Patent ID: 8614534

Claim:
Transducer having natural unidirectionality for surface acoustic waves, in which the interdigital electrode structure is disposed on a piezoelectric crystal substrate ( 1 ) that is built up from interdigital transducers ( 2 ) that consist of collector electrodes ( 3 ; 4 ) and prongs ( 21 ; 22 ; 23 ; 24 ), whereby at least two of the prongs ( 21 ; 23 ) ( 22 ; 24 ) form a transducer cell that has at least one excitation center for exciting an electrical potential wave and at least one reflection center for reflecting electrical potential waves, wherein a) the prongs ( 21 ; 22 ; 23 ; 24 ) are oriented perpendicular to a direction R, whereby the direction R is directed parallel to a monad or triad axis of rotation of the substrate crystal, and wherein b) the derivation dv/dθ=0 holds true for the direction R, where v is the phase velocity of the surface wave and θ is an angle deviation of the perpendicular to the prong direction from this direction R, whereby, however, the directions perpendicular to the mirror plane of the substrate crystal are excepted, and whereby the crystal substrate surfaces parallel to a mirror plane of the substrate crystal are excepted, for the arrangement of the interdigital electrode structure.