Design and Manufacture of Surface Acoustic Wave Sensors for Real-Time Weigh-in-Motion

This paper presents the design and manufacture of Surface Acoustic Wave (SAW) strain sensors which can be produced in a university environment. These sensors can be interrogated wirelessly and operated without a power supply, which allows for greater measurement flexibility than conventional strain gauge systems. The design of an optimised sensor requires accurate experimental data on a number of process parameters and configurations, which for this project requires the testing of several prototype designs. The large prototyping costs typical of SAW devices can be significantly reduced if the design and manufacturing processes are integrated. This paper outlines such a system, where device function and processing issues are integrated at each stage. The result is a range of sensors which have been "designed for manufacture", optimising both the variety of devices per wafer and the yield.