Surface Acoustic Wave (SAW) devices as corrosion monitoring and Gas Sensors - A ReviewS.No TitleAuthor(s)Pub.Yr. Technique usedEssence of paper/ Device usedIDT/

Reflector

materialSensing element materialResults

1SAW 915 MHz Resonator Oscillator Gas Sensor using SnO2 Nano wire-based Nanocomposite LayerM.penza P.Aversa

D.suriano

G.Cassano E.Serra E.Comini G.faglia

G.Sberveglieri2008Freq difference measurement based on mass-loading effect915 MHz Dual SAW Resonator Oscillator based on IDT/Reflectors is used to detect presence of different gases at ppm-level at room temperatureAluminumCadmium arachidate (CdA) composite layer consists of

SnO2 Nano wire13.1KHz/200ppm

2Impact of ambient humidity on surface acoustic wave attenuation and velocity in hematoporphyrin-on-LiNbO3 structureR.Rimeika R.RotomskisV.PoderysD.iplysA.SereikaM.S.Shur2008Attenuation, Freq. and velocity difference measurement based on relative humidity and conductivity86 MHz SAW Delay Line is used to detect effect of ambient humidity.

Freq.& velocity changes are observed by changing relative humidity(RH%) and conductivity respectivelyAluminum Hematoporphyrin (Hp)30KHz/RH

3Carbon nanotube-coated surface acoustic wave sensor for carbon dioxide sensingS.Sivaramakrishna R. RajamaniC.S. SmithK.A. McGeeK.R. MannN.Yamashita2008Attenuation difference measurement based on conductivity changes286 MHz SAW Delay Line with single-wall carbon nano tube is used to detect CO2.Chromium and GoldPolyethyleneimine (PEI)-starch functionalized single-walled nanotube (SWNT)CO2 concentration changes 0%-10%

Enhaunced sensitivity &low signal/noise ratio is achieved

4Application of Laser-Generated Ultrasound for Evaluation of Wall thinning in Carbon Steel ElbowDo-Youn Kim

Seung-Joon Lee Joon-Hyun Lee2008Amplitude difference measurement based on 1st and 2nd modes of Lamb wavesWall thinning of carbon steel pipe (elbow) due to Flow Accerelated Corrosion (FAC) is evaluated using laser generated Lamb waves and air-coupled transducer.1st and 2nd modes of Lamb wave are excited at 381KHz and 434KHz respectivelyN/AN/AIn the elbow, both 1st and 2nd modes are appeared in defect-free region, but amplitude of 2nd mode is decreased in wall-thinning. So by using the ratio of two modes, defect can be detected

5Interaction of Rayleigh Waves Induced By Interdigital Transducer with Fatigue CrackJeong K.NA

Samuel KUHR

James L.BLACKSHIRE2008Laser generated ultrasonic Rayleigh waves Standalone IDT generates Rayleigh waves beam at normal, 30o counter-clockwise and 30o clockwise based on laser interferometry scanning system. Images of crack are observedAluminum N/AInteraction of ultrasonic fields with cracks is observed using laser interferometry scanned images. Rayleigh wave beam spread is +10.5o. Elastic energy can pass through a tight fatigue crack which gices more precise length of cracks as compared to pulse-echo or pitch-catch methods.

6Humidity Sensor using Surface Acoustic Waves Propagating along Layered StructuresTooru Nomura

Tsutomu Yasuda

Shoji Furukawa1994Conductivity and velocity difference measurement based on relative humidity30 MHz SAW Delay Line is used to detect effect of humidity. Velocity and conductivity changes are observed by changing relative humidity (RH %)Polysterene sulfonic acid sodium

([-CH2CH(C6H4SO3Na)-]n)Linear response of velocity at 20 m/s for 10%RH over the range of 40%-80%RH

7A Mass-Loading Effect LiNbO3 SAW SensorZheng Zhang

Dazhong Zhu

Zhelong Haung2001Center Freq. shift measurement based on massloading effectSAW Delay Line is used to detect 475 KHz freq. shift due to massloading effectAluminum Quadrate groove made of photoresist or polyimideHigh sensitivity 3.82ng/ppm.cm2

8Surface Acoustic Wave Sensors to detect Volatile Gases by measuring Output Frequency ShiftBeom-Keun Yoo

Yong-Wook Park

Chong-Yun Kang

Seok-Jin Yoon

Jin-Sang Kim2006Freq. and phase shift due to massloading effect100 MHz dual SAW Delay Line is used to detect the effect of different gases based on the frequency shift due to massloadingAluminum Titanium Phase decreases linearly with -2.06 degree/Co

9Finite Element Method on Mass Loading Effect for Gallium Phosphate Surface Acoustic Wave ResonatorM.N.Hamidon

S.A.Mousavi

M.M.Isa

A.Ismail

M.A.Mahdi2009Change is resonant freq. due to massloading of IDTs433.92 MHz SAW Resonator is used to observe the effect of metal thickness(massloading) of IDTs on the resonant freq.Platinum and ZirconiumN/AA linear resonse is observed between

metal thickness vs. resonant freq and

metal thickness vs. mass loading

10A Finite Element Model of a MEMS-based Surface Acoustic Wave Hydrogen SensorMohamed M.EL Gowini

Walied A.Moussa2010Change in velocity and attenuation due to hydrogen gas100 MHz SAW Delay Line is used to observe the effect of hydrogen concentration on velocity and attenuation of SAWPalladium Increasing hydrogen absorption causes a decrease in wave velocity.

Magnitude of attenuation also decreases with increase in hydrogen concentration