Design and Optimization of Inverse Phononic Crystals in Gallium Arsenide for Enhanced Surface Acoustic Waveguiding
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Authors
Singh, Karanpreet
Date
2024-07-03
Type
thesis
Language
eng
Keyword
Computational Physics
Alternative Title
Abstract
This research designs and optimizes inverse phononic crystal waveguides for efficient surface acoustic wave (SAW) propagation in Gallium Arsenide. Traditional SAW waveguides often suffer from limitations such as beam spreading and energy leakage into the bulk substrate. This work introduces periodic inclusions into the substrate to reduce the SAW eigenfrequency modes below the bulk shear horizontal mode.
A comprehensive finite element method simulation framework is established to analyze the band structure and displacement fields of various phononic crystal designs, employing rigorous mesh and boundary sensitivity analyses to ensure result accuracy. While initial optimization studies on cylindrical inclusions reveal limitations in achieving strong confinement, exploration of alternative geometries, including ellipsoids and elliptical cylinders, demonstrate significant improvements.
The research culminates in the design of a four-inclusion wide waveguide using elliptical cylinders, which achieves logarithmic reciprocal attenuation ten orders of magnitude better than prior designs indicating extremely strong confinement to the surface and minimal energy leakage into the bulk. This innovative waveguide design promises to enhance a wide range of applications that require efficient on-chip SAW manipulation.