JPH11261313A - Directional coupler - Google Patents

Abstract

PROBLEM TO BE SOLVED: To use a directional coupler with a plurality of frequency bands, to miniaturize it and to obtain a good characteristic by providing first and second main lines and a first auxiliary line, which are constituted of strip lines and connecting the first and second main lines to the first auxiliary line. SOLUTION: Strip line electrode patterns 23-25 are formed so that they are overlapped except a part connected to outer terminals when they are projected from a direction vertical to a dielectric layer. The auxiliary line is formed in a straight line and it is connected to the outer terminals T5 and T6. The length and the width of the strip line pattern electrode 23 becoming the first main line and those of the strip line pattern electrode 24 becoming a second main line become similar, and the thickness of the dielectric layer constituted of the auxiliary line differ. Namely, the thickness of the dielectric layer 13 and the thickness of the dielectric layer 14 (can be constituted of a plurality of dielectric layers) duffer. The first main line and the second main line face to the auxiliary line in the linear part. The degree of connection at the interval is adjusted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a directional coupler used for microwave communication equipment, and more particularly to a laminated chip type directional coupler used for a dual-band portable telephone.

[0002]

2. Description of the Related Art FIG. 5 is a perspective view of a conventional directional coupler using a strip line. In this conventional example, two strip lines 51 and 52 are arranged in parallel on a surface of a dielectric substrate 53 with a distance S therebetween. The parallel lengths of these strip lines 51 and 52 are configured to be the length of a quarter wavelength of the electromagnetic wave propagating in the dielectric substrate. The high-frequency power input from the port 54 passes through the strip line 51 as the main line and is output to the port 55. At this time, the strip line 51 which is the main line
And the strip line 52 as a sub-line,
A part of the power passing through the strip line 51 flows to the strip line 52 and is output to the port 56. At this time, no output appears at the port 57.

Next, a strip line 51 as a main line is used.
When power flows in the opposite direction, that is, from port 55 to port 54, part of the power appears at port 57 and does not appear at port 56. That is, by adopting such a configuration, a part of the forward power and the reverse power flowing through the strip line 51 of the main line is separately extracted to the output ports 56 and 57 terminals of the strip line 52 of the sub line. be able to. This is the basic operation of the directional coupler.

[0004] Coupling from the main line 51 to the sub line 52 is possible by adjusting the distance S between the parallel portions between the two strip lines. In the description of the conventional example of FIG. 5, the main line and the sub line are the strip lines 51 and 52,
As is clear from the symmetrical structure of FIG. 5, even if the roles of the main line and the sub line are switched, the basic operation of the directional coupler can be realized in the same manner.

FIG. 7 shows a block diagram of an application example. The ports P1 and P2 of the main line 72 of the directional coupler 71 are arranged between the transmission power amplifier and the antenna, and
One of the three ports P3 is connected to an automatic gain control circuit, and the other port P4 is connected to a resistance element R for absorbing power.
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 appears at port P4,
It is absorbed by the resistance element R. 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.

In mobile phones and the like, miniaturization is becoming important. Usually, the directional coupler is generally constituted by a strip line having a length of 1/4 wavelength, but the length of the strip line is, for example, 3.3 cm at 900 MHz (1/4 wavelength, (In the case of a relative dielectric constant of 8), a sufficient miniaturization cannot be expected. For this reason, according to Japanese Patent Application Laid-Open No. Hei 7-13111, 3.2 × 1.6 mm is obtained by the configuration shown in FIG.
There has been proposed a stacked directional coupler having a small size, a desired degree of coupling, a low loss, and excellent characteristics.

[0007]

[0004] In recent years, the spread of mobile phones has been remarkable, and the functions of mobile terminals have been improved. As one of the proposals, there has been proposed a dual-band mobile phone which enables a single mobile terminal to communicate in two frequency bands. To configure this dual-band mobile phone, the two frequency bands (for example, 90
0 MHz and 1800 MHz), and the parts to be used must be selected according to each frequency. Therefore, there is a problem that the number of parts increases and the mounting area increases.

For example, the same applies to the directional couplers 71a and 71b in the use example of the block diagram shown in FIG. At this time, since the automatic gain control circuit takes out a constant power of several tens to several tenths and controls the output, it can be shared regardless of the frequency. However, in the directional coupler using FIG. 5 or FIG. 6, as described above, the length of two strip lines or the interval between two strip lines is adjusted according to the frequency band used. , And various characteristics such as coupling loss and insertion loss are different in each frequency band, so that it is difficult to share them in practice. Therefore, it is necessary to use two parts corresponding to each frequency band, and the number of parts increases and the mounting area increases.

A method of further reducing the size of each component is conceivable. However, the use of two components remains the same, and the directional couplers 71a and 71b are still used.
Even if only a part is downsized, it is not easy to reduce the size and cost of the entire device. That is, it is necessary to use two resistive elements R, high-precision dimensions are required for a pattern and a component mounting position on a mounting board due to miniaturization of each component, and the number of components is equivalent to two. There is a problem that mounting time is required.

[0010] In view of the above, it is an object of the present invention to provide a directional coupler that can be used in a plurality of frequency bands, is small, and has good characteristics.

[0011]

Means for Solving the Problems A first invention of the present invention is:
A laminate formed by laminating and integrating dielectric layers,
An electrode pattern is formed in the laminate to form a plurality of strip lines, the first and second main lines including the strip lines, and the first and second main lines. Are directional couplers that are both coupled to the first sub-line.

According to a second aspect of the present invention, in the first aspect, the first main line, the second main line, and the first sub line are formed on separate dielectric layers, respectively, , A directional coupler having a structure in which the first sub-line is located in the middle and the first sub-line is sandwiched between the first main line and the second main line.

A third aspect of the present invention is the directional coupler according to the first aspect, wherein at least one of the plurality of strip lines is formed in a straight line. In this preferred structure, the sub-line is formed in a straight line, the first main line is formed in a shape having a linear portion which is coupled to the straight line portion of the sub-line, and the second main line is also formed. The first main line and the second main line are divided into upper and lower sides of the sub-line so as to sandwich the sub-line. It is desirable that they are arranged.

According to a fourth aspect of the present invention, in the first or second aspect, the first and second main lines and the first sub-line are provided except for a portion connected to an external terminal. It is a directional coupler formed to overlap when viewed in the stacking direction.

According to a fifth aspect of the present invention, in the second aspect, a dielectric layer formed between the first main line and the first sub line, the second main line, and the first This is a directional coupler in which the thickness of a dielectric layer formed between the sub-line and the sub-line is different.

According to a sixth aspect of the present invention, in the first aspect, both ends of the first main line are drawn out from the first side surface of the laminate, and the second side surface is opposed to the first side surface. Are directional couplers in which both ends of the second main line are drawn out, and ends of the sub-line are drawn out on the other two side surfaces, respectively.

According to a seventh aspect of the present invention, in the first aspect of the present invention, any or all of the plurality of strip lines are constituted by an electrode pattern formed in at least two or more layers. It is a vessel. The electrode pattern formed in two or more layers has a winding shape, a spiral shape, a meandering line shape, and the like. In the case of this winding shape, it is preferable that the main line and the sub line are M-coupled.

According to an eighth aspect of the present invention, the first and second main lines are formed of U-shaped strip lines, and the first sub line is formed of a linear strip line. The first and second main lines are respectively disposed above and below the one sub-line with a dielectric layer interposed therebetween, and further, earth electrodes are disposed above and below with a dielectric layer interposed therebetween, and the first main line is disposed. The U-shaped strip line and the U-shaped strip line of the second main line are formed in directions opposite to each other, and the sub-line and the first and second main lines are arranged so as to overlap in the stacking direction. Directional coupler.

According to a ninth aspect of the present invention, there is provided a directional coupler including a plurality of main lines designed to use different frequencies, and one sub-line coupled to the plurality of main lines. In the present invention, a directional coupler corresponding to two or more different working frequencies, a plurality of main lines are formed according to the respective working frequencies, while the sub-line is one sub-line, and This is a directional coupler that can be used for a plurality of different operating frequencies by coupling the main line to one sub-line. Thereby, miniaturization is achieved.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Consider the function of the block diagram of FIG. 8 which constitutes a transmitting section of a dual band portable telephone. Normally, microwave power transmission does not simultaneously transmit the respective powers for the two systems used (for example, the 900 MHz band and the 1800 MHz band), and the two directional couplers 71a and 71b do not operate simultaneously. From this, it is sufficient that one main line and one sub-line are coupled to each other in a certain time zone.
It was thought that a and 73b could be shared.

Therefore, in the present invention, as shown in FIG.
The directional coupler 33 has two main lines 32 and 33 and one sub line 34. By sharing the sub-line in this way, it is easy to reduce the size of the directional coupler, and only one absorption resistance element is required, which can contribute to downsizing of the entire device. The directional coupler sets the line length or the distance between the lines depending on the frequency used, so that the main line cannot be shared.

Therefore, the first and second main lines and the first sub-line are formed, and the first main line and the first sub-line, and the second main line and the first sub-line each time the time. The directional coupler which can contribute to miniaturization and cost reduction of the entire device of the dual band mobile phone by coupling instead can be provided. Of course, the directional coupler of the present invention can be used for applications other than the dual-band mobile phone described above. The present invention is characterized in that a plurality of main lines are coupled to one sub-line, in other words, one sub-line is shared by a plurality of main lines. For example, if the main line is 3
There are two cases.

FIG. 1 is a diagram showing a laminated structure of a laminated directional coupler according to an embodiment of the present invention, and FIG. Figure 1,
In FIG. 2, the hatched portion is a conductor portion. The directional coupler 1 of this embodiment is formed by laminating dielectric layers on which pattern electrodes are formed, and has external electrodes formed on the side and surface. Also, the thickness of the dielectric layer is appropriately set,
In the meantime, a plain dielectric layer on which no electrode pattern is formed can be inserted. The laminated structure of this embodiment will be described in more detail with reference to FIGS.

An earth pattern electrode 21 is formed on the lower dielectric layer 11, and the earth pattern electrode 2 is formed.
Reference numeral 1 has a lead portion connected to the external terminals T7 and T8, and is connected to ground. The dielectric layer 12 on which the strip line pattern electrode 23 serving as the main line is formed is laminated thereon. This pattern electrode 23 is formed in a U-shape and connected to the external terminals T1 and T2. On top of this, a strip line pattern electrode 2 serving as an auxiliary line
The dielectric layer 13 on which 5 is formed is laminated. This pattern electrode 25 is connected to external terminals T5 and T6. The pattern electrode 25 is formed in a straight line, and
Is located at the position of the center line. A dielectric layer 14 on which a strip line pattern electrode 24 serving as another main line is formed is laminated thereon. This pattern electrode 2
4 is formed in a U-shape and is connected to the external terminals T3 and T4. The dielectric layer 15 on which the ground pattern electrode 22 is formed is laminated thereon. The pattern electrode 22 for grounding is formed on the pattern electrode 21 formed on the dielectric layer 11.
And has a lead portion to be connected to the external terminals T7 and T8, and is grounded.
A dielectric layer 16 on which no pattern electrode is formed is laminated thereon.

The strip line electrode pattern 2
The projections 3, 24, and 25 are formed so as to overlap each other except for a portion connected to an external terminal when projected from a direction perpendicular to the dielectric layer. Therefore, the pattern electrodes 23, 25
Has a shape symmetrical with respect to the center line of the dielectric layer.

In this embodiment, a dielectric material which can be fired at a low temperature of about 900 ° C. or less is used. This dielectric material is slurried and then formed into a sheet by a doctor blade. An electrode pattern was formed by appropriately printing a conductor made of Ag by a screen printing method, and after laminating and crimping, a chip was cut and fired. After firing, the external electrodes were printed and baked and then plated to form a laminated directional coupler. Further, the external electrodes may be formed after firing the laminate, or may be formed before firing. Although a dielectric material having a dielectric constant of about 8 was used in this embodiment, the dielectric constant of the present invention is preferably about 5 to 15. Further, the present invention is not limited to the above manufacturing steps.

In this embodiment, as shown in FIGS. 1 and 2, the sub-line is formed in a straight line and connected to the external terminals T5 and T6. Further, the strip line pattern electrode 23 serving as the first main line and the strip line pattern electrode 24 serving as the second main line have the same length and width, and are formed between the sub line and the dielectric. The thickness of the layers is different. That is, the thickness of the dielectric layer 13 in FIG. 1 is different from the thickness of the dielectric layer 14 (may be constituted by a plurality of dielectric layers). Further, the first main line and the second main line are opposed to and connected to the sub-line at the straight portions thereof. Then, the degree of coupling is adjusted at the intervals. According to this configuration, the same printed pattern can be used for the first main line and the second main line, so that the manufacturing cost can be reduced. of course,
A desired degree of coupling can be obtained.

In this embodiment, eight external terminals are formed as shown in FIG. External terminals T1 and T2 of the first main line are formed on the first side surface, and external terminals T3 and T4 of the second main line are formed on a second side surface opposite to the first side surface. . The external terminals T5 and T6 of the sub-line are
Each is formed on another side. Also,
The external terminals T7 and T8 for grounding are formed between the external terminals of the main line. This facilitates miniaturization and facilitates formation of a wiring pattern that connects to other components even when mounted on a circuit board.

FIG. 3 is a circuit block diagram using the directional coupler of this embodiment. In FIG. 3, the directional coupler according to the embodiment of the present invention is indicated by 31 indicated by a broken line, the first main line is 32, the second main line is 33,
There are 34 sub-lines. As compared with the circuit block diagram of the example of using the directional coupler according to the conventional example shown in FIG. 8, the number of parts to be used can be reduced, so that the size and cost of the entire device can be reduced.

The stacked directional coupler shown in FIGS. 1 and 2 has a first operating frequency f1 for 900 MHz and a second operating frequency f2 for 1750 MHz. In the laminated directional coupler of this embodiment, the frequency band of f1 is 880.
915 MHz, frequency band of f2 is 1710-1785
It is used for the transmission unit for dual-band mobile phones of MHz (all transmission frequencies). FIG. 4 shows characteristics of the insertion loss and the coupling loss at this time. By selecting the input terminal for each frequency, the coupling loss is the same as about 20 dB in any frequency band, and the insertion loss is 0.2 dB.
B and below, good characteristics could be obtained. Although not shown in FIG. 4, the isolation characteristics are as good as 30 dB or more.

The conductor pattern of the strip line shown in FIG. 1 has a width of 0.2 mm, a length of 3 to 4 mm, and a thickness of 10 μm.
Ag electrode. Further, the thickness of the dielectric layer 13 shown in FIG.
mm. Note that these dimensions are all dimensions after firing. In addition, the present invention can adjust various characteristics by changing the dimensions of each electrode pattern, the thickness of the dielectric layer (interval between the electrode patterns), the dielectric constant of the dielectric, and the like, and can use the above-mentioned frequency band. It is not limited.

The outer shape of this embodiment is 3.2 × 1.6.
mm and a thickness of 1.0 mm, it was possible to configure a very small size. In the conventional example, there is also a laminated directional coupler having the same dimensions as the outer dimensions of 3.2 × 1.6 mm and the thickness of 1.0 mm. However, when the directional coupler is used for a dual band, two couplers are required. According to the example, the size is reduced to 50% in area ratio. Further, when considering mounting these components on a circuit board, it is necessary to provide a wiring pattern on the board, and according to this embodiment, the pattern can be simplified as compared with the conventional example, so that further miniaturization and Higher efficiency of circuit design can be expected. Further, by reducing the number of components, it is possible to contribute to shortening of the component mounting time.

Next, FIG. 9 shows a laminated structure diagram of a laminated directional coupler according to another embodiment of the present invention. The perspective view of this embodiment is the same as FIG. In FIG. 9, the shaded portions are conductor portions. The directional coupler of this embodiment is formed by laminating dielectric layers on which pattern electrodes are formed, and external electrodes are formed on the side and surface. Also,
The thickness of the dielectric layer is appropriately set, and a plain dielectric layer on which no electrode pattern is formed can be inserted therebetween. The laminated structure of this embodiment will be described in more detail with reference to FIG.

An earth pattern electrode 91 is formed on the lower dielectric layer 81, and the earth pattern electrode 9 is formed.
Reference numeral 1 has a lead portion connected to the external terminals T7 and T8, and is connected to ground. A dielectric layer 82 on which a strip line pattern electrode 93 serving as a first main line is formed is laminated thereon. This pattern electrode 82
Are connected to external terminals T1 and T2. A dielectric layer 83 on which a strip line pattern electrode 95a to be a part of the sub line is formed is laminated thereon. One end of the pattern electrode 95a is connected to the external terminal T6, and a round electrode 95d for a via hole is formed at the other end. A dielectric layer 84 on which a strip line pattern electrode 95b to be a part of the sub line is formed is laminated thereon. One end of the pattern electrode 95b is connected to the external terminal T5, and a via hole electrode 95c is formed at the other end. The via-hole electrode 95c is connected to the via-hole round electrode 95d on the dielectric layer 83, and
a and the pattern electrode 95b form one sub-line in a coil shape.

A dielectric layer 85 on which a strip line pattern electrode 94a to be a part of the second main line is formed. One end of the pattern electrode 94a is connected to the external terminal T4, and the other end is formed with a round electrode 94d for a via hole. A strip line pattern electrode 94 which becomes a part of the second main line is further formed thereon.
The dielectric layer 86 on which b is formed is laminated. One end of the pattern electrode 94b is connected to the external terminal T3, and the other end is formed with a via hole electrode 94c. The via-hole electrode 94c is connected to the via-hole round electrode 94d on the dielectric layer 85, and the pattern electrode 94a and the pattern electrode 94b form a second main line in a coil shape.

On top of this, a dielectric layer 87 on which a ground pattern electrode 92 is formed is laminated. The ground pattern electrode 92 has the same electrode pattern as the pattern electrode 91 formed on the dielectric layer 81.
It has a drawer so as to be connected to T8 and is connected to ground. A dielectric layer 88 on which no pattern electrode is formed is laminated thereon.

The strip line electrode patterns 93, 95a, 95b, 94a, and 94b of this embodiment are formed so as to be overlapped when projected from a direction perpendicular to the dielectric layer. With this structure, the first main line and the first sub line, and the second main line and the first sub line are coil-coupled (M-coupled). This is due to coupling means different from the above embodiment. The directional coupler of the present invention can also be constituted by such a coil connection. In this case, the degree of coupling can be adjusted by the line length, the number of turns, and the interval of each line.

In this embodiment, each line is formed in a coil shape, but may be formed in another shape such as a spiral shape.
Also in this example, a dielectric material having a dielectric constant of about 8 was used as in FIG. Incidentally, also in the present embodiment, the dielectric constant is desirably about 5 to 15, and the present invention is not limited to the above manufacturing steps. According to the present embodiment, it is possible to provide a laminated directional coupler according to the intended use, such as a different frequency band or coupling degree from the above-described embodiment.

In the above embodiment, a directional coupler composed of a plurality of main lines corresponding to a plurality of different operating frequencies and one sub-line coupled to the main lines could be constituted by the laminated structure. As a result, the directional coupler corresponding to a plurality of different operating frequencies can be configured very small. However, the present invention is characterized in that a plurality of main lines are coupled to one sub-line, in other words, one sub-line is shared by a plurality of main lines. Also, the effect of the present invention can be obtained.

[0040]

According to the present invention, a directional coupler which can be used in two or more frequency bands, has a predetermined degree of coupling and good insertion loss characteristics in each frequency band, and is extremely compact. Can be configured. Thus, for example, in a small microwave product such as a mobile phone, it is possible to contribute to miniaturization of the entire device without sacrificing characteristics. It is particularly effective in a dual band portable device.

[Brief description of the drawings]

FIG. 1 is an internal electrode pattern diagram showing a laminated structure of one embodiment according to the present invention.

FIG. 2 is a perspective view of one embodiment according to the present invention.

FIG. 3 is a circuit block diagram of a usage example of the directional coupler according to the present invention.

FIG. 4 is a characteristic diagram of one embodiment according to the present invention.

FIG. 5 is a perspective view of a conventional example.

FIG. 6 is an exploded perspective view of another conventional example.

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

FIG. 8 is a circuit block diagram of a usage example of a directional coupler according to a conventional example.

FIG. 9 is an internal electrode pattern diagram showing a laminated structure of another embodiment according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Laminated directional coupler 11, 12, 13, 14, 15, 16 Dielectric layers 23, 25 Stripline electrode for main line 24 Stripline electrode for subline 21, 22 Earth electrode

Claims (9)

[Claims] 1. A laminated body formed by laminating and integrating dielectric layers, wherein a plurality of strip lines are formed by forming an electrode pattern in the laminated body, and first and second strip lines are formed. Wherein the first and second main lines are both coupled to the first sub line. 2. The first main line, the second main line, and the first sub-line are formed on separate dielectric layers, respectively, and the first sub-line is located at an intermediate position in a stacking direction. The directional coupler according to claim 1, wherein a first sub-line is sandwiched between the first main line and the second main line. 3. The directional coupler according to claim 1, wherein at least one of the plurality of strip lines is formed in a straight line. 4. The method according to claim 1, wherein the first and second main lines and the first sub line are formed so as to overlap each other when viewed in the laminating direction, except for a portion connected to an external terminal. The directional coupler according to claim 1, wherein: 5. A dielectric layer formed between the first main line and the first sub line and a dielectric layer formed between the second main line and the first sub line. The directional coupler according to claim 2, wherein the thickness is different. 6. Both end portions of a first main line are drawn out from a first side surface of the laminate, and both end portions of a second main line are drawn out from a second side surface facing the first side surface, 2. The directional coupler according to claim 1, wherein the end of the sub-line is extended to two other side surfaces. 7. The directional coupler according to claim 1, wherein any or all of the plurality of strip lines are formed of an electrode pattern formed in at least two or more layers. 8. The first and second main lines are formed of U-shaped strip lines, and the first sub line is formed of a linear strip line, and are formed above and below the first sub line. The first and second main lines are respectively disposed with a dielectric layer interposed therebetween, and ground electrodes are disposed above and below with a dielectric layer interposed therebetween, and a U-shaped strip line of the first main line is provided. The U-shaped strip line of the second main line is formed in the opposite direction to the U-shaped strip line, and the sub-line and the first and second
The directional coupler is characterized in that the main lines are arranged so as to overlap in the stacking direction. 9. A directional coupler, comprising: a plurality of main lines designed for different use frequencies; and one sub-line coupled to the plurality of main lines.