Patent ID: 11863159
Assignee: MURATA MANUFACTURING CO., LTD.
Field: Basic communication processes (Electrical engineering)
Classification: CPC H | IPC H

Claim 3:
4. The acoustic wave filter according to claim 1, wherein
the substrate includes:
a piezoelectric layer including two main surfaces, the IDT electrode of each of the first series-arm resonator and the second series-arm resonator being disposed on one of the two main surfaces;
a high-acoustic-velocity support substrate, an acoustic velocity of a bulk wave propagating through the high-acoustic-velocity support substrate being higher than an acoustic wave velocity of an acoustic wave propagating through the piezoelectric layer; and
a low-acoustic-velocity film disposed between the high-acoustic-velocity support substrate and the piezoelectric layer, an acoustic velocity of a bulk wave propagating through the low-acoustic-velocity film being lower than an acoustic velocity of an acoustic wave propagating through the piezoelectric layer.