# US 2021/0242850 A1 · Filter, multiplexer and communication module

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- Number: US 2021/0242850 A1
- Document ID: US20210242850A1
- Status: Published application
- Kind: A1
- Application number: 17/109,876
- Filed: 2020-12-02
- Published: 2021-08-05
- Earliest claimed: 2020-01-31
- Assignees: Taiyo Yuden Co., Ltd.
- Applicants: Taiyo Yuden Co., Ltd.
- Inventors: Hidenori KITAZUME
- Web page: https://patentgrep.com/patent/US20210242850A1

## CPC

- H03H 7/0115: {comprising only inductors and capacitors (H03H7/075, H03H7/09, H03H7/12, H03H7/13 take precedence)}
- H03H 7/09: Filters comprising mutual inductance
- H03H 7/1708: {Comprising bridging elements, i.e. elements in a series path without own reference to ground and spanning branching nodes of another series path (H03H7/07 takes precedence)}
- H03H 7/1716: {Comprising foot-point elements}
- H03H 7/1766: {Parallel LC in series path (H03H7/1783 takes precedence)}
- H03H 7/1775: {Parallel LC in shunt or branch path (H03H7/1791 takes precedence)}
- H03H 7/46: Networks for connecting several sources or loads, working on different frequencies or frequency bands, to a common load or source
- H03H 2001/0085: {Multilayer, e.g. LTCC, HTCC, green sheets}
- H03H: IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS (waveguides, resonators, lines or other devices of the waveguide type H01P)

## Abstract

A filter includes an input terminal, an output terminal, a plurality sets of first capacitors that include first ends connected to a plurality sets of first nodes, respectively, at different locations in a path capable of transmitting a high frequency signal from the input terminal to the output terminal, and second ends commonly connected to a second node, a plurality sets of first inductors that include third ends connected to the first nodes, respectively, and the fourth ends commonly connected to a third node, a second inductor that includes a fifth end connected to the second node, and a sixth end grounded, and a third inductor that includes a seventh end connected to the third node, and an eighth end grounded.

## Claims

### Claim 1

A filter comprising:
an input terminal;
an output terminal;
a plurality sets of first capacitors that include first ends connected to a plurality sets of first nodes, respectively, at different locations in a path capable of transmitting a high frequency signal from the input terminal to the output terminal, and second ends commonly connected to a second node;
a plurality sets of first inductors that include third ends connected to the first nodes, respectively, and the fourth ends commonly connected to a third node;
a second inductor that includes a fifth end connected to the second node, and a sixth end grounded; and
a third inductor that includes a seventh end connected to the third node, and an eighth end grounded.

### Claim 2 (depends on 1)

The filter according to claim 1, wherein
at least a part of the path is formed of magnetic coupling between at least two first inductors among the plurality sets of first inductors.

### Claim 3 (depends on 1)

The filter according to claim 1, wherein
at least a part of the path includes a fourth inductor connected between at least two first nodes among the plurality sets of the first nodes.

### Claim 4 (depends on 1)

The filter according to claim 1, wherein
an inductance of the second inductor is larger than that of the third inductor.

### Claim 5 (depends on 1)

The filter according to claim 1, further comprising:
a laminated body that includes a plurality of laminated dielectric layers, and one or more ground terminals provided on an outer surface in a laminating direction;
a first metal pattern that is provided on a first surface between adjacent dielectric layers among the plurality of dielectric layers, and forms at least a part of the second node;
a second metal pattern that is provided on the first surface, is separated from the first metal pattern on the first surface, and forms at least a part of the third node;
one or more first via wirings that connect the first metal pattern and at least one of the one or more ground terminals, and penetrate at least one of the plurality of dielectric layers; and
one or more second via wirings that connect the second metal pattern and at least one of the one or more ground terminals, and penetrate at least one of the plurality of dielectric layers.

### Claim 6 (depends on 5)

The filter according to claim 5, wherein
a sum of cross-sectional areas of the one or more first via wirings is smaller than that of the cross-sectional areas of the one or more second via wirings.

### Claim 7 (depends on 1)

The filter according to claim 1, further comprising:
a laminated body that includes a plurality of laminated dielectric layers, and one or more ground terminals provided on an outer surface in a laminating direction;
a first metal pattern that is provided on a first surface between adjacent dielectric layers among the plurality of dielectric layers, and forms at least a part of the second node;
a second metal pattern that is provided on a second surface between adjacent dielectric layers among the plurality of dielectric layers, and forms at least a part of the third node, the second surface being closer to the outer surface than the first surface;
one or more first via wirings that connect the first metal pattern and at least one of the one or more ground terminals, and penetrate at least two of the plurality of dielectric layers; and
one or more second via wirings that connect the second metal pattern and at least one of the one or more ground terminals, and penetrate at least one of the plurality of dielectric layers.

### Claim 8 (depends on 1)

The filter according to claim 1, further comprising:
a second capacitor connected in parallel with at least a part of the path.

### Claim 9 (depends on 1)

The filter according to claim 1, wherein
the filter is a bandpass filter.

### Claim 10 (depends on 9)

The filter according to claim 9, wherein
a pass characteristic of the bandpass filter includes:
a first attenuation pole formed by at least the plurality sets of first inductors, the plurality sets of first capacitors and the second inductor at a frequency lower than a pass band; and
a second attenuation pole formed by at least the plurality sets of first inductors, the plurality sets of first capacitors and the third inductor at a frequency higher than the pass band.

### Claim 11 (depends on 1)

A multiplexer comprising:
the filter according to claim 1.

### Claim 12 (depends on 1)

A communication module comprising:
the filter according to claim 1.