basis of SAW technology, this thesis designs a SAW humidity sensor. Include the design of IDT (interdigital transducer), the thin film as well as the frequency measurement system.

To solve these problems, the properties of Lamb wave excited by interdigital transducer in the piezoelectric substrate covered by liquid were studied based on its piezoelectricity and anisotropy.

SAW excited by input interdigital transducer is divided centrosymmetrically into two paths detected by their output interdigital transducer.