Dear Colleagues,

Acoustic wave-based sensors have been around for almost half a century but the field continues to produce exciting new developments, driven in part by (1) new demands and (2) increasing need for miniaturization. There are various types of acoustic wave devices and based on their design, they can be used to develop physical (e.g., torque or pressure) and bio-chemical (e.g., concentration and identification of analytes and bio-molecules, etc.) sensors. Furthermore, depending on their mode of operation, they can be applied in the gas phase (e.g., Rayleigh surface acoustic wave) or liquid phase (e.g., shear horizontally (SH) polarized acoustic wave). While acoustic wave-based sensors are being developed for numerous applications, research has continued in the field for improved and new devices to take advantage of their high sensitivity to both mechanical and electrical loadings perturbation. For example, acoustic wave-based sensors utilizing the thickness shear-mode resonator (TSMR) are still opening up new possibilities such as lateral field excited (LFE) acoustic wave sensors, and more recently, film bulk acoustic resonator (FBAR) sensors. These high sensitivity sensor platforms can all be miniaturized using MEMS fabrication techniques, and thus can be integrated on a chip together with the driving circuitry.

The sensitivity of acoustic wave devices to surface viscoelastic properties has also led to new developments in the field of bio-chemical sensors. One of the key challenges in the field of chemical sensors is specificity. A number of approaches, including (1) the development of systems combining acoustic and optical detection and (2) the use of acoustic wave-based sensor elements with various analyte specific coatings into a sensor array, have been used to address this challenge. Both physical and chemical sensors can also be operated in wireless or passive mode. This has permitted the development of remote sensing devices.

This special issue is intended to highlight current trends in acoustic wave-based sensor technology. Its purpose is to give an up-to-date overview and new developments in the field, but also to invite the reader to envision emerging developments and help define the future of this exciting technology.

Prof. Dr. Fabien J. Josse
Guest Editor