JP4066349B2 - 3-winding non-reciprocal element - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a circulator / isolator that is a non-reciprocal element for high frequency, and more particularly to the field of a three-terminal pair non-reciprocal element having a small insertion loss and a wide band characteristic.
[0002]
[Prior art]
As a technical state of an isolator that is a current high-frequency nonreciprocal element, one terminal of a three-terminal-pair circulator is generally terminated with a matching impedance. This junction type circulator is classified into two types, that is, a distributed constant type circulator and a lumped constant type circulator. The circulator has an irreversible electrical characteristic, and its structure is based on a structure in which a magnetic field is applied perpendicularly to the ferrite thin plate and a conductor is close to the periphery of the ferrite thin plate. The former distributed constant type is selectively used when the size of the isolator element is ¼ or more of the wavelength of the high frequency transmitted through the ferrite thin plate being handled, and the latter lumped constant type is used when the size is １ ／ or less. The lumped constant type is more suitable for miniaturization.
[0003]
FIG. 17 shows a schematic structure and a schematic circuit when an isolator is realized by connecting a matching impedance (resistive element R) to one terminal pair of a three-terminal pair lumped constant circulator currently used in a mobile phone or the like.
The ferrite thin plate G is made of garnet-type ferrite, and three central conductors L1, L2, and L3 are arranged on the upper surface at an angular interval of 120 degrees as shown in FIG. One end of each center conductor is an input / output terminal of the terminal pair (1), (2), and (3), and the other end is connected to a common part GR that becomes the ground conductor GND. Matching capacitors C1, C2, and C3 are connected in parallel between one end of each of the central conductors L1, L2, and L3 and the common portion GR. In order to realize an isolator, a resistance element R for absorbing energy is attached between the terminal pair (3) and the common part GR. A permanent magnet is loaded so that a static magnetic field substantially perpendicular to the main surface of the ferrite thin plate G is applied, but it is omitted in the drawing. By carefully adjusting the direction and strength of the static magnetic field, and the sizes of the center conductors L1, L2, and L3 and the matching capacitors C1, C2, and C3, the structure of FIG. 17 has a desired frequency (hereinafter referred to as the center frequency). The fo operates as a circulator, and the high frequency input from the terminal pair {circle around (1)} is transmitted to the terminal pair {circle around (2)}, and the high frequency input from the terminal pair {circle around (2)} is transmitted to the terminal pair {circle around (3)} with little loss. When the resistance element R is connected to the terminal pair {circle around (3)}, energy is absorbed there, and almost no high frequency propagates from the terminal pair {circle over (2)} to the terminal pair {circle around (1)}. That is, it is possible to realize an isolator which is an element that helps high-frequency propagation in only one direction and blocks it in the opposite direction (for example, Patent Document 1).
[0004]
[Patent Document 1]
JP-A-10-13109 [0005]
[Problems to be solved by the invention]
The prior art structure of FIG. 17 is symmetrical and has the advantage of being easy to make, but has the disadvantage that the insertion loss is not very small and the bandwidth is narrow. The present invention has been made in view of the above-described state of the art, and an object thereof is to provide a three-winding non-reciprocal element having a small insertion loss and a wide bandwidth.
[0006]
[Method for solving the problem]
In the present invention, the first central conductor, the second central conductor, and the third central conductor are arranged close to the ferrite thin plate so as to intersect with each other in an insulated state, and the static magnetic field is applied to the ferrite thin plate by a permanent magnet, end input and output terminals of the first central conductor, Ri other end of the first central conductor Do and another input terminal, one end of the second central conductor is connected to one end of the first central conductor, a third center One end of the conductor is connected to the other end of the first center conductor, the other ends of the second center conductor and the third center conductor are connected to the common portion, and a capacitance element between one end and the other end of the first center conductor And a resistance element are connected in parallel .
In the present invention, the angle formed by the second center conductor and the third center conductor is preferably in the range of 0 to 60 degrees. An inductance element may be connected to one end of the second central conductor and one end of the third central conductor. The central portion of at least one of the first, second, and third central conductors may be divided into three or more conductors.
Moreover, this invention is a 3 winding type nonreciprocal element by which the common part which the said 2nd center conductor and the said 3rd center conductor connect is connected to the ground conductor.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the accompanying drawings.
FIG. 1 shows an assembly diagram of a central conductor and a ferrite thin plate, which is one embodiment showing the principle of the present invention. On the disk-shaped ferrite thin plate G, the first, second, and third central conductors L1, L2, and L3 are arranged so as to intersect while maintaining an electrically insulating state. The difference from the prior art is that one end of the first central conductor L1 is an input terminal (1) and the other end is an output terminal (2). The second center conductor and the third center conductor are placed on the first center conductor so as to intersect at an angle of 120 degrees. That is, the common part GR of the second center conductor L2 and the common part GR of the third center conductor L3 are arranged at positions facing the first center conductor L1. Naturally, one end of the second and third central conductors L2 and L3 is also at a position facing the first central conductor L1. By adopting such a configuration, the bandwidth of insertion loss has been dramatically improved. In addition, although the said electrical insulation state is not described in the figure, it is adhesive such as fluorine resin such as tetrafluoroethylene resin, fluorinated ethylene propylene copolymer resin, perfluoroethylene propene copolymer resin, perfluoroalkoxy resin, or polyimide. This is achieved by inserting a conductive tape between each central conductor. It can also be realized by applying an insulating coating such as a resist on the surface of the central conductor. The definition of the intersection angle φ of the second and third center conductors L2 and L3 will be described later. According to the definition, the intersection angle φ in this case is 60 degrees.
[0008]
FIG. 2 is a circuit diagram realized as an isolator by connecting accessory parts to the central conductor and ferrite thin plate assembly of FIG. 1 which is an embodiment of the present invention. The ferrite thin plate is applied with a static magnetic field by a permanent magnet, which is not shown in the drawing. Both ends of the first central conductor L1 are input / output terminals (1) and (2), respectively. A third impedance element Z3 is connected between the input / output terminals (1) and (2), and second and third terminals are connected between the input / output terminals (1) and (2) and the common part GR. The matching impedance elements Z10 and Z20 are respectively attached. The common part GR is connected to the ground conductor GND through the impedance element Zn. A first impedance element Z1 is connected between one end of the second central conductor L2 and the input / output terminal (1). Similarly, the second impedance element Z2 is connected between one end of the third central conductor L3 and the input / output terminal (2). This is the basic structure of the present invention. Although not shown in the drawing, for symmetry, Z1 is connected between one end of the second central conductor L2 and the input / output terminal (2), and one end of the second central conductor L3 and the input / output terminal (1). Even if Z2 is connected between ▼, the structure is basically the same.
[0009]
FIG. 3 shows an assembly drawing of a central conductor and a ferrite thin plate, which is another embodiment illustrating the principle of the present invention. The difference from the embodiment of FIG. 1 is that the second and third center conductors L2 and L3 are placed on the first center conductor so as to intersect at an angle of 60 degrees. A feature of this configuration is that the common portion GR of the second and third center conductors L2 and L3 is arranged on the same side (lower side in the drawing) with respect to the first center conductor L1. Naturally, the ends of the second and third center conductors L2 and L3 are also located on the opposite side (the upper side in the figure). With this configuration, the common portion GR of the second and third center conductors L2 and L3 can be easily connected to the ground conductor GND and the like.
Here, an intersection angle φ between the second and third central conductors L2 and L3 is defined. The crossing angle φ is a crossing angle in a region on the same one side (upper side or lower side in the drawing) with respect to the first central conductor L1. It does not relate to the direction of the common part and one end of the central conductor. Accordingly, in the device disclosed in FIGS. 1 and 2, the intersecting angle φ of the second and third center conductors L2 and L3 is both 60 degrees.
[0010]
FIG. 4 is a circuit diagram realized as an isolator by connecting accessory parts to the central conductor and ferrite thin plate assembly of FIG. 3 which is an embodiment of the present invention. Both ends of the first central conductor L1 are input / output terminals (1) and (2), respectively. A third impedance element Z3 is connected between the input / output terminals (1) and (2), and second and third terminals are connected between the input / output terminals (1) and (2) and the common part GR. The matching impedance elements Z10 and Z20 are respectively attached. The common part GR is connected to the ground conductor GND through the impedance element Zn. A first impedance element Z1 is connected between one end of the second central conductor L2 and the input / output terminal (1). Similarly, the second impedance element Z2 is connected between one end of the third central conductor L3 and the input / output terminal (2). A fourth impedance element Z4 is connected between one end of the second center conductor L2 and one end of the third center conductor L3. This is another basic structure of the present invention. Although not clearly shown in the drawing, due to symmetry, Z1 is connected between the second central conductor L2 and the input / output terminal (2), and between the third central conductor L3 and the input / output terminal (1). Even when Z2 is connected, the structure is basically the same.
[0011]
FIG. 5 shows a specific example of the circuit of FIG. 2 which is one of the embodiments of the present invention. The capacitance element C1 and the resistance element R are used as the third impedance element Z3, and the matching capacitors C2 and C3 are set as Z10 and Z20. This is a case where the short-circuit element S is used as the impedance element Zn, and the short-circuit element S is used as the first impedance element Z1 and the second impedance element Z2 that contribute to irreversibility. In the present embodiment, the fourth impedance element Z4 is not connected.
[0012]
FIG. 6 shows another specific example of the circuit of FIG. 4, which is another embodiment of the present invention. The third impedance element Z3 includes a capacitance element C1 and a resistance element R, and Z10 and Z20 include matching capacitors C2 and C3. The short-circuit element S is used as the impedance element Zn, the short-circuit element S is used as the first impedance element Z1 contributing to irreversibility, the resistance element R1 is used as the second impedance element Z2, and the inductance element L is used as the fourth impedance element Z4. Is the case.
[0013]
FIG. 7 is a circuit diagram of another embodiment to which FIG. 1 of the principle of the present invention is applied. Considering analogy with the prior art circuit, the matching capacitors C2 and C3 are directly connected in parallel to the second and third center conductors L2 and L3.
[0014]
FIG. 8 is a circuit diagram of another embodiment to which FIG. 3 of the principle of the present invention is applied. Considering analogy with the prior art circuit, the matching capacitors C2 and C3 are directly connected in parallel to the second and third center conductors L2 and L3.
[0015]
Here, the principle of the present invention will be briefly described by comparing the circuit diagram of FIG. 17 of the prior art with the circuit diagram of FIG. 5 of the present invention. In the case of high frequency propagation from the input terminal {circle over (1)} to the output terminal {circle around (2)}, focusing on the insertion loss, in the prior art, as shown in FIG. 17, the transformer coupling between the first center conductor L1 and the second center conductor L2 Achieved. That is, the high frequency is transmitted via two parallel resonant circuits formed by two central conductors. On the other hand, in the case of the present invention, the first center conductor L1 directly serves as an input and output terminal, and energy can be transmitted with a wide band and low loss by adjusting the impedance elements Z10 and Z20. That is. However, irreversibility cannot be realized as it is. The second and third center conductors L2 and L3 contribute to the realization of the irreversibility. A connection method for providing this function is extremely important. In the present invention, one end of the second and third central conductors is connected to one end and the other end of the first central conductor via the impedance elements Z1 and Z2, respectively, and one end of the second and third central conductors is connected to the common portion. It was found that irreversibility can be realized by connecting the third impedance element Z3 to both ends of the first central conductor. Thus, from the viewpoint of insertion loss, the circuit of the present invention has one resonance circuit, that is, the first central conductor, as compared with the prior art in which energy cannot be transmitted without loss of two resonance circuits. It is only necessary to consider the conductor loss of L1, and the possibility of halving the insertion loss compared to the prior art has been found. This is the main point of the present invention.
[0016]
9A and 9B show another embodiment of the present invention. The first central conductor L1 serving as an input / output terminal has a large size and the number of the first central conductors L1 is as large as three, and the second and third central conductors L2 and L3 for realizing irreversibility are narrow and only one. It is a feature. By adopting such a configuration, the insertion loss can be reduced and the bandwidth can be remarkably widened. 9A is an arrangement example corresponding to the embodiment shown in FIG. 1 of the present invention, and FIG. 9B is an arrangement example corresponding to the embodiment shown in FIG. In this embodiment, the intersection angle φ is both 60 degrees.
[0017]
FIG. 10 shows a further embodiment of the present invention, and shows a case where a rectangular shape is used as the ferrite thin plate. By adopting such a configuration, the space factor and assemblability inside the small isolator can be greatly improved.
FIG. 10 shows a case where the intersection angle φ of the second and third central conductors L2 and L3 is 100 degrees. As described above, the characteristics as an isolator could be realized even when the angle increased, but the characteristics were inferior to those disclosed in FIG.
On the other hand, FIG. 11 shows an example in which the intersection angle φ of the second and third center conductors is 10 degrees, and in this case, good isolator characteristics can be realized. For this reason, the preferred crossing angle φ is set to 60 degrees or less.
[0018]
FIG. 12A shows a case where the second and third central conductors L2 and L3 are crossed at the central portion of the first central conductor L1, and then taken out in parallel with the crossing angle φ = 0 degrees. . FIG. 12B shows a case where the second and third central conductors L2 and L3 are not crossed and taken out in parallel at an intersection angle φ = 0 degrees. In both cases, good isolator characteristics were achieved. These embodiments belong to the central conductor structure of FIG. 3 which is the principle structure of the present invention.
[0019]
FIGS. 13 (a) and 13 (b) show the second and third center conductors in the arrangement belonging to the center conductor structure of FIG. 1, which is another principle structure of the present invention, as a method of taking out parallel to the outside of FIG. The case where the common part GR of L2 and L3 is located in the part of the side which a rectangular ferrite thin plate opposes is shown. In this case, it corresponds to the intersection angle φ = 0 degrees.
[0020]
Further, FIGS. 14A, 14B and 14C show another embodiment of the present invention. The case where arrangement | positioning of the 2nd and 3rd center conductors L2 and L3 is not symmetrical with respect to arrangement | positioning of the 1st center conductor L1 is shown. (A) shows a special case in which one of the second or third central conductors L2 and L3 is orthogonal to the first central conductor L1. (B) shows a case where only the third central conductor L3 is bent. (C) shows a case where the second and third center conductors L2 and L3 are parallel but not perpendicular to the first center conductor L1. It is clear that both of these are within the scope of the effect of the present invention.
[0021]
FIGS. 15 (a) and 15 (b) show the results of electrical characteristics of an experiment conducted using a 6 mmφ garnet. The prior art is indicated by a dotted line, and the result of the technique of the present invention is indicated by a solid line. The frequency is in the 650 MHz band. (A) shows the frequency characteristic of the reflection loss and insertion loss of the input terminal, and (b) shows the frequency characteristic of the reverse characteristic and the reflection loss characteristic of the output terminal. In particular, a significant change appeared in the insertion loss characteristics. It has been found that using the technique of the present invention improves the insertion loss peak value by about 0.02 dB to 0.1 dB. The bandwidth is also extremely wide as shown in the figure. When compared with the 20 dB relative bandwidth of the reflection loss of the input terminal, it was 4% in the prior art, but 10% or more in the technique of the present invention. This appeared to result in a significantly wider bandwidth for insertion loss. This also confirmed that the effect of the present invention was industrially significant.
[0022]
【The invention's effect】
As described in detail above with reference to the embodiments, the isolator which is a three-winding non-reciprocal element of the present invention has a small insertion loss and a wide bandwidth, and is suitable as a small isolator for a mobile phone.
[Brief description of the drawings]
FIG. 1 is an assembly diagram of a center conductor and a ferrite thin plate according to the technique of the present invention. FIG. 2 is an equivalent circuit of an isolator based on a three-winding non-reciprocal element according to the technique of the present invention. FIG. 4 is an equivalent circuit of an isolator based on a three-winding non-reciprocal element according to the present invention. FIG. 5 is an equivalent circuit of an isolator based on a three-winding non-reciprocal element according to the present invention. 6 is an equivalent circuit of an isolator based on a three-winding non-reciprocal element according to the technique of the present invention. FIG. 7 is an equivalent circuit of an isolator based on a three-winding non-reciprocal element according to the technique of the present invention. Fig. 9 is an equivalent circuit of an isolator based on a three-winding non-reciprocal element according to the technique of Fig. 9. Fig. 9 is an assembly diagram of a center conductor and a ferrite thin plate according to the technique of the present invention. Assembling diagram of ferrite thin plate [FIG. 11] Assembling diagram of central conductor and ferrite thin plate according to the technology of the present invention [FIG. 12] Assembling diagram of central conductor and ferrite thin plate according to the technology of the present invention [FIG. FIG. 14 is an assembly diagram of a central conductor and a ferrite thin plate according to the technique of the present invention. FIG. 15 is a characteristic comparison diagram of an isolator according to the present invention and an isolator according to the conventional technique. Assembly drawing of center conductor and ferrite thin plate [Fig. 17] Equivalent circuit of isolator based on prior art 3-winding nonreciprocal element [Explanation of symbols]
L1, L2, L3 First, second and third center conductors G Ferrite thin plate GR Common part GND Ground conductors C1, C2, C3 Capacitance element L Inductance element R Resistance element S Short-circuit element (1), (2) Input / Output Terminals Z1, Z2, Z3, Z4, Zn Impedance elements Z10, Z20 Second and third matching impedance elements φ Crossing angle of second and third central conductors

Claims (5)

The first center conductor, the second center conductor, and the third center conductor are arranged close to the ferrite thin plate so as to intersect with each other in an insulated state, and the ferrite thin plate is applied with a static magnetic field by a permanent magnet. end input and output terminals of Ri other end of the first central conductor Do and another input terminal, one end of the second central conductor is connected to one end of the first central conductor, one end of the third center conductor The other end of the first center conductor is connected, the other ends of the second center conductor and the third center conductor are connected to the common portion, and a capacitance element and a resistance element are provided between one end and the other end of the first center conductor. Are connected in parallel . A three-winding nonreciprocal element. 2. The three-winding nonreciprocal device according to claim 1 , wherein an angle formed by the second center conductor and the third center conductor is in a range of 0 degrees to 60 degrees . The three-winding nonreciprocal element according to claim 1 or 2 , wherein an inductance element is connected to one end of the second central conductor and one end of the third central conductor . The center portion of at least one of the first, second, and third center conductors is divided into three or more conductors, 3. Winding type nonreciprocal element. The three-winding nonreciprocal element according to any one of claims 1 to 4 , wherein a common portion where the second central conductor and the third central conductor are connected is connected to a ground conductor .

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