scholarly journals Attenuation coefficient for surface acoustic waves in fluid region

2012 ◽  
Vol 34 (4) ◽  
pp. 225-236 ◽  
Author(s):  
Bui Thu Hang ◽  
Bui Duc Tung ◽  
Nguyen Tien Dat ◽  
Chu Duc Trinh
Keyword(s):  
Acoustic Waves ◽  
Surface Acoustic Waves ◽  
High Sensitivity ◽  
Electrical Signal ◽  
Stream Velocity ◽  
Signal Attenuation ◽  
Leaky Waves ◽  
Sensing Applications ◽  
Fluid Properties ◽  
Acoustic Wave Devices

In recent years, surface acoustic wave devices used in bio-sensing applications have demonstrated high sensitivity in the detection of fluid properties such as density, viscosity, stream velocity. In this paper, a more effective measurement of the SAWsensorstructure is presented. It is reported that at density of 6 g/cm3, the amplitude of mechanical wave is excited while for electrical signal, attenuation at 3 g/cm3 reaches a peak.In our analysis, single–crystal Aluminium Nitride substrate is used. Several parameters of leaky waves including displacement, decay constant in the liquid media are analyzed.

LEAKY SURFACE ACOUSTIC WAVES IN SINGLE-CRYSTAL AlN SUBSTRATE

2004 ◽  
Vol 14 (03) ◽  
pp. 837-846 ◽  
Author(s):  
GANG BU ◽  
DAUMANTAS CIPLYS ◽  
MICHAEL S. SHUR ◽  
LEO J. SCHOWALTER ◽  
SANDRA B. SCHUJMAN ◽  
...  
Keyword(s):  
Single Crystal ◽  
Acoustic Waves ◽  
Electromechanical Coupling ◽  
Surface Acoustic Waves ◽  
Propagation Direction ◽  
Electromechanical Coupling Coefficient ◽  
Coupling Coefficients ◽  
Leaky Waves ◽  
Temperature Coefficient Of Frequency ◽  
Piezoelectric Constants

We report on the velocity V and the electromechanical coupling coefficient K2 of the first and the second leaky surface acoustic waves in various propagation directions in the a-plane AlN single-crystal. For c-propagation direction, the second leaky wave exhibited the velocity of 11016 m/s and K2 of 0.45%. For this direction, the temperature coefficient of frequency was found to be -30 ppm/°C. A near match of the velocities of the plane and leaky waves in the a-plane AlN allowed us to establish analytical relationships between the piezoelectric and elastic constants. A full set of elastic and piezoelectric constants of AlN has been evaluated by fitting the measured and calculated dependencies of velocities and electromechanical coupling coefficients on the propagation direction for both Rayleigh and leaky waves.

scholarly journals Preliminary Exploration of Cell-Based SAW Detection for Water Toxicity

2018 ◽  
Author(s):  
Kun-Lin Lee ◽  
Fang Li ◽  
Anis Nurashikin Nordin ◽  
Ioana Voiculescu
Keyword(s):  
Fundamental Frequency ◽  
Acoustic Waves ◽  
Surface Acoustic Waves ◽  
Phase Cell ◽  
Sh Wave ◽  
Liquid Environment ◽  
Sensing Applications ◽  
Surface Sensing ◽  
Water Based ◽  
Theoretical Fundamental

Nowadays, many surface sensing mechanisms exist, not all of them can be applied in water-based environment. Most of surface sensing techniques were developed in air-based environment. In order to obtain a potential cell-based biosensor, the sensing method needs to be reliable and repeatable in liquid environment. Therefore, we adapt existing air-based surface acoustic sensor and promote the technology into water-based applications. The goal of this study is to apply surface acoustic waves (SAW) for water-based environment sensing. We will use shear horizontal wave (SH wave) as surface sensing mechanism. SH wave is a type of surface acoustic waves (SAW) which can be used for weight/mass sensing in the air environment. Interdigitated transducers (IDTs) induce the deformation of an ST-cut quartz crystal substrate in AC source and generate waves. With a thin layer of polymer like Parylene and polyimide, the SH wave will be confined between the interface of substrate and polymer layer without suffering the energy loss due to the liquid damping from above. The fundamental frequency of the SAW device is defined by the spacing between the electrodes of IDT. The frequency of interests for this research is below 100 MHz in water-based environment. Due to the stable frequency characteristics of ST-cut quartz in room temperature, this SAW device can be a good candidate for field applications. From an early IDTs design, investigation in material and IDTs configuration is necessary to improve signal quality in order to qualify for liquid phase cell-based bio-sensing applications. A simplified 3D unit cell FEM model is created to study the thickness effects of wave-guide and electrodes. Boundary conditions and assumptions are discussed in the modeling. The simulated eigenfrequency of SH mode is close to the theoretical fundamental frequency of the 64μm wavelength IDTs. The mass damping effects from gold electrodes is more significant than aluminum electrodes.

Modeling Development of a High-Sensitivity Escherichia coli O157:H7 Detection Based on SH SAW Sensor

2014 ◽  
Vol 925 ◽  
pp. 595-599
Author(s):  
Seng Teik Ten ◽  
Uda Hashim ◽  
Ahmad Sudin ◽  
Wei Wen Liu ◽  
Kai Loong Foo ◽  
...  
Keyword(s):  
Acoustic Waves ◽  
High Performance ◽  
Surface Acoustic Waves ◽  
Equivalent Circuit Model ◽  
High Sensitivity ◽  
Theoretical Models ◽  
Acoustic Energy ◽  
Sensitive Detection ◽  
Label Free ◽  
Element Analysis

Surface acoustic waves based devices were initially developed for the telecommunication purpose such as signal filters and resonators. The acoustic energy is strongly confined on the surface of the surface acoustic waves (SAW) based devices and consequent their ultra-sensitivity to the surface perturbation. This has made SAW permits the highly sensitive detection of utterly diminutive charges on the surface. Hence, SAW based devices have been modified to be sensors. Food contamination has become critical issue and sensitive detection devices are needed urgently as small amount of harmful bacterial pathogens such as Escherichia coli (E.coli) O157:H7with the dose fewer than 100 organisms in food products or water is enough to cause serious gastrointestinal illness to human. Therefore, ultra-high sensitive, label free biosensors have been designed in this research for the low concentration E.coli detection. After the saturated development in telecommunication filed, SAW sensors were developed for gas detections and have been moving towards biological detections recently. Shear horizontal surface acoustic wave (SHSAW), one of the SAW based types is most suitable for the liquid based application as it has the advantage of acoustic energy is not being radiated into liquid. Therefore, SHSAW device has the potential to provide high-performance sensing platform in this research. There have been a lot of complicated theoretical models for the SAW devices development since 1960 as signal filters and resonators such as from delta function model, equivalent circuit model, to the current SAW models such as coupling-of-modes (COM) model, P-matrix model and finite element analysis (FEA) model. However, SHSAW device in this research is not meant for signal filter or resonators but used for surface sensing purpose, therefore the simplicity method of the modeling is presented in the paper for the E.coli detection sensor development.

scholarly journals Rapid ultrasonic isothermal amplification of DNA with multiplexed melting analysis – applications in the clinical diagnosis of sexually transmitted diseases

2015 ◽  
Vol 51 (13) ◽  
pp. 2589-2592 ◽  
Author(s):  
Gaolian Xu ◽  
Rory N. Gunson ◽  
Jonathan M. Cooper ◽  
Julien Reboud
Keyword(s):  
Sexually Transmitted Diseases ◽  
Clinical Diagnosis ◽  
Acoustic Waves ◽  
Surface Acoustic Waves ◽  
High Sensitivity ◽  
Isothermal Amplification ◽  
Sexually Transmitted ◽  
Melting Analysis

We demonstrate an acoustic platform for the multiplexed isothermal amplification of sexually transmitted diseases. The use of surface acoustic waves (SAW) enabled faster detection with high sensitivity down to 10 copies.

scholarly journals Correlation of BAW and SAW properties of langasite at elevated temperatures

2015 ◽  
Vol 4 (2) ◽  
pp. 331-340 ◽  
Author(s):  
M. Schulz ◽  
E. Mayer ◽  
I. Shrena ◽  
D. Eisele ◽  
M. Schmitt ◽  
...  
Keyword(s):  
Acoustic Wave ◽  
Acoustic Waves ◽  
Elevated Temperatures ◽  
Surface Acoustic Waves ◽  
Propagation Loss ◽  
Bulk Acoustic Wave ◽  
Coupling Coefficients ◽  
Data Set ◽  
Acoustic Wave Devices ◽  
Bulk Acoustic Wave Resonators

Abstract. The full set of electromechanical data of langasite (La3Ga5SiO14) is determined in the temperature range from 20 to 900 °C using differently oriented bulk acoustic wave resonators. For data evaluation a physical model of vibration is developed and applied. Thereby, special emphasis is taken on mechanical and electrical losses at high temperatures. The resulting data set is used to calculate the properties of surface acoustic waves. Direct comparison with experimental data such as velocity, coupling coefficients and propagation loss measured using surface acoustic wave devices with two different crystal orientations shows good agreement.

Integrated ZnO Film Based Acoustic Wave Microfluidics and Biosensors

2010 ◽  
Vol 67 ◽  
pp. 49-58 ◽  
Author(s):  
Jack K. Luo ◽  
Y.Q. Fu ◽  
Greg Ashley ◽  
Williams I. Milne
Keyword(s):  
Acoustic Wave ◽  
Acoustic Waves ◽  
Low Cost ◽  
Surface Acoustic Waves ◽  
Acoustic Streaming ◽  
Film Surface ◽  
High Sensitivity ◽  
Zno Film ◽  
Actuation Mechanism ◽  
Saw Devices

Lab-on-a-chip (LOC) is one of the most important microsystems with promising applications in microanalysis, drug development and diagnosis, etc. We have been developing a LOC biodetection system using acoustic wave as a single actuation mechanism for both microfluidics and biosensing using low cost piezoelectric ZnO film. Surface acoustic waves (SAW) coupled into the liquid will induce acoustic streaming, or move the droplet on the surface. These have been utilized to make SAW-based micropumps and micromixers which are simple in structure, easy to fabricate, low cost, reliable and efficient. SAW devices and thin film bulk acoustic resonators (FBAR) have been fabricated on nanocrystalline ZnO thin films deposited using sputtering on Si substrates. A streaming velocity up to ~5cm/s within a microdroplet and a droplet moving speed of ~1cm/s have been achieved. SAW based droplet ejection and vaporization have also been realized. SAW devices and FBARs have been used to detect antibody/antigen and rabbit/goat immunoglobulin type G molecules, showing their high sensitivity. The results have demonstrated the feasibility of using a single actuation mechanism for the LOC.

scholarly journals Experimental and Theoretical Study of Multifrequency Surface Acoustic Wave Devices in a Single Si/SiO2/ZnO Piezoelectric Structure

Sensors ◽  
2020 ◽  
Vol 20 (5) ◽  
pp. 1380
Author(s):  
Cinzia Caliendo ◽  
Farouk Laidoudi
Keyword(s):  
Acoustic Waves ◽  
Surface Acoustic Waves ◽  
Three Dimensional ◽  
Propagation Loss ◽  
Device Structure ◽  
Scattering Parameter ◽  
Sensing Platform ◽  
Piezoelectric Structure ◽  
Acoustic Wave Devices ◽  
3D Finite Element Method

The propagation of surface acoustic waves (SAWs) along a ZnO/SiO2/Si piezoelectric structure is experimentally and theoretically studied. Six surface acoustic modes were experimentally detected in the 134 to 570 MHz frequency range, for acoustic wavelength λ = 30 μm, and for SiO2 and ZnO layers with a thickness of 1 and 2.4 μm. The numerical and three-dimensional (3D) finite element method analysis revealed that the multilayered substrate supports the propagation of Rayleigh and Sezawa modes (Rm and Sm), their third and fifth harmonics at λ/3 and λ/5. The velocity of all the modes was found in good agreement with the theoretically predicted values. Eigenfrequency, frequency domain, and time domain studies were performed to calculate the velocity, the electroacoustic coupling coefficient, the shape of the modes, the propagation loss, and the scattering parameter S21 of the SAW delay lines based on the propagation of these modes. The sensitivity to five different gases (dichloromethane, trichloromethane, carbontetrachloride, tetrachloroethylene, and trichloroethylene) was calculated under the hypothesis that the ZnO surface is covered by a polyisobutylene (PIB) layer 0.8 µm thick. The results show that the modes resonating at different frequencies exhibit different sensitivities toward the same gas. The multi-frequency ZnO/SiO2/Si single device structure is a promising solution for the development of a multiparameters sensing platform; multiple excitation frequencies with different sensing properties can allow the parallel analysis of the same gas with improved accuracy.

Design of Urinary Biomarker Sensor for Early Ovarian Cancer Detection

2011 ◽  
Author(s):  
Onursal Onen ◽  
Patricia Kruk ◽  
Rasim Guldiken
Keyword(s):  
Ovarian Cancer ◽  
Cancer Progression ◽  
Surface Functionalization ◽  
Acoustic Waves ◽  
Low Cost ◽  
Surface Acoustic Waves ◽  
Coupling Efficiency ◽  
Ultrasound Transducers ◽  
Early Ovarian Cancer ◽  
Acoustic Wave Devices

In this paper, our efforts on the design, surface functionalization and characterization of ultrasonic MEMS sensor for early ovarian cancer is presented. The sensor detects urinary anti-apoptotic protein Bcl-2 level that has been presented as being elevated for different stages of ovarian cancer. Our novel biosensor approach employs a pair of MEMS ultrasound transducers for generating and sensing surface acoustic waves and a delay path in-between with oriented Bcl-2 antibodies (C8C) attached. Piezoelectric surface acoustic wave devices are employed for sensor for their high coupling efficiency and ease of fabrication. The sensor quantifies the cancer progression by detecting mass loading change generated by adhesion of Bcl-2 molecules to antibodies on the sensor surface. The device is fabricated using common MEMS fabrication techniques and a multi-step surface functionalization is utilized for effective protein adhesion. As a result, our biosensor platform has various unique advantages such as: ultra-sensitive (sub pg/ml), low cost, and simple operation (reminiscent of a pregnancy test) not necessitating trained personnel.

scholarly journals Bifurcation-enhanced ultrahigh sensitivity of a buckled cantilever

2018 ◽  
Vol 115 (12) ◽  
pp. 2884-2889 ◽  
Author(s):  
Sangmin An ◽  
Bongsu Kim ◽  
Soyoung Kwon ◽  
Geol Moon ◽  
Manhee Lee ◽  
...  
Keyword(s):  
Acoustic Waves ◽  
Surface Acoustic Waves ◽  
High Sensitivity ◽  
Single Shot ◽  
Nonlinear Phenomenon ◽  
Ambient Conditions ◽  
Research Areas ◽  
Enhanced Sensitivity ◽  
Shot Detection ◽  
Mechanical Sensors

Buckling, first introduced by Euler in 1744 [Euler L (1744) Opera Omnia I 24:231], a sudden mechanical sideways deflection of a structural member under compressive stress, represents a bifurcation in the solution to the equations of static equilibrium. Although it has been investigated in diverse research areas, such a common nonlinear phenomenon may be useful to devise a unique mechanical sensor that addresses the still-challenging features, such as the enhanced sensitivity and polarization-dependent detection capability. We demonstrate the bifurcation-enhanced sensitive measurement of mechanical vibrations using the nonlinear buckled cantilever tip in ambient conditions. The cantilever, initially buckled with its tip pinned, flips its buckling near the bifurcation point (BP), where the buckled tip becomes softened. The enhanced mechanical sensitivity results from the increasing fluctuations, unlike the typical linear sensors, which facilitate the noise-induced buckling-to-flipping transition of the softened cantilever. This allows the in situ continuous or repeated single-shot detection of the surface acoustic waves of different polarizations without any noticeable wear of the tip. We obtained the sensitivity above 106 V(m/s)−1, a 1,000-fold enhancement over the conventional seismometers. Our results lead to development of mechanical sensors of high sensitivity, reproducibility, and durability, which may be applied to detect, e.g., the directional surface waves on the laboratory as well as the geological scale.

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