JP3592963B2 - Method of manufacturing directional coupler - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for manufacturing a directional coupler in which a first line and a second line are opposed to each other via an insulating layer and the first line and the second line are coupled.
[0002]
[Prior art]
As a conventional directional coupler, there is a directional coupler in which two lines are formed on the surface of a dielectric substrate and electromagnetically coupled to each other as shown in FIG. The main line 62 and the sub line 63 are formed on the surface of the dielectric substrate 61 by printing a conductive paste in parallel with a distance S2 therebetween by a screen printing method. The main line 62 and the sub-line 63 are configured such that the length N2 of a portion parallel to each other has a length of 1/4 wavelength. Both ends 62 a and 62 b of the main line 62 and both ends 63 a and 63 b of the sub line 63 are respectively drawn to the side surfaces of the dielectric substrate 61. The main line 62 is connected between the input and output terminals, and the sub line 63 is connected between the coupling terminal and the separation terminal.
[0003]
By the way, the directional coupler can take out an output proportional to only the power traveling in one direction from the high-frequency power flowing through the main line, regardless of the power traveling in the opposite direction. Therefore, in a mobile communication device such as a mobile phone, for example, a main line 62 of a directional coupler is inserted between a transmission amplifier 71 and an antenna 72 as shown in FIG. One end of the sub-line 63 of the directional coupler is connected to an automatic gain control circuit 73, and the output of the transmission power amplifier 71 is adjusted by the automatic gain control circuit 73.
[0004]
[Problems to be solved by the invention]
In recent years, this type of directional coupler has been desired to be downsized as mobile communication devices have been downsized. However, in the conventional directional coupler, two lines are arranged side by side on the surface of the fired dielectric substrate by a screen printing method. Therefore, when the line width W2 of the two lines is reduced, it is attempted to reduce the size. In addition, variations in the line width of the two lines increased due to printing bleeding or the like during printing, and the line width W2 of the two lines after firing could not be reduced to 80 μm or less.
In such a conventional directional coupler, the line width W2 of the two lines and the distance between the two lines are set in a state where the length N2 of the parallel portions of the two lines is set to １ ／ wavelength. The main characteristics are determined by adjusting S2, and the line widths of the two lines vary, and the characteristics of the directional coupler vary greatly. Therefore, the conventional directional coupler could not be reduced in size.
[0005]
SUMMARY OF THE INVENTION An object of the present invention is to provide a method of manufacturing a directional coupler capable of reducing the size and reducing the variation in characteristics by reducing the variation in the line width of two lines.
[0006]
[Means for Solving the Problems]
The method of manufacturing a directional coupler according to the present invention solves the above-mentioned problem by forming two lines by etching a thick conductor layer provided on the surface of another insulating layer.
That is, in the method for manufacturing a directional coupler in which the first line and the second line are opposed to each other via the insulating layer and the first line and the second line are coupled, the conductive paste is applied to the first insulating layer. A conductor layer is formed by coating on the surface, a conductor pattern forming the first line is formed by etching the conductor layer, and a conductor paste is formed on the surface of the second insulating layer by forming a conductor paste. Then, a conductor pattern forming the second line is formed by etching the conductor layer.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
According to the method for manufacturing a directional coupler of the present invention, first, a conductor paste is applied to the surface of a first insulating layer to form a conductor layer, and the conductor layer is etched to form a conductor pattern forming a first line. To form Next, after laminating the insulating green sheets on the first insulating layer, they are integrally fired and then a conductor paste is applied to the surface of the second insulating layer to form a conductor layer. Either etching is performed to form a conductor pattern forming the second line, or a conductor paste is applied to the surface of the insulating green sheet to form a conductor layer, and the conductor layer is etched to form the second line. The insulating green sheet on which the conductive pattern to be formed is formed is laminated on the first insulating layer and then fired integrally to form a second insulating layer.
[0008]
【Example】
Hereinafter, a directional coupler according to the present invention will be described with reference to FIGS.
FIG. 1 is an exploded perspective view showing the directional coupler according to the present invention, FIG. 2 is a perspective view of the directional coupler according to the present invention, FIG. 3 is a top view showing the inside of the directional coupler shown in FIG. FIG. 4 is a cross-sectional view of FIG. 3, and FIG. 5 is a top view showing an embodiment of the method for manufacturing a directional coupler according to the present invention.
The directional coupler according to the present invention has two lines facing each other via an insulating layer as shown in FIGS. 1 to 4, for example.
The first insulating layer 11 is formed of a substrate made of a dielectric material such as alumina, a magnetic material such as ferrite, or the like. The main line 12 is formed on the surface of the first insulating layer 11. The main line 12 is formed on the surface of the first insulating layer 11, and both ends 12 a and 12 b are drawn out to the end surface of the protruding portion of the insulating layer 11, and are formed in a U-shape as a whole.
The second insulating layer 14 is formed on the first insulating layer 11 by using a material obtained by mixing a low-melting glass with a dielectric or a magnetic material. The sub-line 13 is formed on the surface of the second insulating layer 14. The auxiliary line 13 is formed on the surface of the second insulating layer 14, and both ends 13 a and 13 b are drawn out to the end surface of the protruding portion of the insulating layer 14, and are formed in a generally U-shape.
On the second insulating layer 14, a protective insulating layer 15 made of a dielectric material, a magnetic material, or the like is formed.
As shown in FIGS. 3 and 4, the main line 12 and the sub-line 13 are electromagnetically coupled to each other via the second insulating layer 14 except for both ends, and the length of the opposed portion N1 is set to be shorter than １ ／ wavelength of the frequency used. Both ends of the main line 12 and both ends of the sub-line 13 extend in opposite directions and are drawn to mutually facing end surfaces of the laminate. The main line 12 is connected between the input terminal 16 and the output terminal 17, one end 13 a of the sub line 13 is connected to the coupling terminal 18, and the other end 13 b of the sub line is connected to the separation terminal 19.
In such a directional coupler, the coupling degree between the main line 12 and the sub line 13 can be adjusted by the thickness H of the second insulating layer 14 and the line width W1 of the two lines.
[0009]
This directional coupler is manufactured as follows. First, as shown in FIG. 5 (A), a conductive material such as silver or copper or a conductive material such as silver or copper is coated on the entire surface of a substrate formed by firing a dielectric material such as alumina or a magnetic material such as ferrite. A conductive paste obtained by mixing a photosensitive agent into a paste is applied to a predetermined thickness and then dried to form a thick conductive layer 51.
Next, as shown in FIG. 5B, the conductor layer is etched using a technique such as a sputtering technique or a photolithography technique to form a U-shaped conductor forming the main line 12 and both ends 12a and 12b. A pattern 52 is formed on the substrate. The substrate on which the conductor pattern 52 is formed is subjected to a baking (baking) process or an annealing process in order to fix the conductor pattern 52 on the substrate. In FIG. 5, a plurality of conductor patterns are formed so that a plurality of directional couplers can be obtained from the substrate (so-called multiple-devices).
Further, as shown in FIG. 5C, an insulating green sheet 54 made of a material obtained by mixing a low-melting glass with a magnetic material such as a dielectric or ferrite is stacked on the substrate on which the conductor pattern is formed. The substrate and the insulating green sheet 54 are joined by pressing while being heated by a hot press or the like to be integrated. The integrated substrate and the insulating green sheet 54 are fired once.
Next, a conductive material such as silver or copper or a conductive paste obtained by mixing a photosensitive agent into the conductive material is applied to a predetermined thickness on the entire surface of the fired insulating sheet 55 and then dried. Thus, a thick conductor layer is formed. Then, as shown in FIG. 5 (D), the conductor layer is etched by using a technique such as a sputtering technique or a photolithography technique, so that the sub-line 13 and the U-shaped conductor pattern constituting both end portions 13a and 13b are formed. 53 is formed on the insulating sheet. The laminate of the substrate on which the conductor pattern 53 is formed and the insulating sheet 55 is subjected to a baking (baking) process or an annealing process to fix the conductor pattern 53 on the insulating sheet.
Finally, a protective insulating green sheet is stacked on the insulating sheet 55 on which the conductor pattern 53 is formed, integrated and fired. The fired laminate is cut at a predetermined position so that the surface shape becomes H-shaped, and both end portions 12a and 12b of the main line 12 and the end surfaces where both end portions 13a and 13b of the sub line 13 are exposed, That is, a conductor paste such as silver or silver palladium is applied to the end face of the protruding portion of the laminate and baked to form an external terminal.
[0010]
The embodiment of the method for manufacturing a directional coupler according to the present invention has been described above, but the present invention is not limited to this embodiment. For example, a conductor layer is formed by applying a conductor paste on the surface of the insulating green sheet, and the conductor layer constituting the second line is formed by etching the conductor layer. Is laminated on the first insulating layer on which the first line is formed, and then integrally fired to form a second insulating layer. Is also good. Further, the two lines are formed in a U-shape in the embodiment, but may be formed in a meander shape, a spiral shape, or the like. Further, the substrate on which the first insulating layer is to be formed is cut in advance so that the surface shape of each directional coupler is H-shaped, stacked up to the insulating green sheet for protection, and integrally fired. Later, it may be made to be able to be cut along a cutting crack or cut by a cutting device.
[0011]
【The invention's effect】
In the method for manufacturing a directional coupler according to the present invention, a conductor paste is applied to a surface of a first insulating layer to form a conductor layer, and the conductor layer is etched to form a conductor pattern constituting a first line. Then, a conductor paste is applied to the surface of the second insulating layer to form a conductor layer, and the conductor layer is etched to form a conductor pattern constituting the second line. Even if the line width of the line is reduced to about 30 μm, variation in the line width of the line can be reduced as compared with the conventional screen printing method. Further, in the method for manufacturing a directional coupler according to the present invention, an insulating sheet is laminated on a surface of the first insulating layer on which the first line is formed to form a second insulating layer. Since the first line and the second line are opposed to each other via the layer, the thickness of the second insulating layer can be prevented from being varied by managing the thickness of the insulating sheet in advance. Further, in the method for manufacturing a directional coupler according to the present invention, the first line and the second line are opposed to each other with the second insulating layer interposed therebetween, so that the bottom area can be reduced.
Therefore, the method for manufacturing a directional coupler according to the present invention can reduce the size, reduce the variation in the line width of the two lines and the variation in the distance between the two lines, and reduce the variation in the characteristics. Can be reduced.
Still further, in the method of manufacturing a directional coupler according to the present invention, when the length of the opposing portion of the first line and the second line is made shorter than １ ／ wavelength of the operating frequency, Since it can be handled as a circuit, it becomes easier to design.
[Brief description of the drawings]
FIG. 1 is an exploded perspective view showing a directional coupler according to the present invention.
FIG. 2 is a perspective view of a directional coupler according to the present invention.
FIG. 3 is a top view showing a state where the inside is seen through from the top surface of FIG. 2;
FIG. 4 is a sectional view of FIG. 3;
FIG. 5 is a top view illustrating an embodiment of the method for manufacturing a directional coupler according to the present invention.
FIG. 6 is a top view of a conventional directional coupler.
FIG. 7 is a circuit diagram of a circuit in which a directional coupler is used.
[Explanation of symbols]
11 first insulating layer 12 main line 13 sub line

Claims (2)

In a method for manufacturing a directional coupler in which a first line and a second line are coupled to each other with a first line and a second line facing each other via an insulating layer,
A conductor paste is applied to the surface of the first insulating layer to form a conductor layer, and the conductor layer is etched to form a conductor pattern constituting the first line with a portion facing the second line. A first step of forming shorter than 波長 wavelength,
A second step of laminating insulating green sheets on the first insulating layer and then firing them integrally to form a second insulating layer;
A conductor paste is applied to the surface of the second insulating layer to form a conductor layer, and the conductor layer is etched to form a conductor pattern constituting the second line with a length corresponding to a portion facing the first line. A third step of forming the directional coupler to be shorter than １ ／ wavelength . In a method for manufacturing a directional coupler in which a first line and a second line are coupled to each other with a first line and a second line facing each other via an insulating layer,
A conductor paste is applied to the surface of the first insulating layer to form a conductor layer, and the conductor layer is etched to form a conductor pattern constituting the first line with a portion facing the second line. A first insulating layer formed so as to be shorter than １ ／ wavelength, and a conductor layer formed by coating on the surface of an insulating green sheet to form a second line by etching the conductor layer A first step of preparing an insulating green sheet formed such that the length of a portion of the conductor pattern facing the first line is shorter than 1/4 wavelength;
A second step of forming the second insulating layer on the first insulating layer by laminating the green sheets for insulation on the first insulating layer and then firing them integrally. Manufacturing method of a directional coupler.

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