JP2000091125A - Noise filter - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To be effective for a frequency of several GHz exceeding 1 GHz in which noise can be removed.
It is an object of the present invention to provide a noise filter with improved attenuation even in a high frequency range. A metal wire having electrical conductivity, an electrode portion electrically connected to both ends of the metal wire, and a sheath covering the metal wire are provided, and the sheath is sintered. A resin ferrite obtained by mixing a resin with a powdered magnetic material obtained by turning ferrite into a powder, and the sintered ferrite has a frequency of (μ ″) in a complex magnetic permeability represented by {(μ ′) − j (μ ″)}. The configuration is not limited to the limit line.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a noise filter used for various consumer appliances.

[0002]

2. Description of the Related Art Hereinafter, a conventional noise filter will be described.
This will be described with reference to the drawings.

FIG. 6 is a partially cutaway perspective view of a conventional noise filter, FIG. 7 is a perspective view of the noise filter, and FIG. 8 is a permeability frequency characteristic diagram showing the permeability frequency characteristics of ferrite in the noise filter. 9 is an impedance frequency characteristic diagram showing an impedance frequency characteristic in the noise filter, and FIG. 10 is an attenuation frequency characteristic diagram showing an attenuation frequency characteristic in the noise filter.

In FIGS. 6 and 7, a conventional noise filter comprises a metal wire 1 having electrical conductivity, an electrode portion 2 electrically connected to both ends of the metal wire 1, and a sintered ferrite. And an exterior unit 3 that covers the wire 1.

Further, as shown in FIG. 8 to FIG. 10, the permeability frequency characteristics of the sintered ferrite follow the frequency limit line of the neck due to the domain wall resonance phenomenon.

[0006] Generally, the magnetic permeability of sintered ferrite is
A complex magnetic permeability expressed by {(μ ′) − j (μ ″)}, which is a component of magnetic flux density (real part) in phase with the magnetic field (real part) and a magnetic flux density delayed by 90 ° phase (Imaginary part) and (μ ″).

At this time, the frequency limit line (A) of (μ ′)
Is called the limit line of the Sneck, which indicates the limit of the range that restricts the operating frequency of the ferrite. The frequency limit line (B) of (μ ″) corresponds to the energy loss due to the domain wall resonance, Is a limit line that is determined according to the limit line of and affects the impedance value, where (μ ′)
Are (X), (Y), (Z), and correspondingly, the frequency characteristic of (μ ″) is
(X), (y), and (z).

The magnitude of (μ ″) for a specific frequency determines the impedance value up to that frequency and also determines the amount of attenuation.

[0009]

In the above-mentioned conventional configuration,
According to the attenuation frequency characteristic diagram, the range in which noise can be removed is effective only for frequencies up to about 1 GHz, and the attenuation decreases as the frequency shifts from low to high. I will.

That is, in recent years, it is necessary to adapt to a frequency of about several GHz exceeding 1 GHz in order to remove noise of electronic equipment such as a mobile phone and a computer used in a high frequency range. Has the problem that it cannot be adapted to this.

The present invention solves the above-mentioned problems, and is effective for a frequency range of several GHz exceeding 1 GHz in which the noise can be removed. It is intended to provide a filter.

[0012]

In order to achieve the above object, the present invention provides a metal wire having electrical conductivity, an electrode portion electrically connected to both ends of the metal wire, and a coating of the metal wire. And an exterior part, wherein the exterior part is a resin ferrite obtained by mixing a resin with a powdered magnetic material obtained by powdering sintered ferrite, and the sintered ferrite is ｛(μ ′)-j
The configuration is not limited to the frequency limit line of (μ ″) in the complex magnetic permeability represented by (μ ″)｝.

According to the above configuration, the range in which noise can be removed is effective for frequencies of about several GHz exceeding 1 GHz, and the attenuation can be improved even in a high frequency range.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION
A metal wire having electrical conductivity, an electrode portion electrically connected to both ends of the metal wire, and an exterior portion covering the metal wire, wherein the exterior portion is made of powdered magnetic material made of sintered ferrite. A resin ferrite obtained by mixing a resin with a body, and the sintered ferrite is {(μ ′) − j (μ ″)}
This is a configuration that is not limited to the frequency limit line of (μ ″) in the complex magnetic permeability represented by

According to the above configuration, the noise can be removed effectively at a frequency of about several GHz exceeding 1 GHz, and the attenuation can be improved even in a high frequency range.

The second aspect of the present invention is the first aspect of the present invention.
In the described invention, the sintered ferrite is a cubic spinel ferrite or a hexagonal ferrite.

According to the above configuration, the sintered ferrite is a cubic spinel-type ferrite or a hexagonal ferrite, so that the effects described in claim 1 can be more reliably obtained.

The third aspect of the present invention is the second aspect of the present invention.
In the described invention, the cubic spinel type ferrite has a configuration of a Ni-Zn type ferrite or a Mn-Zn type ferrite.

According to the above configuration, the cubic spinel type ferrite is a Ni-Zn type ferrite or a Mn-Zn type ferrite, so that the effect of the first aspect can be more reliably obtained.

(Embodiment) Hereinafter, a noise filter according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a partially cutaway perspective view of a noise filter according to an embodiment of the present invention, FIG. 2 is a perspective view of the noise filter, and FIG. 3 is a permeability diagram showing magnetic permeability frequency characteristics of ferrite in the noise filter. FIG. 4 is an impedance frequency characteristic diagram showing an impedance frequency characteristic in the noise filter, and FIG. 5 is an attenuation frequency characteristic diagram showing an attenuation frequency characteristic in the noise filter.

Referring to FIGS. 1 and 2, a noise filter according to an embodiment of the present invention includes a metal wire 11 having electrical conductivity.
And an electrode portion 12 electrically connected to both ends of the metal wire 11.
And an exterior part 13 that covers the metal wire 11.

The exterior part 13 is a resin ferrite obtained by mixing a resin with a powdered magnetic material obtained by powdering the sintered ferrite, and this sintered ferrite has a ｛(μ ')-j
It is not restricted to the frequency limit line of (μ ″) in the complex magnetic permeability represented by (μ ″)｝.

Further, the sintered ferrite has a structure of a Ni—Zn ferrite which is a cubic spinel type ferrite.
Ni-Cu-Zn, Mn-Mg-Zn, Mg-Ca-Z
There are ferrites such as n.

Here, the magnetic permeability of the sintered ferrite is
A complex magnetic permeability expressed by {(μ ′) − j (μ ″)}, which is a component of magnetic flux density (real part) in phase with the magnetic field (real part) and a magnetic flux density delayed by 90 ° phase (Imaginary part) and (μ ″).

Further, the frequency limit line (A) of (μ ′) is called the limit line of the neck, which indicates the limit of the range that restricts the working frequency of the ferrite, and the frequency limit line (B) of (μ ″). ) Corresponds to the energy loss due to domain wall resonance, is a limit line determined according to the limit line of the neck, and affects the frequency attenuation characteristic value, where the frequency characteristics of (μ ′) are (X), (Y), (Z), and correspondingly, the frequency characteristics of (μ ″) are (x), (y),
(Z).

At this time, as shown in FIG. 3 to FIG. 5, the permeability frequency characteristic of the sintered ferrite of the noise filter according to the embodiment of the present invention is as follows. The frequency limit line (A) is within the range of the frequency limit line of the neck due to the domain wall resonance phenomenon, but (μ ″) is (t)
And exceeds the frequency limit line (B), and numerical data at this time are shown in (Table 1).

[0028]

[Table 1]

The magnitude of (μ ″) for a specific frequency determines the impedance value up to that frequency and the amount of attenuation, but (μ ″) is limited to the frequency limit line (B). However, the frequency limit line (B) is exceeded, and the impedance value is large even at a frequency of about several GHz.

That is, the impedance value is large even at a frequency of about several GHz, so that the attenuation is large.

The characteristics of the noise filter having the above configuration will be described below. The sintered ferrite used for the resin ferrite of the exterior part covering the insulated wire is ｛(μ ')-
j (μ ″)}, the frequency is not limited to the frequency limit line of (μ ″) in the complex magnetic permeability, so that the range in which noise can be removed exceeds 1 GHz as shown in FIGS. It is effective for frequencies of about several GHz, and
The attenuation can be improved even in a high frequency range. Further, since the sintered ferrite is a cubic spinel type ferrite of Ni-Zn type ferrite, the above-mentioned effect can be obtained more reliably.

As described above, according to the embodiment of the present invention, the range in which noise can be removed is several GHz which exceeds 1 GHz.
It is effective for frequencies of about z, and since the attenuation can be improved even in a high frequency range, it is possible to remove noise from electronic devices such as mobile phones and computer devices used in recent high frequency ranges. be able to.

In the present embodiment, the sintered ferrite is a cubic spinel ferrite Ni—Zn ferrite, but the cubic spinel ferrite Mn—
The same effect can be obtained by using Zn-based ferrite or hexagonal ferrite.

When the sintered ferrite is made of Mn-Zn-based ferrite, the Mn-Zn-based ferrite has electrical conductivity. The same effect can be achieved by providing an insulator between the portion 13 and insulating the portion.

Further, in the present embodiment, the metal wire 11 is a straight wire, but a similar effect can be obtained by using a coil.

[0036]

As described above, according to the present invention, the noise elimination range of the electronic device such as a cellular phone or a computer device used in a high frequency band in recent years is more than 1 GHz. A noise filter that is effective for frequencies of about GHz and that has improved attenuation even in a high frequency range can be provided.

[Brief description of the drawings]

FIG. 1 is a partially cutaway perspective view of a noise filter according to an embodiment of the present invention.

FIG. 2 is a perspective view of the noise filter.

FIG. 3 is a magnetic permeability frequency characteristic diagram showing magnetic permeability frequency characteristics of ferrite in the noise filter.

FIG. 4 is an impedance frequency characteristic diagram showing impedance frequency characteristics in the noise filter.

FIG. 5 is an attenuation frequency characteristic diagram showing an attenuation frequency characteristic in the noise filter.

FIG. 6 is a partially cutaway perspective view of a conventional noise filter.

FIG. 7 is a perspective view of the noise filter.

FIG. 8 is a magnetic permeability frequency characteristic diagram showing magnetic permeability frequency characteristics of ferrite in the noise filter.

FIG. 9 is an impedance frequency characteristic diagram showing impedance frequency characteristics in the noise filter.

FIG. 10 is an attenuation frequency characteristic diagram showing attenuation frequency characteristics in the noise filter.

[Explanation of symbols]

 11 Metal wire 12 Electrode part 13 Exterior part

Claims (3)

[Claims] 1. A metal wire having electrical conductivity, an electrode portion electrically connected to both ends of the metal wire, and a sheath covering the metal wire, wherein the sheath comprises sintered ferrite. In addition to the resin ferrite obtained by mixing a resin with the powdered magnetic material, the sintered ferrite has a Δ (μ ′) −
j (μ ″)} A noise filter which is not restricted to the frequency limit line of (μ ″) in the complex magnetic permeability represented by｝. 2. The noise filter according to claim 1, wherein the sintered ferrite is a cubic spinel ferrite or a hexagonal ferrite. 3. The cubic spinel-type ferrite is Ni-
The noise filter according to claim 2, wherein the ferrite is a Zn-based ferrite or a Mn-Zn-based ferrite.