JP4110688B2 - Non-reciprocal circuit device and communication device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a nonreciprocal circuit element used in a high frequency band such as a microwave band, for example, an isolator or a circulator.
[0002]
[Prior art]
This type of nonreciprocal circuit device includes a magnetic assembly 5 as shown in FIG. 7, for example. In the magnetic assembly 5, a common ground portion of the central conductors 51 to 53 is brought into contact with the lower surface of the magnetic body 55, and the three central conductors 51 to 53 are interposed on the upper surface of the magnetic body 55 with an insulating sheet (not shown) interposed therebetween. The ports P1, P2, and P3 corresponding to the tip portions of the center conductors 51 to 53 are formed so as to protrude from the outer periphery of the magnetic body 55. This magnetic body 55 has a rectangular plate shape in order to realize a reduction in size and cost, and one central conductor 53 is arranged in parallel with one side of the magnetic body 55, and the other two central conductors 51. , 52 are arranged so as to be inclined with respect to each side. Each of the central conductors 51 to 53 is composed of two lines.
[0003]
The magnetic assembly 5 is housed in a magnetic yoke that constitutes a magnetic circuit together with a permanent magnet and the like. The matching capacitors are connected to the ports P1 to P3 of the center conductors 51 to 53, and the magnetic assembly 5 is formed by the permanent magnet. A three-port circulator is configured by applying a DC magnetic field to Also, an isolator is configured by connecting a terminating resistor to any one of the ports.
[0004]
[Problems to be solved by the invention]
By the way, normally, the impedance of the input / output section of a circuit in which these nonreciprocal circuit elements are used has a predetermined impedance value (normally 50Ω). However, when a quadrangular magnetic body is used as described above, the magnetic body has a rotationally asymmetric shape in the direction of 120 degrees, and the arrangement relationship between the magnetic body and the central conductor differs for each central conductor, and one side of the magnetic body 55 The impedance at the port P1 of the central conductor 53 parallel to (hereinafter referred to as port impedance) is higher than the port impedances of the other two central conductors 51 and 52. For example, in the conventional non-reciprocal circuit device, when the port impedance of the center conductors 51 and 52 is 50Ω, the port impedance of the center conductor 53 may be 75Ω. That is, the central conductors 51 and 52 are symmetrically arranged in the relationship between the magnetic body and the central conductor, but the central conductor 53 is asymmetrically arranged with the other two central conductors 51 and 52.
[0005]
For this reason, the conventional non-reciprocal circuit device has a problem that the reflection characteristic of the port of the central conductor parallel to one side of the magnetic material is deteriorated.
[0006]
In general, the further the center conductor is away from the magnetic body, the weaker the coupling with the magnetic body and the coupling between the adjacent center conductors, and the port impedance of the center conductor located farthest from the magnetic body becomes the other center. There is a tendency to be higher than the port impedance of the conductor, and even when using a disk-shaped magnetic body, the reflection characteristics of the central conductor located farthest from the magnetic body are higher than those of other central conductors. May deteriorate.
[0007]
Usually, the upper yoke and the lower yoke are joined to form the magnetic yoke. However, since this joining is performed on two of the four sides, the current flowing on the yoke flows in the joining direction of the yoke. This makes it difficult to flow in the direction perpendicular to this. For this reason, the central conductor arranged so as to extend in the joining direction of the yoke is greatly affected by the yoke and the impedance is increased. On the other hand, the central conductor arranged so as to extend in the direction perpendicular to the joining direction does not change the impedance because the influence of the yoke is small. As described above, the port impedance varies depending on the method of joining the magnetic yokes constituting the magnetic circuit.
[0008]
Accordingly, an object of the present invention is to provide a nonreciprocal circuit element that improves the reflection characteristics of the port of the center conductor by increasing the number of lines of a specific center conductor as compared with the other two center conductors, and a communication using the same. It is to provide a machine.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, a nonreciprocal circuit device according to the present invention crosses three central conductors at a predetermined angle with a magnetic body having a rectangular shape in plan view to which a DC magnetic field is applied. In the nonreciprocal circuit device arranged in such a manner, the two central conductors are configured by the same number of lines, one central conductor is configured by more lines than the number of lines of the two central conductors, and more than the two central conductors. A central conductor composed of a large number of lines is arranged in parallel with one side of the magnetic body.
[0010]
According to this configuration, the port impedance of the center conductor with an increased number of lines is lowered, and the reflection characteristics of the port of the center conductor can be improved. Here, the central conductor having the largest port impedance when the three central conductors are all configured with the same number of lines is selected as the central conductor having an increased number of lines. That is, with the above configuration, the port impedance of the three central conductors can be made substantially the same as the impedance of the circuit system by making the port impedance of the central conductor with the increased number of lines closer to the impedance of the circuit system. Therefore, since appropriate impedance matching can be achieved at each port, reflection characteristics at the port of each central conductor can be improved.
[0011]
The present invention works effectively when the shape of the magnetic material is rotationally asymmetric in the direction of approximately 120 degrees, and the shape of the magnetic material is a rectangular shape in plan view from the viewpoint of miniaturization and cost reduction. Is done. In this case, the central conductor arranged in parallel with one side of the magnetic body is composed of more lines than the other central conductors.
[0012]
In addition, the central conductor arranged at the position farthest from the magnetic body is configured with more lines than the other central conductors.
[0013]
In addition, an isolator is configured by connecting a terminating resistor to the port of the central conductor configured with a large number of lines.
[0014]
In addition, a communication device according to the present invention includes a non-reciprocal circuit element having the above characteristics. Thereby, a communication apparatus with good characteristics can be obtained.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
The configuration of the non-reciprocal circuit device according to the first embodiment of the present invention will be described with reference to FIGS.
The nonreciprocal circuit device of this embodiment includes a magnetic assembly 5 in which three central conductors 51, 52, and 53 are arranged on a square plate-like magnetic body 55 having a square shape in plan view as shown in FIG. The center conductors 51, 52, and 53 are formed by punching a metal conductor plate such as copper, and as shown in the development view of FIG. And projecting outward from the ground portion 54.
[0016]
In the magnetic assembly 5, the magnetic body 55 is placed on the common ground portion 54, and the central conductors 51 to 53 are interposed on the upper surface of the magnetic body 55 so as to wrap the magnetic body 55 with an insulating sheet (not shown) interposed therebetween. Are bent and arranged so as to form an angle of approximately 120 degrees. The ports P1 to P3 corresponding to the tip portions of the center conductors 51 to 53 have shapes suitable for connection to other members, and are configured to protrude outward from the outer periphery of the magnetic body 55.
[0017]
The center conductors 51 and 52 are constituted by two lines and are arranged so as to be inclined with respect to each side of the magnetic body 55. The central conductor 53 is composed of three lines and is arranged in parallel with one side of the magnetic body 55. The central conductor 53 is disposed at a position farthest from the magnetic body 55. That is, in the magnetic assembly 5 of the present embodiment, the center conductor 53 arranged in parallel with one side of the magnetic body 55 is configured with more lines than the center conductors of the other two center conductors 51 and 52.
[0018]
An example of a non-reciprocal circuit element configured using the magnetic assembly 5 is shown in FIGS. FIG. 3 is an exploded perspective view showing the overall structure, and FIG. 4 is a plan view with the permanent magnet and the upper yoke removed. This non-reciprocal circuit element is an isolator in which a terminal resistor R is connected to a port P3 of a central conductor 53 constituted by a central conductor 53, that is, three lines, parallel to one side of the magnetic body 55. The direction P2 is the forward direction, and the direction from the port P2 to the port P1 is the reverse direction.
[0019]
In this isolator, a permanent magnet 3 is disposed on the inner surface of a box-shaped upper yoke 2 made of a magnetic metal, and a substantially U-shaped lower yoke 8 also made of a magnetic metal is attached to the upper yoke 2 for magnetic A closed circuit is formed, a terminal case 7 is disposed on the bottom surface 8a in the lower yoke 8, and a magnetic assembly 5, matching capacitors C1 to C3, and a terminating resistor R are disposed in the terminal case 7, and magnetic The assembly 5 is configured by applying a DC magnetic field by a permanent magnet 3.
[0020]
The terminal case 7 is made of an electrically insulating member and has a structure in which a bottom wall 7b is integrally formed with a rectangular frame-shaped side wall 7a. Input / output terminals 71 and 72 and a ground terminal 73 are partially embedded in resin. An insertion hole 7c is formed at a substantially central portion of the bottom wall 7b, and a plurality of recesses are formed at predetermined positions on the peripheral edge of the insertion hole 7c.
[0021]
Matching capacitors C1 to C3 and a terminating resistor R are disposed in a recess formed at the periphery of the insertion hole 7c. A magnetic assembly 5 is inserted into the insertion hole 7c, and a permanent magnet is disposed above the magnetic assembly 5. 3 is disposed.
[0022]
A common ground portion 54 on the lower surface of the magnetic assembly 5 is connected to the bottom surface 8 a of the lower yoke 8. The lower surface electrodes of the matching capacitors C1 to C3 and the electrode on one end side of the termination resistor R are connected to ground terminals 73 and 73, respectively. Ports P1 to P3 of the center conductors 51 to 53 are connected to the upper surface electrodes of the matching capacitors C1 to C3, respectively, and the other end side of the termination resistor R is connected to the port P3.
[0023]
If the port P3 is a third input / output port without connecting the terminal resistor R to the port P3, a circulator is obtained.
[0024]
Next, the effect of the present invention will be described with reference to FIG. FIG. 5 is a diagram showing the reflection characteristics of the embodiment of the port of the central conductor 53 parallel to one side of the magnetic body (configuration of FIG. 1) and the conventional example (configuration of FIG. 7). The dimensions of the magnetic material are all 3.1 mm × 2.7 mm, the thickness is 0.5 mm, and the saturation magnetization is set to 100000 μT. Note that the impedance of the measurement system is 50Ω. In the conventional example, the impedance of the ports P1 and P2 is about 50Ω, the impedance of the port P3 is about 75Ω, the impedance of the ports P1 and P2 of the embodiment is 50Ω, and the impedance of P3 is about 55Ω.
[0025]
As shown in FIG. 5, the reflection characteristics of the embodiment are significantly improved in the required frequency band as compared to the conventional example. For example, the reflection loss at the center frequency is 26.4 dB in the embodiment and 14.0 dB in the conventional example, which is an improvement of about 12.4 dB.
[0026]
As described above, in the present embodiment, the center conductor having the largest port impedance when configured with two lines as in the conventional case, that is, the center conductor 53 arranged in parallel with one side of the magnetic body is formed with three lines. By configuring, the port impedance of the central conductor 53 is lowered, and the reflection characteristic of this port is improved. That is, by increasing the number of lines, the port impedance of the center conductor 53 is lowered so as to be closer to the impedance of the circuit system, so that the values are almost the same as the port impedances of the other center conductors 51 and 52. Thereby, the port impedances of all the central conductors can be set to match the characteristic impedance of the circuit. Therefore, if the magnetic assembly of the above embodiment is used, a non-reciprocal circuit device having good insertion loss and isolation characteristics can be obtained. That is, when the port of the central conductor having a larger number of lines is used as the input / output port, the insertion loss can be improved. Further, when the center conductor port having a larger number of lines is used as the termination port, the isolation characteristic can be improved.
[0027]
In the above embodiment, the central conductors 51 and 52 are described as two lines and the central conductor 53 is configured as three lines. However, the present invention is not limited to this. What is necessary is just to set so that the number of lines of a conductor may become larger than another center conductor. For example, the central conductor 53 may be configured with four or more lines, the central conductors 51 and 52 may be configured with one line, and the central conductor 53 may be configured with two or more lines. The number of lines of the center conductor 53 is set to the number of lines closest to the port impedance of the other two center conductors 51 and 52.
[0028]
Further, the shape of the magnetic body is not limited to that of the above-described embodiment, and the present invention is 1 when a magnetic body that is rotationally asymmetric in the direction of 120 degrees is used and all the central conductors are configured by the same number of lines. This is effective when applied to a non-reciprocal circuit device having a configuration in which one port impedance is higher than the other two impedances.
[0029]
For example, the present invention can be applied to a magnetic material having a rotationally symmetric shape in a 120-degree direction such as a disk or a regular triangle. In this case, when all the center conductors are composed of the same number of lines, the center conductor having the highest port impedance is composed of more lines than the other two center conductors.
[0030]
In the above embodiment, each central conductor made of a metal conductor plate is described as being bent and arranged in a magnetic body. However, the structure of the magnetic body and the central conductor is not limited to this, and the central conductor is a dielectric. Alternatively, it may have a structure in which an electrode film is formed inside or on the surface of a magnetic material.
[0031]
Next, the configuration of the communication device according to the second embodiment of the present invention is shown in FIG. In this communication apparatus, an antenna ANT is connected to an antenna end of a duplexer DPX including a transmission filter TX and a reception filter RX, and an isolator ISO is connected between an input end of the transmission filter TX and a transmission circuit, A reception circuit is connected to the output terminal of the reception filter RX. A transmission signal from the transmission circuit is transmitted from the antenna ANT through the transmission filter TX via the isolator ISO. A reception signal received by the antenna ANT is input to the reception circuit through the reception filter RX.
[0032]
Here, the isolator according to the first embodiment can be used as the isolator ISO. By using the non-reciprocal circuit device with improved reflection characteristics according to the present invention, a communication device having good characteristics can be obtained.
[0033]
【The invention's effect】
As described above, according to the nonreciprocal circuit device according to the present invention, when the three central conductors are configured by the same number of lines, the central conductor having the highest port impedance is more than the number of lines of the other two central conductors. By configuring with a large number of lines, the port impedance of one central conductor can be lowered and the reflection characteristics at this port can be improved. Therefore, according to the present invention, it is possible to obtain a non-reciprocal circuit device having good insertion loss and isolation characteristics.
[0034]
Further, by mounting the non-reciprocal circuit device according to the present invention, a communication device having good characteristics can be obtained.
[Brief description of the drawings]
FIG. 1 is a plan view of a magnetic assembly according to a first embodiment.
FIG. 2 is a development view of a central conductor according to the first embodiment.
FIG. 3 is an exploded perspective view showing the overall structure of the non-reciprocal circuit device according to the first embodiment.
FIG. 4 is a plan view of the nonreciprocal circuit device according to the first embodiment with the permanent magnet and the upper yoke removed.
FIG. 5 is a diagram showing frequency characteristics of reflection loss of the first embodiment and a conventional non-reciprocal circuit device.
FIG. 6 is a block diagram of a communication device according to a third embodiment.
FIG. 7 is a plan view of a conventional magnetic assembly.
[Explanation of symbols]
2 Upper yoke 3 Permanent magnet 5 Magnetic assembly 51-53 Center conductor 54 Grounding part 55 Magnetic body 7 Terminal case 71, 72 Input / output terminal 73 Grounding terminal 8 Lower yoke C1-C3 Matching capacitor R Termination resistor P1-P3 Port

Claims (6)

In a non-reciprocal circuit device in which three central conductors are arranged in a state of being squarely insulated from each other at a predetermined angle on a quadrangular magnetic body to which a DC magnetic field is applied, the same number of lines are provided for the two central conductors. One central conductor is configured with more lines than the two central conductors, and the central conductor configured with more lines than the two central conductors is parallel to one side of the magnetic body. A non-reciprocal circuit device characterized by being arranged . 2. The nonreciprocal circuit device according to claim 1, wherein two central conductors are constituted by two lines, and one central conductor is constituted by three lines. 2. The nonreciprocal circuit device according to claim 1, wherein the two central conductors are constituted by one line, and the one central conductor is constituted by two lines. 4. The nonreciprocal circuit according to claim 1, wherein a center conductor constituted by a larger number of lines than the two center conductors is arranged at a position farthest from the magnetic body. 5. element. 5. The nonreciprocal device according to claim 1, 2, 3, or 4, wherein a termination resistor is connected to a port of the center conductor constituted by a larger number of lines than the two center conductors. Circuit element. A communication apparatus comprising the nonreciprocal circuit device according to claim 1, claim 2, claim 3, claim 4, claim 5, or claim 5.

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