JP2003069315A - Layered directional coupler - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a small-sized layered directional coupler with excellent heat radiation characteristics and less dispersion in the electric characteristics. SOLUTION: A main line 30 is formed spiral and one end 30a is exposed to the left of this side of a sheet 23. The other end 30b of the main line 30 is electrically connected to a lead electrode 32 via a via-hole 29 formed to a sheet 22. One end 32a of the lead electrode 32 is exposed to the right of this side of the sheet 22. A sub line 31 is formed spiral and the one end 31a is exposed to the left of the behind side of a sheet 25. The other end 31b of the sub line 31 is electrically connected to a lead electrode 33 via a via-hole 29 formed to a sheet 25. One end 33a of the lead electrode 33 is exposed to the right of the behind side of a sheet 26. Heat radiation electrodes (floating electrodes) 34, 35 are respectively formed to he left of sheets 20, 28.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated directional coupler, and more particularly to a laminated directional coupler used in a wireless communication device such as a mobile phone.

[0002]

2. Description of the Related Art A directional coupler using a transmission line having an electrical length corresponding to a quarter wavelength has been conventionally used for high frequency equipment. Further, the laminated directional coupler is also widely used for small wireless communication devices such as mobile phones because of its small size.

As this type of laminated directional coupler, the one described in Japanese Patent Laid-Open No. 8-191206 is known.
As shown in FIG. 7, this directional coupler includes a dielectric sheet 2 having line portions 3a and 3b of a main line 3 provided on the surfaces thereof.
And a dielectric sheet 2 having line portions 4a and 4b of the sub line 4 provided on the surface thereof. Line parts 3a and 3
b is electrically connected via a via hole 6 provided in the dielectric sheet 2 to form the main line 3. Track section 4a
And 4b are electrically connected to each other through a via hole 6 provided in the dielectric sheet 2 to form a sub line 4. The main line 3 and the sub line 4 are electromagnetically coupled to form a coupler.

The sheets 2 are stacked and integrally fired to form a rectangular laminated body 10 as shown in FIG. On the side surface of the laminated body 10, the input external electrode 11a and the output external electrode 11b of the main line 3 and the sub line 4 are provided.
Input external electrode 12a and output external electrode 12b are formed.

[0005]

However, the conventional directional coupler 1 does not have a large area ground electrode pattern inside or on the surface of the laminated body 10, and it is not necessary to form a ground external electrode. . However, since it does not have a ground electrode pattern, heat dissipation is poor, and when the conventional directional coupler 1 is used in a circuit that transmits a high-power high-frequency signal (for example, a transmission side circuit of a mobile phone), The directional coupler 1 becomes hot. Therefore, the characteristics are deteriorated, the main line 3 and the sub line 4 are broken, the mounting solder is melted, and the peripheral circuits are adversely affected (for example, heat is conducted to raise the temperature of the peripheral electronic components, etc.). ). If the line widths of the main lines 3 and 4 are increased in order to suppress the temperature rise, the directional coupler 1 is increased in size. Further, there is a problem that a magnetic field generated by a high-frequency signal flowing through the main line and the sub line easily leaks to the outside of the directional coupler 1 and electric characteristics easily vary.

Therefore, the object of the present invention is to provide excellent heat dissipation.
Further, it is to provide a small-sized laminated directional coupler with less variation in electrical characteristics.

[0007]

In order to achieve the above object, a laminated directional coupler according to the present invention comprises: (a) a main line; and (b) a sub-line electromagnetically coupled to the main line. A line, (c) a heat dissipation electrode, (d) a dielectric layer respectively disposed between the main line, the sub line, and the heat dissipation electrode, (e) the main line, the sub line, and the heat dissipation A laminated body formed by laminating electrodes and the dielectric layer, and (f) an input of a main line provided on one side surface of the laminated body and electrically connected to ends of the main line, respectively. An electrode and an output external electrode; and (g) an input external electrode and an output external electrode of the sub line, which are provided on the other side surface of the laminated body and electrically connected to the ends of the sub line. It is characterized by

It is preferable that the heat dissipation electrode is not connected to any of the electrodes, and that the laminated body is not provided with a ground external electrode. Further, by forming the heat dissipation electrode by the via hole, the heat inside the laminated body can be efficiently dissipated to the outside. Further, by disposing the heat dissipation electrode above the main line, heat is dissipated more efficiently.

In the laminated directional coupler according to the present invention, the input external electrode and the output external electrode of the main line and the sub line are electrically connected to the folded portion provided on the surface of the laminated body, The folded-back portion is formed by printing on the surface of the dielectric layer. With the above configuration, variations in the shape of the folded portion can be reduced, and the size of the folded portion of the input / output external electrode can be easily increased.

The laminated directional coupler according to the present invention is characterized in that each of the main line and the sub line has a spiral shape. Generally, when it is attempted to obtain the same degree of coupling, a spiral line becomes longer than a straight line, and in order to make it longer, it is necessary to make it thinner than a straight line. is there. Therefore, the direct current resistance of the line increases, the heat generated in the line increases, and the heat dissipation by the heat dissipation electrode becomes more effective.

In the laminated directional coupler according to the present invention, the main line and the sub line are opposed to each other in the laminating direction with the dielectric layer interposed therebetween and are electromagnetically coupled (so-called broadside coupling). Characterize. In general, broadside coupling has a larger coupling than side-edge coupling (a main line and a sub-line arranged in the same layer are electromagnetically coupled so as to face each other in the horizontal direction). Therefore, the heat generated in the line becomes large, and the heat dissipation by the heat dissipation electrode becomes more effective.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a laminated directional coupler according to the present invention will be described below with reference to the accompanying drawings. In each embodiment, the same reference numerals are given to the same parts and the same parts.

[First Embodiment, FIGS. 1 to 3] As shown in FIG. 1, the laminated directional coupler 15 includes heat dissipation electrodes 34 and 3.
5, dielectric sheets 20 and 28 each provided on the surface,
Dielectric sheet 23 having main line 30 provided on the surface, dielectric sheet 25 having sub line 31 provided on the surface, and extraction electrode 3
Dielectric sheets 22 and 2 provided with surface 2 and 33, respectively
It is composed of 6 etc.

As the material of the dielectric sheets 20 to 28,
A resin such as epoxy or a ceramic dielectric is used. The sheet thickness of each of the dielectric sheets 20 to 28 is set to a predetermined dimension. That is, the sheets 21, 24, 27
Is set thicker than the other sheets 20, 22, 23, 25, 26, 28. At this time, the sheets 21, 24
The thickness of 27 may be secured by stacking a plurality of sheets having the same sheet thickness as the other sheets 20 or the like, or may be secured by using one thick sheet.

The main line 30 has a spiral shape and one end 3
0a is exposed on the left side of the front side of the seat 23.
The other end 30b of the main line 30 is electrically connected to the extraction electrode 32 via a via hole 29 provided in the sheet 22. One end 32 a of the extraction electrode 32 is exposed on the right side of the front side of the sheet 22.

The sub line 31 has a spiral shape and has one end 3
1a is exposed on the left side of the back side of the sheet 25. The other end 31b of the sub line 31 is electrically connected to the extraction electrode 33 via a via hole 29 provided in the sheet 25. One end 33 a of the extraction electrode 33 is exposed on the right side of the back side of the sheet 26. Main line 30 and sub line 31
Have electric lengths corresponding to ¼ wavelength of the use center frequency, respectively.

Generally, when trying to obtain the same degree of coupling,
The spiral track is longer than the straight track,
Further, in order to make it long, it is necessary to make it thinner than a straight line. Therefore, the main line 30 and the sub line 3
The DC resistance of 1 is relatively large, and the main line 30 and the sub line 31
The heat generated in is relatively large, and the heat dissipation electrode 3 described later
The heat radiation by 4, 35 becomes more effective.

The heat dissipation electrodes (floating electrodes) 34 and 35 are formed on the left side of the sheets 20 and 28, respectively. However, the heat dissipation electrode 35 disposed on the lower side is not necessarily provided. Main line 30, sub line 31, extraction electrode 32,
33 and the heat dissipation electrodes 34 and 35 are formed by a sputtering method,
It is formed by a method such as a vapor deposition method, a printing method, or a photolithography method, and is made of Ag-Pd, Ag, Pd, Cu, Ni, Au.
Etc. In the manufacturing process, it is preferable that the material of the heat dissipation electrodes 34 and 35 is the same as the material of the main line 30, etc.
Considering the thermal conductivity, the heat dissipation electrodes 34 and 35 are A
g and Cu are preferred.

The sheets 20 to 28 are stacked and integrally fired to form a rectangular laminated body 40 as shown in FIG. Four external electrodes 36a, 36b, 37a, 37b are formed on the laminated body 40. These external electrodes 36a to 37b are formed by a sputtering method,
It is formed by a vapor deposition method, a coating method (dip method), a printing method, or the like, and is made of a material such as Ag-Pd, Ag, Pd, Cu, or a Cu alloy.

External electrodes 36a and 36b formed on the front side surface of the laminated body 40 are electrically connected to the main line 30 and the extraction electrode 32, respectively, and the input external electrode and the output external electrode of the main line 30 are respectively connected. Function as. External electrodes 37a and 37b formed on the inner side surface of the laminate 40
Are electrically connected to the sub line 31 and the extraction electrode 33, respectively, and function as an input external electrode and an output external electrode of the sub line 31, respectively. The laminated directional coupler 1 shown in FIG.
5 shows an electrical equivalent circuit diagram of FIG.

The directional coupler 15 having the above structure is
The main line 30 and the sub line 31 are formed so as to face each other with the sheets 23 and 24 interposed therebetween. Therefore, the spiral pattern of the main line 30 and the spiral pattern of the sub line 31 substantially overlap each other in a plan view, and are electromagnetically coupled (so-called broadside coupling) at the facing portions. In general, broadside coupling has a larger coupling than side-edge coupling (a main line and a sub-line arranged in the same layer are electromagnetically coupled so as to face each other in the horizontal direction). Therefore, the heat generated in the main line 30 and the sub line 31 becomes relatively large, and the heat dissipation electrode 3
The heat radiation by 4, 35 becomes more effective.

The input external electrode 36a of the main line 30
The output external electrode 36b is formed on the front side surface of the laminated body 40, and the input external electrode 37a and the output external electrode 37b of the sub line 31 are formed on the rear side surface of the laminated body 40. Therefore, as shown in FIG.
The main line 30 connected between 6a and 36b and the sub line 31 connected between the input / output external electrodes 37a and 37b do not necessarily have to intersect in the directional coupler 15. As a result, the degree of freedom in designing the arrangement positions of the main line 30 and the sub line 31 and the arrangement positions of the input / output external electrodes 36a to 37b is increased.

Further, the directional coupler 15 has a laminated body 40.
Since the heat dissipation electrode 34 that is not connected to any of the electrodes is provided on the upper surface of, the temperature rise can be suppressed even in the structure having no ground electrode or ground external electrode. Therefore, the pattern widths of the main line 30 and the sub line 31 can be reduced, and the directional coupler 15 can be downsized.

The heat dissipation electrode 34 prevents the magnetic field generated by the high-frequency signal flowing through the main line 30 and the sub line 31 from leaking to the outside. On the contrary, the heat dissipation electrode 3
4 shields the magnetic field entering the directional coupler 15 from the outside, so that the electrical characteristics of the directional coupler 15 are stabilized.

When the directional coupler 15 is viewed from above, the position of the heat dissipation electrode 34 is deviated from the center and is unevenly distributed (in the case of the first embodiment, it is offset to the left end face). Therefore, the heat dissipation electrode 34 also functions as an identification mark in the left-right and up-down directions of the directional coupler 15.

Further, since a high-frequency signal of large power flows through the main line 30, it is easy to generate high heat as compared with the sub line 31. Therefore, in the first embodiment, the heat dissipation electrode 34 is arranged above and in the vicinity of the main line 30 so as to efficiently dissipate heat.

Further, in the first embodiment, since the heat dissipation electrode 35 is also provided on the lower side of the laminated body 40, more excellent heat dissipation and electromagnetic shielding properties can be obtained.

[Second Embodiment, FIGS. 4 and 5] In the second embodiment, a laminated directional coupler provided with a heat dissipation electrode formed of a via hole will be described.

As shown in FIG. 4, the dielectric sheet 43 is provided with a heat dissipation electrode 50 composed of a via hole. The heat dissipation electrode 50 is made of Ag, Cu, Pd, N, by making a hole (oblong hole) in the dielectric sheet 43 with a die or a laser.
It is formed by filling the hole with a material having a good thermal conductivity such as Ag-Pd or by applying it to the inner peripheral surface of the hole. The heat dissipation electrode 50 by the via hole is
It also functions as a horizontal or vertical identification mark. In this respect, not only the directional coupler but also other laminated electronic components (for example, LC filter, inductor,
It is also effective in capacitors, composite modules, baluns, delay lines).

Further, the folded portions 45 to 48 of the external electrodes are formed at the four corners of the upper surface of the dielectric sheet 42 by the printing method. Needless to say, the folded-back portions of the external electrodes may be formed at the four corners of the lower surface of the dielectric sheet 43.

The sheets 23 to 28, 42, 43 are stacked and fired integrally to form a rectangular laminated body 55 as shown in FIG. The laminated body 55 shown in FIG. 5 has the sheets 23 to 2 shown in FIG.
The laminated body obtained by stacking 8, 42 and 43 is turned upside down. Four external electrodes 56a, 56b, 57a, 57b are formed on the side surface of the laminated body 55 by a coating method (dip method).

The external electrodes 56a and 56b formed on the inner side surface of the laminate 55 are electrically connected to the main line 30 and the extraction electrode 32, respectively, and the input external electrode and the output external electrode of the main line 30 are respectively provided. Function as. Laminate 5
External electrodes 57a and 57b formed on the front side surface of No. 5
Are electrically connected to the sub line 31 and the extraction electrode 33, respectively, and function as an input external electrode and an output external electrode of the sub line 31, respectively.

The directional coupler 41 having the above structure is
Since the heat dissipation electrode 50 is formed by the via hole, the thickness of the electrode can be increased, and the heat generated inside the laminate 55 can be efficiently dissipated to the outside. As a method of increasing the thickness of the heat dissipation electrode 50, for example, a plurality of dielectric sheets having via holes are stacked or a via hole is formed in a thick dielectric sheet to form a thick heat dissipation electrode. There is a method of forming.

Further, as shown in FIG. 4, the heat dissipation electrode 50 formed by a via hole is provided on the lowermost dielectric sheet 43, and the folded-back portions 45 to 48 of the external electrodes are provided on the upper surface of the uppermost dielectric sheet 42. By providing the dielectric sheet by a printing method, it is not necessary to turn over the dielectric sheets (printing surface is face down) and stack the dielectric sheets, which facilitates handling of the dielectric sheets.

If heat radiation electrodes are to be formed on the upper and lower surfaces of the laminated body, respectively, when stacking the dielectric sheets having the heat radiation electrodes printed on the surface as in the first embodiment, one of the upper and lower dielectric layers is stacked. The body sheets must be turned upside down (printing side down) and stacked, which complicates the handling of the dielectric sheets. However, when the heat dissipation electrode is formed by the via hole as in the second embodiment, the dielectric sheets can be stacked without turning over, and the dielectric sheets can be easily handled.

Further, since the folded-back portions 45 to 48 of the external electrodes are formed on the upper surface of the dielectric sheet 42 by the printing method before forming the laminated body 55, variations in the shapes of the folded-back portions 45 to 48 are small. Therefore, it is possible to obtain the directional coupler 41 in which the variation in the electric characteristics due to the variation in the folding portions 45 to 48 is small. Moreover, the folded portions 45 to 4
The size of 8 can be easily increased, and the soldering strength between the directional coupler 41 and the mounting substrate can be improved.

[Other Embodiments] The laminated directional coupler according to the present invention is not limited to the above embodiment, but can be variously modified within the scope of the gist thereof.

For example, as shown in FIG. 6, the heat dissipation electrode may cover the surface of the dielectric sheet 20 over a wide area. The heat dissipation electrode 60 is excellent in heat dissipation and electromagnetic shielding properties, and also functions as an identification mark in the vertical direction of the laminated body 40.

The main line and the sub line may have any shape, and may have a meandering shape or a linear shape in addition to the spiral shape.
Further, the main line and the sub line do not necessarily have to be set to have a length of ¼ wavelength, and the line width does not have to be set to have the same dimension for all lines.

In the first embodiment, the transmission line is arranged in the order of the main line and the sub line from the upper surface side to the lower surface side of the laminated body, but the present invention is not necessarily limited to this. For example, the sub line and the main line may be arranged in this order.
Similarly in the second embodiment, the vertical relationship between the main line and the sub line may be reversed.

Although the above embodiment has been described by taking the case of an individual product as an example, in the case of mass production, a mother substrate having a plurality of directional couplers is manufactured and cut into a desired size. Can be a product. Further, in the above-described embodiment, the dielectric sheets having the conductors formed thereon are stacked and then integrally fired, but the present invention is not necessarily limited to this. The sheet may be pre-baked. The directional coupler may be manufactured by the manufacturing method described below. After a paste-like dielectric material is applied by means of printing or the like to form a dielectric layer, a paste-like conductor material is applied on the surface of the dielectric layer to form an arbitrary conductor. Next, a paste dielectric material is applied over the conductor. By sequentially coating the layers in this manner, a directional coupler having a laminated structure is obtained.

[0042]

As is apparent from the above description, according to the present invention, the input / output external electrodes of the main line are provided on one side surface of the laminated body, and the input / output external electrodes of the sub-line are provided on the other side surface. Since the main line and the sub line do not necessarily intersect in the directional coupler because they are provided, the degree of freedom in designing the placement positions of the main line and the sub line and the placement positions of the input / output external electrodes is increased. Get higher

Further, by providing the heat dissipation electrode which is not connected to any of the electrodes, the temperature rise can be suppressed even in the structure having no ground electrode or ground external terminal. Therefore, the pattern widths of the main line and the sub line can be reduced, and the directional coupler can be downsized. Further, this heat dissipation electrode prevents the magnetic field generated by the high-frequency signal flowing through the main line and the sub line from leaking to the outside. On the contrary, the heat dissipation electrode prevents the magnetic field entering the directional coupler from the outside. Since it shields, the electrical characteristics of the directional coupler can be stabilized.

The heat dissipation electrode can also function as an identification mark in the left-right direction or the up-down direction of the directional coupler. Furthermore, by forming the heat dissipation electrode by the via hole, the heat inside the laminate can be efficiently dissipated to the outside.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing a first embodiment of a laminated directional coupler according to the present invention.

FIG. 2 is a perspective view showing an appearance of the laminated directional coupler shown in FIG.

FIG. 3 is an electrical equivalent circuit diagram of the stacked directional coupler shown in FIG.

FIG. 4 is an exploded perspective view showing a second embodiment of the laminated directional coupler according to the present invention.

5 is a perspective view showing the outer appearance of the laminated directional coupler shown in FIG. 4. FIG.

FIG. 6 is a perspective view showing another embodiment.

FIG. 7 is an exploded perspective view showing a conventional laminated directional coupler.

8 is a perspective view showing the appearance of the laminated directional coupler shown in FIG. 7. FIG.

[Explanation of symbols]

15, 41 ... Laminated directional coupler 20-28, 42, 43 ... Dielectric sheet 30 ... Main track 31 ... Sub track 34, 35, 50, 60 ... Heat dissipation electrode 36a, 56a ... Input external electrodes of main line 36b, 56b ... Main line output external electrodes 37a, 57a ... Input external electrodes of sub line 37b, 57b ... Output external electrodes of sub line 40, 55 ... laminated body 45 to 48 ... Folded portion of external electrode

Claims (8)

[Claims] 1. A main line, a sub line electromagnetically coupled to the main line, a heat dissipation electrode, and a dielectric layer disposed between the main line, the sub line, and the heat dissipation electrode, respectively. A laminated body formed by laminating the main line, the sub line, the heat dissipation electrode, and the dielectric layer, and provided on one side surface of the laminated body, and the ends of the main line are electrically connected to each other. An input external electrode and an output external electrode of the main line, and an input external electrode and an output external electrode of the sub line, which are provided on the other side surface of the laminated body and electrically connected to the ends of the sub line. And a laminated directional coupler. 2. The laminated directional coupler according to claim 1, wherein the heat dissipation electrode is not connected to any of the electrodes. 3. The laminated directional coupler according to claim 1, wherein the laminated body is not provided with a ground external electrode. 4. The laminated directional coupler according to claim 1, wherein the heat dissipation electrode is a via hole. 5. An input external electrode and an output external electrode of each of the main line and the sub line are electrically connected to a folded portion provided on the surface of the laminated body, and the folded portion is formed of the dielectric layer. The laminated directional coupler according to any one of claims 1 to 4, wherein the laminated directional coupler is formed on the surface by printing. 6. The laminated directional coupler according to claim 1, wherein the heat dissipation electrode is arranged above the main line. 7. The laminated directional coupler according to claim 1, wherein each of the main line and the sub line has a spiral pattern shape. 8. The main line and the sub line are electromagnetically coupled so as to face each other in the stacking direction with the dielectric layer sandwiched therebetween. Stacked directional coupler.