  Surface acoustic waves (SAWs) are versatile tools to manipulate fluids at
small scales for microfluidics and bio- logical applications. A non-exhaustive
list of operations that can be performed with SAW includes sessile droplet
displacement, atomization, division and merging but also the actuation of
fluids embedded in microchannels or the manipulation of suspended particles.
However, each of these operations requires a specific design of the wave
generation system, the so-called interdigitated transducers (IDTs). Depending
on the application, it might indeed be necessary to generate focused or plane,
propagating or standing, aligned or shifted waves. Furthermore, the
possibilities offered by more complex wave-fields such as acoustical vortices
for particle tweezing and liquid twisting cannot be explored with classical
IDTs. In this paper, we show that the inverse filter technique coupled with an
interdigitated transducers array (IDTA) enables to synthesize all classical
wave-fields used in microfluidics and biological applications with a single
multi- function platform. It also enables to generate swirling SAWs, whose
potential for the on-chip synthesis of tailored acoustical vortices has been
demonstrated lately. The possibilities offered by this platform is illustrated
by performing successively many operations on sessile droplets with the same
system.
