# US 2013/0154769 A1 · Band-pass filter

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- Number: US 2013/0154769 A1
- Document ID: US20130154769A1
- Status: Published application
- Kind: A1
- Application number: 13/705,588
- Filed: 2012-12-05
- Published: 2013-06-20
- Earliest claimed: 2011-12-19
- Assignees: Murata Manufacturing Co., Ltd.
- Inventors: Yutaka MASUDA
- Web page: https://patentgrep.com/patent/US20130154769A1

## CPC

- H01P 7/08: Strip line resonators
- H01P 1/20345: {Multilayer filters}
- H03H 7/0161: {Bandpass filters (H03H7/12 takes precedence)}
- H03H 2001/0085: {Multilayer, e.g. LTCC, HTCC, green sheets}
- H01P: WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE (operating at optical frequencies G02B)
- H03H: IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS (waveguides, resonators, lines or other devices of the waveguide type H01P)

## Abstract

A capacitor of a certain LC resonator, among multiple LC resonators in a band-pass filter, is arranged at a side of one main surface in a stacking direction of a multilayer body of the band-pass filter and the capacitors of the remaining LC resonators are arranged at a side of the other main surface in the stacking direction of the multilayer body. One of a pair of capacitor electrodes of the capacitor of the certain LC resonator is grounded. The one capacitor electrode that is grounded covers at least the plurality of LC resonators, as viewed from the stacking direction of the multilayer body.

## Claims

### Claim 1

A band-pass filter comprising:
a multilayer body including a plurality of dielectric layers that are stacked on each other, capacitor electrodes and line electrodes provided on the plurality of dielectric layers, and a via inductor including a plurality of via electrodes that are connected to each other and that penetrate through the plurality of dielectric layers;
wherein
a plurality of LC resonators are arranged in a direction perpendicular or substantially perpendicular to a stacking direction of the multilayer body;
each of the plurality of LC resonators includes an inductor including the via inductor being connected to a capacitor including a pair of the capacitor electrodes;
in each of the plurality of LC resonators, one end of the inductor is connected to one of the pair of capacitor electrodes of the capacitor;
the capacitor of at least one of the plurality of LC resonators is arranged at a side of one main surface in the stacking direction of the multilayer body and the capacitors of remaining ones of the plurality of LC resonators are arranged at a side of another main surface in the stacking direction of the multilayer body; and
the other of the pair capacitor electrodes of the capacitor of the at least one of the plurality of LC resonators is grounded.

### Claim 2 (depends on 1)

The band-pass filter according to claim 1, wherein the other of the pair of capacitor electrodes that is grounded is arranged so as to cover at least the plurality of LC resonators, as viewed from the stacking direction of the multilayer body.

### Claim 3 (depends on 1)

The band-pass filter according to claim 1, wherein one of the plurality of LC resonators includes an input terminal and one of the plurality of LC resonators includes an output terminal; and
one of the plurality of LC resonators next to the one of the plurality of LC resonators including the input terminal is the at least one of the plurality of LC resonators.

### Claim 4 (depends on 1)

The band-pass filter according to claim 1, wherein the inductor of each of the plurality of LC resonators includes the line electrode and a pair of via inductors, and one end of one of the pair of via inductors and one end of the other of the pair of via inductors are connected to one end and another end of the line electrode to define a loop inductor.

### Claim 5 (depends on 1)

The band-pass filter according to claim 1, wherein the inductor of the at least one of the plurality of LC resonators is defined by the via inductor.

### Claim 6 (depends on 3)

The band-pass filter according to claim 3, wherein
each of the one of the plurality of LC resonators including the input terminal and the one of the plurality of LC resonators including the output terminal includes the line electrode;
both ends of the line electrode are electrically connected to the via inductor to define a loop inductor;
a coupling electrode is arranged so as to oppose the line electrodes; and
the coupling electrode is arranged so as to be connected to the inductor of one of the plurality of LC resonators adjacent to the one of the plurality of LC resonators including the input terminal and the one of the plurality of LC resonators including the output terminal.

### Claim 7 (depends on 6)

The band-pass filter according to claim 6, wherein the coupling electrode is arranged so as to oppose the line electrode of the one of the plurality of LC resonators including the input terminal and the line electrode of the one of the plurality of LC resonators including the output terminal.