JP2006135897A - Isolator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a noise-reduced and performance-improved isolator. <P>SOLUTION: An isolator of the present invention comprises a plate-like ferrite member 4, first, second and third central conductors 5, 6 and 7 positioned on the ferrite member 4, provided on different vertical surfaces with a dielectric in between and partially crossing in the vertical direction, and magnets 2 disposed on the central conductors 5, 6 and 7 for applying a DC magnetic field to the ferrite member 4. Since the strength of a magnetic field G to the first central conductor 5 is weakened at the side of a port 5b rather than at the side of a ground 5a and the magnetic field G applied to the first central conductor 5 is made non-uniform, out of the passband (2×f0), an attenuation amount is enlarged rather than the conventional. Noise is thereby reduced and superior performance is obtained. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an isolator suitable for application to an antenna duplexer or the like.

  FIG. 10 is an exploded perspective view of a conventional isolator. Next, the configuration of the conventional isolator will be described with reference to FIG. 10. The conventional isolator includes a box-shaped first yoke 51 and a first yoke 51. A U-shaped second yoke 52 coupled to the first and second yokes 51 and 52, a resin case 53 made of a synthetic resin molding, and positioned above the resin case 53. And a square plate-like magnet 54 disposed in the first yoke 51.

Further, the conventional isolator is composed of a ferrite member 55 positioned and attached to the lower portion of the resin case 53, and a metal plate partially crossed over the ferrite member 55 at intervals of 120 degrees. The first, second, and third center conductors 56, 57, and 58 are formed on one end side of these center conductors 56, 57, and 58, respectively.
Grounding portions 56a, 57a, and 58a to be grounded are provided, and port portions 56b, 57b, and 58b are provided on the other end side of the central conductors 56, 57, and 58.

  A capacitor C1 is connected to the port portion 56b that is the input terminal of the first center conductor 56, a capacitor C2 is connected to the port portion 57b that is the output terminal of the second center conductor 57, and A capacitor C3 and a resistor R are connected to the port portion 58b of the third central conductor 58.

  In addition, an input / output substrate 59 is disposed in the lower portion of the second yoke 52, and the port portions 56b and 57b of the first and second central conductors 56 and 57 are connected to the land portion 60. It is configured. (For example, see Patent Document 1)

  In the conventional isolator, the area of the magnet 54 and the ferrite member 55 facing each other is such that the area of the magnet 54 is larger than the ferrite member, the ferrite member 55 is located within the area of the magnet 54, and the magnet 54 and the ferrite member The center of 55 is positioned and attached by the resin case 53 so as to coincide with each other.

As shown in FIG. 8, the magnet 54 applies a DC magnetic field G to the ferrite member 55. In this case, the strength of the magnetic field G of the magnet 54 is stronger on the center side than on the outer peripheral edge side.
When the centers of the magnet 54 and the ferrite member 55 are aligned as in the prior art, uniform magnetic field strength is applied to the entire surface of the ferrite member 55 as shown in FIG.

  Then, as shown in FIG. 9, the current input from the port portion 56b of the first center conductor 56 is transferred to the second center conductor 57 from the position beyond the crossover portion K, and the second center conductor 57 FIG. 7 is a graph showing the results of measuring the relationship between frequency (MHz) and attenuation (dB).

  The conventional isolator has a small attenuation amount in the pass band (f0) as shown by a one-dot chain line S3 in FIG. 7, but the attenuation amount is −15. This is a small 4 dB, which causes a situation where noise is generated. This is because a resonance circuit having a high Q is formed by the first and second central conductors in a uniform magnetic field G. Presumed to be.

Japanese Patent Laid-Open No. 9-213523

  In the conventional isolator, it is assumed that a resonance circuit having a high Q is formed by the first and second center conductors in the uniform magnetic field G, and as a result of the measurement, the outside isolator (2 × f0 ) Has a problem that the amount of attenuation is small and noise is generated due to this.

  Therefore, an object of the present invention is to provide an isolator with low noise and good performance.

  As a first means for solving the above problems, a flat ferrite member and a ferrite member positioned on the ferrite member, provided on different surfaces in the vertical direction across the dielectric, and partially in the vertical direction First, second, and third center conductors that intersect, a magnet that is disposed on the center conductor and that applies a DC magnetic field to the ferrite member, and a first yoke that is disposed so as to cover the upper surface of the magnet And a second yoke which is disposed on the lower surface side of the ferrite member and forms a magnetic closed circuit with the first yoke, and a ground portion to be grounded is provided at one end side of each of the central conductors. And the other end side of the first center conductor is a port portion which is an input terminal connected to a capacitor, and the other end side of the second center conductor is an output terminal connected to a capacitor. The port part that is A port portion connected to a capacitor and a resistor is provided on the other end side of the third center conductor, and the strength of the magnetic field with respect to the first center conductor is weaker on the port portion side than on the ground portion side. Thus, the magnetic field applied to the first central conductor is made non-uniform.

  Further, as a second solution, the magnet and the ferrite member are opposed to each other in a state where the centers are shifted from each other, and the strength of the magnetic field with respect to the first central conductor is closer to the port portion than to the ground portion. And the magnetic field applied to the first central conductor is made non-uniform.

  As a third solution, the area of the magnet is larger than the area of the ferrite member so that the ferrite member is positioned within the area of the magnet.

  Further, as a fourth solving means, the magnet forms a polygon of four or more squares, the ferrite member forms a polygon of four or more squares, and the port portions of the first and second center conductors And the outer periphery of the ferrite member in which the port portions of the first and second center conductors are disposed. The peripheral edge and the outer peripheral edge of the magnet are made to coincide with each other in the vertical direction.

The isolator according to the present invention includes a flat ferrite member, first, second and second portions located on the ferrite member, provided on different surfaces in the vertical direction across the dielectric, and partially intersecting in the vertical direction. A third central conductor, a magnet disposed on the central conductor and applying a DC magnetic field to the ferrite member, a first yoke disposed to cover the upper surface of the magnet, and a lower surface of the ferrite member And a second yoke constituting a magnetic closed circuit with the first yoke, and having a grounding portion grounded at one end side of each center conductor and the other end side of the first center conductor The port portion that is the input terminal connected to the capacitor, the port portion that is the output terminal connected to the capacitor on the other end side of the second center conductor, and the third center conductor. On the end side, capacitors and resistors A configuration in which the port portion is connected and the strength of the magnetic field with respect to the first central conductor is made weaker on the port portion side than on the ground portion side so that the magnetic field applied to the first central conductor is non-uniform. did.
That is, the strength of the magnetic field with respect to the first central conductor is made weaker on the port side than on the ground side, and the magnetic field applied to the first central conductor is made non-uniform. It is presumed that this is due to the low Q of the resonance circuit formed by.
Further, as a result of the measurement, it can be confirmed that the attenuation is larger than the conventional one outside the pass band (2 × f0), and therefore, noise is reduced and a good performance can be obtained.

  Further, the magnet and the ferrite member are opposed to each other with their centers shifted from each other, and the strength of the magnetic field with respect to the first central conductor is made weaker on the port side than on the ground side and applied to the first central conductor. Since the applied magnetic field is made non-uniform, the structure is simple and a product with good productivity can be obtained.

  In addition, since the area of the magnet is larger than the area of the ferrite member so that the ferrite member is positioned within the area of the magnet, a good application of a DC magnetic field to the ferrite member by the magnet is obtained, A small attenuation in the passband (f0) is obtained.

  In addition, the magnet forms a polygon having a square shape or more, the ferrite member has a polygon shape having a square shape or more, and the port portion of the first and second central conductors is a ferrite in which the port portion of the third central conductor is disposed. Since the outer peripheral edge of the ferrite member and the outer peripheral edge of the magnet, which are disposed on the outer peripheral edge facing the outer peripheral edge of the member and where the port portions of the first and second central conductors are disposed, are aligned at the vertical position, the ferrite member The process of combining the outer periphery of the magnet and the magnet is simple, the productivity is good, and the strength of the magnetic field for the first central conductor can be weaker on the port side than on the ground side. Outside (2 × f0), the amount of attenuation becomes larger, noise can be reduced, and a good performance can be obtained.

  FIG. 1 is a cross-sectional view of an essential part of an isolator according to the present invention. FIG. 2 is a plan view showing a state in which a first yoke and a magnet are removed according to the isolator of the present invention. 3 is an explanatory view showing the relationship between a ferrite member and a magnet on which a central conductor is arranged, and a magnet according to the first embodiment of the isolator of the present invention, and FIG. 4 is related to a second embodiment of the isolator of the present invention, in which the central conductor is arranged. It is explanatory drawing which shows the relationship between a ferrite member and a magnet.

  FIG. 5 relates to a third embodiment of the isolator of the present invention, and is an explanatory view showing the relationship between the ferrite member having the central conductor and the magnet, and FIG. 6 relates to the fourth embodiment of the isolator of the present invention. FIG. 7 is a graph showing the relationship between the frequency and attenuation in the isolator, FIG. 8 is a diagram showing the state of the magnetic field in the isolator, and FIG. 9 is a current flow in the isolator. It is explanatory drawing which shows.

  Next, the configuration of the isolator according to the present invention will be described with reference to FIGS. 1 to 9. The first yoke 1 made of a U-shaped or box-shaped magnetic plate (iron plate or the like) has a rectangular upper plate 1 a. And a side plate 1b bent downward from the side of the upper plate 1a.

The rectangular (rectangular) magnet 2 is positioned in the first yoke 1, and the upper surface thereof is in contact with the inner surface of the upper plate 1a. It is attached.
The magnet 2 may have a polygonal shape having outer peripheral edges 2a, 2b and 2c, 2d facing each other that are equal to or more than square.

  The second yoke 3 made of a U-shaped or box-shaped magnetic plate (iron plate or the like) has a rectangular bottom plate 3a and a side plate 3b bent upward from the side of the bottom plate 3a. The yoke 3 of No. 2 is coupled with the side plate 1b of the first yoke 1 in a state where the bottom plate 3a is disposed facing the upper plate 1a, thereby forming a magnetic closed circuit.

A flat ferrite member 4 made of YIG (Yttrium iron garnet) or the like is disposed in the second yoke 3 so as to face the magnet 2.
Further, the ferrite member 4 is shown as an octagonal shape in this embodiment, but a polygonal shape having outer peripheral edges 4a, 4b and 4c, 4d opposed to each other having a square shape or more may be used.
And the area of the ferrite member 4 is smaller than the area of the magnet 2, and is in a state of being arranged facing the area of the magnet 2.

The first, second and third center conductors 5, 6 and 7 made of a thin conductive plate such as copper are provided on the other end side with grounded ground portions 5a, 6a and 7a provided on one end side. Port portions 5b, 6b, and 7b.
These first, second, and third center conductors 5, 6, and 7 are arranged at 120 degree intervals on different surfaces in the vertical direction with a dielectric (not shown) interposed therebetween on the ferrite member 4. It is provided, and a part is arranged crossing in the up-and-down direction.

  At this time, the port portions 5b and 6b of the first and second center conductors 5 and 6 and the ground portion 7a of the third center conductor 7 are formed on the outer peripheral edge 4a side which is one long side of the ferrite member 4. In addition, the port portion 7b of the third central conductor 7 and the ground portions 5a and 6a of the first and second central conductors 5 and 6 are disposed on the outer peripheral edge 4b side which is the other long side. The ground portions 5 a, 6 a, 7 a of the first, second, and third center conductors 5, 6, 7 are grounded to the second yoke 3.

  The chip-type first, second, and third capacitors C1, C2, and C3 are respectively opposed to the first electrode 11a provided on the insulator 10 and the first electrode 11a across the insulator 10. A second electrode 11b is provided.

  The first, second, and third capacitors C1, C2, and C3 are grounded with the first electrode 11a connected to the bottom plate 3a of the second yoke 3 in a state of being disposed on the outer periphery of the ferrite member 4. It becomes a state.

  The chip-type resistor R has a pair of electrodes 12a and 12b provided on opposite end surfaces, and the resistor R is disposed in the vicinity of the third capacitor C3 and is connected to one electrode 12a. Is connected to the bottom plate 3a of the second yoke 3 and grounded, and the other electrode 12b is insulated from the bottom plate 3a.

  The port portion 5b that is the input terminal of the first center conductor 5 is connected to the second electrode 11b of the first capacitor C1, and the port portion 6b that is the output terminal of the second center conductor 6 is Are connected to the second electrode 11b of the second capacitor C2, and the port portion 7b of the third central conductor 7 is connected to the second electrode 11b of the third capacitor C3 and the other electrode 12b of the resistor R. It is connected to the.

  Further, as shown in FIG. 3, the isolator according to the first embodiment of the present invention has a state in which the center A1 of the magnet 2 and the center A2 of the ferrite member 4 are shifted from each other. When the center A2 of the member 4 approaches the outer peripheral edge 2a side of the magnet 2 (displaces about 0.2 mm from the center A2 of the magnet 2), the port portion 5b of the first and second center conductors 5 and 6 is obtained. 6b approaching the outer peripheral edge 2a side of the magnet 2, the ground portions 5a and 6a of the first and second center conductors 5 and 6 are brought closer to the center side of the ferrite member 4. It will be in the state.

In general, as shown in FIG. 8, the magnet 2 applies a DC magnetic field G to the ferrite member 4. In this case, the strength of the magnetic field G of the magnet 2 is stronger on the center side than on the outer peripheral side.
Then, as in the first embodiment of the present invention, the port portions 5b and 6b of the first and second central conductors 5 and 6 approach the outer peripheral edge 2a side of the magnet 2, and the first and second central conductors 5 , 6 is in a state where the ground portions 5a, 6a are brought closer to the center side of the ferrite member 4, the strength of the magnetic field G with respect to the first and second center conductors 5, 6 is more port than the ground portions 5a, 6a side. The portions 5b and 6b are weakened, and in particular, the magnetic field G applied to the first central conductor 5 is in a non-uniform state.

  Then, as shown in FIG. 9, the current input from the port portion 5b of the first center conductor 5 is transferred to the second center conductor 6 from the position beyond the crossover portion K, and the second center conductor 6 FIG. 7 is a graph showing the results of measuring the relationship between frequency (MHz) and attenuation (dB).

  As shown by the dotted line S2 in FIG. 7, the isolator according to the first embodiment of the present invention has a small attenuation amount in the pass band (f0) and is in a preferable state, and the attenuation amount outside the pass band (2 × f0) is −. 17.4 dB, which is larger than the conventional one, can reduce noise. This is because a low-Q resonance circuit is formed by the first and second center conductors 5 and 6 in a non-uniform magnetic field G state. It is estimated that

FIG. 4 shows a second embodiment of the isolator according to the present invention. This second embodiment is provided outside the ferrite member 4 in which the port portions 5b and 6b of the first and second center conductors 5 and 6 are arranged. The peripheral edge 4a and the outer peripheral edge 2a of the magnet 2 are made to coincide with each other at a position in the up-and-down direction (a state shifted by about 0.4 mm from the center A1 of the magnet 2).
In this case, the strength of the magnetic field G with respect to the first and second center conductors 5 and 6 is weaker at the port portions 5b and 6b than at the ground portions 5a and 6a, and is applied particularly to the first center conductor 5. The applied magnetic field G becomes more non-uniform.

  The isolator according to the second embodiment of the present invention is in a preferable state with a small attenuation amount in the pass band (f0) and an attenuation amount outside the pass band (2 × f0) as indicated by the solid line S1 in FIG. However, the noise is further reduced to −18.7 dB and noise can be reduced.

  FIG. 5 shows a third embodiment of the isolator of the present invention. In this third embodiment, the center A2 (outer peripheral edge 4c) of the ferrite member 4 approaches the outer peripheral edge 2c side of the magnet 2 (the magnet 2). In this state, the port portion 5b side of the first center conductor 5 is brought closer to the outer peripheral edge 2c side of the magnet 2 so that the strength of the magnetic field G with respect to the first center conductor 5 is increased. Is a state in which the magnetic field G applied to the first central conductor 5 is non-uniform so that the port portion 5b side is weaker than the ground portion 5a side.

  As in the first embodiment, the isolator in the third embodiment of the present invention is in a preferable state with a small attenuation in the pass band (f0) as shown by the dotted line S2 in FIG. The amount of attenuation at the outside (2 × f0) becomes larger than before, and noise can be reduced.

FIG. 6 shows a fourth embodiment of the isolator according to the present invention, which is the outer peripheral edge 4c of the ferrite member 4 on the port 5b side of the first central conductor 5 and the outer peripheral edge 2c of the magnet 2. Are matched at the position in the vertical direction (a state shifted by about 0.4 mm from the center A1 of the magnet 2).
In this case, the strength of the magnetic field G with respect to the first central conductor 5 is weaker on the port portion 5b side than on the ground portion 5a side, and the magnetic field G applied to the first central conductor 5 is more uneven. Become.

  As in the second embodiment, the isolator in the fourth embodiment of the present invention is in a preferable state with a small attenuation in the pass band (f0) as shown by the solid line S1 in FIG. The attenuation amount outside (2 × f0) is further increased, and noise can be reduced.

The principal part sectional drawing which concerns on the isolator of this invention. The top view which concerns on the isolator of this invention and shows the state which removed the 1st yoke and the magnet. Explanatory drawing which concerns on 1st Example of the isolator of this invention, and shows the relationship between the ferrite member and magnet which have arrange | positioned the center conductor. Explanatory drawing which shows the relationship between the ferrite member and magnet which have arrange | positioned the center conductor in connection with 2nd Example of the isolator of this invention. Explanatory drawing which concerns on 3rd Example of the isolator of this invention, and shows the relationship between the ferrite member which has arrange | positioned the center conductor, and a magnet. Explanatory drawing which concerns on 4th Example of the isolator of this invention, and shows the relationship between the ferrite member which has arrange | positioned the center conductor, and a magnet. The graph which shows the relationship between the frequency and attenuation in an isolator. Explanatory drawing which shows the state of the magnetic field in an isolator. Explanatory drawing which shows the flow of the electric current in an isolator. The disassembled perspective view of the conventional isolator.

Explanation of symbols

1: First yoke 1a: Upper plate 1b: Side plate 2: Magnet 2a-2d: Outer peripheral edge A1: Center of magnet 3: Second yoke 3a: Bottom plate 3b: Side plate 4: Ferrite member 4a-d4: Outer peripheral edge A2 : Center of ferrite member 5: First central conductor 5a: Grounding part 5b: Port part (input terminal)
6: 2nd center conductor 6a: Earth part 6b: Port part (output terminal)
7: 3rd center conductor 7a: Earth part 7a: Port part C1: 1st capacitor C2: 2nd capacitor C3: 3rd capacitor 10: Insulator 11a: 1st electrode 11b: 2nd electrode R : Resistor 12a: Electrode 12b: Electrode G: Magnetic field

Claims (4)

A flat ferrite member and first, second, and third central conductors that are located on the ferrite member and are provided on different surfaces in the vertical direction across the dielectric, and partially intersect in the vertical direction; A magnet disposed on the central conductor for applying a DC magnetic field to the ferrite member, a first yoke disposed so as to cover an upper surface of the magnet, and a lower surface side of the ferrite member. And a second yoke constituting a magnetic closed circuit with one yoke, and having a grounding portion grounded on one end side of each of the center conductors, and on the other end side of the first center conductors Is a port portion which is an input terminal connected to a capacitor, and a port portion which is an output terminal connected to a capacitor at the other end of the second central conductor, and further, the third central conductor The other end has a capacitor and resistor And the strength of the magnetic field with respect to the first central conductor is weaker on the port side than on the ground side, so that the magnetic field applied to the first central conductor is not affected. An isolator that is made uniform. The magnet and the ferrite member are opposed to each other with their centers shifted from each other, and the strength of the magnetic field with respect to the first central conductor is made weaker on the port side than on the ground side, so that the first An isolator characterized in that a magnetic field applied to a central conductor is made non-uniform. 3. The isolator according to claim 2, wherein an area of the magnet is larger than an area of the ferrite member so that the ferrite member is positioned within the area of the magnet. The magnet has a quadrangular or more polygon, the ferrite member has a quadrangular or more polygon, and the port portions of the first and second central conductors are the port portions of the third central conductor. The outer peripheral edge of the ferrite member and the outer peripheral edge of the magnet, which are arranged on the outer peripheral edge side facing the outer peripheral edge of the ferrite member, and in which the port portions of the first and second central conductors are arranged, are moved up and down. The isolator according to claim 3, wherein the isolators are matched at a position in a direction.

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