Abstract
This thesis gives a historical account of the development, and the theory of piezoelectric phenomenon, Rayleigh wave, shear horizontal plate wave, interdigital transducer (IDT), surface acoustic wave (SAW), performance criteria and device for application in sensor. The detection results for organic vapors by different polymer deposited on 128° YX-LiNbO3 surface acoustic wave (SAW) delay lines are studied in this work. The gas sensor array is based on 2×2 non-continuously working oscillators equipped with differently polymer-coated surface acoustic wave sensors.The SAW detection system which is employed to detect various organic molecules and bio-sample was prepared using two-port SAW resonators and a computer for signal acquisition and data process. This gas sensor array system consists of SAW sensors, polymers with different polarity and function groups, and signal readout electronics. The appropriate coating materials on to the SAW crystal would be used for gas detection. The gas sensing properties of polymer film, deposited onto 1280YX-LiNbO3 substrate, have been monitored shift in frequency by SAW delay lines and analysis the properties of the gas sensor. The good result of tree-view from the two-way hierarchical clustering analysis is studied in this work after comparing the correlation between the coating materials and organic vapors. Furthermore, the SAW detection system can distinguish unknown gas or mixed gas by the database of pattern recognition in the future. The Rayleigh-wave presents the very high decay and the SH-SAW presents a less energy decay when operating in liquid phase. For this reason, the SH-SAW device is selected to be used in gaseous and liquid phase application and The Y360-X LiTaO3 was selected as the substrate of the SH-SAW sensor chip. we developed an SH-SAW sensor to detect ipaB molecules by means of the antibody–antigen binding mechanism. The sensor showed stable relationship between its the oscillation frequency and the ipaB concentration in a protein solution. A SiO2 layer was on both the IDTs and the sensing area. The SiO2 waveguide used in these devices can be easily functionalized with 3-aminopropyltriethoxysilane (APTES) and to detect protein concentrations as low as 3 μg / ml. To replace the sensor surface antibody, the cell isolation and purification studied targeted cells (Jurkate), as a model for low abundance cells (1 ∶1,000), with more dilute cells as the ultimate goal. T cells were successfully separated on-chip from the mixed cell medium (Jurkate cells/ K562 cells, 1/1000). The results are quite promising and the developed SH-SAW sensor can be applied to the detection of various protein molecules with different antibody immobilization layers while maintaining all the beauties of general SAW sensors.