JP2607675Y2 - 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 a non-reciprocal circuit device, and more particularly, to a non-reciprocal circuit device used as a high-frequency component in a microwave band, for example, an isolator and a circulator.

[0002]

2. Description of the Related Art Generally, non-reciprocal circuit devices such as isolators and circulators have a function of hardly attenuating in a signal transmission direction and increasing in a reverse direction. Mobile phones used in
It is used in a transmission circuit of a mobile communication device such as a car phone. The non-reciprocal circuit device used in this mobile communication device is required to be small and light in terms of its application.
Lumped constant type, which can reduce the weight, is widely used. As such a lumped constant type circulator, a microstrip line type non-reciprocal circuit device and a strip line type non-reciprocal circuit device have been conventionally known.

FIGS. 7A and 7B are views showing an example of the configuration of a conventional microstrip line type circulator. In particular, FIG. 7A is an external perspective view of a ferrite assembly in a circulator. , FIG. 7 (b)
7 shows a cross-sectional view of the ferrite assembly shown in FIG. In this figure, this conventional circulator has a ground plate 20 in contact with the lower surface of one ferrite plate 1 and three center electrodes 21 to 21 on the upper surface of the ferrite plate 1.
23 are arranged in an electrically insulated state with an insulating sheet 3 interposed therebetween and intersected at every 120 ° angular interval, and a DC magnetic field is applied to the intersection. One end of each of the center electrodes 21 to 23 is connected to the matching circuit 4.
The input / output ports 51 to 53 are connected to the input / output ports 51 to 53 through 1 to 43, and the other ends are connected to the ground plate 20.

FIGS. 8 (a) and 8 (b) are views showing an example of the configuration of a conventional circulator of a strip line type. In particular, FIG. 8 (a) is an external perspective view of a ferrite assembly in a circulator. FIG. 8B shows FIG.
FIG. 2 shows a cross-sectional view of the ferrite assembly shown in FIG.
In this figure, this conventional circulator has a pair of ferrite plates 1a, 1b at the intersection of three center electrodes 21 to 23.
1b, and the ferrite plates 1a,
1b, the ground plates 20a and 20b are in contact with the outer surface.

Next, the operation of the circulator shown in FIGS. 7 and 8 will be described. When a high-frequency signal is input to the input / output port 51, a high-frequency magnetic field generated around the center electrode 21 rotates by a predetermined angle due to the DC magnetic field, and is inductively coupled via the ferrite plate 1 (or the ferrite plates 1a and 1b). As a result, an induced current is generated in the center electrode 22 on the left side (left side when viewed from the center of the ferrite plate). Therefore, the high-frequency signal input from the input / output port 51 is transmitted to the input / output port 52 on the left and not transmitted to the input / output port 53 on the right. Similarly, the high-frequency signal input from the input / output port 52 is transmitted to the input / output port 53 on the left side and not transmitted to the input / output port 51 on the right side. Further, the high-frequency signal input from the input / output port 53 is transmitted to the input / output port 51 on the left and not transmitted to the input / output port 52 on the right.

In the circulator shown in FIG. 7 or FIG. 8, a terminating resistor R is connected to a matching circuit (for example, matching circuit 43) instead of one of the input / output ports (for example, input / output port 53). For example, the circulator shown in FIG. 7 or 8 can be used as an isolator. In this case, the isolator transmits a high-frequency signal only in one direction from the remaining one input / output port (for example, input / output port 51) to the other input / output port (for example, input / output port 52).

[0007]

[Problems to be Solved by the Invention] Meanwhile, mobile communication devices used in the UHF band, such as mobile phones and car phones, are being developed to achieve further miniaturization.
Along with this, there is a growing demand for smaller and lighter isolators and circulators. In order to meet such a demand, it is effective to make the diameter of the ferrite plate as small as possible, for example. However, in each conventional non-reciprocal circuit device having the above-described structure, when the diameter of the ferrite plate is reduced, it is difficult to secure a required value of the inductance of the center electrode, and as a result, the electrical characteristics deteriorate. There was a point. That is, in the lumped constant type non-reciprocal circuit device, the frequency is not adversely affected even if the diameter of the ferrite plate is reduced,
In order to obtain the necessary electrical characteristics, the inductance value of the center electrode must be set large from the conditions of the matching circuit. This inductance value is determined by the length of the center electrode, and the length of the center electrode is determined by the diameter value of the ferrite plate. Therefore, the smaller the diameter of the ferrite plate, the shorter the effective length of the center electrode, and accordingly the smaller the inductance value. Here, as a method of increasing the inductance value, it is conceivable to narrow the width of the center electrode. However, in such a method, another problem is that the Q of the center electrode decreases and the insertion loss of the nonreciprocal circuit element increases. Cause problems. Therefore, at present, it is difficult to reduce the diameter of the ferrite plate, which is a factor that hinders miniaturization of mobile communication devices.

Therefore, an object of the present invention is to provide a small and lightweight non-reciprocal circuit device capable of reducing the diameter of a ferrite plate without deteriorating electrical characteristics.

Another object of the present invention is to provide a non-reciprocal circuit device in which the winding operation of the center electrode is easy and the productivity is good.

[0010]

According to the present invention, there is provided a non-reciprocal circuit device having an extremely small attenuation in a signal transmission direction and an extremely large attenuation in a reverse direction.
Each major surface and a ferrite plate having a side surface, and arranged to intersect at a and predetermined angular intervals while maintaining the electric insulation state from each other in the first and second major surfaces on the ferrite plate 1 Two strip-shaped leads
A plurality of center electrodes made of a body, each center electrode being wound so as to be in close contact with a first main surface, a second main surface, and a side surface of the ferrite plate; The laminated structure of each of the center electrodes on the main surface and the laminated structure of each of the center electrodes on the second main surface of the ferrite plate are symmetrical to each other.

[0011]

In the present invention, the effective length of the center electrode is made longer by winding the band-shaped center electrode around the ferrite plate as compared with the conventional structure in which the center electrode is arranged only on one side of the ferrite plate. ing. Therefore, the diameter of the ferrite plate can be reduced while sufficiently securing the inductance value of the center electrode.

Further, in the present invention, since the band-shaped center electrode is used, the ratio of the surface area to the cross-sectional area of the center electrode is increased. Therefore, the non-reciprocal circuit device of the present invention is
For example, when using in a high frequency band of 250 MHz or more,
The degree of the decrease in the effective area due to the so-called skin effect is small, and the increase in the transmission loss due to the increase in the effective resistance can be reduced. Also, in the present invention, the use of the band-shaped center electrode reduces the height of the intersection, so that the entire component can be reduced in size and weight and the electrical characteristics can be prevented from deteriorating. When a conductor having a small surface area with respect to the cross-sectional area is used as the center electrode,
Even if the diameter of the center electrode is increased to reduce the resistance value, the high-frequency current is concentrated on the surface of the center electrode due to the skin effect described above, so that only the portion where the high-frequency current does not flow increases, thus reducing transmission loss. The effect is low. Also, in this case, the intersection of the center electrodes rises and rises,
The size of the entire component is increased, and the distance between the intersection and the case is reduced, so that the electromagnetic field characteristics are deteriorated. further,
Since the distance between the ferrite plate and the center electrode is greatly different for each center electrode, imbalance of the electric characteristics occurs between the center electrodes, and as a result, the symmetry of the electric characteristics between the input / output ports is reduced. Be impaired.

Further, in the present invention, the first ferrite plate is used.
Since the laminated structure of each center electrode on the main surface of the ferrite plate and the laminated structure of each center electrode on the second main surface of the ferrite plate have symmetry with each other, the winding operation of the center electrode around the ferrite plate is performed. Can be facilitated. That is, according to such a laminated structure, since each center electrode can be sequentially wound around the ferrite plate, the winding operation by a machine can be automated, and the productivity can be improved.

[0014]

FIG. 1, FIG. 2, FIG. 3 and FIG. 4 are views showing the structure of an isolator according to an embodiment of the present invention. In particular, FIG. 1 is an exploded perspective view of a ferrite assembly, and FIG. Is a perspective view of the appearance of the completed ferrite assembly shown in FIG.
FIG. 3 is a schematic diagram of a laminated structure of each center electrode wound around a ferrite plate, and FIG. 4 is an exploded perspective view of the entire configuration of the isolator. Hereinafter, the configuration of the isolator according to an embodiment of the present invention will be described with reference to FIGS.

As shown in FIG. 1, in the isolator of this embodiment, winding type center electrodes 201 to 203 are used. Each of the winding-type center electrodes 201 to 203 is configured by bending a strip-shaped conductor at a central portion. First, the center electrode 201 is wound around the ferrite plate 1. Then, the insulating sheet 30 is attached from the upper surface of the ferrite plate 1, and the insulating sheet 31 is attached from the lower surface of the ferrite plate 1. Next, the center electrode 202
The ferrite plate 1 is wound around the center electrode 201 at an interval of 120 °. Then, the insulating sheet 30 is attached from the upper surface of the ferrite plate 1, and the insulating sheet 31 is attached from the lower surface of the ferrite plate 1. Next, the center electrode 203 is the center electrode 201 and the center electrodes 202 and 12.
It is wound around the ferrite plate 1 with an interval of 0 °.
Then, an insulating sheet 30 is attached from the upper surface of the ferrite plate 1, and the insulating sheet 31 is attached from the lower surface of the ferrite plate 1.
Can be pasted. The lower surface of each insulating sheet 30 (the surface facing the upper surface of the ferrite plate 1) and the upper surface of each insulating sheet 31 (the surface facing the lower surface of the ferrite plate 1)
Have tackiness or adhesiveness, respectively. Therefore, each of the center electrodes 201 to 203 is insulated from each other by the insulating sheets 30 and 31, and is securely fixed and held to the ferrite plate 1.

As shown in FIG. 2, the ferrite assembly manufactured as described above has the center electrodes 201-203.
Are on the upper and lower surfaces of the ferrite plate 1, for example, 1
The configuration is such that they intersect at an angle interval of 20 °. Further, as shown in FIG. 3, each of the center electrodes 20 on the upper surface of the ferrite plate 1
The laminated structure of Nos. 1 to 203 and the laminated structure of the center electrodes 201 to 203 on the lower surface of the ferrite plate 1 are configured to have symmetry with each other. That is, the distance from the upper surface of the ferrite plate 1 to each of the center electrodes 201 to 203 is different from the lower surface of the ferrite plate 1 to each of the center electrodes 2 to 203.
It is almost equal to the distance from 01 to 203. The isolator of the present embodiment having such a laminated structure is manufactured by winding the center electrodes 201 to 203 around the ferrite plate 1 in order as described above. for that reason,
The winding operation of the center electrodes 201 to 203 is easy, and the number of winding steps can be reduced. Therefore, the center electrode 20
It is possible to automate the winding operation of Nos. 1 to 203 by a machine, and it is excellent in productivity.

As shown in FIG. 6, the ferrite plate 1
It is conceivable that the center electrodes are arranged in the order of the center electrodes 201, 202, and 203 on the upper surface of the ferrite plate 1, and the center electrodes are arranged in the order of the center electrodes 203, 202, and 201 on the lower surface of the ferrite plate 1. However, in this case, after each center electrode crosses the upper surface (or lower surface) of the ferrite plate 1, the lower surface (or upper surface) of the ferrite plate 1
The winding operation must be performed so that the center electrodes cross each other. Therefore, an extremely complicated winding operation is required, and the number of winding steps is increased. As a result, it is difficult to automate the winding operation, and the productivity decreases.

As shown in FIG. 2, one end of the center electrode 201 is connected to the input / output port 51 via a matching circuit constituted by a capacitor C1. Also, the center electrode 202
Is connected to the input / output port 52 via a matching circuit formed by the capacitor C2. One end of the center electrode 203 is connected to a terminating resistor R via a matching circuit formed by a capacitor C3. The other ends of the center electrodes 201 to 203 are grounded. The isolator thus configured transmits a high-frequency signal only in one direction from the input / output port 51 to the input / output port 52.

In the isolator shown in FIG.
By removing the terminating resistor R and connecting the input / output port to one end of the center electrode 203, the isolator shown in FIG. 2 can be used as a circulator as shown in FIG. 7 or FIG.

Next, referring to FIG. 4, a resin substrate 7 is mounted on lower yoke 6 made of a conductor. Various electrodes are formed on the upper and lower surfaces of the resin substrate 7 by, for example, molding. First, a ground electrode 7 a is formed on the lower surface of the resin substrate 7. On the other hand, on the upper surface of the resin substrate 7, ground electrodes 7b to 7h and input / output electrodes 7i to 7k are formed. Ground electrodes 7b to 7f
Respectively penetrate the resin substrate 7 and form a ground electrode 7a on the lower surface.
Is connected to The ground electrodes 7g and 7h are
The side surface of the resin substrate 7 is connected to the ground electrode 7a on the upper surface. The ground electrodes 7a to 7h are preferably formed by bending a single metal plate. The input / output electrodes 7i and 7j are bent along the side surface of the resin substrate 7,
Input / output ports 51 and 52 are formed on side surfaces of the resin substrate 7 respectively. Note that a through hole 70 is formed in the center of the resin substrate 7.

The ferrite assembly 10 shown in FIG. 2 is placed at the center of the surface of the resin substrate 7 and fixed by soldering or the like. At this time, one ends of the center electrodes 201 to 203 are in contact with the input / output electrodes 7i to 7k, respectively. The other ends of the center electrodes 201 to 203 are in contact with the ground electrodes 7b to 7d, respectively. The ferrite plate 1
In the central part of the lower surface of the device, a projecting portion is formed when the center electrodes 201 to 203 cross each other.
0, no gap is formed between the upper surface of the resin substrate 7 and the ferrite assembly 10. This prevents the ferrite assembly 10 from rattling on the resin substrate 7.

Next, chip capacitors C1 to C3 forming a matching circuit and a chip resistor R as a terminating resistor are fixed to the upper surface of the resin substrate 7 by soldering or the like. The chip capacitor C1 has one electrode in contact with the ground electrode 7e and the other electrode in contact with the input / output electrode 7i.
The chip capacitor C2 has one electrode in contact with the ground electrode 7f and the other electrode in contact with the input / output electrode 7j. The chip capacitor C3 has one electrode in contact with the ground electrode 7g and the other electrode in contact with the input / output electrode 7k. The chip resistor R has one end in contact with the ground electrode 7h and the other end in contact with the input / output electrode 7k.

Next, an upper yoke 8 made of a conductor is put on the lower yoke 6. Note that a magnet 9 is fixed to the back surface of the upper yoke 8. The magnet 9 is for applying a DC magnetic field to the ferrite assembly 10.

In the above embodiment, only one surface of the insulating sheet is made to have adhesiveness. However, both surfaces of the insulating sheet may be made to have adhesiveness or adhesiveness.
In this case, the insulating sheet attached on the uppermost center electrode 203 can be omitted.

As shown in FIG. 5, the center electrodes 201 to 203 are prepared by bending a band-shaped metal plate into a substantially U-shape.
203 may be mounted on the ferrite plate 1 in order.

In the above embodiment, a non-reciprocal circuit device having a structure in which three center electrodes are attached to the ferrite plate 1 at an angle of 120 ° is shown, but the present invention is not limited to this. Is not done, ferrite plate 1
However, the present invention can also be applied to a non-reciprocal circuit device in which two or four or more center electrodes are attached at predetermined angular intervals.

[0027]

According to the present invention, the band-shaped center electrode is wound around the ferrite plate, so that the effective length of the center electrode is smaller than that of the conventional structure in which the center electrode is arranged only on one side of the ferrite plate. As a result, the diameter of the ferrite plate can be reduced while sufficiently securing the inductance value of the center electrode.

Further, according to the present invention, since the band-shaped center electrode is used, the ratio of the surface area to the cross-sectional area of the center electrode can be increased. Therefore, when the non-reciprocal circuit device of the present invention is used in a high-frequency band of, for example, 250 MHz or more, the degree of reduction in the effective cross-sectional area due to the so-called skin effect can be small, and the increase in transmission loss due to an increase in effective resistance can be reduced. . In addition, since the height of the intersection of the center electrodes is reduced, the whole component can be reduced in size and weight, and the deterioration of the electrical characteristics can be prevented.

Further, according to the present invention, the laminated structure of each center electrode on the first main surface of the ferrite plate and the laminated structure of each center electrode on the second main surface of the ferrite plate are symmetric with each other. Therefore, the work of winding the center electrode on the ferrite plate can be facilitated. That is, if such a laminated structure is adopted,
Since each center electrode may be wound around the ferrite plate in order, the winding operation by a machine can be automated and productivity can be improved.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing a configuration of a ferrite assembly in an isolator according to an embodiment of the present invention.

FIG. 2 is an external perspective view showing a configuration of a completed state of the ferrite assembly shown in FIG.

FIG. 3 is a diagram schematically showing a laminated structure of respective center electrodes in the ferrite assembly shown in FIG.

FIG. 4 is an exploded perspective view showing an overall configuration of an isolator using the ferrite assembly shown in FIG.

FIG. 5 is an exploded perspective view showing a configuration of a ferrite assembly in an isolator according to another embodiment of the present invention.

FIG. 6 is a schematic diagram showing a configuration of a ferrite assembly having a laminated structure of a center electrode different from the present invention.

FIG. 7 is a diagram showing an example of a configuration of a conventional microstrip line type circulator.

FIG. 8 is a diagram showing an example of the configuration of a conventional stripline type circulator.

[Explanation of symbols]

 1: Ferrite plate 6: Lower yoke 7: Resin substrate 8: Upper yoke 9: Magnet 10: Ferrite assembly 201 to 203: Center electrode 30, 31: Insulating sheet 51 to 53: Input / output port C1 to C3: Matching circuit Constituting capacitor R: Terminating resistor

Continued on the front page (72) Inventor Takashi Kawanami 2-26-10 Tenjin, Nagaokakyo-shi, Kyoto Inside Murata Manufacturing Co., Ltd. (72) Katsuyuki Ohira 2-26-10 Tenjin, Nagaokakyo-shi, Kyoto Murata Co., Ltd. In-house colleague Judge Kesaihiko Takei Judge Haruki Yamamoto Judge Judge Naoyuki Yazu (56) References JP-A-58-85609 (JP, A)

Claims (1)

(57) [Scope of request for utility model registration] 1. A non-reciprocal circuit device having an extremely small attenuation in a signal transmission direction and an extremely large attenuation in a reverse direction, comprising: a ferrite having a first main surface, a second main surface, and a side surface. plates, and are disposed so as to intersect at a and predetermined angular intervals while maintaining the electric insulation state from each other in the first and second major surfaces on the ferrite plate it
A plurality of center electrodes each formed of a band-shaped conductor , and each of the center electrodes is wound so as to be in close contact with a first main surface, a second main surface, and a side surface of the ferrite plate; The laminated structure of each of the center electrodes on the first main surface of the ferrite plate and the laminated structure of each of the center electrodes on the second main surface of the ferrite plate have symmetry with each other. Irreversible circuit element.