Angular spectrum of waves analysis of SAW filters with dispersive transducers

The extended annular-spectrum-of-waves (ASoW) model is applied to the simulation of SAW (surface acoustic wave) devices with dispersive transducers. Both inline and slanted interdigital transducer (IDT) geometries are analyzed. Two extensions of the existing model are presented. The wave propagation between two slanted IDTs is modeled in the ASoW with a three-prism model considering exactly the quadrupole refraction effect at the bus bars between the input and the output IDT. Different velocity dispersions in the bus bars and in the transducers, due to both the electrical loading and the mechanical loading effects, are taken into account. The measurements of two delay lines are compared with the corresponding simulations. Excellent agreement, even at the band edges, is shown. Simulations demonstrate the strong effect of refraction at the bus bars