Patent ID: 11012052

Abstract:
A longitudinally coupled resonator type surface acoustic wave filter includes a high-acoustic-velocity member, a low-acoustic-velocity film provided on the high-acoustic-velocity member, a piezoelectric film provided on the low-acoustic-velocity film, a plurality of interdigital transducers provided on the piezoelectric film and along a propagation direction of a surface acoustic wave and each including a plurality of electrode fingers, and reflectors arranged such that the interdigital transducers are interposed therebetween from both sides in the propagation direction of the surface acoustic wave. An electrode finger pitch is uniform or substantially uniform in each of the interdigital transducers. When a wavelength determined by the electrode finger pitch in the reflector is defined as λ, an inter-electrode finger center distance that is an interval between each of the interdigital transducers and the interdigital transducer adjacent thereto is not shorter than about 0.25λ and not longer than about 0.37λ.