JP3204423B2 - Non-reciprocal circuit device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an isolator and a circulator which are non-reciprocal circuit devices used in microwave bands such as VHF and UHF bands. In recent years, such isolators and circulators have been mainly used as components of high-frequency sections of remarkably miniaturized mobile phones and mobile phones.

[0002]

2. Description of the Related Art Conventionally, there is a lumped-constant type isolator as shown in FIG. 5 as a non-reciprocal circuit device used in a microwave band such as a VHF band or a UHF band. This conventional example will be described with reference to the structural diagram of FIG. In this isolator, a ground plate 34 is soldered onto a magnetic metal case 33, a dielectric substrate 35 is soldered thereon, and a center conductor portion 41 is inserted into a center hole 36 of the dielectric substrate 35. Solder. FIG. 7 shows the combination of the center conductors 41. The center conductor is formed by processing a copper plate, and a ferrite core 38 is set on a central circular portion 37. The center conductors 60 of the book are bent and arranged so as to be insulated from each other via an insulating sheet 39 and intersect every 120 degrees. Since it is necessary to apply a DC magnetic field vertically to the ferrite core 38 of the assembly 42, the assembly 44 in which the metal case 40 and the magnet 43 are bonded is adjusted so as to cover the assembly 42. FIG. 8 shows a perspective view of both planes of the dielectric substrate 35 described above. On the upper surface of this dielectric substrate 35, three capacitor electrode films 45,
Reference numerals 46 and 47 are formed by thick film printing in which an Ag paste is baked, and one of the electrode films 47 is connected to a terminal portion 51 protruding from the central conductor portion 41 by soldering. The film 47 is connected to a through-hole electrode film 49 via a resistance film 48,
Reference numeral 9 denotes a through hole 59 connected to the ground electrode film 50 on the lower surface of the dielectric substrate 35. Regarding the other two electrode films, the electrode film 45 is connected to the terminal portion 52 protruding from the central conductor portion 41, and the electrode film 46 is connected to the terminal portion 53 protruding from the central conductor portion 41 by soldering. . Terminal 5
Reference numerals 2 and 53 denote the input / output terminals of the isolator exposed to the outside through the opening 54 of the metal case. As a method of grounding the isolator, a method of directly soldering to the metal case 33 or 40 or a method of screwing the metal case 33 are used.

[0003]

However, in order to reduce the size of the above-mentioned conventional isolator, the only method of reducing the size of each component is basically used.
The size of the corner was the limit. The optimum ratio between the diameter of the magnet and the diameter of the ferrite core can be expressed by Equation 1.

[0004]

[Equation 1] Magnet: Ferrite core = 1.5: 1

In consideration of this ratio, in order to maintain the characteristics of the isolator, there is a tendency that the larger the diameter of the ferrite core, the better the characteristics of the isolator. Therefore, it is not preferable to reduce the diameter of the ferrite core. . For this reason, it is desired to increase the diameter of the ferrite core as much as possible.
5, the gap width 55 becomes small, and the pattern area of the electrode film 47 becomes small. When the pattern area of the electrode film is reduced, there is a risk that the electrode film is peeled off, and there is a problem in reliability. In particular, the width 58 portion of the electrode film 47 is easily peeled off. Also, as for the through-holes, if the dielectric substrate becomes smaller, the gap widths 56 and 57 become smaller, so that there is a problem that the substrate may be cracked and the electrode film may be peeled off. There is also a problem that the surface mounting cannot be performed with the structure of the conventional isolator.

[0006]

According to the present invention, three center conductors protrude from a circular shield plate, a ferrite core is disposed on the circular shield plate, and the three center conductors are disposed on the ferrite core. Has a central conductor portion configured by being bent in an insulated state from each other, the central conductor portion is disposed in a central hole of the dielectric substrate, and the three central conductors are connected to electrodes of the dielectric substrate, In a nonreciprocal circuit device in which permanent magnets for applying a DC magnetic field to the ferrite core are housed in a metal case, (1) one of the electrodes to which the center conductor of the dielectric substrate is connected Is connected to a dummy resistor, and the dummy resistor is connected to a ground electrode, and the ground electrode is connected to the ground by using a projection formed on the shield plate. (2) A projecting portion is formed in the portion to enlarge the board area, and the board projecting portion is inserted into a notch formed in a metal case. (3) An insulating substrate is mounted on a mounting surface of the metal case, A non-reciprocal circuit device, wherein an end of a center conductor is taken out of the metal case and bent toward the insulating substrate to enable surface mounting.

[0007]

With respect to the internal structure of the nonreciprocal circuit device according to the present invention, a projection is provided on a part of the center conductor, and this projection is used as a substitute for a through hole. Therefore, it is not necessary to make an extra hole in the dielectric substrate, so that the substrate can be prevented from cracking and the strength can be increased. Further, by providing a projection on a part of the dielectric substrate, the pattern area of the electrode film can be increased, so that the peel strength of the electrode film is improved and the reliability is improved. Further, according to the non-reciprocal circuit device of the present invention, by mounting the insulating substrate on the bottom surface of the case, the input / output terminal and the ground terminal protruding from the device are bent and fixed so as to cover the insulating substrate bottom surface side. Thereby, the surface mounting of the non-reciprocal circuit device can be performed. Also, the magnetic circuit is surrounded by a metal case made of a magnetic material like a conventional magnetic shield, so that the magnetic circuit is securely closed without changing the structure. As described above, since the strength of each component of the internal structure of the non-reciprocal circuit device can be effectively used without deteriorating, the size of 5 mm square is possible according to the present invention, so that further miniaturization is possible. It goes without saying that automatic mounting by taping is also possible.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings. FIGS. 1, 2, 3 and 4 are views for explaining a non-reciprocal circuit device according to an embodiment of the present invention, and an isolator will be described. FIG. 1 is a perspective view of a lumped-constant isolator according to an embodiment of the present invention as viewed from above (a).
And (b) a perspective view seen from the bottom. Referring to the structural diagram of FIG. 2, this isolator 1 has a ground plate 5 soldered onto a magnetic metal case 4, a dielectric substrate 6 is soldered thereon, and a central hole of the dielectric substrate 6 is formed. The central conductor 11 is inserted into the inside 7 and soldered. The combination of the center conductors 11 is shown in FIG. 3A. The center conductor 8 is made by processing a copper plate, and a ferrite core 9 is set on the center circular shield plate 2 and the ferrite core 9 is set. On the upper surface of the core 9, three center conductors 8 are placed on an insulating sheet 10.
Are bent and arranged so that they are insulated from each other via a cross and intersect every 120 degrees. Since it is necessary to apply a DC magnetic field vertically to the ferrite core 9 of the assembly 12 described above, the assembly 15 in which the metal case 13 and the magnet 14 are bonded with an adhesive is adjusted so as to cover the assembly 12. FIG. 4 is a perspective view of both planes of the dielectric substrate 6. On the upper surface of the dielectric substrate 6, three capacitor electrode films 16, 1
7 and 18 are formed by thick film printing in which an Ag paste is baked. One of the electrode films 18 is the central conductor 1
The electrode film 18 is connected by soldering to the terminal portion 22 protruding from the terminal 1, so that the resistor film 19 formed by thick-film printing of a resistor paste is baked because the electrode film 18 needs to be subjected to non-reflection termination. It is connected to the electrode film 20 through the intermediary. The projection 23 protruding from the central conductor 11 is connected to the electrode film 20 to be electrically connected to the ground electrode film 21 on the lower surface of the dielectric substrate 6. That is, the central conductor 11 is provided with a protrusion such as 23, which is replaced by a through hole. In addition, depending on the pattern of the substrate, the projection of the center conductor may be formed as 3 in FIG.
The one in position 2 was also used. As for the other two electrode films, the electrode film 16 is connected to the terminal portion 24 protruding from the central conductor portion 11 and the electrode film 17 is connected to the terminal portion 25 protruding from the central conductor portion 11 by soldering. . Terminals 24, 2
Reference numeral 5 denotes an input / output terminal of the isolator exposed to the outside from the opening of the metal case. Also, this dielectric substrate 6
It has a protruding part 31 in a part to enlarge the substrate area. The protrusions 31 prevent the width of the electrode 18 from becoming extremely narrow, thereby preventing peeling of the electrode film and securing the capacitance. Further, the metal case 4 is provided so that the protrusion 31 does not increase the size of the non-reciprocal circuit device.
The notch 3 is formed in advance, and the protrusion 31 of the dielectric substrate 6 is inserted into the notch 3. At this time, the protruding portion 31 of the dielectric substrate 6 was formed so as not to protrude from the outside of the metal case 4. An insulating substrate 26 is mounted on the mounting surface side of the metal case 4. In the insulating substrate 26, a conductor pattern 27 is formed on almost the entire surface in contact with the metal case 4, and four electrode patterns 28 are formed on the mounting surface. The metal case 4 and the insulating substrate 26 are connected by soldering with the conductor pattern 27. Also, input / output terminals 24 and 25 of the center conductor
Are bent toward the mounting surface side of the insulating substrate 26 and soldered to the electrode pattern 28. Also, the ground plate 5 is formed with a projection on a part thereof to form ground terminals 29, 30. The ground terminals 29, 30 are bent toward the mounting surface side of the insulating substrate 26 and soldered to the electrode pattern 28. According to the embodiment of the present invention, a non-reciprocal circuit device which is ultra-small and can be surface-mounted can be constructed.

[0009]

The isolator, which is a nonreciprocal circuit device used in the microwave band of the VHF and UHF bands of the present invention, usually has a function of preventing the backflow of signals such as microwaves, and is particularly useful for radio equipment. It is an indispensable part for preventing the destruction of the power amplifier (amplifier) circuit. The present invention can be used as a surface mount component while maintaining the characteristics of a conventional isolator. In recent years, remarkable progress has been made in miniaturization of automobile telephones and mobile telephones. However, according to the present invention, a size of 5 mm square is possible, so that further miniaturization is possible. or,
If the isolator becomes smaller, the number of taping at the time of packing increases per reel, so that the number of reels is reduced and the packing cost is reduced.

[Brief description of the drawings]

FIG. 1 is a top perspective view of one embodiment of the present invention (a).
(B) of FIG.

FIG. 2 is a structural diagram of one embodiment of the present invention.

FIG. 3A is a structural view of a central conductor according to one embodiment of the present invention (a).
And its modification (b).

FIG. 4 is a perspective view of both planes of the dielectric substrate according to one embodiment of the present invention.

FIG. 5 is a perspective view of a conventional example.

FIG. 6 is a structural view of a conventional example.

FIG. 7 is a structural view of a conventional center conductor.

FIG. 8 is a perspective view of both planes of a conventional dielectric substrate.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Isolator 3 Notch part 4, 13 Metal case 5 Ground plate 6 Dielectric substrate 7 Center hole of dielectric substrate 8 Center conductor 9 Ferrite core 10 Insulation sheet 11 Center conductor part 14 Magnet 16, 17, 18, 20 Electrode film 19 Resistance film 21 Earth electrode film 22 Terminal part 23, 32 Projection part 24, 25 Input / output terminal part 26 Insulating substrate 27, 28 Conductive pattern 29, 30 Ground terminal 31 Projection part of dielectric substrate

Claims (4)

(57) [Claims] 1. A ferrite core is disposed on a circular shield plate, wherein three central conductors protrude from the circular shield plate, and the three central conductors are bent on the ferrite core in a state of being insulated from each other. Having a central conductor portion configured, the central conductor portion is disposed in a central hole of the dielectric substrate, the three central conductors are connected to the electrodes of the dielectric substrate,
In a non-reciprocal circuit device in which permanent magnets for applying a DC magnetic field to the ferrite core are housed in a metal case, one of the electrodes to which the center conductor of the dielectric substrate is connected is a dummy resistor. And the dummy resistor is connected to a ground electrode, and the ground electrode is connected to the ground by using a projection formed on the shield plate. 2. A center formed by projecting a plurality of center conductors from a circular shield plate, disposing a ferrite core on the circular shield plate, and bending the plurality of center conductors on the ferrite core in an insulated state. Having a conductor structure,
In the nonreciprocal circuit device, one of the central conductor is connected to the dummy resistor, the shield plate, apart from the central conductor, characterized in that the projections for ground connecting the dummy resistor is formed Irreversible circuit element. 3. The three center conductors are formed from a circular shield plate.
Protruding, ferrite core placed on the circular shield plate
And the three center conductors are placed on the ferrite core.
Has a central conductor section that is bent in an insulated state
The center conductor is disposed in the center hole of the dielectric substrate,
The three center conductors are connected to the electrodes of the dielectric substrate,
A permanent magnet for applying a DC magnetic field to the ferrite core is provided.
Are placed in a metal case and are irreversible.
In the circuit element, a projecting portion is formed on a part of the dielectric substrate to increase a substrate area.
GreatForming a part of the electrode in the enlarged area;
To  Insert the protruding part of the board into a notch formed in the metal case.
A non-reciprocal circuit device characterized by being inserted. 4. An insulating substrate is mounted on a mounting surface of the metal case, and an end of the center conductor is taken out of the metal case,
4. The non-reciprocal circuit device according to claim 1, wherein the non-reciprocal circuit device is bent toward the insulating substrate to enable surface mounting.