JPH10276013A - Yoke structure for irreversible circuit element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thin irreversible circuit element with less insertion loss and dispersion by a simple method by providing a projection on a part facing a microwave ferrite and forming the projection to roughly match the center axis with the center axis of the microwave ferrite. SOLUTION: A disk-shaped garnet 1 is used as the microwave ferrite. On an upper yoke 12, a hill-like projection is formed by using a metalpress at the exact center cart and the hill-like projection is projected in a direction facing the garnet 1. A round hole is provided on the exact center part of the upper yoke 12, that is a position matched with the center axis of the garnet 1, by using a drill. Also, a different disk 6 made of iron provided with the round hole on the center part is prepared and is adhered by an adhesive agent by correcting arrangement so as to match the positions of the hole provided on upper yoke 12 and the hole of the disk 6. Thus, the deformation distortion of the yokes 11 and 12 for affecting the magnetic field distribution of the microwave ferrite is dissolved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nonreciprocal circuit device which is a component of a mobile communication device using a microwave, and more particularly to a small, lumped constant type isolator and circulator.

[0002]

2. Description of the Related Art Non-reciprocal circuit elements such as isolators and circulators are used in mobile communication devices using a frequency band of several hundred MHz to several tens of GHz, that is, PHS (Personal Handy Phone) base stations and mobile phones. Many. This element has a function of transmitting microwaves in the forward direction with low loss and blocking microwaves in the reverse direction. Also, as with other electronic components, it is required to be as thin as possible.

In a typical lumped constant type nonreciprocal circuit device, a magnet, a microwave ferrite, a center conductor, a capacitor, a resistor, and other members are mounted in an iron case also serving as a yoke. This iron case also has a function of reducing the leakage of microwaves to the outside of the element. Usually, the microwave ferrite and the magnet are arranged so as to be stacked. In this case, as far as the arrangement of the microwave ferrite and the magnet is concerned, it cannot be said that it is advantageous for reducing the thickness of the element.

Therefore, for the purpose of reducing the thickness of the element, there has been proposed a method of changing the arrangement of the magnets on the outer peripheral side of the microwave ferrite and horizontally disposing the magnets. For example, JP
The circulator described in JP-A 1-125202 is aimed at reducing the thickness of the element by disposing the microwave ferrite and the magnet in a horizontal arrangement, though the circulator is a distributed constant type non-reciprocal circuit element and the industrial field is different. .

In this example, in order to efficiently apply the magnetic field of the magnet to the microwave ferrite, two yokes connecting the same pole of the magnet are arranged vertically. Furthermore, the two yokes must be sufficiently separated from each other. Otherwise, most of the magnetic flux generated by the magnet reaches the counter electrode via only the yoke and the space, and a sufficient magnetic field is not applied to the microwave ferrite.

It is necessary to ensure a sufficient space between the microwave ferrite and the yoke. Otherwise, the microwave propagating through the center conductor on the microwave ferrite is guided by the yoke and exhibits a large energy loss.

[0007]

In the structure in which the microwave ferrite and the magnet are horizontally arranged as described above, the surface of the yoke and the microwave ferrite are arranged to face each other with a wide gap therebetween. Microwave ferrite has a problem that its outer edge is easily magnetized intensively.

This problem has not been observed in the conventional lumped-constant type nonreciprocal circuit device, that is, the device in which the arrangement of the microwave ferrite and the magnet is vertically arranged. This is supplementarily described as follows.

A conventional lumped constant type non-reciprocal circuit device is
"(Magnet) → (Void) → (Microwave ferrite) →
(Yoke) → (magnet) ”, and the diameter of the microwave ferrite was similar to the diameter of the permanent magnet. The distribution was relatively uniform.

On the other hand, a magnetic circuit formed in a structure in which a microwave ferrite and a magnet are horizontally arranged is described as “(magnet) → (yoke) → (gap) → (microwave ferrite) → (yoke) → (Magnet) ", the magnetic resistance of the magnetic circuit becomes larger than that of the conventional type, and the yoke, not the magnet, faces the microwave ferrite through the air gap. Needless to say, the shape and area of the yoke and the microwave ferrite are very different, so that the distribution of the DC magnetic field applied to the microwave ferrite through the air gap is very different, and the degree of this is comparable to that of the conventional type. It is a big difference that does not become.

In addition, while the conventional yoke is box-shaped, which also serves as a metal case, the gap-side yoke may be a flat plate in structure, so that the yoke is easily distorted, and the slight distortion is determined by the magnetic field distribution described above. Therefore, there is a need to provide a yoke having a structure that is less likely to be distorted because it has an adverse effect.

The above-described non-uniformity of the magnetic field distribution causes an increase in forward insertion loss and a shortage of reverse blocking characteristics, which are basic functions of the nonreciprocal circuit device, and causes a serious defect in quality.

In view of such circumstances, a yoke structure of a lumped-constant type nonreciprocal circuit element for mobile communication equipment using a microwave of several hundred MHz to several tens of GHz, in particular, a microwave ferrite and a magnet are horizontally arranged. With respect to the thin yoke structure of the thin isolator or circulator, the problems to be solved by the present invention are as follows.

That is, the structure is such that the distribution of the DC magnetic field applied to the microwave ferrite from the magnet through the air gap is uniform. Further, the yoke should have a structure which suppresses the deformation distortion of the yoke which affects the magnetic field distribution of the microwave ferrite to a practically sufficient level. A structure that simultaneously realizes the above two structures. and,
Accordingly, a high-performance, high-quality, low-cost, and thin non-reciprocal circuit device is provided to contribute to the development of industry in this technical field.

[0015]

Means for Solving the Problems As a result of earnest studies to solve the above-mentioned problems, the present inventors have conceived of a yoke structure of a non-reciprocal circuit device having a remarkably improved configuration.
That is, in the first invention, a magnet is arranged on the outer peripheral side of a microwave ferrite disk, the same poles of the magnet are bridged by a soft magnetic yoke, and at least one of the yokes and the magnet are connected. In a non-reciprocal circuit device having a structure in which spacers are arranged, the yoke has a convex portion at a portion facing the microwave ferrite through a gap, and the central axis of the convex portion is the same as the central axis of the microwave ferrite. This is a yoke structure of a non-reciprocal circuit device formed so as to substantially match.

In the present invention, the shape of the cross section perpendicular to the central axis of the projection is substantially circular. Further, a hole or a projection may be provided in the vicinity of the center in order to make the central axes coincide.

According to a second aspect of the present invention, in the first aspect, the convex portion is a soft magnetic disk fixed to the surface of the yoke facing the microwave ferrite, and the disk has a diameter corresponding to the soft magnetic disk. This is a yoke structure of a non-reciprocal circuit device configured to be smaller than the diameter of the microwave ferrite.

In the present invention, the disk may be made of any material as long as it is soft magnetic. For example, the cheapest soft iron is sufficient. Also, soft ferrite may be used, or the same material as microwave ferrite may be used to positively compensate for temperature characteristics.

In a third aspect based on the first aspect, the convex portion is a plurality of soft magnetic disks fixed to the yoke surface on the side facing the microwave ferrite, and the plurality of disks are provided. Is the yoke structure of the non-reciprocal circuit device which is configured by stacking in order from the largest diameter.

According to a fourth aspect of the present invention, in any one of the first to third aspects of the present invention, a hole is provided in the yoke and the projection, and the hole has a central axis shared with the microwave ferrite. Is a yoke structure of a non-reciprocal circuit device to which a cylindrical rod is fixed.

According to a fifth aspect of the present invention, there is provided the irreversible structure according to the first aspect, wherein the convex portion is a part of the yoke and is a convex hill-shaped convex portion facing the microwave ferrite. This is a yoke structure of a circuit element.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, a microwave ferrite and a magnet are so-called horizontally arranged. Further, the yokes are fixed so as to bridge the N poles and the S poles of the magnets magnetized in the same direction. This yoke is soft magnetic and usually requires the least expensive iron. A non-magnetic conductor may be arranged between the yoke and the magnet. The non-magnetic conductor is, for example, copper or a conductive resin. It goes without saying that other conductors may be used.

On the other hand, the outline of the structure around the microwave ferrite is as follows. The structure of this part is basically the same as that of a conventional lumped constant type non-reciprocal circuit device for mobile communication. That is, a lower yoke is adhered to an insulating substrate, a copper ground plate is soldered to the lower yoke, and a ground portion of the center conductor is further soldered. A microwave ferrite is bonded thereon with a resin, and one terminal of the center conductor is bent so as to surround the microwave ferrite. Then, another insulating terminal is similarly sandwiched between the other terminal of the center conductor and the terminal to be bent. Repeat the same procedure to fold the remaining terminals.

These terminals are connected to input / output external terminals provided on the insulating substrate, and a matching capacitor is inserted and connected between each terminal and the ground plate. There is also a method of using a ceramic dielectric substrate instead of the capacitor.

If the three input / output terminals are arranged so that one of them is connected to a ground plate via a resistance element, an isolator having the remaining two input terminals and output terminals can be obtained. Can be created.

Of the yokes, the upper yoke has a convex portion. This convex portion has a circular cross section perpendicular to the central axis when the microwave ferrite is a disk, and perpendicular to the central axis when the microwave ferrite is a disk distorted into a triangle. It is desirable that the cross section be a three-fold symmetric figure.

The non-reciprocal circuit device produced in this way can be made into a component that matches the target frequency by adjusting the generated magnetic force of the magnet. However, rough setting to the target frequency band is performed by selecting an appropriate microwave ferrite material.

The above-mentioned microwave ferrite is usually a disk (hereinafter simply referred to as garnet) using YIG such as a Gd-substituted type having a garnet type crystal structure, but the shape material is not limited to this. In general, YIG such as a Gd substitution type is used at a relatively low frequency side, and Al
Substitution type Ni-based ferrite (has a spinel type crystal structure)
Is adopted. As a special shape, a disk deformed into a triangle may be used.

Next, an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a front view of a main part of an isolator for explaining an embodiment of the present invention. In this figure, the part not directly related to the invention, that is, the center conductor,
The illustration of the insulating film, the capacitor and the like is omitted to simplify the drawing. FIG. 3 is a plan view of the same figure. In particular, only the positions of the magnet 13, the garnet 1, and the iron disk are indicated by broken lines.

[0030]

【Example】

(Example 1) In Example 1, a disc-shaped garnet 1 having a diameter of 5 mm and a thickness of 0.4 mm was used as microwave ferrite. The structure around it is as follows. A lower yoke 11 having a thickness of about 0.2 mm is adhered to an insulating substrate 2 having a thickness of about 0.3 mm, an earth plate 3 made of copper is welded to the lower yoke 11, and a ground portion of the center conductor is soldered. Attached.

Here, the insulating substrate 2 can be omitted by changing the shape of the lower yoke 11 and the ground plate 3 and introducing parts made of insulating resin in which the input / output terminals 4 are fitted. .

The garnet 1 was placed on the ground portion of the center conductor, and one terminal of the center conductor was bent so as to surround the garnet 1. Subsequently, a polyimide insulating film was sandwiched between the other terminal of the center conductor and the terminal to be bent in the same manner, and the same procedure was repeated to fold the remaining terminals.

These terminals of the central conductor were connected to input / output external terminals 3 separately provided on the insulating substrate 2 by soldering.
One terminal of a matching capacitor was connected to the ground plate 3 by soldering, and one terminal of the center conductor was connected to the other terminal. Similarly, a second capacitor was connected to the other terminal, and a resistive element was connected to the remaining third terminal to form an isolator.

A magnet 13 was arranged on the lower yoke 11 at a position facing each other with the garnet 1 interposed therebetween and at a distance of about 1 mm from the garnet 1 and fixed with an adhesive. The magnet 13 has a height of about twice the thickness of the garnet 1, a width of about the radius of the garnet 1, and a length of the garnet 1.
A barium ferrite having a diameter of about.

Further, a spacer 14 was placed on the magnet 13, and the upper yoke 12 was placed thereon, and these were fixed together by welding and soldering. 0.4 height for spacer 14
Copper inside and outside 5 mm, inside and outside 2 mm in width, and inside and outside 5 mm in length was used. The central portion of the upper yoke 12 is pre-processed according to the main part of the present invention.

A thin silicon rubber 15 was interposed between the center conductor and the upper yoke 12 to prevent the center conductor from bending. Since the silicone rubber 15 does not directly act on the magnetic circuit or the microwave circuit, it is the same as the gap in the above description. In the following description, it may be used for consent in terms of function. The yokes 11 and 12 have a thickness of 0.2 m.
For the insulating substrate 2, a 0.3 mm thick glass epoxy was used.

The details of the processing previously performed on the central portion of the above yoke 12 are as follows. A 0.5 mm round hole was formed using a drill at the center of the upper yoke 12, that is, at a position coincident with the central axis of the garnet 1. Another 0.1mm thick with a 0.5mm round hole in the center
An iron disk 6 having a diameter of 2.5 mm was prepared, the arrangement was corrected so that the position of the hole provided in the upper yoke 12 and the position of the hole of the disk matched, and the disk was bonded with an adhesive.

The explanation of the parts omitted in FIG. 1 is as follows. The ground portion of the center conductor is arranged between the ground plate 3 and the garnet 1. The terminal of the center conductor is silicone rubber 1 from the side of the garnet 1.
5 and the garnet 1 to reach the input / output terminal 4. The terminals of such a center conductor cross each other at an angle of 120 degrees between the silicone rubber 15 and the garnet 1, and each terminal of the crossed center conductor is insulated by two polyimide films. The film is between the silicone rubber 15 and the garnet 1 and is a circular film each having a thickness of about 20 microns and a diameter of about 5 mm.

Twenty isolators prepared according to the above procedure were prepared, and the magnetizing strength of the magnet 13 was adjusted with an electromagnet, and then evaluated. For comparison, an isolator was also prepared in which the iron disk 6 was not attached and the other structure remained basically the same, and the magnetizing strength of the magnet 13 was similarly adjusted and evaluated (such an isolator was used). Is referred to as Comparative Example 1).

First, the product thickness is about 1.7 mm,
The thickness is 2/3 to 1/2 of that of the conventional product of the same standard. However, the product thickness referred to here is from the outside of the upper yoke 12 to the outside of the lower yoke 11. The insulating substrate 2 and the like do not participate in the present invention and can be omitted, so they are not counted.

The insertion loss evaluated by the network analyzer was improved by an average of 0.06 dB (decibel) compared to Comparative Example 1. The variation is 0.05 d in Comparative Example 1.
In contrast, B was less than 0.03 dB in the present example, and the quality was greatly improved. With respect to the evaluation items such as the standing wave ratio (reflection loss) and the reverse rejection ratio (isolation), similar improvements were observed, although the numerical values were different.

The improvement in the average value of the insertion loss in this embodiment is apparently due to the improvement in the magnetic field distribution of the static magnetic field applied to the garnet 1. The improvement in variation is due to the suppression of the deformation of the yoke.

(Example 2) When only the diameter of the iron disk 6 was changed in Example 1 and evaluated, the result shown in FIG. 2 was obtained. According to this figure, the improvement of the insertion loss becomes remarkable when the diameter of the iron circular plate 6 is close to the diameter of the garnet 1, and the diameter of the iron circular plate 6 is equal to the diameter of the garnet 1.
The maximum effect is obtained when the ratio becomes 5 to 0.6 times.

(Embodiment 3) FIG. 4 shows a sectional structure of the upper yoke 12 in Embodiment 3. The fault position is indicated by X- in FIG.
It corresponds to the position indicated by X. The iron disk of Example 1 was changed to an iron disk having a diameter of 4 mm and a thickness of 0.1 mm, and an iron disk having a diameter of 2 mm and a thickness of 0.05 mm was laminated and bonded to be formed. Example 3 is assumed.

When this was evaluated, the insertion loss was improved by 0.07 dB as compared with Comparative Example 1. This improvement indicates that the magnetic field distribution has become more uniform. The variation in insertion loss was 0.025 dB. This shows that the distortion of the upper yoke 12 has been further reduced.

(Embodiment 4) FIG. 5 shows a sectional structure of the upper yoke 12 in Embodiment 4. The fault position is indicated by X- in FIG.
It corresponds to the position indicated by X. The diameter of the iron disk 6 of Example 1 was changed to 4 mm, and the 0.5 mm round hole formed in the upper yoke 12 and the iron disk 6 was 2.05 m.
The holes were changed to m-shaped holes, and an iron cylindrical rod 7 having a diameter of 2 mm and a length of 0.35 mm was inserted into these holes, and each was fixed with an adhesive. The position of the cylindrical rod 7 was adjusted so that it protruded 0.05 mm from the surface of the iron disk 6 toward the garnet 1.

When the isolator thus manufactured was evaluated, the insertion loss was improved by 0.07 dB as compared with Comparative Example 1. The variation in insertion loss was less than 0.02 dB. This indicates that the distortion of the upper yoke 12 has been further reduced. Further, the operating frequency of the isolator can be easily adjusted by adjusting the mounting position of the cylindrical rod, and the efficiency of the adjusting operation has been significantly improved.

(Embodiment 5) FIG. 6 shows a cross-sectional structure of the upper yoke 12 in Embodiment 5. The fault position is indicated by X- in FIG.
It corresponds to the position indicated by X. In the first embodiment, only the forming method and form of the convex portion of the upper yoke 12 are changed. That is, the upper yoke 12 was formed with a hill-shaped convex portion at the center thereof using a metal press. The hill-shaped convex portion is convex toward the garnet 1, and the maximum diameter of the hill-shaped convex portion is about 4.0.
5 mm, and the height of the hill-shaped protrusion is about 0.15 mm. It goes without saying that the back side of the hill-shaped convex portion is a hill-shaped concave portion.

When the isolator thus manufactured was evaluated, the insertion loss was improved by 0.07 dB as compared with Comparative Example 1. The variation in insertion loss is extremely small, 0.005.
Less than dB (evaluation difficult). This is the upper yoke 12
This indicates that the distortion has been completely eliminated.

[0050]

The effects of the present invention are as follows, summarizing the above results. That is, by applying the yoke having the structure of the present invention, the distribution of the DC magnetic field applied to the microwave ferrite from the magnet through the air gap becomes uniform, and the magnetic field distribution of the microwave ferrite is affected. The deformation distortion of the yoke has been eliminated. As a result, a thin non-reciprocal circuit device with little insertion loss and variation can be provided by a simple method, and complicated adjustment work can be easily performed. Therefore, the present invention greatly contributes to the development of this technical field and the industrial field.

[Brief description of the drawings]

FIG. 1 is a front view of a main part according to an embodiment of the present invention.

FIG. 2 is a graph showing data relating to one embodiment of the present invention.

FIG. 3 is a plan view of FIG. 1;

FIG. 4 is a sectional view of a main part according to another embodiment of the present invention.

FIG. 5 is a sectional view of a main part according to another embodiment of the present invention.

FIG. 6 is a sectional view of a main part according to a different embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Garnet (microwave ferrite) 6 Iron disk 11, 12 Yoke 13 Magnet

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Akinori Misawa 70-2 Minamisakaemachi, Tottori City, Tottori Pref.

Claims (5)

[Claims] A magnet is arranged on the outer peripheral side of a microwave ferrite disk, and the same pole of the magnet is bridged by a soft magnetic yoke, and a spacer is provided between at least one of the yokes and the magnet. In the non-reciprocal circuit device having the above structure, the yoke has a convex portion at a portion facing the microwave ferrite via a gap, and the central axis of the convex portion substantially coincides with the central axis of the microwave ferrite. A yoke structure for a non-reciprocal circuit device, characterized in that the yoke structure is formed as follows. 2. The protruding portion is a soft magnetic disc fixed to the yoke surface on the side facing the microwave ferrite, and the disc has a diameter equal to or less than the diameter of the microwave ferrite. The yoke structure of the non-reciprocal circuit device according to claim 1, wherein: 3. The convex portion is a plurality of soft magnetic disks fixed to the surface of the yoke opposite to the microwave ferrite, and the plurality of disks are arranged in a stacked manner in order from a large diameter. 2. The yoke structure for a non-reciprocal circuit device according to claim 1, wherein: 4. A hole is provided in the yoke and the projection,
2. A soft magnetic cylindrical rod having a central axis shared with the microwave ferrite is fixed to the hole.
The yoke structure of the non-reciprocal circuit device according to claim 3. 5. The projection is a part of the yoke,
2. The yoke structure of a non-reciprocal circuit device according to claim 1, wherein the yoke structure is a hill-shaped convex portion convex on the side facing the microwave ferrite.