Acoustic surface wave device having split-isolated or split-connected multistrip coupler

Abstract

An acoustic surface wave filter has offset transmitting and receiving transducers formed on a wave propagating surface of a piezoelectric substrate. A multistrip coupler interposed between the transducers on the propagating surface includes a plurality of identical conductor groups forming coupler elements uniformly spaced on the surface and selectively attenuates either of the symmetrical or anti-symmetrical mode components of coupled waves within a predetermined range of acoustic wavelengths. In one embodiment, each conductor group includes electrically connected pairs which attenuates the symmetrical mode component while in another embodiment each conductor group includes a first continuous filamentary conductor and a second filamentary conductor having a discontinuity at its approximate center which attenuates the anti-symmetrical mode component.

Dependencies are inferred from the claim text.