| Summary: | 碩士 === 國立臺灣大學 === 應用力學研究所 === 97 === In general, surface acoustic wave and Lamb wave resonator using piezoelectric material with IDTs to generate elastic waves. The resonant cavity is formed by adoption of metal gratings to be reflector. As usual, the efficiency of metal gratings is limited, and the grating structures occupy lots of space. In this thesis, the phononic crystal is imported to improve the resonator performance. The most characteristic of phononic crystals is the band-gap phenomenon, obstructing acoustic waves in a specific frequency range. The purpose is to design a resonator with higher resonance efficiency by phononic crystal reflective gratings.
In this study, the finite element method (FE method) is applied to predict the dispersion relation of two-dimensional air/silicon phononic crystal plate. The effect of reflective distance between wave source and phononic crystal is calculated and discussed. Moreover, air/silicon as phononic crystal plate and ZnO/Si as Lamb wave generator are fabricated. The experimental results are measured and discussed. The effect of phononic crystal gratings is verified.
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