A Research For The Simulation And Application Of The SAW Devices

Nowadays, the cycle of layout design is quite long and the accuracy of the design isconsiderably low. Moreover, there is no any mature software or system in this area. Based onthese poor conditions above, by means of strong calculating, drawing function and build-inGUI technology from MATLAB, an efficient layout of the SAW device based on MSC, willbe built in this dissertation. In the way of inputting the parameters, it can generate the layoutof the device. Firstly, the direct monitoring to the layout of the device would be realized in thedesign stage. Secondly, the design cycle would be shorter greatly. Thirdly the accuracy of thelayout would be higher. Fourthly, the cost of design would be reduced.In order to get the propagation characteristics of SAW along the piezoelectric crystalssurface, the scheme of achieving the propagation characteristics of SAW device based onfinite element analysis with ANSYS was proposed in this paper. In this scheme, the model ofSAW device was built by the finite element analysis, and the parameter of the electrode andthe substrate material was set. The geometry model of SAW device was meshed, and thecontinuous entity was divided into finite element model. The actual problems of boundaryconditions and load in mechanical and electrical were applied to the model. By means ofsimulating a SAW device with center frequency at100MHz, the comparison and analysisbetween the simulation results and the theory results were presented. Experiments resultsconfirm that the SAW energy is confined into a zone close to the piezoelectric crystals surfaceand is1to2wavelengths thick, and the amplitude and energy of the SAW will decreaserapidly with increasing depth.In order to solve the bulk acoustic wave (BAW) interference, the electrodes reflectionand high side lobe in the acoustic surface wave (SAW) device of SAW oscillator system, thenovel SAW oscillator system is proposed was proposed in this paper. In this design scheme,the BAW is separated by the multi-strip coupler, and the electrodes reflection and the sidelobe are suppressed by the split electrode and weighted input and output input interdigitaltransducers, separately. The realization of the SAW device with center frequency at50.8MHz confirms that the scheme can improve the device performances. The measurement results ofSAW oscillator system measured by the oscilloscope Agilent7032A show that the frequencyof oscillator signal is50.1MHz, and the frequency error between the actual measurement andtheoretical design is only1.3%. Furthermore, the SAW oscillator system has good periodicityand stability.