| CPC H04B 1/0057 (2013.01) [H03H 7/463 (2013.01)] | 20 Claims |
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1. A multiplexer comprising:
a common terminal;
a first input/output terminal;
a second input/output terminal;
a first filter circuit that is connected between the common terminal and the first input/output terminal and that has a pass band including a first frequency band;
a second filter circuit that is connected between the common terminal and the second input/output terminal and that has a pass band including a second frequency band higher than the first frequency band; and
an additional circuit connected in parallel to at least a portion of a path connecting the common terminal and the first input/output terminal; wherein
the additional circuit includes a resonator including a plurality of interdigital transducer electrodes on a piezoelectric substrate; and
in a case where a peak frequency for a response that occurs in a bandpass characteristic of the additional circuit and that is attributed to the interdigital transducer electrodes is f1, and a frequency included in a frequency higher than the second frequency band and that corresponds to a lowest impedance in an impedance characteristic at a time of viewing the first filter circuit, the second filter circuit, and the additional circuit from the common terminal is f2,
f2×(1−0.0012)≤f1≤f2×(1+0.0012)
is satisfied.
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