JPH08307111A - Irreversible circuit element - Google Patents

Abstract

PURPOSE: To make the size of a device small and to reduce number of rough assembling steps by using a line capacitance formed between strip lines so as to form a frequency adjustment capacitance to an internal side of a magnetic material. CONSTITUTION: Three center electrodes 36a, 37a, 36b, 37b, 36c, 37c are made up of strip lines divided into two and 1st strip lines 36a-36c and 2nd strip lines 37a-37c of each center electrode are arranged on a straight line and each tip connects by connection conductors 40a-40c, 41a-41c. Furthermore, the center electrodes are arranged in crossing at an angle of 120 deg.. Then the 1st strip lines 36a-36c and 2nd strip lines 37a-37c arranged at an angle of 120 deg.' have a duplicate part via magnetic layers 33, 34, and the overlapped parts form a line capacitance. The line capacitance is adjusted by the thickness of the magnetic layers 33, 34 and used for a frequency adjustment capacitance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-reciprocal circuit device used for, for example, a circulator or an isolator, and particularly uses a sintered body obtained by laminating a magnetic material, a center electrode material and a material for a capacitor electrode, and firing the laminated material. The present invention relates to a non-reciprocal circuit device capable of downsizing the device structure and reducing the manufacturing method cost.

The nonreciprocal circuit device of the present invention is mainly used in a frequency band of about 0.5 to 3 GHz.

[0003]

2. Description of the Related Art In recent years, high-frequency circuits such as mobile communication devices have been integrated, and there is a demand for miniaturization, cost reduction and high reliability of non-reciprocal circuit elements used therein.

Examples of this type of non-reciprocal circuit element include, for example, a plurality of center electrodes arranged in an electrically insulated state so as to intersect with each other, and microwaves above and below the plurality of center electrodes. There is a so-called lumped constant type non-reciprocal circuit element in which a magnetic body is arranged and a DC field is applied by a permanent magnet to a portion where a plurality of center electrodes intersect with each other. Examples include type circulators and isolators.

FIG. 5 is a perspective view for explaining an example of a conventional process for assembling a nonreciprocal circuit device for microwaves. In the microwave nonreciprocal circuit device, first, a disk-shaped microwave magnetic body 12a and a center electrode 10a made of a metal foil, for example, a Cu foil are arranged. The center electrode 12a is
It is formed in a shape that extends in the radial direction through the center of the upper surface of the microwave magnetic body 12a and further reaches the side surface of the microwave magnetic body 12a.

Next, an insulating film 11a made of an insulating material is arranged on the center electrode 10a, and the center electrode 10a is formed thereon.
Another center electrode 10b is arranged so as to intersect with. Further, the insulating film 11b, the central electrode 10c, and the insulating film 11c are sequentially arranged on the center electrode 10b, and the microwave magnetic body 12b is arranged from above.

As a result, a non-reciprocal circuit device is formed. Further, FIG. 6 is an exploded perspective view showing the structure of a non-reciprocal circuit device such as a circulator or an isolator using the non-reciprocal circuit element formed as described above.
This nonreciprocal circuit device is constructed by assembling a nonreciprocal circuit element, a substrate 21, a ground plate 16 and the like between an upper magnetic yoke 18 holding a permanent magnet 17 and a lower magnetic yoke 19.

The substrate 21 is formed by molding an insulating material such as alumina into a rectangular shape, and has a through hole 21a for accommodating the nonreciprocal circuit device in the center. Also,
The center electrodes 10a to 10 of the nonreciprocal circuit device are provided on the upper surface.
capacitance extraction electrodes 14, 14, 14 respectively connected to c
Are formed. Further, a ground electrode (15) is formed on the back surface of the substrate 21 so as to face the capacitance extracting electrode 14 formed on the front surface.

Further, the ground plate 16 is formed with a through hole 16a for inserting a non-reciprocal circuit device in the center thereof.
Each of the center electrodes 10a to 10a faces the through hole 16a.
Projecting pieces 16b, 16b, 16b are formed at positions corresponding to c. The ground plate 16 is arranged on the back surface side of the substrate 21, and the protruding piece 16b is arranged on the substrate 21 in the assembled state.
Through the through hole 21a, protruding upward, and the front surface of the ground plate 16 and the ground electrode (15) formed on the back surface of the substrate 21 are connected by soldering or the like.

FIG. 7 shows a sectional structure of a main part of the nonreciprocal circuit device assembled as described above. FIG. 7 shows the structure of the main part centering on one center electrode 10c. One end of the center electrode 10c is connected to the capacitance extracting electrode 1
4 is connected. The other end is connected to the protruding piece 16b of the ground plate 16.

Here, the capacitance extracting electrode 14, the ground electrode 15 formed on the back surface of the substrate 21, and the portion of the substrate 21 interposed between the two electrodes form a capacitance for impedance matching. Then, as described above, the capacitance extracting electrode 14 and one end of the center electrode 10c are joined by soldering to connect the center electrode and the impedance matching capacitance. Such a structure is similarly configured in each of the pair of center electrodes 10a to 10c.

Again, as shown in FIG. 6, the center electrode 10a
A DC magnetic field is applied from the permanent magnet 17 held by the upper magnetic yoke 18 to the magnetic body 12 on which the ˜10 c are formed.

[0013]

As described above, in the conventional microwave nonreciprocal circuit device, the impedance matching capacitance portion is formed by utilizing the plane area of the substrate in which the nonreciprocal circuit element is inserted. There is. For this reason, there is a problem in that the capacitance portion is formed around the center electrode, which increases the planar size of the non-reciprocal circuit device, or becomes a factor that hinders the miniaturization of the device.

In addition, many assembling steps by hand, such as assembling a plurality of center electrodes and connecting the center electrodes to the capacity extracting electrode or the ground electrode, are required.
For this reason, as the length of the element is reduced to about several millimeters by promoting miniaturization or general-purpose use of the non-reciprocal circuit device, assembly defects such as misalignment between the center electrode and the matching circuit capacitor increase. However, the problems of reduced reliability and increased production costs have arisen.

It is an object of the present invention to provide a non-reciprocal circuit device which can reduce the size of the device and can reduce the manufacturing cost and the reliability by reducing the number of parts assembling steps. .

[0016]

A non-reciprocal circuit device according to the present invention is provided with a plurality of center electrodes which are electrically insulated from each other and arranged so as to cross each other, and a plurality of frequencies connected to the center electrodes. It has an adjusting capacitor and a magnetic body in which a plurality of center electrodes are embedded, and is configured so that a DC magnetic field is applied to the intersection of the center electrodes. Then, each of the center electrodes is divided into two in the microwave transmission direction,
Moreover, the first and second strip lines are formed at different positions in the thickness direction of the magnetic body, and the connection conductors that connect the tip portions of the first and second strip lines to each other. Further, the frequency adjusting capacitance portion is constituted by the intersecting portion of the first and second strip lines extending in the direction intersecting with each other and the magnetic body interposed between the intersecting portions.

[0017]

In the non-reciprocal circuit device according to the present invention, the frequency adjusting capacitance portion has the first and second divided center electrodes.
The first of the strip lines extending in a direction intersecting with each other
And a crossing portion of the second strip line and a magnetic body interposed therebetween. That is, a part of the first and second strip lines is used as a capacitor electrode, and a magnetic body is used as a capacitor dielectric. For this reason, it is not necessary to separately provide the capacitor portion connected to the center electrode around the center electrode, and thus it is possible to reduce the size of the device in which the nonreciprocal circuit element is incorporated. Further, the capacitance of the frequency adjusting capacitance portion can be easily and accurately set by adjusting the thickness of the magnetic body between the first and second strip lines.

Further, the line-to-line capacitance formed between the first and second strip lines forming the center electrode is applied to each center electrode by using the Δ-Y equivalent circuit conversion in the three-phase AC circuit. An equivalent circuit is converted as the connected capacitance.
This functions as a frequency adjustment capacitor.

[0019]

EXAMPLES The present invention will be clarified by explaining examples of the present invention with reference to the drawings.

FIG. 1 is an exploded perspective view of a non-reciprocal circuit device such as a circulator or isolator constructed by using the non-reciprocal circuit device according to the present invention. This non-reciprocal circuit device is configured by incorporating a permanent magnet 2, a non-reciprocal circuit element 3, and an input / output terminal case 4 between an upper magnetic yoke 1 and a lower magnetic yoke 5.

The permanent magnet 2 has a planar shape similar to that of the nonreciprocal circuit element 3, is laminated on the upper surface thereof, and is inserted into the upper magnetic yoke 1. The input / output terminal case 4 is made of an insulating material and has an opening 4a for receiving the nonreciprocal circuit device 3. Also,
On the side surface of the input / output terminal case 4, external lead-out terminals 6a, 6b, 6c connected to the center electrode of the nonreciprocal circuit device 3 are formed.
Are formed.

FIG. 2 is an exploded perspective view showing the structure of the nonreciprocal circuit device 3 according to the embodiment of the present invention. The non-reciprocal circuit element 3 is composed of a sintered body in which a center electrode and the like are embedded inside a magnetic body for microwaves. Here, the structure of the non-reciprocal circuit element 3 will be described by sequentially explaining its manufacturing process. Will be described.

First, a predetermined amount of magnetic powder containing yttrium oxide (Y ₂ O ₃ ) and iron oxide (Fe ₂ O ₃ ) as main components was prepared and calcined at 900 to 1200 ° C. A calcined powder of the body was prepared. Next, this calcined powder was pulverized with an organic solvent and then dispersed in an organic solvent together with a polyvinyl alcohol-based binder to prepare a slurry. Further, this slurry was formed into a magnetic green sheet for microwaves having a uniform thickness of several tens of μm by the doctor blade method and punched into a rectangle of 40 mm × 20 mm, for example.

Next, a predetermined number of the punched microwave magnetic green sheets are stacked to form an upper magnetic layer 31.
Is configured. In addition, a first strip line 3 that forms a part of the center electrode by screen printing with a conductor paste in which palladium or platinum powder and an organic solvent are mixed is formed on another punched microwave magnetic green sheet.
6a to 36c are printed and formed in a pattern such that their open ends are located in the center of the sheet, and a ceramic green sheet for forming the magnetic layer 33 for the center electrode is prepared.

Further, by using another punched microwave magnetic green sheet, the first strip line 3 is formed by printing on the microwave magnetic green sheet.
Connection holes 4 are provided at positions corresponding to the respective tip portions of 6a to 36c.
0a to 40c and 41a to 41c are formed, and a conductor paste is printed in the vicinity of the inside of this connection hole to form the magnetic layer 3 for capacitance.
Prepare a ceramic green sheet for forming No. 4.

Further, the remaining second strip lines 37a to 37c constituting the center electrode are printed with a conductor paste on the surface of another punched microwave magnetic body green sheet to form a center electrode magnetic layer. A ceramic green sheet for forming 35 is prepared.

Further, the strip lines 37a to 37a are formed within the diameter of another punched microwave magnetic green sheet.
37c at the positions corresponding to the respective tip portions of the connection holes 42a-
42c, 43a to 43c were formed, and a ceramic green sheet for forming a lower magnetic layer 32 having a conductive paste printed therein was prepared.

Further, a ground electrode 38 is formed on the front surface or the back surface of the magnetic green sheet forming the lowermost layer of the lower magnetic layer. After stacking the magnetic green sheets for microwaves prepared by the above steps in the order shown in FIG. 2, they are pressed and simultaneously fired at 1200 to 1550 ° C.,
Non-reciprocal circuit element 3 made of a sintered body in which a center electrode is embedded
I got

FIG. 3 is a plan view showing the structure of the center electrode of the nonreciprocal circuit device 3. As shown in FIG. 3, the three center electrodes 36a, 37a, 36b, 37
b, 36c, and 37c are each composed of a strip line divided into two, and the first strip lines 36a to 36c and the second strip lines 37a to 37 of the respective center electrodes.
c are formed so as to be aligned on a straight line, and the respective tip portions are connected by the connection conductors 40a to 40c and 41a to 41c. Further, the respective center electrodes are arranged so as to intersect with each other at an angle of 120 °. Furthermore, FIG.
FIG. 4 is a structural perspective view showing a structure focusing on one center electrode. In addition, for easy understanding, FIG.
One center electrode 36b, 37b is shown as a representative example. As described above, the center electrode is the two strip lines 36b and 37b, and the connecting conductor 40 that makes the two conductive.
b, 41b.

Further, FIG. 4B shows a cutting line X-- in FIG.
It is a cross-section structural diagram which follows X. Referring to FIGS. 3 and 4B, the first strip lines 36a to 36c and the second strip line 37 arranged at an angle of 120 ° to each other.
The a to 37c have portions overlapping with each other with the magnetic layers 33 and 34 interposed therebetween, and these portions form line capacitances C _{1 to} C ₁₂ . The line capacitances C _{1 to} C ₁₂ are the magnetic layers 3
The capacity can be adjusted by the thickness of 3,34. Then, this line-to-line capacitance can be equivalent circuit converted into a capacitor connected to each center electrode by using Δ-Y equivalent circuit conversion in a three-phase AC circuit, and can be used as a frequency adjustment capacitor.

Further, referring again to FIG. 2, the non-reciprocal circuit device 3 having the center electrode and the capacitor section as described above is formed.
The external electrodes 3a to 3d are formed on the side surfaces of the sintered body so that the exposed portions of the respective center electrodes on the side surfaces of the sintered body of the first strip lines 36a to 36c serve as input / output terminals. The external electrodes are formed by baking at 900 to 1200 ° C. using a conductor paste, which is a mixture of metal powder such as Cu, AgPd, and Ag, and glass frit, as an end surface of the sintered body. The external electrode 3b is connected to the ground terminal 44d and further connected to the lower magnetic yoke 5 to short-circuit. The external electrodes 3a, 3d, and 3c are the second strip lines 37, respectively.
a to 37c and are connected to the external output terminals 6a to 6c as input / output terminals, respectively.

As described above, the nonreciprocal circuit device according to the above-mentioned embodiment is integrally formed by embedding the center electrode and the frequency adjusting capacitor in the microwave magnetic body. By doing so, the process of assembling the center electrode part and the frequency adjustment capacitor can be omitted, simplifying the manufacturing process,
Manufacturing cost can be reduced by omitting the number of parts. Further, variations in characteristics due to assembly errors can be reduced, and the reliability of the nonreciprocal circuit device can be improved.

The frequency adjusting capacitance embedded in the magnetic body utilizes the line capacitance generated between the center electrodes, and the capacitance value thereof is the first and second strip lines 3
Since the thickness of the ceramic green sheets 33, 34 forming the magnetic layers interposed between the 6a to 36c and 37a to 37c can be adjusted with high accuracy, the thickness can be adjusted with high accuracy. Therefore, it is possible to extremely reduce the variation in capacitance between the capacitors.

Further, as the magnetic material of the non-reciprocal circuit device, yttrium iron garnet, calcium vanadium garnet, manganese magnesium ferrite, nickel zinc ferrite, lithium ferrite or the like is used. These microwave ferrites have a relatively small dielectric loss, and the frequency adjustment capacitor composed of the line capacitance of the center electrode has a magnetic field higher than the ferromagnetic resonance applied by the permanent magnet, causing a magnetic loss. Less is. Therefore, a matching circuit capacitor having a high charge capacity Q value can be formed.

The method for producing the microwave magnetic green sheet for forming the above magnetic material is not limited to the doctor blade method, and other known methods can be used.
For example, it may be formed by extrusion molding or the like, or may be formed by printing a slurry-like paste composed of magnetic powder and electrode metal powder on a film such as polyester.

Furthermore, the printing method of each center electrode is not limited to the screen printing method, and may be formed by, for example, gravure transfer.

[0037]

As described above, the nonreciprocal circuit device according to the present invention is constructed by using the first and second strip lines formed by dividing the center electrode in the magnetic body and forming them at different positions in the thickness direction, and Since the frequency adjusting capacitance part is formed inside the magnetic body by using the line capacitance formed between the strip lines, it is externally attached to each center electrode in the conventional nonreciprocal circuit device. It is possible to eliminate the need for capacitance, and it is possible to reduce the size of the device using the nonreciprocal circuit device according to the present invention. At the same time, by burying the center electrode and the frequency adjustment capacitance part inside the magnetic body, it is possible to prevent a decrease in reliability due to an assembly error, reduce the number of steps in the assembly process of the device, and reduce the manufacturing cost. Can be planned.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of a non-reciprocal circuit device using a non-reciprocal circuit device according to the present invention.

FIG. 2 is an exploded perspective view showing a structure of a non-reciprocal circuit device according to the present invention.

FIG. 3 is a plan view showing the main structure of the nonreciprocal circuit device shown in FIG.

4 is a structural perspective view of the non-reciprocal circuit device shown in FIG. 2 (a).
And a sectional structure view (b) taken along the line XX in FIG.

FIG. 5 is a perspective view for explaining a conventional process for assembling a non-reciprocal circuit device.

FIG. 6 is an exploded perspective view for explaining an assembling process of a conventional microwave nonreciprocal circuit device.

FIG. 7 is a sectional structural view showing a main part of the nonreciprocal circuit device shown in FIG.

[Explanation of symbols]

 3 ... Non-reciprocal circuit element 31-35 ... Magnetic material layer 36a-36c ... 1st strip line of a center electrode 37a-37c ... 2nd strip line of a center electrode 40a-40c, 41a-41c ... Connection conductor

Claims (1)

[Claims] 1. A plurality of center electrodes which are electrically insulated from each other and arranged so as to intersect with each other, a plurality of frequency adjustment capacitors connected to the center electrodes, and a plurality of the center electrodes embedded therein. A non-reciprocal circuit element having a magnetic body that is configured to apply a DC magnetic field to the crossing portion of the center electrodes, each of the center electrodes being in a microwave transmission direction. A first and a second strip line that are divided into two and are formed at different positions in the thickness direction of the magnetic body; and a connecting conductor that connects the tip ends of the first and the second strip lines. The frequency adjusting capacitance portion is configured by an intersection portion of the first and second strip lines extending in a direction intersecting with each other and the magnetic body interposed between the intersection portions. reversible Road element.