JP2006279997A - Non-reciprocal circuit element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a non-reciprocal circuit that reduces the height and suppresses electronic deterioration. <P>SOLUTION: A first ferrite 60 and a second ferrite 10 have principal planes where either of the sides of each principal plane is opposed to that of the other principal plane with center conductors 64-66 interposed between both planes. The other side of the principal plane of the first ferrite 60 is shielded by a conductor plate G. One side of the principal planes of the center conductors 64 to 66 is electrically connected to the conductor plate G. In the second ferrite 10, the other side of the principal plane is an unshielded plane. <P>COPYRIGHT: (C)2007,JPO&INPIT

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 mobile wireless devices such as mobile phones. This type of non-reciprocal circuit element includes a magnetic metal case functioning as a yoke, a magnetic component such as a magnetic rotor and a permanent magnet composed of a soft magnetic base and a central conductor, a matching capacitor, and a termination resistor. Consists of electrical components.

  This kind of non-reciprocal circuit device is required to be miniaturized as much as possible due to market demand, and further, improvement in characteristics is required in the miniaturization. It is not always easy to satisfy this requirement at the same time.

  For example, in Patent Document 1, a ferrite is disposed in a magnetic circuit yoke, and a plurality of central conductors are wound around the ferrite in an electrically insulated state and crossed, and a permanent magnet attached to the yoke. A non-reciprocal circuit device is disclosed in which a non-reciprocal circuit device configured to apply a DC magnetic field to ferrite and an auxiliary ferrite disposed in a portion facing the permanent magnet with the ferrite in the magnetic circuit yoke is disclosed ing. The auxiliary ferrite is provided in contact with the yoke that becomes the ground potential.

  According to this prior art, it is described that by providing the auxiliary ferrite, the parallelism of the magnetic field can be improved and the insertion loss can be reduced. However, since the auxiliary ferrite is disposed in a portion facing the permanent magnet with the ferrite in the magnetic circuit yoke interposed therebetween, the size is increased accordingly.

  On the other hand, for the purpose of reducing the height of the non-reciprocal circuit element, for example, Patent Document 2 discloses a non-reciprocal circuit element having one ferrite.

  However, if one ferrite is used, it becomes a nonreciprocal circuit element having a narrower band than the case of two ferrites, and deterioration of electrical characteristics is inevitable.

As described above, depending on the prior art, it has been difficult to satisfy both the reduction in height and the improvement in characteristics at the same time.
Japanese Patent Laid-Open No. 6-164111 Japanese Patent No. 2526219 JP-A-10-224118

  An object of the present invention is to provide a non-reciprocal circuit device that does not deteriorate in electrical characteristics while realizing a low profile.

  In order to solve the above-described problem, the non-reciprocal circuit device according to the present invention includes a plurality of center conductors, a first ferrite, and a second ferrite.

  One of the main surfaces of the first ferrite and the second ferrite is opposed to each other with the central conductor interposed therebetween. The first ferrite has the other main surface shielded by a conductor plate. One side of the plurality of central conductors is electrically connected to the conductor plate. In the second ferrite, the other main surface is an unshielded surface.

  In the non-reciprocal circuit device according to the present invention described above, if necessary, the Faraday-rotating ferrite is the first ferrite and the second ferrite, and the second ferrite (permanent magnet side) is grounded. The shield is not arranged. For this reason, the electrical characteristics can be reduced by the thickness of the shield. Further, the second ferrite can be made thinner than the first ferrite, and a low profile of the nonreciprocal circuit element can be realized. In this case, the electrical characteristics are not deteriorated.

  Therefore, according to the present invention, while reducing the height of the non-reciprocal circuit device, the electrical characteristics are not deteriorated (the electrical characteristics are narrowed) as in the case of a single ferrite.

  In addition, the correction capacitance of the nonreciprocal circuit element can be made smaller than that of a single ferrite, and a small capacitor is required, which is effective for downsizing the nonreciprocal circuit element. Compared to the case of two ferrites, a shield part on one side is not necessary, leading to a reduction in the number of parts.

  Preferably, the second ferrite has a thickness smaller than that of the first ferrite. The material of the first ferrite and the second ferrite may be the same or different.

  A general configuration of this type of nonreciprocal circuit element includes a permanent magnet. The permanent magnet is preferably in contact with the unshielded main surface of the second ferrite. In this case, the permanent magnet may be fixed to the non-shield main surface of the second ferrite using, for example, an adhesive.

  Other objects, configurations and advantages of the present invention will be described in more detail with reference to the accompanying drawings. However, the attached drawings are merely examples.

  As described above, according to the present invention, it is possible to provide a non-reciprocal circuit device having no electrical characteristic deterioration while realizing a low profile.

  1 is a cross-sectional view schematically showing a configuration of a non-reciprocal circuit device according to the present invention, FIG. 2 is a perspective view showing an example of a magnetic rotor structure in the non-reciprocal circuit device shown in FIG. 1, and FIG. 3 is a circuit diagram of an isolator using the nonreciprocal circuit device shown in FIG.

  The illustrated non-reciprocal circuit element includes first to third center conductors 64 to 66, a first ferrite 60, and a second ferrite 10. Furthermore, the case member 1 and the permanent magnet 8 are included as general components.

  As for the 1st ferrite 60 and the 2nd ferrite 10, one of each main surface has mutually opposed on both sides of the 1st-3rd central conductors 64-66. As is well known, the first ferrite 60 and the second ferrite 10 are made of a soft magnetic material such as yttrium / iron / garnet (YIG). The first ferrite 60 has the other main surface shielded by the ground portion G. The other of the main surfaces of the second ferrite 10 is an unshielded surface.

  The first to third center conductors 64 to 66 cross each other at a predetermined angle. The intersecting portions are insulated from each other by the insulating member 68. Further, the whole is fixed by an insulating member 68. One end of each of the first to third center conductors 64 to 66 is electrically connected to the ground portion G, and the other end is connected to the electrical components C1, C2, C3, and a resistor.

  The case member 1 includes a magnetic metal material having conductivity and an electrically insulating resin material. The permanent magnet 8 applies a DC magnetic field to a magnetic rotor composed of the first to third central conductors 64 to 66 and the first ferrite 60.

  When used as an isolator, the first to third center conductors 64 to 66 are electrically connected to one end of the first to third capacitors C1 to C3 and the resistor R as shown in FIG. The other ends of the first to third capacitors C1 to C3 and the resistor R are grounded. The first terminal 17 constitutes an input terminal, and the second terminal 20 constitutes an output terminal. In the isolator circuit shown in FIG. 3, the circulator can be configured by removing the resistor R and forming the third terminal.

  In the non-reciprocal circuit element described above, the Faraday-rotating ferrite is the first ferrite 60 and the second ferrite 10, and the ground portion G serving as a ground potential shield is only in the first ferrite 60. The ground potential shield is not disposed on the second ferrite 10 (permanent magnet side). For this reason, the thickness of the shield can be reduced. In addition, the second ferrite 10 can be made thinner than the first ferrite 60, thereby further reducing the height. In this case, the electrical characteristics are not deteriorated.

  Therefore, according to the present invention, it is possible to avoid deterioration of electrical characteristics (narrow band of electrical characteristics) as in the case of a single ferrite, while realizing a low profile of the nonreciprocal circuit element. Become.

  In addition, the capacitance values of the first to third capacitors C1 to C3 can be made smaller than when only one ferrite is used, and a small capacitor is required, so that the nonreciprocal circuit element can be reduced in size. Is also effective. Further, since the shield part on one side is not necessary as compared with the conventional technique using two ferrites (see Patent Document 2), the number of parts is reduced.

  4 is an exploded perspective view showing one embodiment of the non-reciprocal circuit device according to the present invention, FIG. 5 is a perspective view of the non-reciprocal circuit device shown in FIG. 4, and FIG. 6 is a magnetic rotor, a capacitor, It is a figure which shows the arrangement | positioning relationship of a resistor. The illustrated nonreciprocal circuit element includes a case member 1, a cover member 9, a magnetic rotor 6, and a permanent magnet 8. The electrical component includes first to third capacitors C1 to C3 and a resistor R, and constitutes an isolator.

  The case member 1 has a box shape with an open top, and includes a yoke part 300 made of a metal plate material and an insulating part 400 made of an insulating resin. The yoke part 300 can be integrally formed by pressing or bending. Engineering plastic or the like is used for the insulating portion 400 of the case member 1 and can be integrated with the yoke portion 300 by insert molding. The inner bottom surface of the case member 1 includes a conductive portion 160 formed of a metal material portion.

  The insulating part 400 is provided with first to third external terminals 15 to 17. The first and second external terminals 15 and 17 are exposed from the insulating portion 400 and extend inside the case member 1.

  The first to third capacitors C <b> 1 to C <b> 3 are housed in the case member 1 and are disposed at predetermined positions on the conductive portion 160. The resistor R is housed in the case member 1, and one end thereof is electrically connected to the conductive portion 160.

  The magnetic rotor 6 is housed in the case member 1, and the ground portion G is disposed in contact with the conductive portion 160. The first to third center conductors 64 to 66 intersect at a predetermined angle, and one end of the first to third center conductors 64 to 66 is continuous with the substantially rectangular ground portion G.

  The first terminal 641 of the first central conductor 64 is connected to the first capacitor C1 and the resistor R. The second center conductor 65 has a second terminal portion 651 connected to the second capacitor C2. The third center conductor 66 has a third terminal portion 661 connected to the third capacitor C3.

  The pressing member 7 has a hollow portion 70, a frame portion 71, and a low step portion 72, and is provided inside the case member 1. The cavity 70 opens at the upper surface and the lower surface. The cavity 70 has a shape corresponding to the outer shape of the second ferrite 10, and the second ferrite 10 is inserted into the cavity 70 of the pressing member 7 and positioned.

  The frame portion 71 of the pressing member 7 surely presses the first to third terminal portions 641 to 661 against the resistor R and the first to third capacitors C1 to C3, as well as the resistor R and the first to first terminals. 3 capacitors C1 to C3 are pressed against the conductive portion 160 of the case member 1. The pressing member 7 is made of an insulating material such as engineering plastic.

  The lower step portion 72 of the pressing member 7 is a portion that receives the permanent magnet 8. The permanent magnet 8 applies a DC magnetic field to the magnetic rotor 6 and has a circular outer shape. The permanent magnet 8 is in contact with the unshielded main surface of the second ferrite 10 and is fixed using, for example, an adhesive.

  Since the second ferrite 10 contributes to the Faraday rotation action as a high frequency ferrite like the first ferrite 60, the positional relationship with the first to third central conductors 64 to 66 is important. If it deviates from a desired position, the electrical characteristics change. That is, if the position variation is large, the variation in electrical characteristics is also large.

  Therefore, in the embodiment, as the role of the pressing member 7, not only the purpose of mechanical fixation to the first to third terminal portions 641 to 661 but also the role of positioning the second ferrite 10 by the cavity portion 70 is provided. It is. For this reason, the position variation of the second ferrite 10 can be reduced. Further, as the role of the pressing member 7, the role of positioning the permanent magnet 8 by the low step portion 72 is also provided.

  The cover member 9 is made of a magnetic metal material having conductivity, overlaps with the permanent magnet 8, is combined with the case member 1 so as to close the opening of the case member 1, and is magnetically coupled to form a yoke.

  In the above-described embodiment, the two ferrites that perform Faraday rotation are the first ferrite 60 and the second ferrite 10. In this structure, the second ferrite 10 is not provided with a ground potential shield. For this reason, the thickness of the shield can be reduced. In addition, the second ferrite 10 can be made thinner than the first ferrite 60, thereby realizing a further reduction in the height of the nonreciprocal circuit device. In this case, the electrical characteristics are not deteriorated.

  Therefore, according to the above embodiment, it is possible to avoid the deterioration of the electrical characteristics (narrow band of the electrical characteristics) while realizing the low profile of the nonreciprocal circuit element.

  In addition, the first to third capacitors C1 to C3 can be set to a smaller value than when only one ferrite is used, and a small capacitor is sufficient. For this reason, a nonreciprocal circuit element can be reduced in size. In addition, as compared with the prior art using two ferrites, a shield part on one side is not necessary, leading to a reduction in the number of parts. Next, examples will be described.

Example By setting the thickness of the second ferrite 10 to 0.15 mm, the thickness of the permanent magnet 8 to 0.60 mm, and the thickness of the first to third central conductors 64 to 66 to 0.03 mm. The space for adding the second ferrite 10 could be secured. The first ferrite 60 has a thickness of 0.4 mm, but can be made thinner. The ferrite material was the same for both sheets. Depending on the characteristics required for the non-reciprocal circuit element, ferrites of different materials can be used.

  By reducing the thickness of the first to third center conductors 64 to 66 to 0.03 mm, there is an effect that the spring back at the time of assembling the magnetic rotor is reduced and the bending process is facilitated. In addition, since the effective inductance has increased, the required capacitance value can be reduced, and the capacitor can be miniaturized. There is a merit that the DC magnetic field to the magnetic rotor including the second ferrite 10 can be reduced, and the permanent magnet 8 can be thinned to 0.60 mm.

  Since the thickness of the second ferrite 10 is as thin as 0.15 mm, the bending strength is weakened. Therefore, as shown in FIG. 7, the permanent magnet 8 and the second ferrite 10 are fixed by an adhesive, and this is assembled to the pressing member 7. With such a structure, the second ferrite 10 fixed to the permanent magnet 8 does not crack even if it is thin. In the embodiment, the second ferrite 10, the permanent magnet 8, and the pressing member 7 are integrated together with the pressing member 7. As a result, when assembling the non-reciprocal circuit element, an assembly in which the second ferrite 10 and the permanent magnet 8 are integrated can be used offline, so that the assembly efficiency is improved.

  In the embodiment, both the first ferrite 60 and the second ferrite 10 have a size of 2 mm × 2 mm. Of course, the size of the second ferrite 10 may be changed from that of the first ferrite 60. The influence on the characteristics when the size of the second ferrite 10 is changed will be described. First, when the second ferrite 10 is added to the conventional non-reciprocal circuit element of one ferrite, the resonance frequency of the non-reciprocal circuit element is lowered. That is, in order to obtain the same resonance frequency as that of a single ferrite, it is necessary to reduce the capacitance value of the capacitor. When the size of the second ferrite 10 is the same as that of a single ferrite (2 mm × 2 mm), the resonance frequency of the nonreciprocal circuit element is low when the second ferrite 10 is enlarged. Conversely, when the size of the ferrite is reduced, the resonance frequency is increased. In either case, it can be seen that the second ferrite 10 contributes to the Faraday rotation action of the nonreciprocal circuit element. For this reason, even if the second ferrite 10 has the same size, the resonance frequency changes when the saturation magnetization of the ferrite is changed. The garnet yoke described in Patent Document 3 does not act directly on the circulator operation, but acts as a yoke of the magnetic circuit. 2 is different from the ferrite 10 of FIG.

  Next, experimental data comparing the characteristics of the nonreciprocal circuit device according to the example with the characteristics of the conventional nonreciprocal circuit device will be shown. 8 shows reflection characteristics on the input terminal side, FIG. 9 shows reflection characteristics on the output terminal side, FIG. 10 shows insertion loss characteristics, and FIG. 11 shows isolation characteristics. 8 to 10, characteristics L11, L21, L31, and L41 are characteristics of a conventional non-reciprocal circuit element using a single ferrite (comparative example), and characteristics L12, L22, L32, and L42 are related to the present invention. The characteristic of the said Example of a nonreciprocal circuit element is each shown. The conventional non-reciprocal circuit element used for the experiment is different from the non-reciprocal circuit element according to the example in that it does not have the second ferrite 10.

  As is apparent from FIGS. 8 to 11, the embodiment according to the present invention is a conventional non-reciprocal circuit device as a comparative example in any of reflection characteristics, transmission characteristics, insertion loss characteristics, and isolation characteristics. Better than.

  Although the present invention has been described in detail with reference to the embodiments, the present invention is not limited thereto, and various modifications can be made by those skilled in the art based on the basic technical idea and teachings. It is self-evident that you can think of it.

It is sectional drawing which shows schematically the structure of the nonreciprocal circuit device based on this invention. It is a perspective view which shows an example of the magnetic rotor structure in the nonreciprocal circuit element shown in FIG. FIG. 3 is a circuit diagram of an isolator using the non-reciprocal circuit device shown in FIGS. 1 and 2. It is a disassembled perspective view which shows one Example of the nonreciprocal circuit device based on this invention. FIG. 5 is a perspective view of the non-reciprocal circuit device illustrated in FIG. 4. It is a figure which shows the arrangement | positioning relationship of the magnetic rotor in a case, a capacitor | condenser, and a resistor. It is a perspective view explaining the combination of the 2nd ferrite, a permanent magnet, and a press member. It is a figure which shows the reflection characteristic by the side of the input terminal of the nonreciprocal circuit device based on this invention compared with that of the conventional nonreciprocal circuit device. It is a figure which shows the reflection characteristic by the side of the output terminal of the nonreciprocal circuit device based on this invention compared with that of the conventional nonreciprocal circuit device. It is a figure which shows the insertion loss characteristic of the nonreciprocal circuit device based on this invention compared with that of the conventional nonreciprocal circuit device. It is a figure which shows the isolation characteristic of the nonreciprocal circuit device based on this invention compared with that of the conventional nonreciprocal circuit device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Case member 6 Magnetic rotor 60 Soft magnetic base | substrate 64, 65, 66 1st-3rd center conductor 641, 651, 661 Terminal part G Ground part

Claims (8)

A non-reciprocal circuit device including a plurality of center conductors, a first ferrite, and a second ferrite,
In the first ferrite and the second ferrite, one of the principal surfaces faces each other with the central conductor interposed therebetween,
The first ferrite has the other main surface shielded by a conductor plate,
The plurality of central conductors, one side is electrically connected to the conductor plate,
The second ferrite is a non-reciprocal circuit device in which the other main surface is a non-shield surface. The non-reciprocal circuit device according to claim 1,
The second ferrite is a non-reciprocal circuit device having a thickness smaller than that of the first ferrite.   3. The nonreciprocal circuit device according to claim 1 or 2, wherein the first ferrite and the second ferrite are made of the same material.   4. The nonreciprocal circuit device according to claim 1, wherein the first ferrite and the second ferrite are made of different materials.   5. The nonreciprocal circuit device according to claim 1, further comprising a pressing member, wherein the second ferrite is fitted in a cavity provided in the pressing member. element.   6. The nonreciprocal circuit device according to claim 1, further comprising a permanent magnet, wherein the permanent magnet is in contact with the non-shield main surface of the second ferrite.   6. The nonreciprocal circuit device according to claim 1, further comprising a permanent magnet, wherein the permanent magnet is fixed to the nonshield main surface of the second ferrite. .   The nonreciprocal circuit device according to claim 6 or 7, wherein the permanent magnet is fixed to the pressing member.

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