SAW resonators as vapor sensors

Abstract

The application of SAW (surface acoustic wave) resonators as substance-of-abuse vapor sensors is described. High-Q SAW resonators configured as vapor/mass detectors are an optimally sensitive SAW geometry. The SAW resonator is able to achieve sensitivities approaching femtogram levels and exhibits a nearly true fourth-order sensitivity vs. frequency dependence. Detection of drugs at the 1-10 femtogram level was achieved. Scale factors of 20000 Hz/nanogram have been achieved by using very-high-frequency SAW resonators and by confining the depositions to the active area of the resonators.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>