JP2702894B2 - Directional coupler - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a directional coupler using a coiled conductor.

[0002]

2. Description of the Related Art FIG. 4 is a perspective view of a conventional directional coupler using a plurality of strip lines. In this conventional example, a case where the main line and the sub line are formed on the same substrate and are of the same plane type is shown. This is because two strip lines 5 are provided on the surface of a dielectric substrate 51 having a planar ground conductor 52 formed on the back surface.
3, 54 are arranged in parallel at a distance S. The lengths of the parallel portions of the strip lines 53 and 54 are configured to be １ ／ wavelength in length. The high-frequency power input from the port P1 is output to the port P2 through the strip line 53 as the main line. At this time, the strip line 53 which is the main line
And the strip line 54 which is a sub-line,
Part of the power passing through the strip line 53 flows to the strip line 54 and is output to the port P3. At this time, no output appears at the port P4. Next, in the direction opposite to the strip line 53 which is the main line, that is, the port P2
When power flows from port P1 to port P1, part of the power appears at port P4 and does not appear at port P3.
That is, by adopting such a configuration, a part of the forward power and the backward power flowing through the strip line 53 of the main line is separately extracted to the output port P3 or P4 terminal of the strip line 54 of the sub line. be able to. This is the basic operation of the directional coupler. Coupling from the main line 53 to the sub line 54 is possible by adjusting the distance S between the parallel portions of the two strip lines. In the description of the conventional example of FIG. 4, the main line and the sub line are the strip lines 53 and 54. However, as is clear from the symmetrical structure of FIG. 4, the same applies even if the roles of the main line and the sub line are switched. Thus, the basic operation of the directional coupler can be realized. FIG. 5 shows another conventional example, in which a strip line 65 as a main line and a strip line 66 as a sub line are stacked. This is because a flat ground conductor 6
A strip line 66 as a sub-line is arranged on the surface of the dielectric substrate 61 on which the substrate 4 is formed. Above the dielectric substrate 6, a strip line 65 as a main line is formed.
2 are arranged in parallel at a distance D from each other. A protective dielectric substrate 63 is provided thereon. FIG. 6 shows a perspective view of a directional coupler completed by laminating and firing these three substrates and adding external terminals. Also in this case, the same operation as that of FIG. 4 can be realized, and the high-frequency power input from the port P1 is output to the port P2 through the strip line 65 as the main line. At this time, due to the coupling between the strip line 65 as the main line and the strip line 66 as the sub line, part of the electric power passing through the strip line 65 flows to the strip line 66 and is output to the port P3. At this time, no output appears at the port P4. Next, when power flows in the opposite direction of the main line, that is, the strip line 65, that is, from the port P2 to the port P1, a part of the power appears at the port P4 and does not appear at the port P3. That is, by adopting such a configuration, a part of the forward power and the backward power flowing through the strip line 65 of the main line is separately extracted to the output port P3 or P4 terminal of the strip line 66 of the sub line. be able to. The coupling from the main line 65 to the sub line 66 is based on the distance between the parallel portions of the two strip lines in the stacking direction, that is, the thickness D of the dielectric substrate 62.
It is possible by adjusting. Such a directional coupler having a function of separating a part of high-frequency power with directivity is used for controlling transmission power of a transmitter of a microwave communication, for example, a mobile phone. FIG. 7 shows a block diagram of the application example. Ports P1 and P2 of the main line of the directional coupler 71 are arranged between the transmission power amplifier and the antenna 74, and one port P3 of the sub line is connected to the automatic gain control circuit, and power is supplied to the other port P4. The absorbing resistor element 75 is connected. In this case, only a part of the output of the transmission power amplifier appears at the port P3 and is guided to the automatic gain control circuit. Part of the high-frequency power flowing backward from the antenna 74 appears at the port P4 and is absorbed by the resistance element 75. The signal output of the automatic gain control circuit is sent to a transmission power amplifier capable of controlling the gain, and the high-frequency output can be controlled according to the purpose.

[0003]

However, miniaturization of portable telephones is an important issue.
For the directional coupler used for the above purpose, further downsizing is required. In a directional coupler having a quarter wavelength as in the example of FIG. 4 of the related art, the length of the strip line electrode is, for example, 2.5 cm at 1 GHz (1/4 when the relative dielectric constant ε = 9). wavelength)
It requires a length and cannot be expected to be sufficiently miniaturized. A method of shortening the 1/4 wavelength by using a material having a large relative dielectric constant is also conceivable. However, in order to maintain the impedance of 50Ω, the strip line width becomes extremely thin, and the main line and the sub line are not desirably formed. In order to obtain such a combination, high processing accuracy is required, for example, the interval between strip lines becomes extremely narrow. For this reason, there has been a problem that the mass productivity is poor and the power durability is deteriorated. Further, in a structure in which a plurality of strip lines are stacked in the vertical direction as shown in FIG. 5 of the related art, the range of control is widened because the coupling of two lines is performed in a plane, but the situation is small in terms of miniaturization. It is no different from the previous example. As one direction of miniaturization, a method of shortening the line length to less than 波長 wavelength can be considered. The characteristics of the directional coupler shown in FIG. 5 thus prototyped are shown by the dotted lines in FIG. Here, the propagation loss from the port P1 to the port P2 is called an insertion loss, the propagation loss from the port P1 to the port P3 is called a coupling loss, and the propagation loss from the port P1 to the port P4 is called an isolation. The directional coupler is required to have as small an insertion loss as possible and to have as large an isolation as possible. Coupling loss is a parameter given in designing the entire circuit of a portable telephone or the like. As can be seen from the dotted line in FIG. 5, if the line length is simply shortened using the conventional technology, there is a problem that sufficiently high isolation cannot be realized in a wide frequency range. In view of the above, an object of the present invention is to provide a miniaturized directional coupler.

[0004]

SUMMARY OF THE INVENTION The present invention is directed to a directional coupler formed by laminating a dielectric layer on which a conductor film is formed, wherein each of the directional couplers has a region surrounded by a plurality of ground conductors. Two coil-shaped conductors wound one or more times are formed,
The two coil-shaped conductors are directional couplers formed on respective dielectric layers in different regions. Further, according to the present invention, the coil-shaped conductor is formed by connecting conductors formed on two or more dielectric layers with through holes. The present invention also relates to a directional coupler formed by stacking dielectric layers each having a conductor film formed thereon, wherein each of the coils is wound one or more times in a region surrounded by a plurality of ground conductors. The two coil-shaped conductors are formed by connecting conductors formed on two or more dielectric layers with through holes, respectively. One of the coil conductors is formed, and when the two coil conductors are viewed from the axial direction in the winding direction of the coil conductors, the portions surrounded by the respective wound conductors are shifted from each other. Directional coupler.

[0005]

According to the structure of the present invention, two or more coiled conductors wound at least once are provided in a plurality of ground conductors having a spread, and a region surrounded by the plurality of ground conductors. By using the coil-shaped conductors described above, a compact and high-performance directional coupler can be realized. In addition, a directional coupler that is small in size and has high mass productivity can be realized by laminating the dielectric layers on which the conductor films are formed. Further, the dielectric constant of the dielectric layer is 15 or less, and the sintering temperature is 1000
By using a material having a temperature of not more than ° C, simultaneous firing using a conductor such as Ag or Cu is possible. The coil-shaped conductor is formed by connecting conductors formed on two or more dielectric layers with through holes, and each layer is formed with only one of the coil conductors. A highly compact directional coupler having high connectivity can be realized. Further, since the two coil-shaped conductors are formed in different regions on the respective dielectric layers, the degree of coupling can be adjusted. Further, the input terminal and the output terminal of the main line are formed on the same surface of the laminate, the input terminal and the output terminal of the sub line are formed on the same surface of the laminate, and the input terminal and the output terminal of the main line are formed. The surface on which the input terminal and the output terminal of the sub-line are formed is different from each other, and they are the opposite surfaces of the laminate, respectively, between the input terminal and the output terminal of the main line and / or the sub-line. Since the terminal of the ground conductor is formed between the input terminal and the output terminal of the line, the mountability is high. Further, when the two coil-shaped conductors are viewed from the coil-shaped conductor in the axial direction of the winding direction of the coil-shaped conductor, the entire contour of the wound conductor overlaps, so that the main line is formed. And the sub-line can be improved in connectivity. In addition, when the two coiled conductors are viewed from the axial direction in the winding direction of the coiled conductor, the portion surrounded by the wound conductor is displaced, so that the coupling property is reduced. Can be adjusted. In addition, the conductor width of the coiled conductor is set to 0.10 to
By setting the thickness to 0.20 mm, a high-performance directional coupler can be realized.

[0006]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows an assembly component diagram of an embodiment according to the present invention. FIG. 1 shows a chip-type directional coupler, in which a first ground conductor electrode substrate 32, main line stripline electrode substrates 34 and 36, and a subline stripline electrode substrate 33 are provided. , 35, a second ground conductor electrode substrate 37, and a protection substrate 38. For each of these substrates, ceramic green sheets for low-temperature sintering are used. The ground conductor electrode 32a is formed on one surface of the first ground conductor electrode substrate 32 except for a little end on the ceramic green sheet.
Two projections are provided at the center end of the ground conductor electrode 32a, and are connected to the side surfaces. The substrate 33 on which the sub-line strip line electrode is formed is provided with a sub-line strip line electrode 33 on one surface of the ceramic green sheet.
a is formed. The strip line electrode 33a
Is drawn out to the side, and a round electrode 33b for a through hole is formed at the other end. In the substrate 34 on which the main line strip line electrode is formed, a through hole 34c independent of the main line strip line electrode 34a is formed on one surface of the ceramic green sheet. One end of the strip line electrode 34a is drawn out to the side, and the other end is provided with a round electrode 34 for a through hole.
b is formed. There is another board for the sub track,
This is indicated by 35 in the figure. In this case, a through-hole 35c independent of the sub-line strip line electrode 35a is formed on one surface of the ceramic green sheet. One end of the strip line electrode 35a is extended to the side surface, and the other end is formed with a through hole 35b. The sub-line strip line electrodes 33a and 35a are formed by a through-hole round electrode 33b and through-holes 34c and 35b.
Connected via There is another board for the main line,
This is indicated by 36 in the figure. The main line strip line electrode 36a is formed on one surface of the ceramic green sheet. One end of the strip line electrode 36a is extended to the side, and the other end is formed with a through hole 36b. This main line strip line electrode 34
a and 36a are connected via a through-hole round electrode 34b and through-holes 35c and 36b. The second ground conductor electrode substrate 37 has the same configuration as the first ground conductor electrode substrate 32, and a ground conductor electrode 37a is formed on one surface of the ceramic green sheet except for a small end.
The protection substrate 38 has independent external electrodes 38a, 38b, 38c, 38d, 38e, 38f on the upper surface of the green sheet.
Is provided. Each of the green sheets 32 to 38 is stacked after each electrode film is formed by a printing technique, and is baked at a temperature of 900 ° C. or more to be integrated. The input / output of the main line, the input / output of the sub line, and the external terminal for the ground conductor are formed on the side surface of the laminate. In this embodiment, the ceramic green sheets on which the strip line electrodes of the main line and the strip line electrodes for the sub line are formed are alternately laminated, and furthermore, the region where the coil conductor for the main line is wound, and the sub line When the area where the coiled conductor is wound is viewed from the axial direction of the winding direction,
The areas are shifted while being overlapped. As described above, by alternately stacking the green sheets on which the strip line electrodes for the main line are formed and the green sheets on which the strip line electrodes for the sub line are formed, the connectivity can be improved. Of course, the main track and the sub track may be divided into upper and lower sections. The ceramic green sheet of this embodiment has a relative dielectric constant ε of about 8, 90
A dielectric material that can be fired at 0 ° C. and has a thickness of 0.15
mm. Each electrode was a Cu electrode having a thickness of 15 μm, and the width of the strip line electrode was 0.16 mm. The characteristic of the directional coupler manufactured in this example was 0.5
The result of measurement over a wide frequency range from GHz to 2 GHz is shown by a solid line in FIG. As is clear from comparison with the dotted line of the prior art, the directional coupler using the technique of the present invention is extremely excellent in terms of insertion loss and isolation. For example, when the technology of the present invention is compared with the conventional technology in the 1.5 GHz band, the insertion loss is 0.3 dB and 0.1 mm.
There is a difference of 5 dB and an isolation of 48 dB and 23 dB. In particular, the insertion loss appears as a large difference between 0.4 dB and 1.0 dB in the higher frequency 1.9 GHz band. Although there is a difference of about 2 dB in the coupling loss, this is a matter given by design and is not directly subject to comparison when discussing performance. The main point of the present invention is FIG.
As in the prior art shown in FIG.
It is not a strip-shaped conductor but a coil-shaped conductor wound one or more times like a lumped constant circuit component as shown in FIG. By using two such coiled conductors and coil-coupling a plurality of striplines, which are originally distributed constant type lines, with each other, high performance can be realized in a wider frequency range. In the embodiment of the present invention, a coil-shaped conductor having an elongated cross section is used, and the long axis is arranged so as to be parallel to the ground conductor. By doing so, the mounting density in the vertical direction is increased, and strong coupling between the main line and the multiple lines can be realized. Further, a directional coupler was created by changing the conductor width of the coiled conductor. As the conductor width increases, the return loss characteristics deteriorate, and the practicality is lost. This conductor width is desirably 0.20 mm or less. On the other hand, when the conductor width is reduced, characteristics such as insertion loss, isolation, and return loss are in a favorable direction. However, when the width is too small, the power durability is deteriorated and the practicality is reduced. 10
mm or more is desirable. Note that one strip line targeted in the present invention has a structure in which both ends of the strip line are connected to external electrodes and has two ports. The basic structure of the present invention is that a plurality of the strip lines are included in a region surrounded by a plurality of ground conductors. In this embodiment, the two strip lines are connected to independent external electrodes, respectively. However, in some cases, the effect of the present invention does not change even if a plurality of strip lines commonly use one external electrode. . Further, in an embodiment of the present invention,
Although a non-magnetic dielectric substrate has been described, even if a magnetic substrate is used as the substrate, the effects of the present invention can be realized.
Experts in this field can easily understand. In particular, an object of the present invention is to couple a plurality of strip lines with a coil in a space surrounded by a ground conductor. If the substrate is a magnetic material, the effect is further enhanced. Further, in the above embodiment, the total length of the main line including the strip line electrodes 34a and 36a and the strip line electrodes 33a and 35
The total length of the sub-line consisting of b was set to a length corresponding to 1/12 wavelength. Thus, according to the embodiment of the present invention, the directional coupler, which has conventionally been designed so that the length of the strip line is 1/4 wavelength, is designed to be 1/12 wavelength,
Obviously, a directional coupler is achieved, and significant miniaturization is possible. Further, according to the configuration of the present invention, the total length of the strip line electrode is reduced to 1/8 to 1 /
It was designed in the range of 15 wavelengths, and it was confirmed that a directional coupler was achieved. This is because, as described above, the coil-shaped strip line is wound one or more times like the lumped constant circuit component. FIG. 2 shows an assembly component diagram of another embodiment according to the present invention. FIG. 2 shows a chip type directional coupler, in which a first ground conductor electrode substrate 22 and a substrate 2 on which a main line strip line electrode and a sub line strip line electrode are formed.
3, 24, the second ground conductor electrode substrate 25, and the protection substrate 2
6 are laminated. For each of these substrates, ceramic green sheets for low-temperature sintering are used. The first ground conductor electrode substrate 22 is provided on the entire surface of the ground conductor electrode 2 except for a little end on the ceramic green sheet.
2a is formed. Two projections are provided at the center end of the ground conductor electrode 22a, and are connected to the side surfaces.
The substrate 23 on which the main-line and sub-line strip line electrodes are formed has a main-line strip line electrode 23a and a sub-line strip line electrode 23b formed on one surface of a ceramic green sheet. One end of each strip line electrode 23a, 23b is drawn out to the side, and the other end is provided with a round electrode 27 for a through hole.
a, 27b are formed. There is another substrate for the main line and the sub line, which is indicated by 24 in the figure. This is because the main line strip line electrode 24a and the sub line strip line electrode 24b are formed on one side of the ceramic green sheet.
Are formed. Each stripline electrode 2
One end of each of 4a and 24b is drawn out to the side, and the other end is formed with through-hole electrodes 28a and 28b. Second
The ground conductor electrode substrate 25 has the same configuration as the first ground conductor electrode substrate 22, and a ground conductor electrode 25a is formed on one surface of the ceramic green sheet except for a small end. The protection substrate 26 has independent external electrodes 26a, 26b, 26c, 26d, 26e, and 2 on the upper surface of the green sheet.
6f is provided. The input / output of the main line, the input / output of the sub line, and the external terminal for the ground conductor are formed on the side surface of the laminate. In this embodiment, the conductors for the main line and the sub line are formed on one green sheet so as to be arranged in different regions. As described above, by using the technique of the present invention, it was possible to obtain a very small chip-type directional coupler excellent in high frequency characteristics over a wide band.

[0007]

As described above in detail with reference to the embodiments, a very small and high-performance chip-type directional coupler can be constructed using the technique of the present invention. This is extremely useful for miniaturizing microwave components for mobile phones and the like.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of an embodiment according to the present invention.

FIG. 2 is an exploded perspective view of another embodiment according to the present invention.

FIG. 3 is a characteristic comparison diagram of the present invention and the prior art.

FIG. 4 is a perspective view of a conventional technique.

FIG. 5 is an exploded perspective view of a conventional technique.

FIG. 6 is a perspective view of a conventional technique.

FIG. 7 is a circuit block diagram of a usage example of the directional coupler.

[Explanation of symbols]

22, 25, 32, 37 Ground conductor electrode substrate 23, 24, 33, 34, 35, 36 Strip line electrode substrate 26, 38 Protection substrate 22a, 25a, 32a, 37a Ground conductor electrode 23a, 23b, 24a, 24b, 33a , 34a, 3
5a, 36a Strip line electrodes 27a, 27b, 33b, 34b, round electrodes for through holes 28a, 28b, 34c, 35b, 35c, 36b,
Through hole

Claims (3)

(57) [Claims] 1. A method comprising: laminating a dielectric layer on which a conductor film is formed;
A configured directional coupler, surrounded by multiple earth conductors
Coiled, each wound one or more times
Two conductors are formed, and the two coiled conductors
Are formed in separate areas on each dielectric layer.
Directional coupler, characterized in that that. 2. The method according to claim 1, wherein the coil-shaped conductor is
Conductor formed on each of two or more dielectric layers
A directional coupler, wherein the directional coupler is configured to be connected by a cable . 3. The method according to claim 1, wherein the dielectric layer on which the conductive film is formed is laminated.
A configured directional coupler, surrounded by multiple earth conductors
Coiled, each wound one or more times
Two conductors are formed, and the two coiled conductors
Conductors formed on each of two or more dielectric layers
Through a through hole, and each layer has
One of the coil conductors is formed, and the coil-shaped conductor
Looking at the two coiled conductors from the axial direction of the winding direction
Parts surrounded by each wound conductor
A directional coupler characterized by being displaced .