JPH11308024A - Directional coupler - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily set the degree of coupling and also to reduce the variation of the degree of coupling. SOLUTION: A dielectric multilayer board 4 is formed of two layers dielectric layers 5 and 6, and a ground electrode 9 are provided on a rear plane side of the layer 6 over almost the entire plane of the layer 6. A 1st strip line 6 extending linearly is provided on the surface plane side 5a of the layer 5 and also, a 2nd strip line 12 that obliquely crosses the board 4 is provided between the layers 5 and 6. The line 12 is arranged with a preliminarily defined angle of torsion defined in advance against the line 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a directional coupler suitable for use in a high-frequency circuit such as a base station of a mobile terminal or a base station.

[0002]

2. Description of the Related Art In general, a large number of base stations for transmitting radio waves to mobile communication terminals such as mobile phones and PHSs are provided. Such a base station monitors whether or not the base station is operating normally by detecting a reflected wave from the transmitting antenna. For this reason, in such a base station, in order to extract a reflected wave from a transmitted wave and a reflected wave from an antenna, for example, a directional coupler disclosed in Japanese Patent Application Laid-Open Nos. 5-152814 and 6-61709, etc. Is used.

A directional coupler of this type according to the prior art will be described with reference to FIGS.

In FIG. 1, reference numeral 1 denotes a directional coupler 3 described later.
Is applied, the base station 1 includes a modulator 1A, an amplifier 1B, an antenna 1C, and the like, as shown in FIG. 9, amplifies a signal modulated by the modulator 1A by an amplifier 1B, and passes through the antenna 1C. It is output as a transmission wave. Further, a directional coupler 3 described below is connected between the amplifier 1B and the antenna 1C, and the detector 2 is connected to the directional coupler 3.

[0005] Reference numeral 3 denotes a directional coupler.
Is composed of a dielectric multilayer substrate 4 described later, first and second strip lines 7 and 8, and a ground electrode 9, as shown in FIG.

Reference numeral 4 denotes a dielectric multilayer substrate serving as a substrate of a directional coupler. The dielectric multilayer substrate 4 has two dielectric layers 5 made of a dielectric material such as a resin material or a ceramic material.
6 are laminated. At this time, the first strip line 7 is disposed on the front side 5A of the dielectric layer 5. A second strip line 8 is provided on the front side 6A of the dielectric layer 6, and a ground electrode 9 is provided on the back side 6B to cover almost the entire back side 6B.

Reference numeral 7 denotes a first strip line serving as a main line. The strip line 7 extends linearly along the surface 5A of the dielectric layer 5 and is formed of a conductive material such as copper or aluminum. I have. And strip line 7
Has terminals P1 and P2 at both ends, an amplifier 1B is connected to terminal P1, and an antenna 1C is connected to terminal P2.
It is connected to the.

Reference numeral 8 denotes a second strip line serving as a coupling line. The strip line 8 is provided between the two dielectric layers 5 and 6, and is formed of a conductive material similarly to the first strip line 7. ing. The second strip line 8 is formed in a substantially U-shape, and faces the first strip line 7 over a predetermined length L which is, for example, about 波長 wavelength of the transmission wave, The strip line 8 extends parallel to the strip line 7. Further, the strip line 8 is separated from the first strip line 7 by a separation dimension D which is substantially equal to the thickness of the dielectric layer 5, as shown in FIG.

The second strip line 8 has terminals P3 and P4 at both ends, and the antenna 1 is connected to the terminal P3.
A detector 2 for detecting the reflected wave from C is connected, a resistor R is connected to the terminal P4, and the terminal P4 is a non-reflection terminal.

The directional coupler 3 according to the prior art has the above-described configuration, and its operation will now be described.

To transmit a signal from the antenna 1C of the base station 1, the amplifier 1B amplifies the signal from the modulator 1A,
The amplified signal is output to terminal P1 as a transmission wave. This transmission wave propagates through the strip line 7 toward the antenna 1C.

At this time, if a problem such as disconnection occurs in the antenna 1C, a reflected wave propagating from the antenna 1C side to the amplifier 1B is generated. The reflected wave propagates from the terminal P2 to the terminal P1 on the strip line 7 in a direction opposite to the transmission wave.

Here, since the first strip line 7 is opposed to the second strip line 8 over a length L, electric field coupling and magnetic field coupling occur in the two strip lines 7, 8. When the reflected wave propagates from the terminal P2 toward the terminal P1 to the strip line 7, the strip line 8
Generates a current that generates a magnetic field in a direction to cancel the magnetic field generated by the reflected wave, that is, a current that flows from the terminal P4 to the terminal P3. Therefore, a signal corresponding to the reflected wave from the terminal P2 to the terminal P1 is output to the terminal P3, but is not output to the terminal P4.

When a transmission wave propagates from the terminal P1 to the terminal P2 to the strip line 7, a current is generated in the strip line 8 to generate a magnetic field in a direction to cancel the magnetic field generated by the transmission wave, that is, from the terminal P3. Terminal P4
A current flows toward. Therefore, a signal corresponding to the transmission wave from terminal P1 to terminal P2 is output to terminal P4 but not to terminal P3.

As described above, since only the signal corresponding to the reflected wave is output to the terminal P3, the detector 2
3 By detecting the strength of the signal output from
It is possible to easily know whether or not a failure has occurred in the base station 1.

[0016]

In the prior art described above, the distance D between the strip lines 7 and 8 and the length L where the strip lines 7 and 8 are opposed to each other are determined by the distance between the strip lines 7 and 8. The degree of coupling is adjusted. In other words, by adjusting the separation dimension D and the length dimension L, the magnitude of the current of the reflected wave propagating through the strip line 7 can be adjusted to the magnitude of the strip line 8.
Is determined to flow.

However, it is difficult to accurately align the two strip lines 7, 8, and each strip line 7, 8
When the position shifts in the direction of arrow A in FIG. 11, which is the width direction of 8, the degree of coupling may decrease. In addition, since it is difficult to form the dielectric layer 5 and the like to have a uniform thickness, there is a tendency that the degree of coupling varies from one directional coupler 3 to another.

For this reason, the directional coupler 3 according to the prior art
Then, in order to know the intensity of the reflected wave, there is a problem that it is necessary to separately provide a circuit for adjusting the signal output from the terminal P3 for each directional coupler 3.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems of the prior art, and has as its object to provide a directional coupler having a small variation in coupling degree.

[0020]

In order to solve the above-mentioned problems, the invention of claim 1 provides at least one dielectric layer having a dielectric material as a base material, and A directional coupler including a conductive main line provided in a state extending linearly, and a conductive coupling line extending linearly opposite to the main line with the dielectric layer interposed therebetween, The coupling line and the main line are formed at twist positions, and the coupling line and the main line are arranged at an arbitrary twist angle.

With this configuration, the main line and the coupling line are electrically and magnetically coupled, and a signal corresponding to a signal propagating through the main line can be propagated to the coupling line side. Further, by arranging the main line and the coupling line at an arbitrary twist angle, the degree of coupling between the main line and the coupling line can be adjusted according to the twist angle.

According to a second aspect of the present invention, there is provided at least one dielectric layer having a dielectric material as a base material, and a conductive main body provided linearly extending along the dielectric layer. A directional coupler comprising: a line; and at least two or more linearly-connected conductive coupling lines facing the main line with the dielectric layer interposed therebetween, wherein each of the coupling lines, the main line, Is formed at the position of the twist, and each of the coupling lines and the main line are arranged at an arbitrary twist angle.

Thus, a signal corresponding to a signal propagating through the main line can be propagated to two or more coupling lines. Therefore, a signal corresponding to a signal propagating in one direction through the main line is propagated to one of the coupled lines, and a signal propagating through the main line in the other direction is propagated to the other coupled line. The corresponding signal can be propagated. Therefore, signals corresponding to two signals propagating in the opposite directions through the main line can be simultaneously extracted by two of these coupled lines.

According to a third aspect of the present invention, a first coupling line and a second coupling line are provided on the dielectric layer, and the first coupling line and the second coupling line are provided with respect to the main line. Are arranged with a substantially equal twist angle.

Thus, the degree of coupling between the first and second coupled lines can be made substantially equal, and the main lines can be inverted from each other by detecting the intensity of the signal extracted from the first and second coupled lines. The strength of two signals propagating in the direction can be detected simultaneously.

Further, the invention of claim 4 is that the angle of twist is set to an angle of 20 degrees or more and 60 degrees or less.

Thus, the main line and the coupling line are electrically and magnetically coupled, and a signal corresponding to a signal propagating in one direction through the main line can be taken out from the coupling line side.
Directivity can be maintained. Further, the degree of coupling between the main line and the coupling line can be adjusted according to the angle of the twist.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a directional coupler according to an embodiment of the present invention will be described in detail with reference to FIGS. In the present embodiment, the same components as those in the related art are denoted by the same reference numerals, and description thereof will be omitted.

FIGS. 1 to 5 relate to the first embodiment, in which 11 is a directional coupler according to the present embodiment, and the directional coupler 11 is a dielectric comprising two dielectric layers 5 and 6. Multi-layer substrate 4, a first strip line 7 as a main line formed on the front side 5A of the dielectric layer 5, a ground electrode 9 formed on the back side 6B of the dielectric layer 6, and a dielectric layer 5,
6 and a second strip line 12 as a coupled line. The strip line 7 has terminals P1 and P2 at both ends. The terminal P1 is connected to, for example, the amplifier 1B, and the terminal P2 is connected to the antenna 1C.

Reference numeral 12 denotes a second strip line, which is disposed between the two dielectric layers 5 and 6 in substantially the same manner as the conventional strip line 8, and is formed of a conductive material. And the strip line 12
Extends linearly along the surface side 6A of the dielectric layer 6 and obliquely crosses the dielectric multilayer substrate 4. For this reason, the strip line 12 is disposed at a twisted position with respect to the strip line 7 formed on the surface 5A of the dielectric layer 5. The second strip line 12 has the dielectric layer 5 interposed between the second strip line 12 and the first strip line 7, and the center of the second strip line 12 in the length direction is the first strip line 7.
And have an opposing area S.

Further, both ends of the strip line 12 become terminals P3 and P4.
A detector 2 for detecting the magnitude of the current of the reflected wave from C is connected, a resistor R is connected to a terminal P4, and the terminal P4 is a non-reflection terminal.

The strip line 12 according to the present embodiment is different from the conventional strip line 8 in that the strip line 12 faces the strip line 7 at a predetermined twist angle θ1. Here, as shown in FIG. 2, when the second strip line 12 is projected on the front side 5A of the dielectric layer 5 on which the first strip line 7 is formed, the twist angle .theta. The first strip line 7 is rotated counterclockwise around the intersection O between the line 7 and the projected view of the second strip line 12, and the rotation angle until the first strip line 7 overlaps the projected view of the second strip line 12 is obtained. is there.
The angle θ1 of the twist is determined by the strip lines 7, 1
Determined by the degree of coupling C between 2 and 9 greater than 0 degrees
The angle is set to be smaller than 0 degree.

That is, as shown by a characteristic line 13 in FIG.
When the twist angle θ1 is small, the strip lines 7, 1
The facing area S of the portion where the two 2 face each other increases. At this time, since the electric field coupling and the magnetic field coupling between the strip lines 7 and 12 become stronger, the degree of coupling C between the strip lines 7 and 12 takes a large value as shown by the characteristic line 14 in FIG.

On the other hand, as shown by a characteristic line 13 in FIG.
When the twist angle θ1 is large, the strip lines 7, 1
The facing area S of the portion where 2 face each other is reduced. At this time, since the electric field coupling and the magnetic field coupling between the strip lines 7 and 12 are weakened, the degree of coupling C between the strip lines 7 and 12 has a small value as shown by the characteristic line 14 in FIG.

For this reason, the twist angle θ 1 formed by the strip lines 7 and 12 is set to a small angle when the coupling degree C is increased, and is set when the coupling degree C is decreased.
It is set to a large angle.

When the twist angle .theta.1 between the strip lines 7 and 12 is 90 degrees, no current flows through the strip line 12 due to the magnetic field coupling, so that the directionality is deteriorated and the terminal P3 responds to the reflected wave. A signal corresponding to the transmission wave is output in addition to the signal obtained. Therefore, the twist angle θ
1 is never set to about 90 degrees.

From these points, the twist angle θ1 is set in the range of the following equation (1).

[0038]

[Equation 1] 20 ° ≦ θ1 ≦ 60 °

The torsion angle θ 1 is preferably set in the range of the following equation (2).

[0040]

[Equation 2] 25 ° ≦ θ1 ≦ 50 °

The directional coupler 11 according to the present embodiment is configured as described above, and its basic operation is not particularly different from that of the prior art.

That is, when a transmission wave propagates from the terminal P1 to the terminal P2 on the strip line 7, a signal corresponding to the transmission wave from the terminal P1 to the terminal P2 is output to the terminal P4, but is output to the terminal P3. Is not output to

As described above, since only the signal corresponding to the reflected wave is output to the terminal P3, the detector 2
3 By detecting the strength of the signal output from
The magnitude of the current of the reflected wave can be detected, and the base station 1
Can be easily known whether or not a problem has occurred.

However, in the directional coupler 11 according to the present embodiment, since the strip lines 7 and 12 are disposed with the twist angle θ1, the strip lines 7 and 12 are set by setting the twist angle θ1. The degree of coupling C between them can be easily set. Therefore, unlike the directional coupler 3 according to the related art, it is not necessary to change the length L and the like facing the strip lines 7 and 8 depending on the coupling degree C.

Further, even when the strip lines 7 and 12 are displaced during the manufacture of the directional coupler 11, the facing area S of the strip lines 7 and 12 does not change. Therefore, the degree of coupling C between the strip lines 7 and 12 does not differ for each directional coupler 11, and the directional coupler 11 having a substantially constant degree of coupling C can be easily manufactured.

Further, since the twist angle θ 1 is set to be not less than 20 degrees and not more than 60 degrees, preferably not less than 25 degrees and not more than 50 degrees, the desired degree of coupling C is set while maintaining the directionality of the directional coupler 11. can do.

Further, since the coupling degree C between the strip lines 7 and 12 can be set to a relatively small value, the magnitude of the current of the reflected wave can be detected without affecting the transmitted wave. Further, since the twist angle θ1 is not set to about 90 degrees, it can be taken out from the strip line 12 as compared with the case where the strip lines 7 and 12 are arranged with a twist angle θ1 of about 90 degrees, for example. The band of the reflected wave can be broadened.

Thus, according to the present embodiment, since the strip lines 7 and 12 are arranged with the twist angle θ 1, by setting the twist angle θ 1, the degree of coupling C between the strip lines 7 and 12 can be increased. Can be easily set. Further, since the degree of coupling C between the strip lines 7 and 12 of each directional coupler 11 can be maintained at a substantially constant value, the directional coupler 11 with a small variation in the degree of coupling C can be easily and inexpensively manufactured. can do.

FIGS. 6 to 8 show a directional coupler according to a second embodiment of the present invention. The directional coupler according to the present embodiment is characterized in that That is, two strip lines are provided at the twist position. In the present embodiment, the same components as those in the related art are denoted by the same reference numerals, and description thereof will be omitted.

Reference numeral 21 denotes a directional coupler according to the present embodiment. The directional coupler 21 is provided on the dielectric multilayer substrate 4 composed of two dielectric layers 5 and 6 and on the surface 5A of the dielectric layer 5. A first strip line 7 as a formed main line, a ground electrode 9 formed on the back surface side 6B of the dielectric layer 6, and a second strip line 7 formed between the dielectric layers 5 and 6 as a coupled line. The third strip lines 22 and 23 are provided.
The strip line 7 has terminals P1 and P2 at both ends.
The terminal P1 is connected to, for example, the amplifier 1B, and the terminal P2 is connected to the antenna 1C.

Reference numeral 22 denotes a second strip line as a first coupling line. The strip line 22 is disposed between the two dielectric layers 5 and 6 in substantially the same manner as the strip line 12 according to the first embodiment. It extends linearly along the surface side 6A of the dielectric layer 6 and obliquely crosses the dielectric multilayer substrate 4. Therefore, the strip line 22 is twisted with respect to the strip line 7 formed on the front surface 5A of the dielectric layer 5. And strip line 2
Numeral 2 faces the first strip line 7 with the dielectric layer 5 interposed therebetween, and is disposed with a twist angle θ2 with respect to the strip line 7.

The strip line 22 has terminals P3 and P4 at its both ends.
A detector 2 for detecting the magnitude of the reflected wave from C is connected, a resistor R is connected to the terminal P4, and the terminal P4 is a non-reflection terminal.

Reference numeral 23 denotes a third strip line serving as a second coupling line. The strip line 23 is disposed between the two dielectric layers 5 and 6 similarly to the second strip line 22. 6 extend linearly along the front side 6A and cross the dielectric multilayer substrate 4 obliquely.

The third strip line 23 is connected to the second strip line 23.
And is opposed to the strip line 7 at a different position from the second strip line 22. Here, the third strip line 23 is also in a twisted position with respect to the first strip line 7, and the dielectric layer 5 is sandwiched between the third strip line 23 and the strip line 7. Then, the third strip line 23 is connected to the second strip line 22.
Similarly to the first strip line 7, the twist angle θ
2 is arranged. The second and third strip lines 22 and 23 are, for example, strip lines 22 and 2 respectively.
They are separated by a dimension not less than three times the width dimension W such as three. Thus, the strip lines 22 and 23 are not mutually coupled.

Further, both ends of the strip line 23 become terminals P5 and P6, a resistor R is connected to the terminal P5, the terminal P5 is a non-reflection terminal, and a terminal P6 is connected to a terminal P5, for example, a transmission wave from the antenna 1C. A detector (not shown) for detecting the magnitude of the current is connected.

Further, the second strip line 22, the third
The twist angle .theta.2 between the strip line 23 and the first strip line 7 satisfies the relations of Equations 1 and 2 as in the first embodiment.

Thus, in the present embodiment configured as described above, substantially the same operation and effects as those of the first embodiment can be obtained. Since the two strip lines 22 and 23 are provided at a twist position with respect to the above, the magnitude of the current of the reflected wave propagating through the first strip line 7 can be detected by the second strip line 22, and At the same time, the magnitude of the current of the transmission wave propagating through the first strip line 7 can be detected by the third strip line 23.

Thus, by detecting the output from the terminal P3 of the second strip line 22, it is possible to monitor the malfunction of the antenna 1C and the like, and to detect the output from the terminal P6 of the third strip line 23. By detecting, the power of the transmission wave output from the antenna 1C can be measured. For this reason, the power of the transmission wave output from the antenna 1C can be adjusted based on the output detected from the terminal P6.

Since the strip lines 22 and 23 face the strip line 7 at substantially the same twist angle θ 2, the degree of coupling between the strip lines 7 and 22 and the degree of coupling between the strip lines 7 and 23 are substantially equal. Can be equal. Therefore, by comparing the magnitude of the output from the terminal P3 of the strip line 22 with the magnitude of the output from the terminal P6 of the strip line 23, the intensity of the reflected wave and the intensity of the transmitted wave can be easily compared. Therefore,
The ratio between the reflected wave and the transmitted wave can be easily measured, and the trouble of the base station 1 or the like can be reliably monitored based on the ratio.

In the above embodiment, the dielectric multilayer substrate 4 in which the two dielectric layers 5 and 6 are laminated is used. However, the present invention is not limited to this, and three or more dielectric layers are used. May be used, and a dielectric substrate having only one dielectric layer may be used, and a main line and a strip line serving as a coupling line may be formed on the front side and the back side of the dielectric layer. It may be configured.

The dielectric multi-layer substrate 4 may be formed by laminating the same dielectric material without forming the dielectric layers having different dielectric materials as base materials.

In the above embodiment, the ground electrode 9 is provided on the back surface 6B of the dielectric layer 6, but the ground electrode 9 may not be provided on the back surface 6B of the dielectric layer 6. .

Further, in the above embodiment, the case where the directional coupler is applied to a base station for mobile communication has been described as an example. Apply to mobile communication equipment, satellite communication equipment, etc.
It may be configured to monitor the malfunction of these communication devices.

[0064]

As described above in detail, according to the first aspect of the present invention, since the main line and the coupling line are disposed at an arbitrary twist angle, by setting the twist angle, The degree of coupling between the main line and the coupling line can be easily set. In addition, since the degree of coupling between the main line and the coupling line can be maintained at a substantially constant value, a directional coupler with little variation in the degree of coupling can be easily and inexpensively manufactured.

According to the second aspect of the present invention, two or more coupling lines are provided at a position twisted with respect to the main line.
A transmission wave propagating in the main line can be detected by one coupling line, and at the same time, a reflected wave propagating in the main line can be detected by another coupling line.

According to the third aspect of the present invention, since the first and second coupling lines are opposed to the main line at equal torsion angles, the distance between the first coupling line and the main line is small. The degree of coupling and the degree of coupling between the second coupling line and the main line can be made substantially equal. Therefore, the intensity of the transmitted wave detected by the first coupled line and the intensity of the reflected wave detected by the second coupled line can be easily compared, and the ratio between the reflected wave and the transmitted wave can be easily measured. By using this ratio, it is possible to reliably monitor a failure of the base station or the like.

Further, according to the fourth aspect of the present invention, since the angle of twist is set to 20 degrees or more and 60 degrees or less, it is possible to set a desired degree of coupling while maintaining the directionality of the directional coupler. it can.

[Brief description of the drawings]

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

FIG. 2 is a plan view showing the directional coupler according to the first embodiment.

FIG. 3 is a longitudinal sectional view as seen from the direction of arrows III-III in FIG. 2;

FIG. 4 is a characteristic diagram showing a relationship between a twist angle and a facing area by first and second striplines.

FIG. 5 is a characteristic diagram showing a relationship between a twist angle and a coupling degree by the first and second strip lines.

FIG. 6 is a perspective view showing a directional coupler according to a second embodiment of the present invention.

FIG. 7 is a plan view showing a directional coupler according to a second embodiment.

8 is a longitudinal sectional view as seen from the direction of arrows VIII-VIII in FIG. 7;

FIG. 9 is a block diagram illustrating a base station to which a directional coupler according to the related art is applied.

FIG. 10 is a perspective view showing a directional coupler according to the related art.

11 is a longitudinal sectional view as seen from the direction of arrows XI-XI in FIG. 10;

[Explanation of symbols]

 Reference Signs List 4 dielectric multilayer substrate 5, 6 dielectric layer 7 strip line (main line) 11, 21 directional coupler 12, 22, 23 strip line (coupled line) θ1, θ2 twist angle

Claims (4)

[Claims] At least one dielectric layer made of a dielectric material as a base material, a conductive main line provided linearly extending along the dielectric layer, and the dielectric layer A directional coupler having a conductive coupling line extending linearly opposite to the main line with the coupling line interposed between the coupling line and the main line. A line is a directional coupler that is arranged with an arbitrary twist angle. 2. At least one dielectric layer made of a dielectric material as a base material, a conductive main line provided linearly extending along the dielectric layer, and the dielectric layer A directional coupler having at least two or more linearly connected conductive coupling lines opposed to the main line with the respective coupling lines and the main line being formed at a twisted position. A directional coupler, wherein each of the coupling lines and the main line are arranged at an arbitrary twist angle. 3. A first coupling line and a second coupling line in the dielectric layer.
3. The directional coupler according to claim 2, wherein the first coupling line and the second coupling line are arranged at substantially the same twist angle with respect to the main line. 4. 4. The directional coupler according to claim 1, wherein the angle of the twist is set to an angle of 20 degrees or more and 60 degrees or less.