Acoustic multiplexing by beamsteering for SAW chemical multisensors

A new concept for designing an integrated chemical multisensor with only two ports based on surface acoustic waves is presented. Following a principle from antenna theory an acoustic group antenna is assembled consisting of a number of identical interdigital transducers that are fed with currents of equal amplitude, but with a phase difference between neighbors. The propagation of the wave launched by such an antenna is investigated through simulation of the associated surface potential. In order to validate the concept and the simulation arrays with up to ten element-IDTs are built and the distribution of the periodic displacement of the substrate surface is observed by laser interferometry.