Fabrication of a Dual Frequency Lamb Wave Resonator Using Phononic Gratings
Date Issued
2011
Date
2011
Author(s)
Lan, Chih-Wei
Abstract
Phononic crystal (PC) is composed of different materials periodically. One of the most important phenomena of PC is the band gap. Band gap is the frequency space that elastic wave could not propagate through the structure. The resonant phenomena of dual frequency resonator and bandpass filter using PC gratings are studied by numerical simulation and fabrication in this thesis.
The dispersion relations of phononic crystals were calculated by using the finite element method (FEM). To optimize the resonance inside the cavity, the effective reflective plane, transmission coefficient and frequency response were obtained through a series of numerical simulations. Beside, the design of ladder type filter is finish from coupling two one-port resonators together.
On the experimental side, both dual frequency resonator and bandpass filter were fabricated. The measured resonant frequencies are in a good agreement with the numerical predictions. In the dual frequency resonator side, two different resonant with different cavity were measured, 158.29 MHz and 164.45MHz respectively. In the ladder type filter side, a bandpass phenomenon is measured, center frequency is 159.17 MHz and bandwidth is 0.11 MHz.
Subjects
Lamb wave resonator
Lamb wave filter
Phononic crystal
Band gap
Finite element method
Q factor
Type
thesis
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