Thin film Lamb wave resonant structures – The first approach

Resonant Lamb wave based geometries on c-oriented aluminum nitride (AlN) thin film membranes are studied. Attention has been focused on the lowest order symmetric Lamb mode because of its extremely high velocity approaching 10,600 m/s. The Lamb waves have been excited by means of both inter-digital transducers (IDT) and longitudinal wave (LW) transducers. Two basic reflector geometries have been used along with the conventional one-port resonator topology. The experimental results obtained demonstrate that Lamb waves can be successfully used as an alternative to high velocity surface acoustic waves. A discussion regarding the ways for improving the device performance is provided, and hence future research aspects in the area are identified.