Acoustic wave devices are attractive for use in sensors
due to the fact that the wave velocity and damping are
sensitive to outside parameters. Examples are the
adsorption of mass on the propagation path of the wave
(chemical sensing in fluids), the entraining of a viscous
fluid film (sensing of fluid parameters such as viscosity
and density) or an electric field (sensing the strength of
the field).
Acoustic-wave delay-line sensors have some interes-
ting features. They offer a high sensitivity, they are small
and they can be realized using planar production tech-
nology, allowing low fabrication costs. In an oscillator
set-up they show a high signal-to-noise ratio, and
a frequency output which is easy to further process
electronically. In addition, modeling software has
been developed, enabling simulation of the sensor
performance.
In this paper we will focus on five delay-line imple-
mented acoustic-wave devices which use different wave