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Research On The Parameters Of Love Wave Sensor

Posted on:2013-01-14Degree:DoctorType:Dissertation
Country:ChinaCandidate:P MiaoFull Text:PDF
GTID:1118330371498852Subject:Mechanical Manufacturing and Automation
Abstract/Summary:PDF Full Text Request
As a type of acoustic wave sensor, Love wave sensor has many advantages toresearch, such as sensing in the liquid, higher mass sensitivity, robust structure,simple fabrication process. In this thesis, we have several achievements with it.1) The theoretical derivation for the structure of Love sensor has been resolved.For a detailed structure containing quartz substrate and silica waveguide, thedisplacement field, stress field and the electrical field have been derived and plottedas function of depth. Based on the derived dispersive relation, the electromechanicalcoupling coefficient, temperature coefficient of frequency, mass sensitivity andgroup velocity of the structure have been derived.2) With the results obtained above, the maximum sensitivity and the maximumcoupling coefficient can't be achieved together. We supplied a trade-off methodwhich can be used to compromise the two important parameters. After optimization,the coupling coefficient is91.759%of the maximum which increased by19.297%and the sensitivity is89.407%of the maximum which increased by27.549%respectively.3) The lift-off process is used for the interdigital transducer on the quartzsubstrate and the plasma enhanced chemical vapor deposition is utilized for the silicawaveguide fabrication. Then the dicing saw is used in the post-packaging process.4) Electrical characterizations of the device have been identified with the designed PCB. The insertion loss is37dB and the Q factor is670. The temperaturecoefficient of frequency is14.348ppm/K, the standard deviation is0.1861ppm/K.5) The mass sensitivity about100cm2/g for the Love sensor is obtained by usingCyclic Voltammetry method under the liquid environment. Factors that affect thesensitivity of the sensor in the liquid are first analyzed. The effects of the normalizedthickness of waveguide, the density and the thickness of deposited copper layer withthe sensitivity are analyzed quantitatively. Further more the influence of liquid loadand surface roughness of copper layer on the sensitivity is explained.
Keywords/Search Tags:Love wave sensor, Dispersion relation, Mass sensitivity, Electromechanical coupling coefficient, Lift-off, Temperaturecoefficient of frequency
PDF Full Text Request
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