Multiplexer, radio-frequency front end circuit, and communication device
AssigneeMurata Manufacturing Co., Ltd.
InventorsHirotsugu Mori, Masakazu Tani
Life of this patent
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Abstract
A multiplexer (1) includes: a filter (13L) that is arranged between a common terminal (100) and an input/output terminal (130) and that has a first pass band; a filter (12H) that is arranged between the common terminal (100) and an input/output terminal (120), that is formed of at least one acoustic wave resonator, and that has a second pass band located at a higher frequency than the first pass band; and a capacitor (C2) that is serially arranged on a connection path between the common terminal (100) and the filter (12H). When the filter (12H) is regarded as a capacitance, the Q value of the capacitor (C2) in the first pass band is higher than the Q value of the capacitance in the first pass band.
Claims18
A multiplexer comprising:
- a common terminal, a first input/output terminal, and a second input/output terminal;
- a plurality of filters connected to the common terminal, wherein:
- a first filter is arranged between the common terminal and the first input/output terminal, the first filter having a first pass band;
- and
- a second filter is arranged between the common terminal and the second input/output terminal, the second filter including at least one acoustic wave resonator, and having a second pass band located at a higher frequency than the first pass band;
- a first capacitor that is serially arranged on a connection path between the common terminal and the first filter;
- and
- a second capacitor that is serially arranged on a connection path between the common terminal and the second filter,
- wherein the at least one acoustic wave resonator of the second filter utilizes leaky waves that propagate along a piezoelectric substrate composed of LiTaO3 as surface acoustic waves or at least one acoustic wave resonator having a stacked structure comprising a high-acoustic-velocity support substrate, a low-acoustic-velocity film, and a piezoelectric layer,
- wherein when the second filter is regarded as a capacitance, a Q value of the second capacitor in the first pass band is higher than a Q value of the capacitance in the first pass band, and
- wherein a capacitance value of the second capacitor is lower than or equal to 3 pF.
Dependencies are inferred from the claim text.