Abstract
The characteristics of boundary waves propagating along a thin layer between two bonded substrates were investigated both theoretically and experimentally. The structures are PZT/ADHESIVE/PZT and PZT/ADHESIVE/GLASS. It was found that the propagation loss of the devices is greater than theoretical results because of a non-uniform adhesive layer. Therefore, the two substrates must be carefully and accurately bonded to decrease the propagation loss.