# US 10,122,340 B2 · LC filter

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- Number: US 10,122,340 B2
- Document ID: US10122340B2
- Status: Granted
- Kind: B2
- Application number: 15/849,938
- Filed: 2017-12-21
- Published: 2018-04-26
- Granted: 2018-11-06
- Earliest claimed: 2015-07-22
- Assignees: Murata Manufacturing Co., Ltd.
- Applicants: Murata Manufacturing Co., Ltd.
- Inventors: Hiroshi Masuda
- Web page: https://patentgrep.com/patent/US10122340B2

## CPC

- H03H 7/075: Ladder networks, e.g. electric wave filters
- H01F 17/00: Fixed inductances of the signal type
- H01F 17/0013: {with stacked layers}
- H01F 27/00: Details of transformers or inductances, in general
- H01P 1/20345: {Multilayer filters}
- H03H 7/0115: {comprising only inductors and capacitors (H03H7/075, H03H7/09, H03H7/12, H03H7/13 take precedence)}
- H01F 2017/0026: {Multilayer LC-filter}
- 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)
- H01F: MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01P: WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE (operating at optical frequencies G02B)

## Abstract

An LC filter includes a laminate including insulating layers laminated in a lamination direction, an inductor having a spiral or helical shape around an axis parallel or substantially parallel to the lamination direction, and a capacitor in which capacitor conductors face each other. The inductor and the capacitor do not overlap as viewed from the lamination direction and all directions orthogonal or substantially orthogonal to the lamination direction.

## Claims

### Claim 1

An LC filter comprising:
a laminate including a plurality of insulating layers laminated in a lamination direction;
an inductor having a spiral or helical shape around an axis parallel or substantially parallel to the lamination direction; and
a capacitor in which a plurality of capacitor conductors face each other; wherein
the inductor and the capacitor define an LC resonator; and
the inductor and the capacitor do not overlap as viewed from the lamination direction and all directions orthogonal or substantially orthogonal to the lamination direction.

### Claim 2 (depends on 1)

The LC filter according to claim 1, wherein the plurality of capacitor conductors have a rectangular or substantially rectangular shape.

### Claim 3 (depends on 1)

The LC filter according to claim 1, wherein
the laminate includes a bottom surface located at one end in the lamination direction; and
the LC filter further includes an outer electrode that is electrically connected to the inductor and the capacitor and is disposed on the bottom surface.

### Claim 4 (depends on 3)

The LC filter according to claim 3, wherein the outer electrode is disposed on only the bottom surface.

### Claim 5 (depends on 3)

The LC filter according to claim 3, wherein
the laminate further includes a top surface located at another end in the lamination direction; and
the capacitor is disposed nearer to the top surface than the inductor is to the top surface.

### Claim 6 (depends on 5)

The LC filter according to claim 5, wherein, two or more of the plurality of the insulating layers which are provided between the inductor and the bottom surface, no conductor is provided other than a via-hole conductor passing through the insulating layers in a straight line in the lamination direction and a land conductor relaying a connection of the via-hole conductor at a boundary between the two or more of the plurality of insulating layers.

### Claim 7 (depends on 1)

The LC filter according to claim 1, wherein, in the inductor, a plurality of inductor conductors that are provided on respective insulating layers of the plurality of insulating layers and extend around the axis and one or more via-hole conductors passing through the insulating layers are connected.

### Claim 8 (depends on 1)

The LC filter according to claim 1, wherein a relative dielectric constant of one of the plurality of insulating layers that is sandwiched by the plurality of capacitor conductors in the lamination direction is higher than a relative dielectric constant of the plurality of insulating layers at which the inductor is disposed.