Performance of a polymer coated SAW device under pulse excitation

This work examined the capability of a novel pulse excitation technique to interrogate polymer coated SAW devices. Preliminary vapor demonstrated the concept and the validity of the pulse technique. Instead of collecting SAW sensor information in the frequency domain, time domain data was utilized. The rapid sorption of the polymer film was evident in the short time to attain full response, measured in terms of the propagation delay time with respect to a fixed reference, and the magnitude of propagation delay. With respect to the traditional loop oscillator approach, the pulse technique offers several advantages. These include: insensitivity to the straight requirement of loop gain and loop phase shift criteria, allowing potentially higher mass loading on the film; extremely low power consumption; and alleviation of the tedious manual tuning requirement for optimal performance.