Patent ID: 11876506
Assignee: MURATA MANUFACTURING CO., LTD.
Field: Basic communication processes (Electrical engineering)
Classification: CPC H | IPC H

Claim 0:
1. An acoustic wave filter device comprising:
a first input/output terminal and a second input/output terminal to which a radio frequency signal is input or from which a radio frequency signal is output;
a first series-arm resonator including an acoustic wave resonator and disposed on a path that connects the first input/output terminal with the second input/output terminal; and
a first parallel-arm resonator disposed on a path that connects a first node with ground, the first node being located on the path that connects the first input/output terminal with the second input/output terminal; wherein
the first series-arm resonator and the first parallel-arm resonator each include at least a piezoelectric body and an IDT electrode;
the first parallel-arm resonator further includes a first dielectric layer that adjusts an effective electromechanical coupling coefficient, the first dielectric layer being provided between the piezoelectric body and the IDT electrode of the first parallel-arm resonator; and
a dielectric layer that adjusts an effective electromechanical coupling coefficient is not provided between the piezoelectric body and the IDT electrode of the first series-arm resonator.