Theoretical Analysis of Propagation Characteristics of Ultra-Wideband Surface Acoustic Wave Devices
| Autor: | Bing-Jun Zhang, 張稟軍 |
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| Rok vydání: | 2016 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 104 This study focuses on how to use the finite element method (FEM) software Comsol Multiphysics to analyze the propagation characteristics of surface acoustic wave (SAW) devices. The substrate material used in this study is LiNbO3. Characteristics with different propagation directions and various cutting angles will be studied using Comsol Multiphysics 3D module. In addition, the effects of inter-digital transducers (IDTs) will be investigated. Two types of structures such as IDT/ LiNbO3 and IDT/ LiNbO3/IDT will be studied. In this thesis, we determine the optimum thickness of the substrate plate with maximum coupling coefficient via the analysis of SAW characteristics at different thicknesses, different propagation modes, and different propagation directions. The effects of IDTs with different arrangements, different meal materials, various electrode thicknesses, and different metallization ratios on phase velocity, coupling coefficient, and reflectivity are then investigated. Simulation results indicate that when the plate thickness is around 0.1 wavelength, the coupling coefficient is around 70%, which can be used to design the wideband filters for wireless communications applications. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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