Electric filter employing acoustic waves

An surface acoustic wave (SAW) device of the type formed by a piezoelectric substrate having a substrate surface and at least two transducers disposed on said surface, said device comprising

• a first transducer of said two transducers serving as an input means for receiving an electrical input signal and producing acoustic wave energy, said first transducer including a first collecting bus connected to ground potential,
• a second transducer of said two transducers serving as an output means for receiving acoustic wave energy and producing a electrical output signal, said second transducer including a second collecting bus connected to ground potential,
• first shielding means having a first interconnection bus and a first plurality of digital strips extending from the first interconnection bus to occupy a first region on the substrate surface serving as a medium for the acoustic wave energy of said first transducer, the first interconnection bus extending toward the first collecting bus to be electrically connected therewith,
• second shielding means having a second interconnection bus and a second plurality of digital strips extending from the second interconnection bus to occupy a second region on the surface of the substrate serving as a medium for the acoustic wave energy being received by said second transducer, the second interconnection bus extending toward the second collecting bus to be electrically connected therewith, and
• said first and second plurality of digital strips being separated from each other by a predetermined free space therebetween.