Patent ID: 11916536
Assignee: MURATA MANUFACTURING CO., LTD.
Field: Basic communication processes (Electrical engineering)
Classification: CPC H | IPC H

Claim 9:
10. A filter device comprising:
a first filter between an input terminal and an output terminal; and
an additional circuit connected in parallel with the first filter between the input terminal and the output terminal; wherein
the additional circuit includes:
at least two IDT electrode groups connected in parallel with each other and including a first IDT electrode group and a second IDT electrode group; and
at least one capacitance element between the input terminal and the at least two IDT electrode groups or between the output terminal and the at least two IDT electrode groups;

the at least two IDT electrode groups each include a plurality of IDT (Interdigital Transducer) electrodes that are arranged in an acoustic wave propagation direction;
an average pitch of a plurality of electrode fingers of the plurality of IDT electrodes that define the first IDT electrode group and an average pitch of a plurality of electrode fingers of the plurality of IDT electrodes that define the second IDT electrode group are different from each other;
the plurality of IDT electrodes that define the first IDT electrode group include at least one first IDT electrode connected to the input terminal and at least one second IDT electrode connected to the output terminal, and the plurality of IDT electrodes that define the second IDT electrode group include at least one first IDT electrode connected to the input terminal and at least one second IDT electrode connected to the output terminal;
a number of a plurality of electrode fingers of the at least one first IDT electrode in the first IDT electrode group and a number of a plurality of electrode fingers of the at least one first IDT electrode in the second IDT electrode group are different from each other; and
a number of a plurality of electrode fingers of the at least one second IDT electrode in the first IDT electrode group and a number of a plurality of electrode fingers of the at least one second IDT electrode in the second IDT electrode group are different from each other.