Extractor
An extractor includes an external connection terminal, a common terminal, input-output terminals, a band elimination filter that is connected to the common terminal and the first input-output terminal input-output terminal and that uses a first frequency band as a stop band, a band pass filter connected to the common terminal and the second input-output terminal and that uses a second frequency band overlapped with at least a portion of the first frequency band as a pass band, and an inductor connected on a path connecting the common terminal to the external connection terminal. The band elimination filter includes series arm resonators located on a series arm connecting the common terminal to the input-output terminal and an inductor that is located on the series arm between the series arm resonator and the first input-output terminal. The inductor is inductively coupled to the inductor.
1 . An extractor comprising:
an external connection terminal, a common terminal, a first input-output terminal, and a second input-output terminal;
a band elimination filter that is connected between the common terminal and the first input-output terminal and that uses a first frequency band as a stop band;
a band pass filter that is connected between the common terminal and the second input-output terminal and that uses a second frequency band overlapped with at least a portion of the first frequency band as a pass band; and
a first inductor connected in series or in parallel on a path connecting the common terminal to the external connection terminal; wherein
the band elimination filter has a passband including frequencies above and below the stop band;
the band elimination filter is connected between the common terminal and the first input-output terminal without a band pass filter being connected between the band elimination filter and the first input-output terminal;
the band elimination filter includes:
one or more series arm resonators that each include an acoustic wave resonator and that are located on a series arm connecting the common terminal to the first input-output terminal;
a second inductor that is located on the series arm between the first input-output terminal and the series arm resonator closest to a side of the common terminal, among the one or more series arm resonators; and
one or more parallel arm circuits, each of the one or more parallel arm circuits includes a passive element connected between a corresponding node on the series arm and ground; and
any parallel arm circuit included in the band elimination filter does not include a resonator being connected between the corresponding node on the series arm and ground.
2 . The extractor according to claim 1 , wherein each acoustic wave resonator includes a piezoelectric substrate and interdigital electrodes.
3 . The extractor according to claim 2 , wherein the piezoelectric substrate includes a high acoustic velocity supporting substrate, a low acoustic velocity film, and a dielectric film.
4 . The extractor according to claim 3 , wherein the high acoustic velocity supporting substrate confines surface acoustic waves in a portion where the dielectric film and the low acoustic velocity film are laminated.
5 . The extractor according to claim 3 , wherein the high acoustic velocity supporting substrate is a silicon substrate.
6 . The extractor according to claim 2 , wherein the interdigital electrodes each include an interdigital transducer electrode including electrode fingers and busbar electrodes and a close-contact layer and a main electrode layer.
7 . The extractor according to claim 1 , wherein a direction of magnetic flux of the first inductor is the same as a direction of magnetic flux of the second inductor.
8 . The extractor according to claim 7 , further comprising:
a mounting substrate subjected to at least one of incorporation of the band elimination filter and the band pass filter therein and mounting of the band elimination filter and the band pass filter thereon; wherein
each of the first inductor and the second inductor includes a planar coil pattern in the mounting substrate; and
a winding axis direction of the planar coil pattern defining the first inductor is the same as a winding axis direction of the planar coil pattern defining the second inductor.
9 . The extractor according to claim 7 , wherein no conductive member is between the first inductor and the second inductor.
10 . The extractor according to claim 1 , wherein the external connection terminal connects an external device to the extractor, and the extractor is connectable to an antenna.
11 . The extractor according to claim 10 , wherein the extractor is configured to transmit a wireless signal to the antenna.
12 . The extractor according to claim 1 , wherein the second inductor is directly connected to the first input-output terminal with no element therebetween.
13 . The extractor according to claim 1 , wherein the first inductor includes an impedance element to match an impedance of an external device connected to the external connection terminal with a combined impedance of the band elimination filter and the band pass filter.
14 . The extractor according to claim 1 , wherein the band elimination filter includes a third inductor on a parallel arm connecting a node on the series arm to ground.
15 . The extractor according to claim 1 , wherein the first inductor and the second inductor are arranged so that a radio-frequency signal in a frequency band higher than the first frequency band is transmitted on a bypass path through the external connection terminal, the first inductor, the second inductor, and the first input-output terminal not through the one or more series arm resonators due to inductive coupling.
16 . The extractor according to claim 1 , wherein the band pass filter includes:
one or more series arm resonators that each include an acoustic wave resonator and that are located on a series arm connecting the common terminal to the second input-output terminal;
one or more parallel arm resonators that each include an acoustic wave resonator and that are located on parallel arms connecting nodes on the series arm to ground; and
a fourth inductor connected between the one or more parallel arm resonators and the ground.
17 . The extractor according to claim 1 , wherein each acoustic wave resonator is either a surface acoustic wave resonator or an acoustic wave resonator using bulk acoustic waves.
18 . The extractor according to claim 1 , wherein each acoustic wave resonator uses any of surface acoustic waves, Love waves, leaky waves, Rayleigh waves, boundary waves, leaky surface acoustic waves, pseudo surface acoustic waves, or plate waves.
19 . The extractor according to claim 1 , wherein the band pass filter includes LC resonant filters, dielectric filters or LC filters.
20 . The extractor according to claim 2 , wherein the first inductor and the second inductor have a same direction of magnetic flux.
21 . The extractor according to claim 1 , wherein the first inductor is inductively coupled to the second inductor.
22 . An extractor comprising:
an external connection terminal, a common terminal, a first input-output terminal, and a second input-output terminal;
a band elimination filter that is connected between the common terminal and the first input-output terminal and that uses a first frequency band as a stop band;
a band pass filter that is connected between the common terminal and the second input-output terminal and that uses a second frequency band overlapped with at least a portion of the first frequency band as a pass band; and
a first inductor connected in series or in parallel on a path connecting the common terminal to the external connection terminal; wherein
the band elimination filter has a passband including frequencies above and below the stop band;
the band elimination filter includes:
one or more series arm resonators that each include an acoustic wave resonator and that are located on a series arm connecting the common terminal to the first input-output terminal;
a second inductor that is located on the series arm between the first input-output terminal and the series arm resonator closest to a side of the common terminal, among the one or more series arm resonators; and
one or more parallel arm circuits, each of the one or more parallel arm circuits includes a passive element connected between a corresponding node on the series arm and ground; and
any parallel arm circuit included in the band elimination filter does not include a resonator being connected between the corresponding node on the series arm and ground.