Noise elimination circuit and communication device including the same

Patent metadata

Field	Value
Publication number	US-2024322779-A1
Application number	US-202418733924-A
Country	US
Kind code	A1
Filing date	Jun 5, 2024
Priority date	Dec 6, 2021
Publication date	Sep 26, 2024
Grant date	—

Abstract

A noise elimination circuit includes a coupling line and a resonance unit, and is connected between a first transmission line and a second transmission line to eliminate noise between the first and second transmission lines. The coupling line is connected to the first and second transmission lines. The resonance unit includes a plurality of resonance circuits connected in parallel to the coupling line. A band pass filter includes the coupling line and the resonance unit. A real part and an imaginary part of an admittance between the transmission lines are canceled out by the noise elimination circuit.

First claim

What is claimed is:

1 . A noise elimination circuit connected between a first transmission line and a second transmission line to eliminate noise between the first and second transmission lines, the noise elimination circuit comprising:
a coupling line connected to the first transmission line and the second transmission line; and a resonance unit including a plurality of resonance circuits connected in parallel to the coupling line; wherein a band pass filter includes the coupling line and the resonance unit; and a real part and an imaginary part of an admittance between the transmission lines are canceled out by the noise elimination circuit.

2 . The noise elimination circuit according to claim 1 , further comprising a dielectric layer, wherein
the resonance unit includes a circuit pattern and a via within the dielectric layer.

3 . The noise elimination circuit according to claim 2 , wherein
each of the plurality of resonance circuits includes a resonator including a capacitor and an inductor connected in parallel; and a resonance frequency of the resonator is set to generate an attenuation pole in a frequency band of the noise to be eliminated between the first and second transmission lines.

4 . The noise elimination circuit according to claim 3 , further comprising a first ground electrode with a flat plate shape and provided in the dielectric layer, wherein
the first ground electrode is one electrode of the capacitor included in the resonator.

5 . The noise elimination circuit according to claim 4 , further comprising a second ground electrode provided in the dielectric layer to face the first ground electrode, and electrically connected with the first ground electrode; wherein
the coupling line and the resonance unit are between the first ground electrode and the second ground electrode in the dielectric layer.

6 . The noise elimination circuit according to claim 5 , wherein at least one of the first ground electrode and the second ground electrode is exposed to an outer surface of the dielectric layer.

7 . The noise elimination circuit according to claim 2 , wherein the coupling line is within the dielectric layer.

8 . The noise elimination circuit according to claim 2 , wherein
the first transmission line, the second transmission line, and the noise elimination circuit are on a dielectric substrate; and on the dielectric substrate, the coupling line is separated from the resonance unit.

9 . The noise elimination circuit according to claim 2 , wherein a dielectric constant temperature coefficient of the dielectric layer is within a range of more than about −100 ppm/K and less than about +100 ppm/K.

10 . The noise elimination circuit according to claim 2 , wherein the dielectric layer is made of a low temperature co-fired ceramic including more than or equal to about 50% by weight and less than or equal to about 80% by weight of a glass component.

11 . The noise elimination circuit according to claim 2 , wherein the dielectric layer includes a material mainly including SiO 2 , SiN, a fluororesin, a liquid crystal polymer, poly phenylene ether (PPE), LiNbO 3 , or LiTaO 3 .

12 . The noise elimination circuit according to claim 2 , further comprising a first circuit provided to the coupling line and including a reactance element.

13 . The noise elimination circuit according to claim 12 , wherein the first circuit is on the dielectric layer.

14 . The noise elimination circuit according to claim 1 , wherein the resonance unit includes a capacitor and an inductor including discrete elements.

15 . A communication device comprising:
a first antenna connected to a first transmission line; a second antenna connected to a second transmission line; and a noise elimination circuit connected between the first transmission line and the second transmission line to eliminate noise between the transmission lines; wherein the noise elimination circuit includes:
a coupling line connected to the first transmission line and the second transmission line; and
a resonance unit including a plurality of resonance circuits connected in parallel to the coupling line;
a band pass filter includes the coupling line and the resonance unit; and a real part and an imaginary part of an admittance between the transmission lines are canceled out by the noise elimination circuit.

16 . The communication device according to claim 15 , wherein the first antenna is a transmitting antenna, and the second antenna is a receiving antenna.

17 . The communication device according to claim 15 , wherein the first antenna and the second antenna are transmitting antennas.

18 . The communication device according to claim 15 , wherein the first antenna and the second antenna are receiving antennas.

19 . The communication device according to claim 15 , further comprising a front end circuit that includes the noise elimination circuit.

20 . The communication device according to claim 19 , wherein the front end circuit further includes a signal processing circuit.

Assignees

• Murata Manufacturing Co
• National Univ Corporation Toyohashi Univ Of Technology

Inventors

• Saeki Hiromasa
• Tamura Masaya
• Takagi Masaya

Classifications

• H03H7/0115 Primary

  comprising only inductors and capacitors (H03H7/075, H03H7/09, H03H7/12, H03H7/13 take precedence) · CPC title

• H03H7/1775

  Parallel LC in shunt or branch path (H03H7/1791 takes precedence) · CPC title

• H04B1/525 Primary

  with means for reducing leakage of transmitter signal into the receiver · CPC title

• H04B1/10

  Means associated with receiver for limiting or suppressing noise or interference · CPC title

• H03H7/075

  Ladder networks, e.g. electric wave filters · CPC title