DEVELOPMENT OF INTERDIGITATED ACOUSTIC-WAVE TRANSDUCERS FOR BIOSENSORAPPLICATIONS

The principle of operation, development and evaluation of two interdig itated 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 evanesce nt surface acoustic wave design. Both transducer structures employ sen sing from the bottom surface of a lithium niobate piezoelectric crysta l. Acoustic wave mode selection from electrical performance data with respect to frequency response and phase shift spectrum of the transduc ers is discussed. A prerequisite for an acoustic biosensor is to demon strate its suitability for operation in a wide range of liquid environ ments. Therefore, preliminary experimental results are presented detai ling the effect of fluid viscosity on acoustic transducer response.