JPH0580009U - Non-reciprocal circuit element - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a non-reciprocal circuit device that can be made compact and lightweight without deteriorating the electrical characteristics, and that is easy to wind the center electrode and has excellent productivity. It is to be. [Structure] The ferrite plate 1 has a strip-shaped center electrode 201.
Up to 203 are wound in an insulated state from each other and at a predetermined angular interval. Here, the laminated structure of the center electrodes 201 to 203 on the upper surface of the ferrite plate 1,
Each of the center electrodes 201 to 20 on the lower surface of the ferrite plate 1
The laminated structure of 3 has symmetry with each other. That is, the center electrodes 201 to 203 are sequentially arranged in the ferrite plate 1.
Such a laminated structure can be obtained by winding.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a non-reciprocal circuit device, and more particularly to a non-reciprocal circuit device, such as an isolator or a circulator, which is adopted as a microwave band high frequency component.

[0002]

[Prior Art]

 In general, non-reciprocal circuit elements such as isolators and circulators have the function of causing little attenuation in the signal transmission direction and increasing attenuation in the opposite direction, and are used in the UHF band, for example. It is used in the transmission circuit of mobile communication devices such as mobile phones and car phones. The non-reciprocal circuit element used in this mobile communication device is required to be small and lightweight for its application. Therefore, at present, it is possible to make the non-reciprocal circuit element smaller and lighter than the distributed constant type. The constant type is widely used. As such a lumped constant type circulator, a microstrip line type non-reciprocal circuit element and a strip line type non-reciprocal circuit element have been conventionally known.

FIGS. 7A and 7B are views showing an example of the structure of a conventional microstrip line type circulator. In particular, FIG. 7A shows the appearance of a ferrite assembly in the circulator. FIG. 7B is a perspective view, and FIG. 7B is a cross-sectional view of the ferrite assembly shown in FIG. 7A. In the figure, this conventional circulator is configured such that a ground plate 20 is brought into contact with the lower surface of one ferrite plate 1 and three center electrodes 21 to 23 are electrically connected to the upper surface of the ferrite plate 1 with an insulating sheet 3 interposed therebetween. They are arranged in an electrically insulating state and intersect at an angle interval of 120 °, and a DC magnetic field is applied to the intersecting portions. Further, one ends of the center electrodes 21 to 23 are connected to the input / output ports 51 to 53 via the matching circuits 41 to 43, respectively, and the other ends thereof are connected to the ground plate 20.

FIG. 8A and FIG. 8B are views showing an example of the configuration of a conventional stripline type circulator, and in particular, FIG. 8A is an external perspective view of a ferrite assembly in the circulator. 8 (b) is a sectional view of the ferrite assembly shown in FIG. 8 (a). In this figure, the conventional circulator has a pair of ferrite plates 1a and 1b abutting on the intersections of the three center electrodes 21 to 23, and the ground plates 20a and 1b on the outer surfaces of the ferrite plates 1a and 1b. 20b is abutted.

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, the high-frequency magnetic field generated around the center electrode 21 is rotated by a predetermined angle by the DC magnetic field, and passes through the ferrite plate 1 (or the ferrite plates 1a and 1b). Due to the inductive coupling, an induced current is generated in the center electrode 22 on the left side (on the 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 side and is not transmitted to the input / output port 53 on the right side. 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 is 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 side and is not transmitted to the input / output port 52 on the right side.

In the circulator shown in FIG. 7 or FIG. 8, a terminating resistor R may be connected to a matching circuit (eg, matching circuit 43) instead of any one input / output port (eg, 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 the high frequency signal only in one direction from the other one input / output port (for example, the input / output port 51) to the other other input / output port (for example, the input / output port 52).

[0007]

[Problems to be solved by the device]

 Meanwhile, mobile communication devices used in the UHF band, such as mobile phones and car phones, are under development to further reduce their size. As a result, isolators and circulators are becoming smaller and lighter. Requests are getting stronger. In order to meet these requirements, it is effective to make the diameter of the ferrite plate as small as possible. However, in each conventional non-reciprocal circuit device having the above-mentioned structure, it is difficult to secure the required value of the inductance of the center electrode when the diameter of the ferrite plate is reduced, and as a result, the electrical characteristics deteriorate. There was a problem. That is, in the lumped-constant type nonreciprocal circuit element, the frequency does not adversely affect even if the diameter of the ferrite plate is reduced. Must be set large. 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 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, but such a method decreases Q of the center electrode and increases the insertion loss of the nonreciprocal circuit device. Cause problems. Therefore, it is currently difficult to reduce the diameter of ferrite plates, which is a factor that hinders the miniaturization of mobile communication devices.

[0008] Therefore, an object of the present invention is to provide a non-reciprocal circuit device which can reduce the diameter of a ferrite plate without deteriorating the electrical characteristics and which is small and lightweight.

Another object of the present invention is to provide a non-reciprocal circuit device which facilitates the winding work of the center electrode and has good productivity.

[0010]

[Means for Solving the Problems]

 The present invention is a non-reciprocal circuit device having extremely small attenuation in the signal transmission direction and extremely large attenuation in the opposite direction, and a direct current from the first main surface toward the second main surface. A ferrite plate to which a magnetic field is applied, and a ferrite plate that is wound so as to be orthogonal to the direction of the DC magnetic field, and maintains a predetermined electrical insulation on the first and second main surfaces of the ferrite plate. A plurality of strip-shaped center electrodes arranged so as to intersect each other at an angular interval are provided, and a laminated structure of each center electrode on the first main surface of the ferrite plate and each of the center electrodes on the second main surface of the ferrite plate are provided. It is characterized in that the laminated structure of the center electrode has symmetry with each other.

[0011]

[Action]

 In the present invention, by winding the strip-shaped center electrode around the ferrite plate, the effective length of the center electrode is made longer than that of the conventional structure in which the center electrode is arranged on only one side of the ferrite plate. There is. Therefore, it is possible to reduce the diameter of the ferrite plate while ensuring a sufficient inductance value of the center electrode.

Further, in the present invention, since the strip-shaped center electrode is used, the ratio of the surface area to the cross-sectional area of the center electrode becomes large. Therefore, when the nonreciprocal circuit device of the present invention is used in a high frequency band of 250 MHz or more, for example, the degree of reduction in the effective area due to the so-called skin effect is small, and the increase in transmission loss due to the increase in effective resistance can be reduced. .. Further, in the present invention, since the height of the intersecting portion is reduced by using the strip-shaped center electrode, it is possible to reduce the size and weight of the entire component and prevent deterioration of the electrical characteristics. When a wire with a circular cross-section, that is, a conductor with a small surface area to 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 effect due to the skin effect Since the current concentrates on the surface of the center electrode, only the portion where high-frequency current does not flow increases, and the effect of reducing transmission loss is low. Further, in this case, since the intersection of the center electrodes rises and becomes high, the size of the entire component increases, and the distance between the intersection and the case becomes small, resulting in deterioration of electromagnetic field characteristics. Furthermore, since the distance between the ferrite plate and the center electrode differs greatly for each center electrode, an imbalance in the electrical characteristics occurs between the center electrodes, and as a result, the symmetry of the electrical characteristics between each input / output port is generated. Sex is impaired.

Further, in the present invention, the laminated structure of the center electrodes on the first main surface of the ferrite plate and the laminated structure of the center electrodes on the second main surface of the ferrite plate are symmetrical to each other. Since it has the property, the work of winding the center electrode around the ferrite plate 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 work by the machine can be automated and the productivity can be improved.

[0014]

【Example】

 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. Fig. 3 is an external perspective view of the completed ferrite assembly shown in Fig. 3, Fig. 3 is a schematic view of the laminated structure of the center electrodes wound on the ferrite plate, and Fig. 4 is an exploded perspective view of the entire structure of the isolator. .. The configuration of the isolator according to the embodiment of the present invention will be described below with reference to FIGS.

As shown in FIG. 1, the isolator of this embodiment uses winding type center electrodes 201 to 203. Each of these winding-type center electrodes 201 to 203 is formed by bending a strip-shaped conductor at the center. 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 is wound around the ferrite plate 1 with a distance of 120 ° from the center electrode 201. 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 wound around the ferrite plate 1 with the center electrode 201 and the center electrode 202 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. 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 stickiness or adhesiveness. There is. Therefore, the center electrodes 201 to 203 are insulated from each other by the insulating sheets 30 and 31, and are securely fixed and held to the ferrite plate 1.

In the ferrite assembly manufactured as described above, as shown in FIG. 2, the center electrodes 201 to 203 are arranged such that they intersect with each other on the upper surface and the lower surface of the ferrite plate 1 at an angular interval of 120 °, for example. It is arranged. As shown in FIG. 3, the ferrite assembly has a laminated structure of the center electrodes 201 to 203 on the upper surface of the ferrite plate 1 and a laminated structure of the center electrodes 201 to 203 on the lower surface of the ferrite plate 1. Are symmetric with respect to 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 substantially equal to the distance from the lower surface of the ferrite plate 1 to each of the center electrodes 201 to 203. As described above, the isolator of this embodiment having such a laminated structure is manufactured by sequentially winding the center electrodes 201 to 203 around the ferrite plate 1. Therefore, the winding work of the center electrodes 201 to 203 is easy, and the number of winding steps is small. Therefore, the winding work of the center electrodes 201 to 203 can be automated by a machine, and the productivity is excellent.

As shown in FIG. 6, the center electrodes 201, 202, 203 are arranged in this order on the upper surface of the ferrite plate 1, and the center electrodes 203, 202, 201 are arranged on the lower surface of the ferrite plate 1. It is also possible to arrange each center electrode in this order. However, in this case, after the center electrodes are crossed on the upper surface (or the lower surface) of the ferrite plate 1, the winding work is performed so that the center electrodes are crossed on the lower surface (or the upper surface) of the ferrite plate 1. I have to. Therefore, a very troublesome winding operation is required, and the number of winding processes is increased. As a result, it is difficult to automate the winding work, resulting in reduced productivity.

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

In the isolator shown in FIG. 2, if the terminating resistor R is removed and the input / output port is connected to one end of the center electrode 203, the isolator shown in FIG. 2 is used as a circulator as shown in FIG. 7 or 8. You can also

Next, referring to FIG. 4, a resin substrate 7 is placed on the lower yoke 6 made of a conductor. Various electrodes are formed on the upper surface and the lower surface of the resin substrate 7 by molding, for example. First, the ground electrode 7a is formed on the lower surface of the resin substrate 7. On the other hand, ground electrodes 7b to 7h and input / output electrodes 7i to 7k are formed on the upper surface of the resin substrate 7. The ground electrodes 7b to 7f penetrate the resin substrate 7 and are connected to the ground electrode 7a on the lower surface. The ground electrodes 7g and 7h are connected to the ground electrode 7a on the upper surface of the side surface of the resin substrate 7. 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, and the input / output ports 51 and 52 are formed on the side surface portion of the resin substrate 7, respectively. A through hole 70 is formed in the central portion of the resin substrate 7.

The ferrite assembly 10 shown in FIG. 2 is placed on 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 brought into contact with the input / output electrodes 7i to 7k, respectively. The other ends of the center electrodes 201 to 203 are brought into contact with the ground electrodes 7b to 7d, respectively. At the center of the lower surface of the ferrite plate 1, a protrusion is formed by the intersection of the center electrodes 201 to 203. Since this protrusion is housed inside the through hole 70, No gap is formed between the ferrite assembly 10 and the ferrite assembly 10. This prevents the ferrite assembly 10 from rattling on the resin substrate 7.

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

Next, the upper yoke 8 made of a conductor is put on the lower yoke 6. 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.

Although the insulating sheet is made to have adhesiveness only on one side in the above-mentioned embodiment, both sides 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.

Further, as the center electrodes 201 to 203, as shown in FIG. 5, for example, those formed by bending a strip-shaped metal plate into a substantially U shape are prepared, and the center electrodes 201 to 203 are sequentially formed by ferrite. It may be attached to the plate 1.

Further, the above-mentioned embodiment shows a non-reciprocal circuit device having a structure in which three center electrodes are attached to the ferrite plate 1 at an angular interval of 120 °. However, the present invention is not limited to this, and can be applied to a non-reciprocal circuit device in which two or four or more center electrodes are attached to the ferrite plate 1 at a predetermined angular interval.

[0027]

[Effect of the device]

 According to the present invention, since the strip-shaped center electrode is wound around the ferrite plate, the effective length of the center electrode can be increased as compared with the conventional structure in which the center electrode is arranged on only one side of the ferrite plate. As a result, the diameter of the ferrite plate can be reduced while ensuring a sufficient inductance value of the center electrode.

Further, according to the present invention, since the strip-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 nonreciprocal circuit device of the present invention is used in a high frequency band of, for example, 250 MHz or more, the degree of decrease in the effective cross-sectional area due to the so-called skin effect is small, and the increase in effective resistance increases the transmission loss. Can be reduced. Also, since the height of the intersection of the center electrodes is reduced, the entire component can be made smaller and lighter, and the deterioration of electrical characteristics can be prevented.

Further, according to the present invention, the laminated structure of the center electrodes on the first main surface of the ferrite plate and the laminated structure of the center electrodes on the second main surface of the ferrite plate are symmetrical to each other. Since it is configured to have, it is possible to facilitate the work of winding the center electrode around the ferrite plate. That is, if such a laminated structure is adopted, each center electrode may be wound around the ferrite plate in order, so that the winding work by a machine can be automated and the productivity can be improved.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing a structure 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.

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

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

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

FIG. 6 is a schematic view showing a structure of a ferrite assembly having a center electrode laminated structure different from that of 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 a 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 201-203: Center electrode 30, 31: Insulation sheet 51-53: Input / output ports C1-C3: Matching circuit Constituting capacitor R: Termination resistance

Front page continued (72) Inventor Keiji Okamura 2-10-10 Tenjin Tenjin, Nagaokakyo City, Kyoto Prefecture Murata Manufacturing Co., Ltd. (72) Inventor Katsuyuki Ohira, 26-10 Tenjin, Tenjin, Nagaokakyo, Kyoto Prefecture Murata Manufacturing Co., Ltd.

Claims (1)

[Scope of utility model registration request] 1. A nonreciprocal circuit device having extremely small attenuation in the signal transmission direction and extremely large attenuation in the opposite direction, and a DC magnetic field from the first main surface toward the second main surface. Is applied to the ferrite plate, and the ferrite plate is wound around the ferrite plate so as to be orthogonal to the direction of the direct-current magnetic field. A plurality of strip-shaped center electrodes arranged so as to intersect at an angular interval, and a laminated structure of the respective center electrodes on the first main surface of the ferrite plate, and a second main surface of the ferrite plate A non-reciprocal circuit device, wherein the laminated structure of each of the center electrodes above has symmetry with each other.