Performance of SAW ring waveguide resonator: 3D FEM and experiments

A new regular electrode structure called ring waveguide resonator (RWR) on surface acoustic waves (SAW) is estimated at first by 3D finite element method (FEM). The structure consists of an aluminum (Al) interdigital transducer (IDT) in the form of a ring placed on the Z-cut of aluminum nitride (AlN). The IDT itself creates a waveguide effect on the substrate. Observed resonance peaks of the electrical admittance of RWR correspond to excited radial modes. The lower frequency peak has a high quality factor. The electrical admittance of RWR does not have sidelobes between the peaks. First experimental results confirm these findings.