scholarly journals Highly Confined Love Waves Modes by Defects States in a Phononic Crystal Based on Holey-SiO2/ST-Cut Quartz Structure

Proceedings ◽  
2018 ◽  
Vol 2 (13) ◽  
pp. 729
Author(s):  
Yu-Xin Liu ◽  
Abdelkrim Talbi ◽  
Philippe Pernod ◽  
Olivier Bou Matar
Keyword(s):  
Band Gap ◽  
High Performance ◽  
Quartz Substrate ◽  
Phononic Crystal ◽  
Optimal Choice ◽  
Comsol Multiphysics ◽  
Geometrical Parameters ◽  
Transmission Spectra ◽  
Cavity Resonators ◽  
Made In

We investigate the properties of highly confined Love modes in a phononic crystal based on an array of holes made in SiO2 deposited on ST-cut Quartz substrate. An optimal choice of the geometrical parameters of the holes enables us to obtain wide stop-bands frequency for shear wave’s modes. The introduction of defect by removing lines of holes leads to nearly flat modes within the band gap and consequently paves the way to implement advanced design of electroacoustic filters and high-performance cavity resonators based on shear wave modes. The calculations are performed using finite element method based on the commercial software (COMSOL-Multiphysics). For transmission spectra, piezoelectric excitations are applied by considering the interdigital transducers, with results corroborating well the band structure predictions and the position of defects modes within the band gap.

Low-frequency and tuning characteristic of band gap in a symmetrical double-sided locally resonant phononic crystal plate with slit structure

2016 ◽  
Vol 30 (27) ◽  
pp. 1650203 ◽  
Author(s):  
X. P. Wang ◽  
P. Jiang ◽  
A. L. Song
Keyword(s):  
Band Gap ◽  
Power Transmission ◽  
Phononic Crystal ◽  
Low Frequency ◽  
Band Gaps ◽  
Geometrical Parameters ◽  
Band Frequency ◽  
Practical Applications ◽  
Tuning Characteristic ◽  
Lower Frequencies

In this paper, the low-frequency and tuning characteristic of band gap in a two-dimensional phononic crystal structure, consisting of a square array of aluminum cylindrical stubs deposited on both sides of a thin rubber plate with slit structure, are investigated. Using the finite element method, the dispersion relationships and power transmission spectra of this structure are calculated. In contrast to a typical phononic crystal without slit structure, the proposed slit structure shows band gaps at lower frequencies. The vibration modes of the band gap edges are analyzed to clarify the mechanism of the lowest band gaps. Additionally, the influence of the slit parameters and stub parameters on the band gaps in slit structure are investigated. The geometrical parameters of the slits and stubs were found to influence the band gaps; this is critical to understand for practical applications. These results will help in fabricating phononic crystal structures whose band frequency can be modulated at lower frequencies.

scholarly journals Numerical Analysis of Viscous Dissipation in Microchannel Sensor Based on Phononic Crystal

Micromachines ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 994
Author(s):  
Juxing He ◽  
Honglang Li ◽  
Yahui Tian ◽  
Qiaozhen Zhang ◽  
Zixiao Lu ◽  
...  
Keyword(s):  
Band Gap ◽  
Viscous Dissipation ◽  
Chemical Sensors ◽  
Phononic Crystal ◽  
Micro Electro Mechanical System ◽  
Channel Length ◽  
Optimal Choice ◽  
Phononic Crystals ◽  
Flowing Liquid ◽  
Area Of Interest

Phononic crystals with phononic band gaps varying in different parameters represent a promising structure for sensing. Equipping microchannel sensors with phononic crystals has also become a great area of interest in research. For building a microchannels system compatible with conventional micro-electro-mechanical system (MEMS) technology, SU-8 is an optimal choice, because it has been used in both fields for a long time. However, its mechanical properties are greatly affected by temperature, as this affects the phononic bands of the phononic crystal. With this in mind, the viscous dissipation in microchannels of flowing liquid is required for application. To solve the problem of viscous dissipation, this article proposes a simulation model that considers the heat transfer between fluid and microchannel and analyzes the frequency domain properties of phononic crystals. The results show that when the channel length reaches 1 mm, the frequency shift caused by viscous dissipation will significantly affect detecting accuracy. Furthermore, the temperature gradient also introduces some weak passbands into the band gap. This article proves that viscous dissipation does influence the band gap of phononic crystal chemical sensors and highlights the necessity of temperature compensation in calibration. This work may promote the application of microchannel chemical sensors in the future.

ONE-DIMENSIONAL PHONONIC CRYSTAL SLABS BORDERED WITH ASYMMETRIC UNIFORM LAYERS

2012 ◽  
Vol 26 (23) ◽  
pp. 1250133 ◽  
Author(s):  
HONG-BO ZHANG ◽  
JIU-JIU CHEN ◽  
XU HAN
Keyword(s):  
Band Gap ◽  
Lamb Waves ◽  
Phononic Crystal ◽  
Comsol Multiphysics ◽  
Total Thickness ◽  
Plane Wave Expansion ◽  
Fe Method ◽  
One Dimensional ◽  
Gap Width ◽  
Band Gap Width

We investigate theoretically the propagation of Lamb waves in a one-dimensional phononic crystal (PC) slabs bordered with asymmetric uniform layers based on the supercell plane wave expansion (SC-PWE) method. The validity is proved by using the finite-element (FE) method with Comsol Multiphysics 3.5a. The effect of changing the thickness of substrate and superstrate on the variation of the band gap width and frequency are studied when the total thickness of the loading layers is fixed. We also investigate the property of band gap maps by changing the total thickness or the material of the loading layers. The results show that the band structure can be tuned by changing the material or the thickness of the substrate or the superstrate. These structures may be used as filters and acoustic sensors.

scholarly journals Tunable Low Frequency Band Gap and Waveguide of Phononic Crystal Plates with Different Filling Ratio

Crystals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 828
Author(s):  
Shaobo Zhang ◽  
Jiang Liu ◽  
Hongbo Zhang ◽  
Shuliang Wang
Keyword(s):  
Band Gap ◽  
Composite Structure ◽  
Structural Parameters ◽  
Phononic Crystal ◽  
Low Frequency ◽  
Filling Ratio ◽  
Height Ratio ◽  
Road Vehicles ◽  
Aluminum Base ◽  
Gap Width

Aiming at solving the NVH problem in vehicles, a novel composite structure is proposed. The new structure uses a hollow-stub phononic-crystal with filled cylinders (HPFC) plate. Any unit in the plate consists of a lead head, a silicon rubber body, an aluminum base as outer column and an opposite arranged inner pole. The dispersion curves are investigated by numerical simulations and the influences of structural parameters are discussed, including traditional hollow radius, thickness, height ratio, and the new proposed filling ratio. Three new arrays are created and their spectrum maps are calculated. In the dispersion simulation results, new branches are observed. The new branches would move towards lower frequency zone and the band gap width enlarges as the filling ratio decreases. The transmission spectrum results show that the new design can realize three different multiplexing arrays for waveguides and also extend the locally resonant sonic band gap. In summary, the proposed HPFC structure could meet the requirement for noise guiding and filtering. Compared to a traditional phononic crystal plate, this new composite structure may be more suitable for noise reduction in rail or road vehicles.

Electronic structure engineering of tin telluride through co-doping of bismuth and indium for high performance thermoelectrics: a synergistic effect leading to a record high room temperature ZT in tin telluride

2019 ◽  
Vol 7 (16) ◽  
pp. 4817-4821 ◽  
Author(s):  
U. Sandhya Shenoy ◽  
D. Krishna Bhat
Keyword(s):  
Electronic Structure ◽  
Synergistic Effect ◽  
Band Gap ◽  
High Performance ◽  
Room Temperature ◽  
Band Offset ◽  
Valence Band Offset ◽  
Co Doping ◽  
Tin Telluride ◽  
Structure Engineering

Resonance states due to Bi and In co-doping, band gap enlargement, and a reduced valence-band offset in SnTe lead to a record high room-temperature ZT.

Optical Studies of Poly (N-Carbazole) (PVK) Blending with Polyvinylpyrrolidone (PVP) Using Tauc/Davis-Mott Model

2013 ◽  
Vol 652-654 ◽  
pp. 527-531 ◽  
Author(s):  
A.N. Alias ◽  
T.I. Tunku Kudin ◽  
Z.M. Zabidi ◽  
M.K. Harun ◽  
Ab Malik Marwan Ali ◽  
...  
Keyword(s):  
Band Gap ◽  
Urbach Energy ◽  
Quartz Substrate ◽  
Optical Studies ◽  
Direct Band Gap ◽  
Mott Model ◽  
Blended Polymer ◽  
Electronic Parameters ◽  
Direct Band ◽  
Indirect Band Gap

The optical absorption spectra of blended poly (N-carbazole) (PVK) with polyvinylpyrrolidone (PVP) in various compositions are investigated. A doctor blade technique was used to coat the blended polymer on a quartz substrate. The electronic parameters such as absorption edge (Ee), allowed direct band gap (Ed), allowed indirect band gap (Ei), Urbach edge (Eu) and steepness parameter (γ) were calculated using Tauc/Davis-Mott Model. The results reveal that the Ee, Ed and Ei increase with increasing of PVP ratio. There also have variation changing in Urbach energy and steepness parameter.

Band gap and defect state engineering in a multi-stub phononic crystal plate

2015 ◽  
Vol 117 (15) ◽  
pp. 154301 ◽  
Author(s):  
Ping Jiang ◽  
Xiao-Peng Wang ◽  
Tian-Ning Chen ◽  
Jian Zhu
Keyword(s):  
Band Gap ◽  
Phononic Crystal ◽  
Crystal Plate ◽  
Defect State
Sign in / Sign up

Export Citation Format

Share Document