Development of interdigitated acoustic wave transducers for biosensor applications

Abstract

The principle of operation, development and evaluation of two interdigitated acoustic wave transducers optimized for biosensor applications in liquid environments is presented. The first transducer is based on a plate mode wave approach whilst the second utilizes a novel evanescent surface acoustic wave design. Both transducer structures employ sensing from the bottom surface of a lithium niobate piezoelectric crystal. Acoustic wave mode selection from electrical performance data with respect to frequency response and phase shift spectrum of the transducers is discussed. A prerequisite for an acoustic biosensor is to demonstrate its suitability for operation in a wide range of liquid environments. Therefore, preliminary experimental results are presented detailing the effect of fluid viscosity on acoustic transducer response.