Acoustic wave devices

An acoustic wave device comprising a substrate structurally orientated to enhance the propagation of acoustic surface skimming bulk waves in the substrate adjacent a predetermined surface of the substrate, said substrate having a pair of opposing end faces arranged to multiply reflect said waves propagating adjacent said surface so as to form a resonant cavity capable of supporting an acoustic surface skimming bulk standing wave at a predetermined frequency, and a transducer disposed on said surface and within said cavity for coupling with acoustic surface skimming bulk standing wave energy at said frequency, and wherein said transducer extends over substantially the whole distance between said pair of end faces.

An acoustic wave band-pass filter device comprising a substrate structurally oriented to enhance the propagation of acoustic surface skimming bulk waves in the substrate adjacent a predetermined surface thereof, said substrate having at least one pair of opposed end faces arranged to multiply reflect said waves propagating adjacent said surface so as to form first and second resonant cavities capable of supporting acoustic surface skimming bulk standing waves at a predetermined frequency, an input transducer disposed on said surface within said first resonant cavity and arranged to launch acoustic surface skimming bulk wave energy into said first cavity to form a standing wave therein at the predetermined frequency, means for coupling said first and second resonant cavities so that an acoustic surface skimming bulk standing wave is formed in the second cavity, and an output transducer disposed on said surface within said second resonant cavity and arranged to receive energy from the acoustic surface skimming bulk standing wave in the second cavity.