Novel acoustic-surface-wave directional coupler with diverse applications

Abstract

An acoustic-surface-wave directional coupler is proposed that may be used on materials having a large electromechanical coupling constant to couple two acoustic beams which are many wavelengths wide. The normal modes of the coupler are identified and used with an equivalent-circuit representation of the device to predict the length of the structure needed for complete energy transfer. The theory indicates that the device can have an intrinsic bandwidth near to 100%.