Design,Preparation And Some Applied Research Of Surface Acoustic Wave Device

In recent years,with the development of electronic information technology,both researchers and industry technical staff are increasing interest in surface acoustic wave devices.Surface acoustic wave is a kind of propagation along the surface,the energy to focus on near the surface of the elastic wave,has been widely used in today's world of radio communications,military electronic equipment,biological sensing,personal and home consumer electronics,and many other fields.Nowadays Billions of SAW devices are manufactured and applied in the Global mobile phone markets.So SAW devices are closely linked with all aspects of human life.This thesis is mainly focused on the design and preparation of IDT,and has been Theoretical research and experimental observationlocal of the resonant surface phononic crystals based on lithium niobate substrate and Microfluidic based on surface acoustic wave system.The details are list as follows:On LiNbO3,the author developed two kinds of preparation processes to fabricate the IDT practically:one is using lift off process,This method need to printing the pattern of the structured,then plating metal film,the last is lift off.Another is wet etching process,this method need to be coated with a layer of metal film,and then printing the pattern of the structured,Finally the samples into the chemical etching liquid for processing.On LiNbO3,the author developed two kinds of preparation processes to fabricate the phononic crystal practically:one is based on the reactive ion etching(RIE)technique to realize periodical hollow structure.Another is based on the LIGA technique to get periodic metal pillars attached on the substrate.By using three dimensional finite element method(3D-FEM),the author established a method based on piezoelectric,dielectric and elastic relations to calculate the band structure of phononic,especially with the lithium niobate(LiNb03)substrate.This method has been provided of great accuracy/efficiency,and is applied in the full thesis.The velocity of surface acoustic wave propagation is different in the solid surface and in the liquid,the fluid-solid coupling will be produced and use this kind of effect can be observed in the microfluidic channels a lot of interesting phenomenon,including the atomized droplets,the flow of the liquid droplets and so on.