Patent ID: 6378370
Filing Date: 2002-04-30
Classification: G01N

Abstract:
A temperature matched surface-launched acoustic wave sensor comprising:a piezoelectric substrate or a non-piezoelectric material coated with a layer which provides acousto-electric coupling, referred to herein as the substrate; a plurality of surface-launched acoustic wave delay lines or surface-launched acoustic wave resonators; at least one of said delay lines or resonators that are reference channels, to be used as frequency references to which the oscillation frequencies of the remainder of said delay lines or resonators that are sensing channels, are compared; a plurality of amplifiers, one for each of said delay lines or resonators, each having an input and an output or a combined input and output, each of said delay lines or resonators connected from the output of a corresponding one of said amplifiers to the input thereof in a feedback relationship so as to form an oscillator, the output of which is at a natural frequency of the related one of said delay lines or resonators; a plurality of substantially identical thin films, which are physically, chemically, biologically, or otherwise sensitive to one or more gaseous or liquid-born analytes, said films being deposed upon said delay lines or resonators; a thin coating of material, referred to herein as the passivation layer, which is not sensitive to said analytes, configured such that said passivation layer covers said sensing films on said reference channels, blocking or impeding interaction of said sensing films and said analytes thereby, and is covered by said sensing films on said sensing channels, allowing interaction between said sensing films and said analytes thereby.