JP4639540B2 - Non-reciprocal circuit device and communication device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a non-reciprocal circuit device and a communication device.
[0002]
[Prior art]
In general, a lumped constant isolator employed in a mobile communication device such as a mobile phone has a function of allowing a signal to pass only in the transmission direction and preventing transmission in the reverse direction. Such a lumped constant type isolator includes a center electrode assembly composed of a permanent magnet and ferrite and a plurality of center electrodes arranged on the ferrite, a metal case for housing the center electrode assembly and the permanent magnet, and the like. . In order to improve the electrical performance of this isolator, a permanent magnet having a size that sufficiently covers ferrite has been used.
[0003]
However, it is considered that the permanent magnets are made smaller with the recent reduction in size and height of communication devices. In recent years, the frequency of communication devices has been increased. In a nonreciprocal circuit element, when it is intended to operate at a high frequency, a high magnetic force must be applied accordingly. However, if the permanent magnet is made small for size reduction and low profile, it becomes difficult to obtain the strength of the magnetic field necessary to operate at a desired frequency. In addition, the magnetic field distribution applied to the ferrite also deteriorates, and as a result, characteristics (such as insertion loss) deteriorate. Furthermore, in the case of a structure in which the side surfaces 209b and 210b on both sides of the permanent magnets 209 and 210 are in contact with the metal case 205 as in the isolator 200 described in Japanese Patent Laid-Open No. 6-260812 shown in FIG. Magnetic field lines coming out from portions (edge portions) of the magnetic pole surfaces 209 a and 210 a of the magnets 209 and 210 that are close to the metal case 205 are not applied to the ferrite 220 and leak to the metal case 205. This is because the metal case 205 has a higher magnetic permeability than air. Thereby, the magnetic field distribution applied to the ferrite becomes worse. In FIG. 10, reference numeral 221 denotes a wiring board provided with a plurality of center electrodes on the surface, 212 denotes a ground plate, and C denotes a matching capacitor element.
[0004]
Therefore, in the nonreciprocal circuit device such as an isolator, as shown in FIG. 11, a structure in which gaps t1 are equally provided between the inner surface 235a of the metal case 235 and the side surfaces 239b and 240b of the permanent magnets 239 and 240, respectively. Has been proposed. At this time, the center positions of the magnetic pole surfaces 239a and 240a of the permanent magnets 239 and 240 and the center position of the center electrode assembly 250 are arranged on a substantially straight line L.
[0005]
Further, the center electrode assembly 250 is disposed at the center position between the permanent magnet 239 and the permanent magnet 240. The distances from the center position of the center electrode assembly 250 to the magnetic pole faces 239a and 240a of the permanent magnets 239 and 240 are distances d, respectively.
[0006]
In the isolator 231 configured as described above, the magnetic lines of force that emerge from the edges of the magnetic pole faces 239a and 240a of the permanent magnets 239 and 240 do not leak to the metal case 235, and the DC magnetic field can be efficiently applied to the center electrode assembly 250. it can.
[0007]
[Problems to be solved by the invention]
However, in the conventional isolator 231, the center positions of the permanent magnets 239 and 240 and the center position of the center electrode assembly 250 are arranged on a substantially straight line L. Therefore, the side surfaces 239 b and 240 b of the permanent magnets 239 and 240 and the metal case 235 are arranged. The gap t1 between the inner side surface 235a and the inner side surface 235a must be equidistant.
[0008]
On the other hand, miniaturization of the isolator 231 itself is progressing. For example, when the length dimension W1 of the permanent magnets 239 and 240 is 2.0 mm with respect to the inner dimension W2 of the metal case 235 = 2.2 mm, the gap t1 Is only 0.1 mm. For this reason, when the isolator 231 is actually assembled, it is very difficult to accurately place the permanent magnets 239 and 240 in the metal case 235 by providing the left and right gaps t1 of 0.1 mm. Therefore, the assembling workability of the isolator 231 is poor, and the variation in the arrangement positions of the permanent magnets 239 and 240 is large. In addition, due to this variation, characteristic variation increases, and as a result, there is a problem that the yield rate of products is also reduced.
[0009]
In order to solve this problem, it is conceivable to position the permanent magnet with a resin mold or the like as in the isolator described in JP-A-11-308013. However, this method has a problem in that the number of parts constituting the isolator is increased, production takes time, and manufacturing costs are increased.
[0010]
Accordingly, an object of the present invention is to provide a non-reciprocal circuit device and a communication device that have a small number of components, are easy to assemble, and are small and have high performance.
[0011]
[Means and Actions for Solving the Problems]
In order to achieve the above object, a non-reciprocal circuit device according to the present invention comprises:
(A) a first permanent magnet having a magnetic pole surface and a side surface substantially perpendicular to the magnetic pole surface;
(B) a second permanent magnet having a magnetic pole surface and a side surface substantially perpendicular to the magnetic pole surface;
(C) A DC magnetic field is applied between the magnetic pole surface of the first permanent magnet and the magnetic pole surface of the second permanent magnet and formed from the first permanent magnet toward the second permanent magnet. A center electrode assembly comprising a ferrite and a plurality of center electrodes disposed on the ferrite;
(D) A first inner surface and a second inner surface that are parallel to and opposite to the side surfaces of the first and second permanent magnets, and a magnetic pole surface of the first and second permanent magnets and that are opposite to each other. A metal case for housing the first permanent magnet, the second permanent magnet, and the center electrode assembly, and a third inner surface and a fourth inner surface .
(E) The long side lengths of the magnetic pole surfaces of the first and second permanent magnets are smaller than the long side lengths of the third and fourth inner surfaces of the metal case, and the long side length of the ferrite is the first and second permanent magnets. Smaller than the long side length of the magnetic pole surface of the second permanent magnet,
(F) The magnetic pole surface and the side surface of the first permanent magnet are in contact with the third inner surface and the first inner surface of the metal case, and the magnetic pole surface and the side surface of the second permanent magnet are the fourth inner surface of the metal case. And the center position of the center electrode assembly is disposed between the center position of the first permanent magnet and the center position of the second permanent magnet.
It is characterized by.
[0012]
With the above configuration, the first to fourth inner side surfaces of the metal case serve as reference surfaces for arranging the first permanent magnet and the second permanent magnet, and the side surfaces of the first permanent magnet and the second permanent magnet are used as the reference surfaces. The first permanent magnet and the second permanent magnet can be easily and accurately arranged simply by contacting the surface. Further, since the center position of the center electrode assembly is arranged between the center position of the first permanent magnet and the center position of the second permanent magnet, the magnetic field lines of the first and second permanent magnets are most intense. The edge portion approaches the ferrite, and a strong DC magnetic field is applied to the ferrite from the first and second permanent magnets, and the insertion loss characteristic is improved.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of a nonreciprocal circuit device and a communication device according to the present invention will be described below with reference to the accompanying drawings. In each embodiment, the same parts and the same parts are denoted by the same reference numerals, and redundant description is omitted.
[0014]
[First Embodiment, FIGS. 1 to 6]
FIG. 1 is an exploded perspective view showing a configuration of an embodiment of a non-reciprocal circuit device according to the present invention. The nonreciprocal circuit device 1 is a lumped constant isolator.
[0015]
As shown in FIG. 1, the isolator 1 is roughly composed of a metal case 5, an internal electrical component 8, a circuit board 40, and the like. The internal electrical component 8 is generally composed of two permanent magnets 9 and 10, a center electrode assembly 13, matching capacitor elements C 1 to C 4, a resistance element R, and a ground plate 30.
[0016]
The metal case 5 has an upper wall 5a and four side walls 5b. Here, the set of inner side surfaces (inner side surfaces in the long side direction) of the four side walls 5b are 6a and 6b, and the other set of inner side surfaces are 6c and 6d (see FIG. 2). The metal case 5 is formed by punching and bending a metal plate.
[0017]
Each of the two permanent magnets 9 and 10 has a substantially rectangular shape. The permanent magnet 9 has magnetic pole surfaces 9a and 9b and side surfaces 9c and 9d perpendicular to the magnetic pole surface 9a. Similarly, the permanent magnet 10 has magnetic pole surfaces 10a and 10b and side surfaces 10c and 10d perpendicular to the magnetic pole surface 10b.
[0018]
The circuit board 40 is a substantially rectangular board. Three through holes 46 each divided into two are formed on the side surface in the long side direction of the circuit board 40, and one through hole 46 divided into two is formed on the side surface in the short side direction. An earth electrode pattern 45, an input electrode pattern 43, and an output electrode pattern 44 are formed on the upper surface 41 of the circuit board 40. The electrode patterns 43 to 45 extend to the lower surface 42 through through holes 46 formed on the side surface of the circuit board 40.
[0019]
The matching capacitor elements C1 to C4 have connection capacitor electrodes on the upper and lower surfaces.
[0020]
The resistance element R has a rectangular parallelepiped shape, and has connection electrodes on the left and right sides thereof.
The resistance element R is set to have substantially the same thickness as the matching capacitor elements C1 to C4.
[0021]
The ground plate 30 has a rectangular parallelepiped shape. The ground plate 30 is formed of a copper plate or the like and has electrical conductivity. The ground plate 30 is set to have substantially the same thickness as the matching capacitor elements C1 to C4.
[0022]
The center electrode assembly 13 is formed by crossing a substantially rectangular microwave ferrite 20 and two conductors (for example, a copper wire and a silver wire) coated with an insulator so that the crossing angle is approximately 90 degrees. The center electrodes 21 and 22 are wound around the surface of 20.
[0023]
The above components are assembled as follows. The matching capacitor elements C1 to C4, the ground plate 30 and the resistance element R are placed on the circuit board 40 and mounted by a method such as soldering. At this time, the connecting capacitor electrode on the lower surface of the matching capacitor elements C1 and C2 is connected to the ground electrode pattern 45 formed on the upper surface 41 of the circuit board 40, and the connecting capacitor electrode on the lower surface of the matching capacitor element C3 is connected to the upper surface. The connection capacitor electrode on the lower surface of the matching capacitor element C4 is electrically connected to the output electrode pattern 44 formed on the upper surface 41 by a method such as soldering. Connecting.
[0024]
The resistance element R is placed on the non-electrode pattern portion 49 of the circuit board 40. That is, the ground electrode pattern 45 and the resistance element R are in an electrically non-contact state.
[0025]
Next, the center electrode assembly 13 is placed on the matching capacitor elements C1 to C4, the resistance element R, and the ground plate 30, and mounted by a method such as solder bonding. At this time, one end of the center electrode 21 is electrically connected to the connection capacitor electrode on the upper surface of the matching capacitor elements C1 and C3 and one terminal electrode of the resistance element R. One end of the center electrode 22 is electrically connected to the connection capacitor electrode on the upper surface of the matching capacitor elements C2 and C4 and the terminal electrode at the other end of the resistance element R. The other ends of the center electrodes 21 and 22 are electrically connected to the ground plate 30. Accordingly, the center electrode assembly 13 is fixed to the elements C1 to C4, R and the ground plate 30.
[0026]
Next, as shown in FIG. 2, the two permanent magnets 9 and 10 are stuck in the metal case 5, and the metal case 5 is put on the circuit board 40. At this time, the permanent magnets 9 and 10 are arranged unevenly with the inner side surfaces 6a and 6b of the side wall 5b of the metal case 5 as reference surfaces. That is, the side surface 9 d of the permanent magnet 9 is in contact with the inner surface 6 a of the side wall 5 b of the metal case 5, and the side surface 10 c of the permanent magnet 10 is in contact with the inner surface 6 b of the side wall 5 b of the metal case 5. The magnetic pole surfaces 9b and 10a of the permanent magnets 9 and 10 are in contact with the inner side surfaces 6c and 6d, respectively. Here, for example, the inner dimension W2 of the metal case 5 is 2.2 mm, and the length dimension W1 of the permanent magnets 9 and 10 is 2.0 mm.
[0027]
The ferrite 20 of the center electrode assembly 13 is disposed at the center position between the two permanent magnets 9 and 10 and at the same distance from the inner side surfaces 6 a and 6 b of the metal case 5. Therefore, the center line L1 of the permanent magnet 9, the center line L2 of the permanent magnet 10, and the center line L3 of the ferrite 20 are shifted in parallel to each other. The distances from the center position of the center electrode assembly 13 to the magnetic pole surfaces 9a and 10b of the permanent magnets 9 and 10 are distances d. A DC magnetic field formed from the magnetic pole surface 9 a of the permanent magnet 9 toward the magnetic pole surface 10 b of the permanent magnet 10 is applied to the ferrite 20. Since the thicknesses of the elements C1 to C4 and R and the ground plate 30 are substantially the same, the upper surfaces of the elements C1 to C4 and R and the upper surface of the ground plate 30 are the same plane substantially parallel to the circuit board 40, respectively. Configure. Therefore, the ferrite 20 of the center electrode assembly 13 mounted on the same surface can be disposed substantially perpendicular to the circuit board 40.
[0028]
Further, the metal case 5 and the ground electrode pattern 45 of the circuit board 40 are joined by soldering. Thus, the isolator 1 as shown in FIG. 3 is formed. FIG. 4 is an electrical equivalent circuit diagram of the isolator 1 shown in FIG.
[0029]
The permanent magnets 9 and 10 do not necessarily have to be in contact with the different inner side surfaces 6a and 6b of the metal case 5, respectively. For example, as shown in FIG. It may be in contact with the same inner surface 6a.
[0030]
In the above isolator 1, the inner side surfaces 6 a, 6 b, 6 c, 6 d of the metal case 5 serve as reference surfaces when the permanent magnets 9, 10 are arranged. That is, the inner side surfaces 6a and 6b serve as contact reference surfaces for the side surface 9c (or 9d) of the permanent magnet 9 and the side surface 10c (or 10d) of the permanent magnet 10. Furthermore, the inner side surfaces 6 c and 6 d serve as reference contact surfaces for the magnetic pole surface 9 b of the permanent magnet 9 and the magnetic pole surface 10 a of the permanent magnet 10. Therefore, the permanent magnets 9 and 10 can be easily and accurately arranged in the metal case 5. As a result, since there is no variation in the arrangement positions of the permanent magnets 9 and 10, there is no variation in electrical characteristics, and a high-performance isolator 1 can be obtained.
[0031]
Further, since it is not necessary to position the permanent magnets 9 and 10 with a resin mold or the like as in the conventional isolator, the isolator 1 with a small number of parts and easy assembly can be obtained, and its productivity and yield rate are improved. Can be made.
[0032]
Even if the sizes of the permanent magnets 9 and 10 and the metal case 5 are reduced, the permanent magnets 9 and 10 use the inner side surfaces 6a, 6b, 6c, and 6d of the metal case 5 as reference surfaces for contact. The permanent magnets 9 and 10 can be easily arranged in the metal case 5.
[0033]
Furthermore, the magnetic field distribution in the metal case 5 can be improved by bringing the permanent magnets 9 and 10 into contact with the inner side surfaces 6a and 6b of the metal case 5 and offset from the inner side surfaces 6a and 6b. . That is, the lines of magnetic force are strongest from the edge portions e of the magnetic pole surfaces 9a and 10b of the permanent magnets 9 and 10. By shifting the permanent magnets 9 and 10 toward the inner side surface 6a and the inner side surface 6b, the edge portion e where the magnetic field lines appear most strongly approaches the ferrite 20 as compared with the conventional isolator 231 shown in FIG. As a result, a strong DC magnetic field is applied to the ferrite 20 from the permanent magnets 9 and 10, and the insertion loss characteristic of the isolator 1 can be improved.
[0034]
FIG. 6 is a graph obtained by measuring insertion loss of various isolators 1 (test bodies No1 to No4) in which the arrangement positions of the permanent magnets 9 and 10 are changed. For comparison, the insertion loss of the conventional isolator 231 (test body No. 5) shown in FIG. 11 is also shown. The insertion loss of the isolator 1 of the test bodies No. 1 and No. 2 in which the permanent magnets 9 and 10 are brought into contact with the different inner side surfaces 6a and 6b is about 0.2 dB compared to the insertion loss of the conventional isolator 231 of the test body No. 5. It has been improved. Further, the insertion loss of the isolator 1 of the test bodies No. 3 and 4 in which the permanent magnets 9 and 10 are brought into contact with the same inner side surface 6a (or 6b) is smaller than the insertion loss of the conventional isolator 231 of the test body No. 5. It is improved by 0.1 to 0.15 dB.
[0035]
[Second Embodiment, FIGS. 7 and 8]
As shown in FIG. 7, in the second embodiment, instead of the matching capacitor elements C1 to C4, the resistance element R, and the circuit board 40, LTCC (Low Temperature Combined Ceramic) incorporating these elements C1 to C4 and R is included. The isolator 2 using the multilayer substrate 50 is shown.
[0036]
An earth electrode pattern 45 and connection electrode patterns 51 and 52 are formed on the upper surface of the LTCC multilayer substrate 50. An input external electrode pattern 53, an output external electrode pattern 54, and an earth external electrode pattern 55 each having a through hole 46 divided into two are provided at the edge of the TLCC multilayer substrate 50. The connection electrode patterns 51 and 52 are connected to one end of the center electrodes 21 and 22, and the ground electrode pattern 45 is connected to the other end of the center electrodes 21 and 22.
[0037]
Here, the LTCC multilayer substrate 50 is formed by laminating layers made of a low-temperature sintered material or a low-temperature fired ceramic with an internal conductor film or an internal resistance film interposed therebetween. Furthermore, a via hole is formed in the specific layer, and is electrically connected to the internal conductor film and the internal resistance film inside the LTCC multilayer substrate 50, and from the resistance element R and the matching capacitor elements C1 to C4. An electric circuit is formed.
[0038]
As shown in FIG. 8, in the isolator 2, the center electrode assembly 13 is placed on the multilayer substrate 50. The permanent magnet 9 and the permanent magnet 10 are in contact with and stuck to the inner side surfaces 6a and 6b of the metal case 5 in the same manner as the isolator 1 of FIG. 2 of the first embodiment.
[0039]
The isolator 2 described above has the same operational effects as the first embodiment. Furthermore, since the matching capacitor elements C1 to C4 and the resistance element R are formed in the LTCC multilayer substrate 50, the number of solder joints can be reduced compared to the isolator 1, and the production cost of the isolator 2 is low. Can be.
[0040]
[Third Embodiment, FIG. 9]
In the third embodiment, an embodiment of a communication device will be described using a mobile phone as an example.
[0041]
FIG. 9 is an electric circuit block diagram of the RF portion of the mobile phone 120. In FIG. 9, 122 is an antenna element, 123 is a duplexer, 124 and 126 are transmission side power amplifiers, 125 is a band pass filter for transmission side stages, 127 is a transmission side mixer, 128 is a reception side low noise amplifier, and 129 is reception. The interstage side band pass filter, 130 is a receiving side mixer, 131 is an isolator, 132 is a voltage controlled oscillator (VCO), and 133 is a local band pass filter.
[0042]
Here, as the isolator 131, the isolators 1 and 2 of the first embodiment and the second embodiment can be used. By mounting the isolators 1 and 2, a high-performance mobile phone can be realized at low cost.
[0043]
[Other Embodiments]
The present invention is not limited to the above-described embodiment, and can be changed to various configurations within the scope of the gist of the present invention. For example, the center electrodes 21 and 22 are not limited to conductive wires (cross-sectional shape is substantially circular), but may be metal foils (cross-sectional shape is flat plate). In addition to the rectangular shape, the shape of the center electrode assembly 13 is arbitrary, such as a cylindrical shape or a deformed angular shape. Moreover, the shape of the permanent magnets 9 and 10 is not limited as long as the side surfaces of the permanent magnets can contact the inner surface of the metal case. In addition to the rectangular shape, for example, a rectangular shape with rounded corners, a circular shape, or a deformed angular shape. Also good.
[0044]
In addition to the isolator, the present invention can be applied to various nonreciprocal circuit elements such as a circulator.
[0045]
【The invention's effect】
As apparent from the above description, according to the present invention, the first to fourth inner surface side and the pole face and side surfaces and the pole surface of the second permanent magnet of the first permanent magnets, opposing each metal case Therefore, the first permanent magnet and the second permanent magnet can be easily positioned on the inner surface of the metal case. Therefore, an irreversible circuit element and a communication device that can be easily assembled can be obtained.
[0046]
Further, the side surfaces of the first permanent magnet and the second permanent magnet is brought into contact with the first and second inner surfaces of the metal case, since is arranged offset to the first and second inner surface, a metal case Thus, the insertion loss characteristics of the nonreciprocal circuit element and the communication device can be improved.
[Brief description of the drawings]
FIG. 1 is an exploded perspective view of a first embodiment of a non-reciprocal circuit device according to the present invention.
2 is a schematic plan view showing an arrangement relationship between a metal case of the nonreciprocal circuit device shown in FIG. 1, a permanent magnet, and ferrite. FIG.
3 is a perspective view after the non-reciprocal circuit device shown in FIG. 1 is assembled. FIG.
4 is an electrical equivalent circuit diagram of the non-reciprocal circuit device shown in FIG. 3. FIG.
5 is a schematic plan view showing a positional relationship between a metal case, a permanent magnet, and ferrite, showing a modification of the non-reciprocal circuit device shown in FIG. 1. FIG.
6 is a graph showing the relationship between the non-reciprocal circuit device shown in FIGS. 1, 5 and 11 and insertion loss. FIG.
FIG. 7 is an exploded perspective view of a second embodiment of a non-reciprocal circuit device according to the present invention.
8 is a schematic plan view showing an arrangement relationship between a metal case of the non-reciprocal circuit device shown in FIG. 7, a permanent magnet, and ferrite.
FIG. 9 is a block diagram showing an embodiment of a communication apparatus according to the present invention.
FIG. 10 is a vertical sectional view showing an embodiment of a conventional non-reciprocal circuit device.
FIG. 11 is a schematic plan view showing an arrangement relationship between a metal case of another conventional nonreciprocal circuit device, a permanent magnet, and ferrite.
[Explanation of symbols]
1, 2 ... Isolator (non-reciprocal circuit element)
5 ... Metal case 5b ... Metal case side wall 6a, 6b ... Metal case inner side surface 9, 10 ... Permanent magnet 9a, 9b, 10a, 10b ... Permanent magnet magnetic pole surface 9c, 9d, 10c, 10d ... Permanent magnet side surface 13 ... Center electrode assembly 20 ... Microwave ferrite 21, 22 ... Center electrode 120 ... Mobile phone (communication device)

Claims (2)

A first permanent magnet having a magnetic pole surface and a side surface substantially perpendicular to the magnetic pole surface;
A second permanent magnet having a magnetic pole surface and a side surface substantially perpendicular to the magnetic pole surface;
A ferrite disposed between a magnetic pole surface of the first permanent magnet and a magnetic pole surface of the second permanent magnet, to which a DC magnetic field formed from the first permanent magnet toward the second permanent magnet is applied; A center electrode assembly composed of a plurality of center electrodes disposed on the ferrite;
A first inner surface and a second inner surface that are parallel to the side surfaces of the first and second permanent magnets and that face each other, and a third inner surface that is parallel to the magnetic pole surface of the first and second permanent magnets and face each other. A metal case having an inner side surface and a fourth inner side surface, and housing the first permanent magnet, the second permanent magnet, and the center electrode assembly;
The long side lengths of the magnetic pole surfaces of the first and second permanent magnets are smaller than the long side lengths of the third and fourth inner surfaces of the metal case, and the long side length of the ferrite is the first and second permanent magnets. Smaller than the long side length of the magnetic pole face of the magnet,
The magnetic pole surface and side surface of the first permanent magnet are in contact with the third inner surface and first inner surface of the metal case, and the magnetic pole surface and side surface of the second permanent magnet are the fourth inner surface and second surface of the metal case. contact with the inner surface, the center position of the center electrode assembly is arranged between the center position and the center position of the second permanent magnet of the first permanent magnet,
A nonreciprocal circuit device characterized by the above. A communication apparatus comprising the nonreciprocal circuit device according to claim 1 .

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