JPH08213808A - Irreversible circuit element - Google Patents

Abstract

PURPOSE: To make the irreversible circuit element small in size and thin in profile while keeping a sufficient magnetic field by securing thermal stability. CONSTITUTION: A center conductor 104 is provided to a capacitive board 100 to enclose a ferrite 102 and a termination resistor 106 is connected to one port. A terminal 108 is provided to each port. Lead electrodes and the terminals 108 are soldered by using a solder with a conventional softening temperature. A thermal insulation material (heat resistant material) 110 is applied to soldered parts of the capacitive board 100. The same thermal insulation material 110 is applied also to the surface of magnets 120, 122, for DC magnetic field application. An isolator is assembled by inserting the capacitive board 100, the magnets 120, 122 between a cover 10 and a shield case 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-reciprocal circuit device such as an isolator used in a microwave band, and more specifically, to improve its thermal stability, downsizing and thinning. Regarding

[0002]

BACKGROUND ART As a non-reciprocal circuit device used in a microwave band, there is, for example, one shown in FIG. This example is an isolator, in which the magnets 14 and 16 and the capacitor substrate 18 are stacked between the cover 10 and the shield case 12 in the order shown. Of these, the capacitance substrate 18 includes a plurality of center conductors 20 and a magnetic body (for example, ferrite) 22 that forms a circuit (waveguide), and a terminating resistor 24 is provided at one port. Further, a plurality of terminals 26 are provided on the side portion so as to project.

The terminating resistor 24 is used to make the circulator an isolator. In a 3-port circulator, the traveling direction of electromagnetic waves is usually bent by 120 °. Here, if a terminating resistor is inserted in any of the ports, all the output to this port will be converted into heat, and it will act as an isolator.

A detailed structure of the capacitance substrate 18 is disclosed in, for example, JP-A-5-37206 and 5-2.
There is one disclosed in Japanese Patent Publication No. 99904, or
There is an application filed as Japanese Patent Application No. 6-261013.

Above and below the capacitance substrate 18, the center conductor 2 is provided.
Magnets 14 and 16 for forming a DC magnetic field are provided in the 0 and ferrite 22 portions. There is also a structure in which the magnet 16 is omitted. In this case, the cover 10 and the shield case 12 have a function as a magnetic yoke.

By the way, when such a non-reciprocal circuit device is surface-mounted by the method of reflow soldering, stability to withstand a high temperature during reflow soldering is required. Specifically, in consideration of the manufacturing process as well, thermal stability at a high temperature close to 300 degrees is required. Therefore, as the solder material used for the soldering portion inside the element, high-temperature solder having a high softening and melting temperature that does not cause melting during reflow soldering after surface mounting after the product is used. Specifically, the external lead-out portion 28 of the center conductor 20 of the capacitor substrate 18
In addition, solder with a high softening and melting temperature is used. Alternatively, the peripheral portion of the externally drawn-out portion 28 is formed of a member having a high heat insulating property such as liquid crystal polymer to ensure the heat insulating property during surface mounting. Further, as the DC magnetic field applying magnets 14 and 16, a material that is stable against heat during solder reflow during surface mounting is selected as a top priority.

Next, the non-reciprocal circuit device is used for mobile communication such as a mobile phone and a cordless phone, and is required to be smaller and thinner. In order to meet this demand, the distributed constant type, which depends on the size of the wavelength, has been changed to the lumped constant type. Further, even after becoming a lumped constant type, the signal line is changed from a strip line to a microstrip line to be thinner. Furthermore, at present, by using a cover or a shield case as a magnetic yoke, the number of magnets for applying a DC magnetic field is reduced from two to one,
It is being made even thinner.

[0008]

However, the above background art has the following disadvantages. (1) As described above, the solder used during the manufacture of the non-reciprocal circuit element is a material that softens and melts at a temperature higher than usual from the viewpoint of thermal stability, so the solder reflow temperature during the manufacturing stage should be controlled. It is necessary to raise it. Then, thermal stability at extremely high temperatures is required for all members constituting the nonreciprocal circuit device,
As a result, there is an inconvenience that the material of each part is limited.

(2) When the thermal stability is given the highest priority, the shape of the magnet must be increased in order to obtain a desired magnetic field, which in turn violates the request for thinning. More specifically, as the material of the magnet used in the conventional non-reciprocal circuit device, a ferrite-based material is used because of its high cost stability and high thermal stability. However, at the present time when the thickness is reduced, even if the thickness is further reduced, the limit of the ferrite magnet is almost reached. That is, if it is made thinner than the current one, it becomes impossible to obtain a desired magnetic field.

Even if a magnet made of another material is used,
Although a desired magnetic field can be obtained, it is not satisfactory in terms of thermal stability such that irreversible demagnetization occurs when heated to around 300 degrees.

The present invention focuses on the above points,
Its purpose is to avoid material limitations while ensuring thermal stability. Another object is to satisfactorily reduce the size and thickness of the non-reciprocal circuit device while ensuring thermal stability. Still another object is to ensure thermal stability and obtain a sufficient magnetic field, and to reduce the size and thickness of the nonreciprocal circuit device.

[0012]

In order to achieve the above object, according to the present invention, a heat insulating material is applied to a magnet for DC magnetic field and a soldering portion. Since the solder reflow time is not so long, it is possible to sufficiently suppress the temperature rise of those portions by applying a heat insulating material to the soldered portions and the magnets.

According to another aspect of the invention, an SmCo.2-17 series magnet is used which is relatively stable to heat and has a very high maximum residual magnetic flux density and coercive force than a ferrite magnet. As a result, the DC magnetic field required for the non-reciprocal circuit element can be obtained with a magnet having a relatively small and thin shape. In addition, the pinning effect of the domain wall works to suppress the reversal of magnetization and the occurrence of irreversible demagnetization. The thermal stability is almost the same as that of ferrite magnets, and there is no problem in practical use.

According to still another aspect of the invention, since the SmCo · 2-17 series magnet and the heat insulating material are used, good thermal stability can be obtained as a whole, and the entire element can be made smaller and thinner. Can be realized. The above and other objects, features and advantages of the present invention will be apparent from the following detailed description and the accompanying drawings.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS While there may be many embodiments of the present invention, a suitable number of embodiments will now be shown and described in detail.

<Example 1> First, with reference to FIG. 1, Example 1 in which the thermal stability was mainly improved
Will be described. First, the first example will be described with reference to FIG. The capacitor substrate 100 is basically the same as the background art. That is, a plurality of center conductors 104 are provided so as to enclose the ferrite 102, and these are housed in the capacitor substrate 100 to form a 3-port circuit. Further, the terminating resistor 106 is provided in one port, so that the characteristics as an isolator can be obtained. Also,
A terminal 108 is provided corresponding to each port of the circuit. The electrode for extraction with respect to the central conductor 104 is fixed by soldering at a normal softening temperature, for example, about 230 ° C. Further, the terminal 108 is also fixed to the capacitor substrate 100 with solder having a similar softening temperature.

By the way, in this embodiment, as indicated by hatching in the figure, a silicone resin 110 as an adhesive is applied as a heat insulating material (heat resistant material) to the solder joint portion of the capacitor substrate 100. The same heat insulating material 110 is applied to the surfaces of the DC magnetic field applying magnets 120 and 122 located above and below the capacitive substrate 100. The capacitance substrate 100 and the magnets 120 and 122 are sandwiched between the cover and the shield case as in the background art of FIG.
The isolator is assembled.

In this way, the isolator according to the present embodiment, which is provided with heat insulation measures, and the isolator according to the background art, which is not provided with heat insulation measures, are 260 ° C. and 30 se, respectively.
Solder reflow process of c was performed. As a result, with respect to the isolator manufactured in this example, no particular change in characteristics and shape was observed before and after reflow. However, in the conventional isolator that does not have a heat insulation measure, the terminal 10
No dropout of 8 occurred, and the characteristics could not be evaluated.

The area of the soldered portion at the time of reflow is extremely small, the solder in the narrow portion may be melted, and at the time of solder reflow, it is not kept at a high temperature for a long time. Therefore, by applying a heat insulating material to the portion already soldered during the manufacture of the non-reciprocal circuit element, the temperature of the portion does not rise to the reflow temperature during the solder reflow.

As described above, according to the present embodiment, by taking a heat insulating measure for the soldered portion, it is possible to use the solder which is usually used frequently, without using a special solder which is softened and melted at a high temperature. Further, the softening and melting of the solder and the displacement of the member due to the thermal history caused by the solder reflow at the time of surface mounting do not occur. Therefore, it is not necessary to use a material such as a liquid crystal polymer having a high heat insulating property, and the range of selection of the material to be used is widened.

Further, by providing the magnet with a heat insulating material, it is possible to prevent heat from being transferred to the magnet within the time of the solder reflow process. Thereby, the temperature rise of the magnet due to the solder reflow can be suppressed, and the problem of irreversible demagnetization accompanying it can be solved. Further, since the condition of thermal stability for the magnet is relaxed, the limitation of the material is relaxed also from this point,
Further, the shape can be made smaller and thinner, and as a result, the entire element can be made smaller and thinner.

In the above embodiment, the heat insulating material 110 is applied only to the solder joint portion of the capacitor substrate 100, but if it is applied to the entire surface of the substrate, the same effect can be obtained for the reflow process. However, it is necessary to take measures against heat generation from the terminating resistor 106, and the heat insulating material 11 for that portion is required.
Avoid applying 0. Further, the magnet 122 may be omitted, and the cover and the shield case may have a function as a magnetic yoke.

Next, a second example will be described with reference to FIG. In this embodiment, a heat insulating measure is provided around the magnet. The capacitor substrate 100 has the same configuration as that of the above example, and the electrodes and terminal portions of the central conductor 104 are fixed by soldering at a normal softening temperature of 230 ° C.

By the way, in this embodiment, a heat-insulating polyimide film having an adhesive on one surface (on the magnet side) is placed as a heat-insulating insulating sheet 200 on the upper surface of the capacitor substrate 100, that is, the entire solder joint surface. . Then, this heat insulating and insulating sheet 200 was adhered to the magnet 14 shown in FIG. 5, and further the isolator was assembled by the cover 10 and the shield case 12. The same applies to the magnet 16 side.

In the heat insulating sheet 200, a notch 202 is formed in a portion where the terminating resistor 106 is located in consideration of heat generated from the terminating resistor 106. By doing so, the heat dissipation in the terminating resistor 106 is not obstructed, and the termination resistance 106 is satisfactorily performed.

The thus-prepared isolator and the isolator which was not treated for heat insulation were subjected to solder reflow treatment at 260 ° C. for 30 seconds, respectively. As a result, the isolator manufactured in this example has
No change in shape was observed before and after reflow. However, with the isolator without heat insulation measures, the terminals dropped out and the characteristics could not be evaluated.

<Second Embodiment> Next, a second embodiment will be described with reference to FIG. First, the embodiment shown in FIG. In this embodiment, as the magnets 300 and 302, samarium-cobalt magnets 2-17 series (hereinafter referred to as "SmCo-2-17 series") magnets are used instead of the ferrite series magnets. This magnet has the advantage that it is relatively stable to heat and has a much higher maximum residual magnetic flux density and coercive force than a ferrite magnet.

Since the SmCo.multidot.2-17 magnet is conductive, a heat insulating sheet 304 is sandwiched between the capacitive substrate 18 and the magnets 300 and 302. Since this sheet has a high temperature in the reflow process as described above, not only the insulating property but also the heat insulating property is required. As the heat insulating insulating sheet 304, for example, a material such as polyimide or silicone is used. Further, a cutout 305 is provided in a portion corresponding to the terminating resistor 24.

Then, with respect to the element having the structure of two magnets shown in FIG. 2A, the magnets 300 and 302 were made thin, and the characteristics as a non-reciprocal circuit element were examined. When two magnets are used, a DC magnetic field can be easily obtained, but the magnetic field becomes weaker as it is made thinner.
However, if the distance between the capacitance substrate 18 and the magnets 300 and 302 is set to be substantially “0” with the heat insulating sheet 304 interposed therebetween, even if the thickness of the magnets 300 and 302 is reduced to about 0.3 mm, The characteristics as a reversible circuit element were obtained.

On the other hand, as an example of a ferrite magnet, an element having the same structure was prepared by using an Sr anisotropic magnet, and a similar experiment was conducted. As a result, the distance between the capacitance substrate and the magnet was almost "0".
Even in such a case, the thickness of about 0.5 mm was the limit for producing the characteristics of the non-reciprocal circuit device.

In the case of this embodiment, the magnet 30
When the thickness of 0,302 is made thinner than about 0.3 mm,
Although the desired magnetic field can be obtained, the influence of the demagnetizing field becomes large,
When the reflow soldering process is performed, the characteristics start to be disturbed.

FIG. 2B shows an embodiment of a type in which the metal cases 10 and 12 covering the entire non-reciprocal circuit device have a function as a magnetic yoke, and the number of magnets is reduced from two to one. Similarly, for this type,
The case where SmCo · 2-17 series magnet was used as 00 was compared with the case where Sr anisotropic magnet was used. As a result, when an Sr anisotropic magnet was used, a thickness of about 0.7 mm was the limit for producing the characteristics as a nonreciprocal circuit device. However, when the SmCo · 2-17 series magnet of this embodiment is used, the thickness is 0.4 mm.
It was possible to make it thinner.

Although the heat insulating sheet is used in the above-mentioned embodiment, a space is provided between the SmCo · 2-17 series magnet and the capacitance substrate arranged below it to control the lines of magnetic force. You may choose to do so. Further, instead of the heat insulating / insulating sheet, a resin or adhesive for heat insulating / insulating may be applied on the capacitance substrate 18. As such a resin or adhesive, for example, an epoxy type, an ultraviolet curing type, a silicone type, or the like is used.

As described above, according to the second embodiment, since the SmCo · 2-17 series magnet is used instead of the ferrite series magnet, desired characteristics can be obtained with an extremely thin magnet, and the nonreciprocal circuit is obtained. It is possible to make the element thinner. Further, by using the heat insulating material, satisfactory results can be obtained with respect to thermal stability.

That is, the SmCo · 2-17 series magnet is relatively stable against heat, and has the characteristics that both the maximum residual magnetic flux density and the coercive force are much higher than those of the ferrite series magnet. Therefore, a desired DC magnetic field can be obtained with a shape smaller than that of the conventional ferrite magnet. Also,
The pinning effect of the domain wall, that is, the domain wall movement is suppressed by defects in the magnetic body, internal stress, and out of phase to suppress the magnetization reversal. This suppression of the magnetization reversal causes magnetization reversal and irreversible demagnetization. Deterioration of the magnetic material can be suppressed well.

Further, the thermal stability of the SmCo.2-17 series magnet is not superior to that of the ferrite series magnet, but substantially the same as that, and there is practically no problem. That is, it is possible to obtain a DC magnetic field of sufficient strength without causing a thermal problem even if the device is made thin. If a heat insulating material is used for this, of course, sufficient thermal stability can be obtained.

<Third Embodiment> Next, a third embodiment will be described with reference to FIG. First, replace the magnet shown in (A) with 2
An example of a type in which one sheet is used will be described. Also in this embodiment, the magnets 400 and 402 are formed of SmCo · 2-17 series magnets. Further, instead of the heat insulating insulating sheet of the above-mentioned embodiment, in order to prevent heat conduction during solder reflow to the magnet and prevent contact between the magnet and the center conductor on the ferrite, the entire magnets 400 and 402 (or Resin or adhesive 404 for heat insulation insulation on at least the capacitor substrate side
It is covered with. As the heat insulating resin 404, a thermosetting resin, for example, a resin such as a nylon resin or a liquid crystal polymer resin, an epoxy resin, an ultraviolet curing resin,
Silicone type is used. Other parts are the same as the background art.

With respect to the isolator thus obtained,
When the degree of thinning that can maintain the performance as the non-reciprocal circuit device was examined in the same manner as in Example 2, the magnets 400, 40
The thickness of 2 can be reduced to 0.2 mm.

FIG. 3B shows an embodiment in which one magnet is used. In the case of this type, the magnet 400 can be thinned to a thickness of about 0.3 mm.

<Fourth Embodiment> Next, a fourth embodiment will be described with reference to FIG. This embodiment is the same as the second embodiment.
And Example 3 is a combined example. Same figure (A)
Is a type that uses two magnets, and FIG. 6B is a type that uses one magnet.

In any case, the magnets 500, 502
Has an insulating resin or adhesive 504 applied to the entire surface (at least on the side of the capacitance substrate).
Between the magnet and the magnets 500 and 502, a heat insulating sheet 506
It is configured to interpose. Further, a cutout 507 is provided in a portion corresponding to the terminating resistor 24. Alternatively, the metal case side (or the whole) of the magnets 500 and 502 may be covered with a heat insulating insulating sheet, and the heat insulating insulating resin may be applied to the surface of the capacitor substrate 18. Even with such a configuration, it is possible to obtain the same effect as that of the above embodiment.

<Other Embodiments> The present invention can be variously modified based on the above disclosure, and includes, for example, the following. (1) In the above-described embodiment, the present invention is applied to an isolator, but it is also applicable to other non-reciprocal circuit devices. Further, whether the magnet for applying the DC magnetic field is of one type or two types may be selected according to need.

(2) The shape and size of each part, especially the structure of the capacitor substrate, are not limited to those in the above embodiment. The same applies to a sheet for heat insulation, a resin, and an adhesive, and various types may be used. (3) Furthermore, the solder reflow conditions and the like shown in the above embodiment are also arbitrary and may be set appropriately.

[0044]

As described above, the present invention has the following effects. (1) Since the solder reflow process is performed by applying a heat insulating material around the soldered part and the magnet, material restrictions are avoided while ensuring thermal stability, and demagnetization due to temperature rise is prevented. It

(2) SmCo ・ 2-17 as magnet for DC magnetic field
Since the system magnet is used, the non-reciprocal circuit device can be favorably downsized and thinned.

(3) SmCo ・ 2-17 as a magnet for DC magnetic field
Since the heat insulating material is used together with the system magnet, the non-reciprocal circuit device can be downsized and thinned while ensuring thermal stability and obtaining a sufficient magnetic field.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing a configuration of a first embodiment.

FIG. 2 is an exploded perspective view showing a configuration of a second embodiment.

FIG. 3 is an exploded perspective view showing a configuration of a third embodiment.

FIG. 4 is an exploded perspective view showing a configuration of a fourth embodiment.

FIG. 5 is an exploded perspective view showing a general configuration of a non-reciprocal circuit device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Cover 12 ... Shield case 18,100 ... Capacitance substrate 24, 106 ... Termination resistance 102 ... Ferrite 104 ... Central conductor 108 ... Terminal 110 ... Insulation material 120, 122, 300, 302, 400, 402, 5
00, 502 ... Magnet 200, 304, 506 ... Thermal insulation sheet 202, 305, 507 ... Notch 404, 504 ... Thermal insulation resin

Claims (3)

[Claims] 1. A capacitance substrate comprising a central conductor and a magnetic substance forming a circuit, and having a terminal for external connection; at least one magnet for applying a DC magnetic field to the magnetic substance; A non-reciprocal circuit device including a soldering part and a heat insulating material applied to a magnet. 2. A capacitor substrate including a central conductor and a magnetic body forming a circuit and having a terminal for external connection; at least one magnet for applying a DC magnetic field to the magnetic body; , SmCo ・ 2-17 series magnet non-reciprocal circuit element. 3. The nonreciprocal circuit device according to claim 2, wherein a heat insulating material is provided between the magnet and the capacitance substrate.