JPH10270910A - Irreversible circuit element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a small and thin irreversible circuit element with less deterioration and dispersion of an electric characteristic and to facilitate precise assembly with simple structure by arranging plural columnar permanent magnets in the peripheral area of a disk-like microwave ferrite. SOLUTION: The two columnar permanent magnets 15 are arranged so that they sandwich the microwave ferrite 14 on the outer peripheral side of the garnet of the microwave ferrite 14. Then, they are fixed to a soft magnetic lower yoke 11. The end parts of a central conductor 17 are pulled out in three directions and they are connected with a capacitor electrode film which is printed/formed on a dielectric substrate 13. An upper yoke 16 is fixed to the permanent magnets 15 so that it covers the microwave ferrite 14. The permanent magnets 15 are made in square poles or triangle poles and three or four magnets can be provided. Thus, the element can be thinned and intervals between the permanent magnets 15 and the garnet 14 can be detached. Thus, the forward transmission loss of the electric characteristic can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a VHF band, a UHF band,
The present invention relates to a non-reciprocal circuit device used in a high frequency band such as a band and a microwave band.

[0002]

2. Description of the Related Art A non-reciprocal circuit device has a function of hardly attenuating a signal in a signal transmission direction (forward direction) and having a large attenuation in a reverse direction. Circulators and the like, for example, VHF band, U
It is used in a transmission / reception circuit section of a mobile communication device represented by a mobile phone, a car phone, or the like using a high frequency band such as an HF band and a microwave band. In recent years, with the reduction in size and weight of mobile communication devices, there has been a strong demand for the nonreciprocal circuit devices mounted on mobile communication devices to be reduced in size (thinned) in addition to being reduced in cost.
A conventional example of such a non-reciprocal circuit device will be described.

As a first conventional example, a general structure of a surface mount type isolator used in a recent portable telephone will be described with reference to an exploded perspective view of FIG. The isolator is
Insulating substrate (1), upper metal case (2), lower metal case (8), ground plate (3), dielectric substrate (4), center conductor (5), microwave ferrite (6), permanent magnet (7) )
And other accompanying parts.

A soft metal lower case (8) and an earth plate (3) are sequentially stacked on an insulating substrate (1), and these are fixed by soldering so as to be electrically connected. On this, a dielectric substrate (4) having a hole at the center and a capacitor electrode film (9) and a resistive film (10) formed by thick film printing on other portions is arranged. A microwave ferrite (6) is arranged in the hole. This microwave ferrite (6)
Is provided with a central conductor (5) produced by processing one copper plate. On the other hand, the permanent magnet (7) for applying a DC magnetic field to the microwave ferrite (6) is a metal upper case (2).
It is stuck to. In the case of this conventional example, the microwave ferrite and the permanent magnet are arranged so as to be stacked via a gap.

A second conventional example is disclosed in Japanese Patent Application Laid-Open No. 61-125.
The structure of the circulator described in Japanese Patent Publication No. 202 will be described with reference to FIG. In the figure, the same reference numerals are given to the same functional units as the first conventional example. In this conventional example, an annular concave portion having an inner diameter larger than the diameter is formed in a region around the microwave ferrite (6), and the magnet (7) is arranged in the annular concave portion. Also, a yoke made of soft iron or the like for the permanent magnet (2, 8)
Has been arranged.

[0006]

The isolator described in the first conventional example is assembled so that many components are stacked in the thickness direction, and the thickness of each component constituting the isolator is limited to the isolator itself. Determine the thickness dimension of In particular, the thickness of the permanent magnet, which is one of these components, occupies about 1/3 to 1/2 of the thickness of the isolator itself. Therefore, in this structure, it was difficult to reduce the thickness of the fundamental isolator.

[0007] As a measure for the above-mentioned thinning, there is a method of reducing the thickness of the permanent magnet or reducing the distance between the permanent magnet and the microwave ferrite. However, a permanent magnet that can generate a sufficient magnetic field even if the thickness is reduced is extremely expensive and impractical. Therefore, there is a limit to the thickness reduction by these methods.

In the first conventional example, the gap between the permanent magnet and the microwave ferrite is so narrow that the microwave loss increases due to the interaction between the microwave and the permanent magnet, thereby deteriorating the electrical characteristics of the element. there were.

[0009] Further, the spacing between the permanent magnet and the microwave ferrite is increased by synergistic factors such as the distortion of the metal upper and lower cases, the assembly variation of the center conductor and the like, and the thickness variation of the permanent magnet and the dielectric ferrite. It fluctuated, and the electrical characteristics also fluctuated in conjunction with this.

In the circulator described in the second conventional example, an annular concave portion having an inner diameter larger than the diameter is formed in the peripheral region of the microwave ferrite, and a permanent magnet is arranged in the annular concave portion so that the thickness can be reduced. I have. Certainly, by arranging the annular permanent magnet on the side surface of the microwave ferrite, the thickness limitation as seen in the first conventional example is reduced. In addition, the possibility of improvement in deterioration of electrical characteristics and variation in electrical characteristics has been increased.

However, by using an annular permanent magnet,
External dimensions smaller than this diameter are impossible, so the parts will be large, it will be difficult to pull out the center conductor to the external terminal without dividing the permanent magnet, and the permanent magnet will be divided and positioned for positioning. There is a problem that the concave portion needs to be formed and the structure becomes complicated.

It is an object of the present invention to provide a non-reciprocal circuit device which solves the above-mentioned problems of the prior art, is small and thin, has little deterioration or variation in electric characteristics, has a simple structure, is accurate and is easy to assemble. It is.

[0013]

Means for Solving the Problems As a result of intensive studies to solve the above-mentioned problems, the present inventors have conceived of a non-reciprocal circuit device having a remarkably improved structure. That is, the first invention is a non-reciprocal circuit device in which two columnar permanent magnets are arranged in a peripheral region of a disk-shaped microwave ferrite.

A second invention is a nonreciprocal circuit device according to the first invention, wherein the permanent magnet has three or four pillars.

A third invention is the non-reciprocal circuit device according to any one of the first and second inventions, wherein the permanent magnet is a square pole.

A fourth invention is the nonreciprocal circuit device according to any one of the first and second inventions, wherein the permanent magnet has a triangular prism.

According to a fifth aspect of the present invention, in any one of the first to fourth aspects, a cross section perpendicular to the central axis of the microwave ferrite is formed into an arc-shaped concave portion for a portion facing the microwave ferrite. It is a non-reciprocal circuit device.

A sixth invention is a nonreciprocal circuit device in which the microwave ferrite is three-fold symmetric and the permanent magnet is made of three pillars.

However, in any one of the first, second and sixth inventions, the column may be a cylinder, an ellipse, or an n prism (n: natural number). Preferably,
The portion facing the microwave ferrite is a column having an arcuate concave portion similar to the outer peripheral shape of the microwave ferrite.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The outline of a non-reciprocal circuit device according to the present invention will be described by taking an isolator as an example. FIG. 1 is an exploded perspective view thereof.

This isolator comprises an insulating substrate (25),
Upper yoke (16), lower yoke (11), ground plate (1
2) Consists of a dielectric substrate (13), a center conductor (17), a microwave ferrite (14), a permanent magnet (15) and other associated parts.

Two columnar permanent magnets (15) are arranged on the outer peripheral side of the microwave ferrite (14) so as to face each other with the microwave ferrite (14) interposed therebetween. ). Here, the permanent magnet is, for example, a square column barium ferrite magnet, the microwave ferrite is, for example, a disc-shaped garnet, and the lower yoke is, for example, soft iron.

The columnar permanent magnet (15) may be arranged at a position in contact with the outer peripheral surface of the dielectric substrate (13), or may be arranged near the side surface of the microwave ferrite (14).

The ends of the central conductor (17) are drawn out in three directions and connected to the capacitor electrode films (18, 19, 20) formed on the dielectric substrate (13).

The upper yoke (16) is provided with a permanent magnet (15) from above in the figure so as to cover the microwave ferrite (14).
Stick to

[0026]

The embodiments will be described below in detail. The embodiment conforms to the specifications of the surface mount isolator used in the 900 MHz band. (Embodiment 1) FIG. 2 is a partial perspective plan view of Embodiment 1 and FIG.
It is -A 'sectional drawing.

In the figure, portions denoted by the same reference numerals as those in FIG. 1 are the same portions or portions having the same functions, and the description thereof may be omitted below.

The lower yoke (11) was stacked on the insulating substrate (25), and then the ground plate (12) was stacked, and these were fixed by soldering so as to be electrically connected. On top of this, a dielectric substrate (13) having a hole in the center and having a capacitor electrode film (18, 19, 20) and a resistive film (21) formed by thick film printing in other portions was arranged. A disc-shaped garnet (14) was arranged in the hole. This garnet (1
4) has a center conductor (1) fabricated by processing one copper plate.
7) is folded so that it wraps around the garnet (14) so that it crosses at the center of the garnet (14), and the end is drawn out in three directions at an angle of 120 °.
The insulating substrate (25) has input / output terminals (2
3, 24) are formed.

Next, a barium ferrite magnet (15) prepared separately was arranged so as to face the garnet (14). In the present embodiment, a barium ferrite magnet (15) was disposed so as to be substantially the same length as the dielectric substrate (13) and in contact with the dielectric substrate (13), and was bonded to the lower yoke (11).

The thickness of the barium ferrite magnet (15) needs to be somewhat larger than that of the garnet (14). The length is desirably longer than the garnet (14).

On the upper surface of the dielectric substrate (13) in the drawing, three capacitor electrode films (18, 19, 20) were previously formed by thick film printing in which a silver paste was baked. The capacitor electrode films (18, 19, 20) were connected to the ends where the central conductor (17) extended. Among them, the capacitor electrode film (20) is connected to the earth electrode film via the resistance film (21), and the earth electrode film is widely formed on the lower surface of the dielectric substrate (13) through the through hole (22). The ground electrode film is connected to the ground plate (12) or the lower yoke (11).

Next, the capacitor electrode films (18, 19)
The end extending from the central conductor (17) connected to the terminal was connected to the input / output terminals (23, 24). The connection between the electrode films, the ends, the terminals, and the lower yoke (11) was performed by soldering.

Further, the garnet and the upper yoke (16) are placed on the garnet (14) on which the central conductor (17) is arranged.
A spacer (26) made of Teflon was inserted so as to maintain an interval between the barium ferrite magnet (15) and the upper yoke (16).

The isolator thus manufactured is
It was confirmed that the thickness was 2/3 or less of that of the conventional isolator. Further, due to the separation between the permanent magnet and the garnet, the electrical characteristics were improved by an average of 0.05 dB in forward transmission loss on average.

(Embodiment 2) FIG. 3 is a partial perspective plan view of Embodiment 2 and a cross-sectional view taken along line AA '. In this embodiment, the number of barium ferrite magnets in the first embodiment is basically three.

That is, in the lower yoke (11), three barium ferrite magnets (15) separately prepared were arranged with the garnet (14) interposed therebetween. In this embodiment, a barium ferrite magnet (15) having a length substantially equal to the diameter of the garnet (14) is arranged and bonded to the lower yoke (11). Subsequent assembling is the same as in the first embodiment, and a description thereof will not be repeated.

The isolator thus manufactured is
As in Example 1, it was confirmed that the thickness was に or less of that of the conventional isolator. Further, an improvement of 0.03 dB in average in forward transmission loss was observed. (Embodiment 3) FIG. 4 is a partial perspective plan view of Embodiment 3 and FIG.
It is -A 'sectional drawing. In this embodiment, the number of barium ferrite magnets in the first embodiment is basically four.

That is, in the lower yoke (11), four barium ferrite magnets (15) prepared separately were arranged with the garnet (14) interposed therebetween. In this embodiment, two barium ferrite magnets (15) having substantially the same length as the diameter of the garnet (14) and two barium ferrite magnets (15) having substantially the same length as the dielectric substrate (13) are arranged. It adhered to the yoke (11). Subsequent assembling is the same as in the first embodiment, and a description thereof will not be repeated.

The isolator thus manufactured is
As in Example 1, it was confirmed that the thickness was に or less of that of the conventional isolator. Further, an improvement of 0.03 dB in average in forward transmission loss was observed. (Embodiment 4) FIG. 5 is a partial perspective plan view of an embodiment 4 and FIG.
It is -A 'sectional drawing. In this embodiment, the shape of the garnet in the first embodiment is basically a triangular plate, and the number of barium ferrite magnets in the form of quadrangular prisms is three.

That is, three barium ferrite magnets (15) prepared separately were arranged on the lower yoke (11) with the garnet (14) interposed therebetween. In this embodiment, a barium ferrite magnet (15) having substantially the same length as one side of the garnet (14) is arranged and adhered to the lower yoke (11). Subsequent assembling is the same as in the first embodiment, and a description thereof will not be repeated.

The isolator thus manufactured is
As in Example 1, it was confirmed that the thickness was に or less of that of the conventional isolator. Further, an improvement of 0.03 dB in average in forward transmission loss was observed.

The isolators according to the first to fourth embodiments are as follows.
Accurate assembly was easy because of the simple structure.

The barium ferrite magnet having a quadrangular prism in these embodiments may be a cylinder, an elliptical cylinder, a triangular prism, a hexagonal prism, a hexagonal prism, or an octagonal prism as long as it is a columnar body. Pillars are fine. It goes without saying that the effect of the present invention does not change even if any column is adopted.

According to these embodiments, an isolator that is small and thin, has improved electrical characteristics, has a simple structure, and is easy to assemble accurately can be realized. Further, it goes without saying that the present invention is not limited to the isolator, but can be applied to a non-reciprocal circuit device such as a circulator.

[0045]

According to the present invention, it is possible to provide a non-reciprocal circuit device which is small and thin, has excellent electric characteristics, has a simple structure, and can be easily assembled accurately.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of an isolator according to one embodiment of the present invention.

FIG. 2 is a partial perspective plan view of the first embodiment according to the present invention and a cross-sectional view taken along the line AA ′.

FIG. 3 is a partial perspective plan view and a cross-sectional view taken along the line AA ′ of a second embodiment according to the present invention.

FIG. 4 is a partial perspective plan view and a cross-sectional view taken along the line AA ′ of a third embodiment according to the present invention.

FIG. 5 is a partial perspective plan view and a cross-sectional view taken along line AA ′ of a fourth embodiment according to the present invention.

FIG. 6 is an exploded perspective view of the first conventional example.

FIG. 7 is a partial perspective plan view of a second conventional example and its AA 'line.
It is sectional drawing.

[Explanation of symbols]

 Reference Signs List 11 lower yoke 12 ground plate 13 dielectric substrate 14 microwave ferrite 15 permanent magnet 16 upper yoke 25 insulating substrate

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

Claims (6)

[Claims] 1. A non-reciprocal circuit device comprising two columnar permanent magnets arranged outside the outer periphery of a disk-shaped microwave ferrite. 2. The non-reciprocal circuit device according to claim 1, wherein the permanent magnet is three or four pillars. 3. The non-reciprocal circuit device according to claim 1, wherein the column is a quadrangular prism. 4. The non-reciprocal circuit device according to claim 1, wherein the column is a triangular column. 5. A cross section of the column perpendicular to a center axis of the microwave ferrite, wherein a portion facing the microwave ferrite is an arc-shaped concave portion. The non-reciprocal circuit device according to any one of the above. 6. A non-reciprocal circuit device, wherein the microwave ferrite is three-fold symmetric and the permanent magnet is three pillars.