In this study, a set of surface acoustic wave sensor optimization design method based on the variational method is proposed, which organically combines the multilayer membrane structure with the virtual instrumentation technology, and fundamentally improves the sensor performance indexes. During the research process, a comprehensive objective general function containing sensitivity, temperature stability and signal-tonoise ratio is constructed, and the optimization problem of the sensor structure parameters is solved by the variational method, which has achieved remarkable results. The experimental data confirm that the optimized sensor achieves a comprehensive improvement in the key performance indexes, which is reflected in the 17.1% increase in sensitivity, 23.1% improvement in temperature stability, and 38.4% increase in quality factor. The multilayer membrane structure design makes full use of the complementary characteristics of the temperature coefficients of different materials, so that the temperature coefficient is greatly reduced from the original – 94.3kHz/°C to -4.2kHz/°C, and the temperature stability has gained a qualitative leap. At the same time, the combination of virtual instrument technology and adaptive detection method is applied to the signal processing link, which greatly enhances the signal-to-noise ratio and measurement accuracy of the whole sensing system. The research results of this paper provide a solid technical foundation and theoretical support for the wide application of surface acoustic wave sensors in the field of industrial detection, environmental monitoring systems and medical diagnosis.
