Design Of Dual-path Surface Acoustic Wave Sensor

The surface acoustic wave technology is a new field of science and technology, it is acombinational interdisciplinary of acoustics, electronics, optics, piezoelectric materials andsemiconductor planar process. Some parameters, such as gas concentration, temperature,quality, can be indirectly got by measuring the parameters of the surface acoustic wave deviceitself, therefore, surface acoustic wave sensor currently becomes one of the new hot spot ofinternational devices and has been infiltrated into the sectors of national economies.However, theories and programs of the surface acoustic wave sensor are not mature andsystem enough at present. Focusing on these issues, this thesis conducts systematictheoretical study and experimental test on device modeling, designing and testing.Because the SAW device performance relates to many factors,such as variousparameters of the substrate material, thickness and so on, the paper uses the coupled-modetheory, which is a theory about the general law of coupling between two or moreelectromagnetic modes, on the design and characteristic simulation of the SAW device,analyzes the internal structure and performance of surface acoustic wave device, calculatesthe surface acoustic wave device’s coupled mode equations, and solves the equation to get theanalytical solution of the equation, so the simulation parameters of the device are moreaccurate and approach to the actual measurement results.After producing and packaging the designed device,we measure various parameters ofthe device using the Agilent E5062A ENA-L radiofrequency network analyzer,on thisbasis,design a analysis software of surface acoustic wave device theory and measurementparameters, the software will comprehensive analysis the surface acoustic wave deviceparameter curves got by the coupled mode theory and the measured parameter curvesmeasured by network analyzer on the same interface. We design a dual-path surface acousticwave sensor of101.764MHz center frequency using the device design,, the device is adual-path structure to compensate the impacts of external environmental factors, one way isthe referencing acoustic path, and another way is the measuring acoustic path, then test thistwo paths by Agilent MSO7032A oscilloscope.