Design of interdigitated transducers for acoustofluidic applications.

Interdigitated transducers (IDTs) were originally designed as delay lines for radars. Half a century later, they have found new life as actuators for microfluidic systems. By generating strong acoustic fields, they trigger nonlinear effects that enable pumping and mixing of fluids, and moving particles without contact. However, the transition from signal processing to actuators comes with a range of challenges concerning power density and spatial resolution that have spurred exciting developments in solid-state acoustics and especially in IDT design. Assuming some familiarity with acoustofluidics, this paper aims to provide a tutorial for IDT design and characterization for the purpose of acoustofluidic actuation. It is targeted at a diverse audience of researchers in various fields, including fluid mechanics, acoustics, and microelectronics. HIGHLIGHTS: • The electric power efficiency of IDT-based acoustofluidic devices is discussed. • The different types of SAW that can be generated by IDTs and their applications in acoustofluidics are reviewed. • Methods to predict the surface acoustic wave field generated by a given IDT geometry are reviewed. [ABSTRACT FROM AUTHOR]