JP2012029123A - Nonreciprocal circuit device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a nonreciprocal circuit device having excellent electrical properties through reduction of deformation on an upper surface of a lower yoke by suppressing stress generated at a joint interface between a plate-shaped support and the lower yoke with a simple configuration.SOLUTION: A nonreciprocal circuit device includes: a circulator portion in which ferrite plates and a central conductor are arranged on top of each other on a first main surface of a yoke; and a plate-shaped support which is joined with the circulator portion. The plate-shaped support is composed of a metal having larger thermal expansion coefficient than the yoke, and is fixed with the yoke by placing the yoke on top thereof and brazing a part of a second main surface opposing the first main surface of the yoke.

Description

  The present invention relates to non-reciprocal circuit elements such as isolators and circulators.

Non-reciprocal circuit elements such as isolators and circulators are used in, for example, mobile phones, wireless communication devices (mobile stations), communication devices used in base stations, and the like, allowing signals to pass only in the transmission direction and in the reverse direction. It has a function to block transmission to the network.
FIG. 16 is an external view of a distributed constant type nonreciprocal circuit device disclosed in Patent Document 1, and FIG. 17 is an exploded perspective view thereof. The nonreciprocal circuit device 1 is configured by arranging a central conductor portion 10 and a resistor 14 in a housing 12.

The housing 12 is made by die-casting (high-pressure casting) aluminum or the like, or cut from a lump by cutting, and a protruding portion for positioning the resistor 14 with the wall portion 12b standing upward from the flat plate portion 12a. 12c is formed. The inner side of the wall portion 12b provided at three places is a storage portion 12d having a bottom surface that is flush with the flat plate portion 12a, and the central conductor portion 10 is disposed in the storage portion 12d.
The center conductor portion 10 is formed of a copper thin plate and has a center conductor 20 having strip electrodes 21a, 21b, 21c extending radially in three directions, and garnet plates 22, 23 (hereinafter referred to as ferrite plates) that are microwave ferrites. ), The iron plate 24, and the permanent magnet 26 are stacked and bonded together, and are housed in the housing portion 12d of the housing 12.

  The strip electrode 21c of the center conductor 20 is connected to the resistor 14 and short-circuited. The resistor 14 is positioned by the protrusion 12c of the housing 12 and fixed to the housing 12 with solder or the like. Since the resistor 14 is mounted on the casing 12 having a high heat dissipation effect, the heat generated by the resistor 14 is easily diffused, and the power durability is improved.

The non-reciprocal circuit device is always required to be inexpensive, but the housing 12 is manufactured by die-casting or cutting, so that there is a problem that the manufacturing cost is higher than a simple shape.
Therefore, as shown in FIG. 18, the portion of the housing 12 that houses the central conductor and the garnet plate is separated using a yoke (upper yoke 50 and lower yoke 55) that functions as a magnetic circuit (referred to as the circulator portion 7 for convenience). And fixing to a separately prepared plate-like support 16 is performed.

  According to such a configuration, when there is a change in structure, it is possible to easily cope with it by changing either the yoke or the plate-like support, and it is also possible to share members between different products. Therefore, it is effective for reducing the manufacturing cost.

In such a nonreciprocal circuit element, copper having excellent electrical resistance and thermal conductivity is provided as a metal constituting the plate-like support 16 after being plated to improve rust prevention and solderability. The yokes 50 and 55 were made of steel such as SPCC. They account for a large proportion of non-reciprocal circuit elements, which increases the weight. In addition, since the yoke and the plate-like support are overlapped, the height is easily increased.
In communication devices, miniaturization, reduction in height, and weight reduction are important technical issues, and nonreciprocal circuit elements have similar issues. Therefore, in order to reduce the weight and height, the thickness of the metal constituting the upper and lower yokes 50 and 55 is reduced, and the metal material constituting the plate-like support 16 is replaced with copper, so that the aluminum has a density of about 1/3. Came to use.

JP-A-11-186813

The lower yoke 55 and the plate-like support 16 are fixed by brazing with solder or the like. In solder joining, the members (plate support and lower yoke, etc.) are heated to a temperature at which the solder melts, and then cooled to room temperature. Therefore, when the lower yoke and the plate support have different thermal expansion coefficients. The stress caused by the difference in thermal expansion coefficient acts on the bonding interface.
The thermal expansion coefficient of the metal material constituting the upper and lower yokes 50 and 55 and the plate-like support 16 is about 24 × 10 ⁻⁶ / ° C. for aluminum, and about 12 × 10 ⁻⁶ / ° C. for steel, for example, SPCC. And copper is about 14 to 17 × 10 ⁻⁶ / ° C. The solder used for joining has a thermal expansion coefficient of about 20 × 10 ⁻⁶ / ° C.
For this reason, for example, when the lower yoke is made of SPCC and the plate-like support is made of aluminum, a compressive stress is applied to the lower surface of the lower yoke and a tensile stress is applied to the upper surface of the plate-like support due to the difference in thermal expansion coefficient. Comes to work.
Due to the stress generated after brazing, the upper surface of the lower yoke is deformed following the deformation at the joint interface. As a result of the thinning of the yoke and the plate-like support, the deformation became more conspicuous. As a result, the amount of deformation sometimes showed a deformation of 100 μm or more, depending on the temperature change and the size and thickness of the lower yoke.

  Due to the deformation of the upper surface of the lower yoke, the gap generated at the interface with a conductor member (for example, an earth plate 30 described later) disposed adjacently increases. Since the upper surface of the lower yoke is a ground plane which is an electrical high-frequency current path, the electrical connection between the conductor member and the lower yoke is reduced, and a stable ground potential cannot be obtained, resulting in excellent electrical characteristics. There was a problem that it was not possible. Even if it is configured so that excellent electrical characteristics can be obtained by optimizing the constituent members such as the permanent magnet and the garnet plate constituting the non-reciprocal circuit element, the original performance cannot be exhibited.

  In addition, when a large stress is applied to the bonding interface between the plate-like support and the lower yoke, there is a problem that the bonding strength is reduced due to a crack in the bonding portion.

  In order to ensure electrical connection between the upper surface of the lower yoke and the conductor member, it may be joined using solder or conductive adhesive, but there are various load conditions such as environmental temperature and input high frequency power. In non-reciprocal circuit elements used in various changing environments, there is a problem that electrical characteristics fluctuate over time due to stress repeatedly acting due to temperature fluctuations depending on the usage environment, causing cracks in the joints, etc. .

As long as members with different coefficients of thermal expansion are joined and used, it is inevitable that stress acts on the joint interface, but until now there has been no recognition of the deformation of the upper surface of the lower yoke. No consideration was given to making it smaller.
Therefore, in the present invention, a non-reciprocal circuit device having excellent electrical characteristics can be obtained by suppressing the stress generated at the bonding interface between the plate-like support and the lower yoke and reducing the deformation of the upper surface of the lower yoke with a simple configuration. The purpose is to provide.

According to a first aspect of the present invention, there is provided a yoke having a first main surface and a second main surface that face each other, a circulator portion in which a ferrite plate and a central conductor are arranged on the first main surface of the yoke, and a second of the yoke. A non-reciprocal circuit device including a plate-like support joined to a main surface, wherein the plate-like support is made of a metal having a thermal expansion coefficient larger than that of the yoke, and the yoke is used as the plate-like support. The non-reciprocal circuit device is characterized in that it is fixed to the part of the second main surface of the yoke by brazing joint.
The brazing joint portion is particularly limited to a central portion, a peripheral portion, or a plurality of portions of the second main surface of the yoke as long as the joint portion with the plate-like support is less than the area of the second main surface of the yoke. Not.

  In the present invention, it is preferable that the plate-like support has a hole opening at least on a lower surface side of the lower yoke, and the lower yoke covers the hole and is overlapped with the plate-like support.

Moreover, it is preferable that a solder resist is partially formed on the second main surface of the lower yoke or a portion overlapping the lower yoke of the plate-like support. Examples of the solder resist include polyimide, acrylic, and epoxy resins.
When brazing, the brazing material may unintentionally spread to the part that is not originally joined. By forming the hole and the solder resist, the joint area between the yoke and the plate-like support can be surely reduced. The opening area of the hole or the formation area of the solder resist is set in consideration of the bonding strength between the lower yoke and the plate-like support, but is 80% or less with respect to the total area of the first main surface of the lower yoke. Preferably there is. In addition, when providing a some hole part and a soldering resist, the opening area of a hole part or the formation area of a soldering resist becomes the opening area and formation area of those total.

  The first main surface of the lower yoke is preferably convex in the same direction between −25 ° C. and + 85 ° C.

  According to the present invention, since the brazing between the lower yoke and the plate-like support is performed at a part of the joining interface, the stress at the joining interface can be reduced, thereby reducing the deformation of the main surface of the lower yoke.

  When the hole is provided in the plate-like support, a step is provided on the outer peripheral portion of the opening, a lower yoke is dropped into the step, and brazing is performed at the outer edge, thereby reducing the height of the nonreciprocal circuit element. It is preferable because it is possible. Further, since the corner of the step is likely to have an R shape, a recess may be provided in the corner so as to prevent contact interference with the lower surface of the lower yoke.

The temperature environment in which the nonreciprocal circuit element is used varies, and the amount of heat generated by the resistor varies depending on the signal power handled. Usually, it is required to satisfy predetermined characteristics in an environment at −25 ° C. to + 85 ° C.
If the deformation direction of the main surface of the lower yoke changes with the temperature change, the connection point with the conductor member changes, so the function as the ground surface of the lower yoke is reduced and the electrical characteristics are unstable. At the same time, cracks and the like are likely to occur in the constituent members. Therefore, in the present invention, the deformation of the main surface of the lower yoke is convex toward the ferrite plate so as to obtain a uniform deformation direction so that stable electrical characteristics can be obtained. If the deformation is convex, the connecting portion between the first main surface of the lower case and the conductor member can always be secured at the substantially central portion of the upper surface of the lower case to obtain stable electrical characteristics.

In addition, the lower yoke accommodates components including a ferrite plate and a central conductor constituting the non-reciprocal circuit element, and there are cases in which they are fixed by sandwiching them between the upper yoke and the lower yoke and applying a pressing force.
If the deformation state is convex, ideally, the force point acting on the ferrite plate coincides with the fulcrum, and if the deformation amount is small, the ferrite plate is not easily cracked by the pressing force.

  The plate-like support is preferably copper, copper alloy, aluminum or aluminum alloy, and the lower yoke is preferably steel. The lower yoke uses a soft steel such as SPCC in order to constitute a magnetic circuit, and a metal having a small thermal conductivity and specific resistance is selected for the plate-like support. Since the plate-like support and the lower yoke form a high-frequency current path, it is also preferable to perform plating so as to improve the electrical conductivity.

  According to the present invention, it is possible to reduce the stress generated at the bonding interface between the plate-like support and the lower yoke, and thus to provide a nonreciprocal circuit device having excellent electrical characteristics by suppressing deformation of the upper surface of the lower yoke. I can do it.

It is a perspective view which shows one Embodiment of the nonreciprocal circuit device based on this invention. It is a perspective view which shows the decomposition | disassembly structure of one Embodiment of the nonreciprocal circuit device based on this invention. It is the elements on larger scale of one embodiment of the nonreciprocal circuit device concerning the present invention. It is a top view of the plate-shaped support body used for the nonreciprocal circuit device based on this invention. (A), (b), (c) is sectional drawing of the plate-shaped support body used for the nonreciprocal circuit device based on this invention. It is a top view of the plate-shaped support body of the other aspect used for the nonreciprocal circuit device based on this invention. It is a perspective view for demonstrating the assembly of the nonreciprocal circuit device based on this invention. It is a perspective view which shows other embodiment of the nonreciprocal circuit device based on this invention. It is a perspective view which shows the decomposition | disassembly structure of other embodiment of the nonreciprocal circuit device based on this invention. It is an insertion loss characteristic figure of a nonreciprocal circuit device concerning the present invention, and a comparative example. It is a return loss characteristic view of a nonreciprocal circuit device according to the present invention and a comparative example. It is an isolation characteristic figure of a nonreciprocal circuit device concerning the present invention, and a comparative example. (A) is a figure which shows the deformation | transformation state of the lower yoke of the nonreciprocal circuit device based on this invention, (b) is a figure which shows the deformation | transformation state of the lower yoke of a comparative example. It is a bottom face top view of the lower yoke used for other embodiments of the nonreciprocal circuit device concerning the present invention. It is a bottom face top view which shows the measurement part of the lower yoke deformation | transformation amount of the nonreciprocal circuit device based on this invention. It is a perspective view of the conventional nonreciprocal circuit device. It is a disassembled perspective view which shows the structure of the conventional nonreciprocal circuit element. It is a front view of the nonreciprocal circuit element of the other conventional aspect.

Less than. A nonreciprocal circuit device according to an embodiment of the present invention will be described.
FIG. 1 is a perspective view showing an embodiment of a non-reciprocal circuit device according to the present invention, FIG. 2 is a perspective view showing an exploded structure thereof, and FIG. 3 is a direction perpendicular to the main surface of a plate-like support. It is the partial expanded cutaway view cut | disconnected.

This nonreciprocal circuit element is formed by mounting a circulator unit 7 and a resistor 14 on one surface of a plate-like support 16.
The plate-like support 16 is made of a metal material having a thermal expansion coefficient larger than that of the metal material constituting the lower yoke 55 and having a high thermal conductivity in consideration of the heat generated by the resistor 14. In the present embodiment, SPCC using the lower yoke 55 as a magnetic yoke is used, and the plate-like support 16 is made of an aluminum alloy, which is a metal material having a larger thermal expansion coefficient than SPCC.
As the plate-like support 16, a metal material such as copper may be used. The plate-like support 16 is provided with a base Ni plating and a Sn plating thereon. The metal plating film formed on the surface is preferably formed of a metal material having a small electric resistance, and is set in consideration of the brazing property with the lower yoke 55.

FIG. 4 is a plan view of the plate-like support 16. The plate-like support 16 has a rectangular shape in plan view, and has a plurality of large and small holes. A circular hole 60 for reducing deformation of the main surface of the lower yoke is formed in the substantially central portion. The shape of the hole 60 is not particularly limited, and may be a polygonal shape. A circular or elliptical shape can be easily formed on the plate-like support 16.
Hole portions 70a to 70d penetrating through the four corners are formed. This is a screw hole used when attaching a nonreciprocal circuit element to an electronic device. In two places around the hole 60, there are formed through-holes 90a and 90b. This is a jig hole through which a positioning pin of the jig is inserted when the plate-like support 16 and the lower yoke 55 of the circulator unit 7 are brazed. The holes 70a to 70d, 90a, and 90b are provided as necessary, and the number, size, position, and the like of the holes are appropriately changed.
5A, 5B, and 5C are sectional views of the plate-like support 16 taken along the line aa ′. The hole 60 may be a through hole as shown in FIG. 5A, or may be opened only on one side as shown in FIG. 5B. Further, as shown in FIG. 5C, a stepped portion 82 may be provided around the hole 60. If the second main surface side of the lower yoke is dropped into the stepped portion, the nonreciprocal circuit element can be reduced in height. In this case, the shape of the main surface of the lower yoke and the shape of the hole 60 are preferably the same.
The hole 60 is formed so as to overlap the second main surface of the lower case, but a part thereof may be configured to be larger than the second main surface of the lower case.

  The top view of the plate-shaped support body of another aspect is shown in FIG. The hole 60 is not limited to one for the plate-like support, and the same effect can be obtained even if it is provided at a plurality of locations. The diameters of the holes may be the same or different.

  In the plate-like support body 16 shown here, five hole portions 60 are formed at positions substantially overlapping with the second main surface of the lower yoke 55. The second main surface of the lower yoke 55 and the plate-like support body 16 are overlapped, and are joined by brazing at an outer edge portion excluding the central portion of the second main surface.

  The brazing is performed using solder powder and flux, or paste-like high-temperature solder kneaded with a vehicle added thereto. As long as the bonding strength with the plate-like support 16 is ensured, and the deformation form of the upper surface of the lower yoke 55 is convex, the brazing location is not limited and may be a plurality of locations. Preferably, it is preferable to carry out at substantially the entire peripheral edge of the hole 60 so that the first main surface of the lower yoke is arcuate and convexly deformed toward the ferrite plate.

  The lower yoke 55 used in this embodiment has a substantially circular shape in plan view, and is formed from a steel plate in a cap shape or a case shape having a wall portion standing from the bottom portion. Although the shape is not particularly limited, it is usually formed in a substantially rectangular or substantially circular shape. The steel plate is preferably 0.5 mm to 1.5 mm thick.

On the inner side of the lower yoke 55, components are stacked from the bottom (first main surface) in the order shown. First, a ground plate 30 made of a thin copper plate is disposed at the bottom of the lower yoke. A thin copper plate having a thickness of 0.02 mm to 0.2 mm is used, and the surface thereof is subjected to protective plating such as Ag or Au plating so as to prevent oxidation. As the protective plating, metal plating having a low electrical resistivity is selected so as not to deteriorate the electrical characteristics, and the electrical resistivity is preferably 1.0 × 10 ⁻⁷ Ω · m or less. A ground plate 31 to be described later is also plated with metal. The outer periphery of the ground plate 30 is formed smaller than the inner diameter of the lower yoke 55, and projecting pieces are provided at three locations. The ground plate 30 is in contact with the first main surface of the lower yoke 55 but is not brazed, and a part of the projecting piece is in contact with the inside of the wall.

  A disk-shaped ferrite plate 23 is disposed on the ground plate 30, and the central conductor 20 is disposed thereon. The central conductor 20 is also called a microstrip line, and is formed by etching a thin metal plate having a thickness of 30 to 250 μm. Branch lines 29a to 29c extending in three directions from the central portion are provided, and a strip-shaped low impedance line functioning as a matching circuit is provided in a portion up to the outer peripheral edge of the ferrite plate 23. The end portions 21a to 21c of the branch lines 29a to 29c extend from openings provided on three sides of the wall portion of the lower yoke 55, and function as input / output ends for high-frequency signals.

  When adding a resistor to one of the input / output terminals to create a circulator, if there are many reactance components at the operating frequency, an impedance shift occurs between the other input / output terminals and the electrical characteristics May cause deterioration. In order to compensate for this, the width of the branch line connected to the resistor may be different from that of the other branch lines, and the size and shape of the low impedance line may be adjusted to be different from those of the other low impedance lines.

  A ferrite plate 22 is further disposed on the center conductor 20, and a ground plate 31, an iron plate 41, a permanent magnet 26 and an iron plate 28 are disposed thereon. Finally, like the lower yoke 55, the upper yoke 50 made of SPCC is pressed to prevent the stored items in the yokes 50, 55 from moving.

Since the upper yoke 50 and the lower yoke 55 serve as a high-frequency current path, metal plating with a low electrical resistivity is applied so as to improve electrical characteristics. The electrical resistivity is preferably 1.0 × 10 ⁻⁷ Ω · m or less.

  A resistor 14 is mounted on the plate-like support 16 and brazed with solder. The resistor 14 has electrode patterns on both ends of rectangular aluminum nitride, and an insulated resistor pattern is formed by applying overcoat glass between the electrode patterns. On the back surface, an electrode pattern is formed on almost the entire surface, connected to the electrode pattern on one end side, and Joule heat generated by the resistor 14 is radiated through the plate-like support 16 having excellent thermal conductivity.

FIG. 7 shows a perspective view of the non-reciprocal circuit element in a state of being arranged on the assembly jig. Hereinafter, an example of a method for assembling the non-reciprocal circuit element will be described with reference to FIG.
The non-reciprocal circuit element is assembled using the assembly jig 150. This assembling jig 150 is provided with positioning pins 120 standing upright at two locations on the main surface thereof, and has a height protruding from the main surface of the plate-like support 16. The positioning pin 120 is inserted into the holes 90 a and 90 b of the plate-like support 16 to restrict the movement of the plate-like support 16.

  A plate-like resistance positioning jig (not shown) is arranged on the plate-like support 16 arranged on the assembly jig 150. The resistance positioning jig has positioning pins at positions corresponding to the two holes 70 c and 70 d of the plate-like support 16. Further, a portion corresponding to the resistor 14 is cut out, and solder is applied to the plate-like support 16 therefrom, and then the resistor is arranged with the cutout as a positioning.

  Further, after applying solder to the outer edge of the hole 60 of the plate-like support 16 by a dispenser, the circulator part 7 is supported in a plate-like manner so that the lower surface (second main surface) of the lower yoke 55 overlaps the hole 60. Place on the body 16. Notches 95 a and 95 b are provided on the side surface of the bottom of the lower yoke 55 at positions corresponding to the positioning pins 120 and are positioned by the positioning pins 120 protruding from the main surface of the plate-like support 16. . Solder is also applied to the electrode pattern of the resistor 14 in contact with the end 21c of the branch line.

  The plate-like support 16 and the circulator unit 7 are placed in a thermostat adjusted to a predetermined temperature (above the melting point of solder) while being placed on the assembly jig 150. After a while, it is taken out and cooled to room temperature, and is removed from the assembly jig 150 to obtain a non-reciprocal circuit element in which the plate-like support 12 and the circulator unit 7 are soldered.

  In the obtained non-reciprocal circuit element, the stress acting on the lower yoke 55 is reduced by the hole 60, so that the first main surface of the lower yoke is convexly deformed. It is reduced as compared with the case of brazing and joining the substantially entire surface of the two main surfaces.

  FIG. 8 is a perspective view of a non-reciprocal circuit device according to another embodiment. FIG. 9 is an exploded perspective view showing the structure. Since the basic configuration is the same as that of the non-reciprocal circuit device shown in FIGS. 1 and 2, the same reference numerals are given to components having the same functions. The difference is that, in the circulator unit 7, the lower yoke 55 is formed in a circular plate shape, and the upper yoke 50 is formed in a cap shape. Since the leakage flux is reduced by forming the upper yoke 50 in the cap shape, a sufficient operating magnetic field can be applied to the ferrite plate without using the iron plate 28. By reducing the iron plate 28, the nonreciprocal circuit element can be reduced in height, and the cost can be reduced by reducing the part cost.

Hereinafter, the nonreciprocal circuit device according to the present invention will be described in detail. Since the entire configuration is the same as that of FIGS. 1 and 2 already described, the description of the overlapping parts is omitted.
A lower case 55 made of SPCC having a thickness of 1.2 mm and a height of 8 mm was prepared, and a circular earth plate 30 having a thickness of 0.1 mm was disposed on the inner bottom surface (first main surface). On the surface of the lower case 55, a plating layer having a total thickness of 30 μm is formed in the order of Cu plating, Ni plating, and Ag plating. The bottom surface of the lower case 55 has a substantially circular shape with a diameter of 30 mm.

A central conductor assembly is disposed on the ground plate 30. The center conductor assembly is obtained by sandwiching the center conductor 20 between disc-shaped ferrite plates 22 and 23 and bonding and fixing them with an epoxy resin. The disk-shaped ferrite plates 22 and 23 are each made of garnet ferrite having a diameter of 23 × 1.0 mm, a relative dielectric constant εr of 11, a saturation magnetization 4πMs of 1600 mT, and a dielectric loss tan δε of 2 × 10 ⁻⁴ . . The center conductor 20 is formed by etching a thin Cu plate having a thickness of 150 μm into a predetermined shape. A plating layer made of a good conductor is also formed on the surface of the central conductor 20.

  Further thereon, a ground plate 31 having a thickness of 0.1 mm, an iron plate 24 having a thickness of 0.3 mm, a permanent magnet 26, and an iron plate 28 having a thickness of 1.0 mm are disposed so as to overlap the central conductor assembly. The permanent magnet 26, φ25 × 4.15 mm thick La-Co substitutional ferrite magnet YBM-9BE made by Hitachi Metals, Ltd. was used. As for the magnetic properties, the residual magnetic flux density (Br) is 430 to 450 mT, and the intrinsic coercive force (iHc) is 382 to 414 KA / m.

  On the iron plate 28, an upper yoke 50 made of SPCC having a thickness of 0.2 mm and an outer diameter of 30.5 mm was disposed. The upper end of the lower yoke 55 is folded back into a bowl shape, and the end of the upper yoke 50 is caulked to fix the internal constituent members, thereby constituting the circulator portion 7 having a height of 9 mm. The components other than the central conductor assembly are fixed by the pressing force by the upper and lower yokes 50 and 55.

The plate-like support 16 is formed of an aluminum alloy having an outer dimension of 33.2 mm × 40 mm × 1.2 mm, and a through hole 60 is provided at a substantially central portion thereof. The hole 60 is formed at a position overlapping the bottom surface of the lower yoke 55, and in the embodiment, the hole diameter is φ25 mm.
Solder is applied to the overlapping part of the outer edge plate support 16 excluding the central part of the lower surface of the lower yoke 55, the lower yoke 55 and the plate support 16 are overlapped, and placed in a thermostatic chamber set at 265 ° C. It was put in for 7 minutes, taken out, and naturally cooled to room temperature to obtain a nonreciprocal circuit device corresponding to a frequency band of 925 MHz to 960 MHz.
For comparison, a non-reciprocal circuit device was prepared in the same manner as in Example except that the plate-like support 16 without the hole 60 was prepared and was joined to the plate-like support 12 over substantially the entire lower surface of the lower yoke 55. .

  About the nonreciprocal circuit element of the obtained Example and comparative example, the electrical characteristic (insertion loss, return loss, isolation) was evaluated in the temperature environment of room temperature 22 degreeC using the network analyzer. The results are shown in Table 1 and FIGS. Each characteristic value in Table 1 is an average value of five samples. Since each characteristic varies depending on the frequency, the worst data in the frequency band is picked up and used as the characteristic value of each sample, and these are averaged and shown in Table 1. 10 to 12 show the frequency characteristics of one sample.

  The non-reciprocal circuit device of the example is equivalent to the electrical characteristic obtained by mounting the circulator part directly on the measurement substrate formed of the glass epoxy substrate, and has superior electrical characteristics than the comparative example. It was.

In the non-reciprocal circuit element, since it is difficult to measure the deformation amount of the lower yoke, the deformation amount of the first main surface of the lower yoke 55 is determined for the joined body in which only the plate-like support 16 and the lower yoke 55 are soldered. evaluated.
Samples a to c are obtained by joining the lower yoke 55 to each of the plate-like supports 16 having holes of φ15 mm, φ20 mm, and φ25 mm, and the sample d is a region including a substantially central portion of the lower surface of the lower yoke 55. A polyimide film (φ25 mm) is bonded to the plate-like support 16 having no hole. FIG. 14 shows a plan view of the sample d viewed from the second main surface side. Sample c corresponds to the nonreciprocal circuit device of the above-described embodiment. Sample e is obtained by joining the lower yoke 55 to the plate-like support 16 having no hole, and corresponds to the non-reciprocal circuit device of the comparative example described above.

  About the obtained joined body, it measured using the surface roughness meter about the 1st main surface of the lower yoke, and the deformation | transformation was evaluated. FIG. 15 shows a portion where the deformation amount is measured. The measurement length is 23 mm including the central portion of the first main surface which is the bottom surface inside the lower yoke. The measurement results are summarized in Table 2. FIG. 13A shows a deformed state of the sample c, and FIG. 13B shows a deformed state of the sample e.

In the lower yoke alone, the deformation of the upper surface was 5 μm or less and was substantially flat. However, the deformation of each of the lower yokes after the bonding was convex upward, and showed an arc-shaped deformation with the center at the apex.
The amount of deformation is greatest when the plate-like support has no hole and the polyimide film is not attached to the lower case. In addition, when it measured using the surface roughness meter about the back surface side (surface facing a joining surface) of a plate-shaped support body, it deform | transformed following the lower case.

  According to the present invention, it is possible to provide a nonreciprocal circuit device having excellent electrical characteristics by suppressing the stress generated at the bonding interface between the plate-like support and the lower yoke and reducing the deformation of the upper surface of the lower yoke. I can do it.

DESCRIPTION OF SYMBOLS 1 Nonreciprocal circuit element 16 Plate-like support body 14 Resistance 20 Center conductors 22 and 23 Ferrite plate 26 Permanent magnets 24 and 28 Iron plates 30 and 31 Earth plate 50 Upper yoke 55 Lower yoke

Claims (5)

A yoke having opposing first main surface and second main surface, a circulator portion in which a ferrite plate and a central conductor are arranged on the first main surface of the yoke, and a second main surface of the yoke. A non-reciprocal circuit device comprising a plate-like support,
The plate-like support is made of a metal having a thermal expansion coefficient larger than that of the yoke, and the yoke is overlapped with the plate-like support and fixed to a part of the second main surface of the yoke by brazing. A nonreciprocal circuit device characterized by the above. The plate-like support has a hole opening at least on the lower surface side of the lower yoke,
The nonreciprocal circuit device according to claim 1, wherein the lower yoke covers the hole and is overlapped with the plate-like support.   2. The nonreciprocal circuit device according to claim 1, wherein a solder resist is partially formed on the second surface of the lower yoke or a portion of the plate-like support that overlaps the lower yoke.   4. The nonreciprocal circuit device according to claim 1, wherein the first main surface of the lower yoke is convex in the same direction between −25 ° C. and + 85 ° C. 5.   5. The nonreciprocal rotating element according to claim 1, wherein the plate-like support is copper, a copper alloy, aluminum, or an aluminum alloy, and the lower yoke is steel.

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