Patent ID: 7053523

Claim:
An interdigital lateral field excitation Bulk Acoustic Wave transducer device, comprising: a first comb of interdigital electrode fingers deposited on a surface of a piezoelectric substrate interleaves with an opposing second comb of interdigital electrode fingers deposited on said surface; said first comb being connected to a first bus bar and said second comb being connected to a second bus bar, said first and second bus bars being conductive and defining an active region on said surface, said piezoelectric substrate having a substrate acoustic impedance; a first electrode of said first comb and a second electrode of said second comb having an opposite polarity and an acoustic impedance matching said substrate acoustic impedance, being paired, positioned parallel and proximate to one another further comprising a period, said period having a period gap, G 1 , separating said first electrode from said second electrode, said period gap G 1 having a first edge opposing said first electrode and a second edge opposing said second electrode; said period having a plurality of electrode edges separated by an electrode gap, G 2 , said electrode gap G 2 being wider than, and parallel to, said period gap G 1 ; a dielectric coating covers at least a portion of said period; an exciting AC voltage placed across said period generates a plurality of alternating lateral electrical fields that alternate in polarity and a plurality of piezoelectric mechanical surface tractions produced at said electrode edges being spatially distributed over said surface; said period having a given metallization ratio; said device having a multitude of periods; said alternating lateral electrical fields, said multiple periods, said dielectric coating and the positioning of said first electrode and said second electrode within each period generate a low-voltage, planar, lateral field excitation Bulk Acoustic Wave propagating away from said surface that suppresses production of a surface acoustic wave; and said Bulk Acoustic Wave provides a lateral electric field with a constant magnitude substantially uniform over said active area, reducing a plurality of electrode field intensity spikes, with a phase progression substantially parallel to said surface, producing a plurality of spatially distributed lateral electric fields pointing substantially in a single direction over said active area.