Surface acoustic wave gas sensor or surface acoustic wave (SAW) sensors consist of an input transducer, a chemically adsorbent polymer film, and an output transducer on a piezoelectric substrate, which is typically made of quartz.
Such a device made at Sandia National Laboratories runs at a very high frequency (approximately 525 MHz), and the velocity and attenuation of the signal are sensitive to the viscoelasticity and mass of the thin film.
The SAW device also contains three Application Specific Integrated Circuit chips (ASICs), containing the electronics that functions to analyze the signals and release a DC voltage output signal proportional to the phase shift.
It contains transducers and ASICs that are bonded to a piece of quartz glass, which is placed in a leadless chip carrier (LCC).
Wire bonds connect the terminals of the leadless chip carrier to the SAW circuits.