JPH0884004A - Nonreversible circuit device - Google Patents

Abstract

PURPOSE: To provide a device which withstands the temperature of heat treatment for mounting by providing a center conductor and a ground conductor on one face and the other of a ferrimagnetic substrate respectively and facially joining a magnet to the center conductor and/or the ground conductor. CONSTITUTION: A ferrimagnetic substrate 1 has a center conductor 11 on one face and has a ground conductor 12 on the other face. Conductors 11 and 12 are thin film conductors made of an Ag-Pd or the like. A magnet 2 has a metallic component as a conductive component and is facially joined to at least one of conductors 11 and 12 by a metallized layer 13 containing vitreous frit. Since the fusion temperature of vitreous frit is higher than a normal solder fusion temperature, it sufficiently withstands the soldering temperature, and it is surely joined. Thus, the relative position relation of the magnet 2 to the center conductor 11 is fixed, and a strip line type device whose characteristic is stable is obtained.

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 such as a circulator or an isolator mainly used in microwave communication equipment.

[0002]

2. Description of the Related Art Conventional non-reciprocal circuit devices for microwave communication equipment are small in size, low in price, easy to install, etc.
The strip line type is often used. A stripline nonreciprocal circuit device often has a structure in which a ground conductor is provided on one surface of a ferrimagnetic substrate and a center conductor is provided on the other surface, and a magnet is fixed on either or both of the ground conductor and the center conductor. . Various methods for fixing the ferrimagnetic substrate and the magnet have been proposed. For example, JP-A-58-1596
Japanese Patent Laid-Open No. 3 and Japanese Utility Model Laid-Open No. 60-172402 disclose a technique of fixing a ferrimagnetic substrate and a magnet with an organic adhesive or soldering. Japanese Unexamined Patent Publication No. 6-85508 discloses a technique in which a ground conductor and a center conductor are made of copper, and the ground conductor or the center conductor and a magnet are directly joined by melting copper.

[0003]

However, the above-mentioned conventional technique has the following problems. (A) When mounting this type of non-reciprocal circuit device on a printed circuit board or the like, soldering by reflow has been widely used in recent years. Therefore, the non-reciprocal circuit device is exposed to a temperature higher than the curing temperature of the organic adhesive or a temperature close to the melting temperature of the solder when it is mounted on the printed board. For this reason, the organic adhesive or solder that fixes the ferrimagnetic substrate and the magnet is deteriorated, and the magnet moves or falls off. (B) In the non-reciprocal circuit device disclosed in Japanese Patent Laid-Open No. 6-85508, copper is melted and directly bonded, and therefore, in a high temperature atmosphere not lower than the melting temperature of copper and in an atmosphere that prevents oxidation. It has to be processed, resulting in high costs.

An object of the present invention is to provide a non-reciprocal circuit device having heat resistance capable of sufficiently withstanding a heat treatment temperature during mounting, particularly a soldering temperature.

Another object of the present invention is to provide an inexpensive non-reciprocal circuit device.

[0006]

In order to solve the above problems, the nonreciprocal circuit device according to the present invention includes a ferrimagnetic substrate and a magnet. The ferrimagnetic substrate has a central conductor on one surface and a ground conductor on the other surface. The magnet has a metallized layer containing a metal component as a conductive component and a vitreous frit or a metal oxide bonding agent,
It is surface-bonded to at least one of the center conductor and the ground conductor.

[0007] Preferably, the metal component is silver, platinum,
It contains at least one of palladium, gold or copper or alloys thereof.

As a concrete mode of the metallized layer,
When the metallization layer is provided on the center conductor and the ground conductor, and when at least one of the center conductor and the ground conductor is the metallization layer, the metallization layer is commonly used as the metallization layer for joining the magnets. There are two possible cases.

[0009]

In the ferrimagnetic substrate, the center conductor is provided on one surface side and the ground conductor is provided on the other surface side, and the magnet is surface-bonded on one or both of the center conductor and the ground conductor.
A relative positional relationship of the magnet with respect to the central conductor is fixed, and a stripline nonreciprocal circuit device having stable characteristics can be obtained.

Since the magnet is surface-bonded to one or both of the center conductor and the ground conductor via the metallized layer containing the glassy frit, the magnet is melted to make the magnet a center conductor or a grounding conductor. The surface can be firmly bonded to.

The melting temperature of the glassy frit varies depending on the metal components used together, but it is 850 to 950.
It is in the range of ° C. This temperature is the normal solder melting temperature 18
Higher than 0 ° C. Therefore, when mounting on a circuit board,
It can withstand the soldering temperature sufficiently, and can reliably prevent the magnet from moving or falling off. Similar effects can be obtained by using a metal oxide bonding agent instead of the glassy frit.

Furthermore, since the metallized layer contains a vitreous frit or a bonding agent of a metal oxide, the metallized layer is usually formed between an inorganic material such as ferrite and a magnet.
The coefficient of thermal expansion can be balanced. Moreover, since the metallized layer contains a metal component, it is possible to balance the coefficient of thermal expansion with the center conductor or the ground conductor which is mainly composed of metal. Therefore, as a whole metallized layer, a non-reciprocal circuit device having a small thermal stress and a thermally stable junction structure can be obtained.

The metallized layer as described above can be formed by applying a conductive paste and baking it. As is well known, such a conductive paste is obtained by mixing fine metal powder, a vitreous frit or a bonding agent of a metal oxide, and an appropriate organic vehicle to form a paste. In the present invention, the fine metal powder is silver, platinum,
It contains at least one of palladium, gold or copper or alloys thereof. The conductive paste can be formed into a metallized layer by heat treatment at the melting temperature of the glassy frit or metal oxide bonding agent contained therein. Therefore, the heating temperature 1100 required for direct bonding of copper is 1100.
A heat treatment temperature as low as 150 to 250 ° C. may be used. Therefore, the energy consumption in the joining process is reduced.

Moreover, since the baking process for metallization can be performed in the air, the bonding process can be performed in comparison with the conventional technique which requires the heat treatment in a non-oxidizing or neutral atmosphere such as a nitrogen atmosphere. The process is significantly simplified.

[0015]

1 is a perspective view of a nonreciprocal circuit device according to the present invention, and FIG. 2 is a sectional view taken along line A2-A2 of FIG. The nonreciprocal circuit device according to the present invention includes a ferrimagnetic substrate 1
And a magnet 2. The ferrimagnetic substrate 1 has a center conductor 11 on one surface and a ground conductor 12 on the other surface. The center conductor 11 and the ground conductor 12 can be formed of a thick film conductor such as Ag-Pd. As is well known, the center conductor 11 has three terminals which are led out from a center portion having a circular shape at an angle of about 120 degrees, and these three terminals are circuits necessary for constructing a circulator or an isolator. Is connected to an external circuit.

The magnet 2 has metallized layers 13 and 14 containing a metallic component as a conductive component and vitreous frit.
It is surface-bonded to at least one of the center conductor 11 and the ground conductor 12. The metal component contained in the metallized layers 13 and 14 preferably contains at least one of silver, platinum, palladium, gold or copper, or an alloy thereof. The magnet 2 applies a magnetic field required for the nonreciprocal circuit operation to the ferrimagnetic substrate 1 and the center conductor 11.

As described above, the ferrimagnetic substrate 1 is provided with the center conductor 11 on one surface side and the ground conductor 12 on the other surface side, and the magnet 2 is provided on one or both of the center conductor 11 and the ground conductor 12. Since the magnets 2 are surface-bonded to each other, the relative positional relationship between the magnet 2 and the central conductor 11 is fixed, and a stripline nonreciprocal circuit device having stable characteristics can be obtained.

Since the magnet 2 is surface-bonded to one or both of the center conductor 11 and the ground conductor 12 through the metallized layers 13 and 14 containing the glassy frit, the magnet 2 is melted by melting the glassy frit. 2 can be firmly surface-bonded to the center conductor 11 or the ground conductor 12.

Although the melting temperature of the glassy frit varies depending on the metal components used together, it is 850 to 950.
It is in the range of ° C. This temperature is the normal solder melting temperature 18
Higher than 0 ° C. Therefore, when mounting on a circuit board,
It can withstand the soldering temperature sufficiently, and can reliably prevent the magnet 2 from moving or falling off.

Further, since the metallized layers 13 and 14 contain the glassy frit, the coefficient of thermal expansion can be balanced with the magnet 2 which is usually made of an inorganic material such as ferrite. Moreover, the metallized layer 1
Since 3 and 14 contain a metal component, the coefficient of thermal expansion can be balanced with the center conductor 11 or the ground conductor 12 which is composed mainly of metal. Therefore, as a whole metallized layer, a non-reciprocal circuit device having a small thermal stress and a thermally stable junction structure can be obtained.

The metallization layers 13 and 14 as described above are
It can be formed by applying a conductive paste on one surface of the magnet 2, mounting it on the ferrimagnetic substrate 1, and then baking the conductive paste. In addition, the conductive paste is applied to the ferrimagnetic substrate 1 by printing or the like, and the magnet 2 is applied thereon.
After mounting, the baking process may be performed. As is well known, such a conductive paste is obtained by mixing fine metal powder, vitreous frit, and an appropriate organic vehicle to form a paste. In the present invention,
The fine metal powder can contain at least one of silver, platinum, palladium, gold or copper, or an alloy thereof. The conductive paste is metallized by heat-treating the glassy frit contained therein at a melting temperature of 850 to 950 ° C., whereby the metallized layers 13 and 14 are formed.
Therefore, a heat treatment temperature as low as 150 to 250 ° C. lower than the heating temperature 1100 ° C. required for directly joining copper is sufficient. Therefore, the energy consumption in the joining process is reduced.

In addition, since the baking process for metallization can be performed in air, compared with the conventional technique that requires heat treatment in a non-oxidizing or neutral atmosphere such as a nitrogen atmosphere, the bonding The process is significantly simplified.

FIG. 3 is a sectional view showing another example of the nonreciprocal circuit device according to the present invention. In the figure, the same reference numerals as those in FIG. 2 denote the same components. In this example, at least one of the center conductor 11 and the ground conductor 12 is a metallized layer, which is commonly used as a metallized layer for joining the magnet 2. Since the center conductor 11 or the ground conductor 12 formed of the metallized layer contains the metal component and the glassy frit, the thermal expansion coefficient can be balanced between the ferrimagnetic substrate 1 and the magnet 2. Therefore, similar to the example shown in FIG. 2, a non-reciprocal circuit device having a small thermal stress and a thermally stable joining structure can be obtained.

In the non-reciprocal circuit device described above, the conductive paste is applied to the ferrimagnetic substrate 1 in an appropriate pattern, the magnet 2 is mounted on the conductive paste, and the conductive paste is baked to obtain the central conductor. 11 or a metallized layer to be the ground conductor 12 is formed, and the glass frit contained in the metallized layer forms the ferrimagnetic substrate 1.
At the same time as fixing the magnet 2 to the magnet 2, it is possible to secure necessary conductivity for the center conductor 11 and the ground conductor 12 by the metal component. Therefore, it is not necessary to independently form a metallized layer for fixing the magnet 2, and a further inexpensive nonreciprocal circuit device can be obtained.

[0025]

As described above, according to the present invention, the following effects can be obtained. (A) It is possible to provide a non-reciprocal circuit device having heat resistance enough to withstand a heat treatment temperature during mounting, particularly a soldering temperature. (B) An inexpensive non-reciprocal circuit device can be provided.

[Brief description of drawings]

FIG. 1 is a perspective view of a non-reciprocal circuit device according to the present invention.

FIG. 2 is a cross-sectional view taken along the line A2-A2 of FIG.

FIG. 3 is a cross-sectional view showing another example of the non-reciprocal circuit device according to the present invention.

[Explanation of symbols]

 1 Ferrimagnetic Substrate 11 Center Conductor 12 Grounding Conductor 13, 14 Metallized Layer 2 Magnet

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[Procedure amendment]

[Submission date] September 13, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Claims

[Correction method] Change

[Correction content]

[Claims]

2. The nonreciprocal circuit device according to claim 1, wherein the metallized layer is provided on the center conductor and the ground conductor.

3. The nonreciprocal circuit device according to claim 1, wherein at least one of the center conductor and the ground conductor is formed of the metallized layer and is shared as the metallized layer for joining the magnets.

Claims (1)

1. A nonreciprocal circuit device including a ferrimagnetic substrate and a magnet, wherein the ferrimagnetic substrate has a central conductor on one surface and a ground conductor on the other surface. The magnet has a non-reciprocal circuit which is surface-bonded to at least one of the center conductor and the ground conductor by a metallized layer containing a metallic component as a conductive component and a bonding agent for glassy frit or a metal oxide. apparatus. 3. The nonreciprocal circuit device according to claim 1, wherein the metallized layer is provided on the center conductor and the ground conductor. 4. The nonreciprocal circuit device according to claim 1, wherein at least one of the center conductor and the ground conductor is formed of the metallized layer and shared as the metallized layer for joining the magnets.