The Research Of Sensor Technology Based On SAW Principle

SAW(Surface Acoustic Wave) was first demonstrated by Lord Rayleigh, a physicist in UK, in 1885. Hereafter, SAW attractted much attention of researchers, and then was applied to the fields of communication, radar, broadcast and TV. SAW sensor is an important branch of SAW technology. Its development starting time is 1980s and SAW sensor has the characteristics of high accuracy, high sensitivity, low cost, low power loss, stable and smart and so on, It is easy to realize the measurement of many kinds of physical, chemistry and the biologic parameters, therefore SAW sensor becomes more and more important in the sensor world.This thesis gives comprehensive research in view of the SAW sensor technology. Firstly, the SAW sensor technology history and its development in the domestic and foreign countries are summed up. Afterwards this thesis analyzed the SAW work principle, further systematically elaborated SAW sensor's some basic concepts, and also classified the SAW sensor, carried on the analysis to basic principle of each kind, and compared with each kind of SAW sensor. Furthermore, some examples in physical and chemistry application are showed in this thesis. At the same time, the thesis detailedly introduced the manufacture process of SAW sensor.On the basis of SAW technology, this thesis designs a SAW humidity sensor. Include the design of IDT (interdigital transducer), the thin film as well as the frequency measurement system. Each parameter of IDT and the thin film material is selected carefully, the frequency measurement system has mainly made of the monolithic integrated circuit and the CPLD(Complex Programable Logic Device), the monolithic integrated circuit was programmed by highly effective assembly language and CPLD by VHDL language. The frequency measurement system is tested and result was satisfying. In addition, this thesis used finite element analysis software ANSYS on the simulation analysis to the SAW humidity sensor under low relative humidity environment, has also obtained the satisfying result.