scholarly journals Experimental study of guiding and filtering of acoustic waves in a two dimensional ultrasonic crystal

2005 ◽  
Vol 220 (9-10) ◽  
Author(s):  
Abdelkrim Khelif ◽  
Abdelkrim Choujaa ◽  
Sarah Benchabane ◽  
Bahram Djafari-Rouhani ◽  
Vincent Laude
Keyword(s):  
Band Gap ◽  
Acoustic Waves ◽  
Theoretical Study ◽  
Phononic Crystal ◽  
Wide Frequency Range ◽  
Two Dimensional ◽  
Full Band ◽  
Side Walls ◽  
Difference Time ◽  
Good Agreement

AbstractWe present a combined experimental and theoretical study of the guiding, bending and filtering of acoustic waves in an ultrasonic crystal. The crystal consists of a two-dimensional periodical array of steel rods immersed in water, for wich a complete acoustic band gap extending from 240 to 325 kHz is found experimentally. Waveguides for acoustic waves are further created by removing a line defect, on which stubs can be added by removing rods from the side-walls of the waveguide. Full transmission is observed for a one-period-wide straight waveguide within the full-band-gap of the perfect phononic crystal, i.e. for a waveguide aperture smaller than one acoustic wavelength. Waveguiding over a wide frequency range is also obtained for a one-period-wide waveguide with two sharp 90° bends. Finite-difference time-domain computations are found to be in good agreement with the measurements in all experimental configurations.

scholarly journals Full band gap for surface acoustic waves in a piezoelectric phononic crystal

2005 ◽  
Vol 71 (3) ◽  
Author(s):  
Vincent Laude ◽  
Mikaël Wilm ◽  
Sarah Benchabane ◽  
Abdelkrim Khelif
Keyword(s):  
Band Gap ◽  
Acoustic Waves ◽  
Phononic Crystal ◽  
Surface Acoustic Waves ◽  
Full Band

A Novel Micromechanical Resonator Using Two-Dimensional Phononic Crystal Slab

2011 ◽  
Vol 254 ◽  
pp. 195-198
Author(s):  
Nan Wang ◽  
Fu Li Hsiao ◽  
Moorthi Palaniapan ◽  
Ming Lin Julius Tsai ◽  
Jeffrey B.W. Soon ◽  
...  
Keyword(s):  
Acoustic Waves ◽  
Phononic Crystal ◽  
Acoustic Resonance ◽  
Two Dimensional ◽  
Free Standing ◽  
Sensing Applications ◽  
Aln Film ◽  
Digital Transducers ◽  
Square Array ◽  
Quality Factor Q

Two-dimensional (2-D) Silicon phononic crystal (PnC) slab of a square array of cylindrical air holes in a 10μm thick free-standing silicon plate with line defects is characterized as a cavity-mode PnC resonator. Piezoelectric aluminum nitride (AlN) film is deployed as the inter-digital transducers (IDT) to transmit and detect acoustic waves, thus making the whole microfabrication process CMOS-compatible. Both the band structure of the PnC and the transmission spectrum of the proposed PnC resonator are analyzed and optimized using finite element method (FEM). The measured quality factor (Q factor) of the microfabricated PnC resonator is over 1,000 at its resonant frequency of 152.46MHz. The proposed PnC resonator shows promising acoustic resonance characteristics for RF communications and sensing applications.

Far-field focusing of acoustic waves by a two-dimensional phononic crystal with surface grating

2009 ◽  
Vol 87 (5) ◽  
pp. 57003 ◽  
Author(s):  
Zhaojian He ◽  
Xiaochun Li ◽  
Ke Deng ◽  
Jun Mei ◽  
Zhengyou Liu
Keyword(s):  
Acoustic Waves ◽  
Phononic Crystal ◽  
Far Field ◽  
Two Dimensional ◽  
Surface Grating

Full Band-Gap Silicon Phononic Crystals for Surface Acoustic Waves

2006 ◽  
Author(s):  
Saeed Mohammadi ◽  
Abdelkrim Khelif ◽  
Ryan Westafer ◽  
Eric Massey ◽  
William D. Hunt ◽  
...  
Keyword(s):  
Band Gap ◽  
Acoustic Waves ◽  
Phononic Crystal ◽  
Surface Acoustic Waves ◽  
Hexagonal Lattice ◽  
Phononic Crystals ◽  
Bulk Wave ◽  
Filling Fraction ◽  
Phononic Band Gap ◽  
Wide Range

Periodic elastic structures, called phononic crystals, show interesting frequency domain characteristics that can greatly influence the performance of acoustic and ultrasonic devices for several applications. Phononic crystals are acoustic counterparts of the extensively-investigated photonic crystals that are made by varying material properties periodically. Here we demonstrate the existence of phononic band-gaps for surface acoustic waves (SAWs) in a half-space of two dimensional phononic crystals consisting of hexagonal (honeycomb) arrangement of air cylinders in a crystalline Silicon background with low filling fraction. A theoretical calculation of band structure for bulk wave using finite element method is also achieved and shows that there is no complete phononic band gap in the case of the low filling fraction. Fabrication of the holes in Silicon is done by optical lithography and deep Silicon dry etching. In the experimental characterization, we have used slanted finger interdigitated transducers deposited on a thin layer of Zinc oxide (sputtered on top of the phononic crystal structure to excite elastic surface waves in Silicon) to cover a wide range of frequencies. We believe this to be the first reported demonstration of phononic band-gap for SAWs in a hexagonal lattice phononic crystal at such a high frequency.

Acoustic Waves in Two-Dimensional Phononic Crystals With Reticular Geometric Structures

2011 ◽  
Vol 133 (3) ◽  
Author(s):  
Zi-Gui Huang ◽  
Zheng-Yu Chen
Keyword(s):  
Band Gap ◽  
Acoustic Waves ◽  
Phononic Crystals ◽  
Band Gaps ◽  
Sound Insulation ◽  
Two Dimensional ◽  
Elastic Band ◽  
Geometric Structures ◽  
2D And 3D ◽  
Elastic Band Gaps

Previous studies on photonic crystals raise the exciting topic of phononic crystals. This paper presents the results of tunable band gaps in the acoustic waves of two-dimensional phononic crystals with reticular geometric structures using the 2D and 3D finite element methods. This paper calculates and discusses the band gap variations of the bulk modes due to different sizes of reticular geometric structures. Results show that adjusting the orientation of the reticular geometric structures can increase or decrease the total elastic band gaps for mixed polarization modes. The band gap phenomena of elastic or acoustic waves can potentially be utilized to achieve vibration-free, high-precision mechanical systems, and sound insulation.

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