JP2002084113A - Directional coupler and directional coupling method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compact low-loss directional coupler and directional coupling method which has prior harmonics spurious suppression characteristics, even in the wave bands ranging from microwave to millimeter. SOLUTION: An input terminal 101 is connected to an output terminal 102 via an open stab 107, a main line 105 and an open stab 108. A coupling terminal 103 is connected to an isolation terminal 104 via a sub-line 106 electromagnetically coupled with the main line 105. The open stabs 107, 108 have stab lengths corresponding to a quarter wavelength at a desired cut off frequency.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a directional coupler and a directional coupling method applicable to a strip line used in a wireless communication device such as a cellular phone and a wireless data communication terminal used in a microwave to millimeter wave band. .

[0002]

2. Description of the Related Art Generally, in a radio communication apparatus, a directional coupler using a λ / 4 strip line or a laminated directional coupler that can be downsized is used to monitor transmission power. . For example, Japanese Unexamined Patent Application Publication No. 10-290108 (directional coupler) discloses a directional coupler to which a function of a low-pass filter is added. By integrating the directional coupler and low-pass filter capacitors and parallel resonators into a laminated structure, it is more compact and has lower loss compared to the case where the directional coupler and low-pass filter are realized separately. Can be obtained.

[0003] Here, with the spread of mobile phones and the demand for high-speed data communication, the carrier frequency of wireless communication tends to increase in frequency from the microwave band to the millimeter wave band where frequency resources are abundant. Then, the harmonic frequency band to be suppressed by the low-pass filter is a high frequency band that is an integral multiple of the increased carrier frequency.

[0004]

In such a high frequency band, the size of the component with respect to the wavelength cannot be ignored, and the circuit behaves like a distributed constant. Therefore, in the conventional wireless communication device, the required characteristics cannot be realized in the capacitor and the parallel resonator constituting the low-pass filter, and a desired suppression amount cannot be obtained as a filter.

The present invention has been made in view of the above points, and has a directional coupler and a directional coupler capable of obtaining a small size, low loss, and excellent harmonic spurious suppression characteristics even in a microwave band to a millimeter wave band. The aim is to provide a method.

[0006]

A directional coupler according to the present invention is connected to a main line through which a high-frequency signal is transmitted, a sub line electromagnetically coupled to the main line, and an input side of the main line. A first open stub and a second open stub connected to the output side of the main line, wherein the first and second open stubs have a stub length that short-circuits at a desired frequency; A configuration is adopted in which the line and the first and second open stubs constitute an impedance matching circuit with an external circuit at a passing frequency.

With this configuration, it is possible to obtain a small-sized and low-loss characteristic as compared with a case where the directional coupler and the low-pass filter are individually realized, and to achieve both the suppression characteristic at the cut-off frequency and the low-loss characteristic at the pass frequency. Moreover, a small directional coupler can be realized.

The directional coupler of the present invention employs a configuration in which the first and second open stubs are short-circuited at different frequencies.

With this configuration, a function of removing spurious components at two different cutoff frequencies is added to the directional coupler, so that better spurious component suppression characteristics can be obtained.

The directional coupler of the present invention includes a third open stub connected to the main line and having a stub length that is short-circuited at a different frequency from the first and second open stubs. The first, second, and third open stubs are configured to form an impedance matching circuit with an external circuit at a pass frequency.

With this configuration, a function of removing spurious signals at three different cutoff frequencies is added to the directional coupler, so that better spurious signal suppression characteristics can be obtained.

A directional coupler according to the present invention includes a short stub having a stub length connected to a main line and short-circuiting at a desired frequency, wherein the main line, the first and second open stubs, and the short stub are used. , An impedance matching circuit is formed at a pass frequency with an external circuit.

With this configuration, it is possible to obtain a suppression characteristic in a low-frequency region, so that a better spurious suppression characteristic can be obtained.

The directional coupler of the present invention employs a configuration in which the first and second open stubs are short-circuited at different frequencies.

With this configuration, a function of removing spurious signals at two different cutoff frequencies is added to the directional coupler, so that better spurious signal suppression characteristics can be obtained.

The directional coupler according to the present invention includes a third open stub connected to the main line and having a stub length shorted at a different frequency from the first and second open stubs, and a stub shorted at a desired frequency. A short stub having a length, wherein said main line and said first and second
The third open stub and the short stub form an impedance matching circuit with an external circuit at a passing frequency.

According to this configuration, a function of removing spurious components at three different cutoff frequencies is added to the directional coupler, and a suppression characteristic in a low frequency region can be obtained. Therefore, a better spurious suppression characteristic can be obtained. Obtainable.

A directional coupler according to the present invention includes a main line through which a high-frequency signal is transmitted, a sub line electromagnetically coupled to the main line, and a first short stub connected to an input side of the main line. A second short stub connected to the output side of the main line, wherein the first and second short stubs have a stub length that short-circuits at a desired frequency, and the main line and the first and second short stubs have a stub length. The second short stub employs a configuration in which an impedance matching circuit is formed at a pass frequency with an external circuit.

According to this configuration, it is possible to obtain a suppression characteristic in a low frequency range, so that a better spurious suppression characteristic can be obtained.

The directional coupler of the present invention employs a configuration in which the first and second short stubs are short-circuited at different frequencies.

According to this configuration, since a function of removing spurious signals at two different cutoff frequencies is added to the directional coupler, better spurious signal suppression characteristics can be obtained.

The directional coupler according to the present invention includes an open stub having a stub length connected to the main line and short-circuiting at a desired frequency. The stub is connected to the main line, the first and second short stubs, and the open stub. , An impedance matching circuit is formed at a pass frequency with an external circuit.

According to this configuration, a function of removing spurious at least two cutoff frequencies is added to the directional coupler, and a suppression characteristic in a low frequency region can be obtained, so that a better spurious suppression characteristic can be obtained. Obtainable.

A radio communication apparatus according to the present invention comprises: a variable gain amplifier for variably amplifying an input high-frequency signal; any one of the above-described directional couplers for performing impedance matching of a signal output from the variable gain amplifier; An automatic power control circuit that controls the gain of the variable gain amplifier so that the transmission output extracted by the directional coupler falls within a specified range is adopted.

With this configuration, it is possible to obtain a small size, low loss and good harmonic spurious suppression characteristics even in a microwave band to a millimeter wave band, so that required characteristics are realized in a capacitor and a parallel resonator constituting a low-pass filter. And a desired amount of suppression can be obtained as a filter.

According to the directional coupling method of the present invention, there is provided a step of electromagnetically coupling a main line and a sub-line, and connecting an open stub short-circuited at a desired frequency to an input side and an output side of the main line. And a step of performing impedance matching at a pass frequency, and a step of transmitting a high-frequency signal to the main line and the open stub.

According to the directional coupling method of the present invention, a stub for suppressing high-frequency spurious is arranged at the input / output of the main line of the directional coupler, and the susceptance of the stub and the main line at the carrier frequency are connected to the input / output terminal. A method of performing impedance matching between circuits is employed.

With these methods, it is possible to obtain a small-sized and low-loss characteristic as compared with a case where the directional coupler and the low-pass filter are individually realized, and to achieve both the suppression characteristic at the cut-off frequency and the low-loss characteristic at the pass frequency. And a compact directional coupler can be realized.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The gist of the present invention is that a stub for suppressing high-frequency spurious is arranged at the input and output of the main line of the directional coupler, and the susceptance of the stub and the main line are connected to the input and output terminals at the carrier frequency. Is to perform impedance matching between the performed circuits.

According to the present invention, a stub for suppressing high frequency spurious is arranged at the input and output of the main line of the directional coupler, and the susceptance of the stub and the impedance between the circuit where the main line is connected to the input and output terminals at the carrier frequency. By performing the matching, it is possible to obtain a small, low-loss, and favorable harmonic spurious suppression characteristic even in the microwave band to the millimeter wave band. Note that a stub is a type of line loaded on a signal line, and has three parameters of an electrical length, a characteristic impedance, and a termination condition (open / short). The electrical length is a parameter determined by the length of the stub, and the characteristic impedance is a parameter determined by the width of the stub.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1) FIG. 1 is a diagram showing a configuration example of a directional coupler according to Embodiment 1 of the present invention.
This is applied to a directional coupler for monitoring transmission power.

The directional coupler 100 has an input terminal 101,
It mainly includes an output terminal 102, a coupling terminal 103, an isolation terminal 104, a main line 105, a sub line 106, an open stub 107, and an open stub 108.

The input terminal 101 is connected to the open stub 10
7, connected to the output terminal 102 via the main line 105 and the open stub 108. The coupling terminal 103 is connected to the isolation terminal 104 via a sub-line 106 that is electromagnetically coupled to the main line 105.

Open stub 107 and open stub 1
08 has the same characteristics, and has a stub length corresponding to a quarter wavelength at a desired cutoff frequency fs11. The following description is based on the assumption that the characteristic impedance of the directional coupler constituted by the main line 105 and the sub line 106 is equal to the impedance of the external circuit.

First, the realization of unnecessary wave suppression at a desired cutoff frequency will be described. The susceptance Bos (f) of the open stub becomes Bos (fsos) = infinity at a frequency f = fsos in which the electrical length of the stub corresponds to １ ／ wavelength. Therefore, at the frequency fsos, the impedance Zos after the insertion of the open stub is the impedance Zip at the stub insertion point.
The following equation (1) is obtained regardless of the value of, and the circuit is short-circuited.

Zos (fsos) = 1 / [1 / Zip + jBos (fsos)] = 0 Ω (1) Therefore, in the configuration shown in FIG. 1, the main line is provided by the open stubs 107 and 108 in fs11. Since 105 is short-circuited, unnecessary waves at cutoff frequency fs11 can be suppressed.

Next, a case will be described in which impedance matching is performed with an external circuit (not shown) connected to the input and output of the directional coupler 100 at the pass frequency. FIG.
, The main line 105 and the open stub 107, 1
08 can be composed of a distributed constant element such as a microstrip line, for example. Generally, the distributed constant element has a frequency characteristic different from that of a lumped constant element such as an inductor or a capacitor. However, if the frequency is limited to a single frequency, the distributed constant element can approximate the lumped constant element with high accuracy.

FIG. 2 shows that the input terminal 101 and the output terminal 1 of the directional coupler 100 shown in FIG.
Matching circuit 200 approximating up to 02 with a lumped element
Is shown. 2, the input terminal 201 is the input terminal 101 in FIG. 1, the output terminal 202 is the output terminal 102 in FIG. 1, the inductor 203 is the main line 105 in FIG. 1, the capacitor 204 is the open stub 107 in FIG. The capacitors 205 respectively correspond to the open stubs 108 in FIG. Here, since the matching circuit 200 has the same configuration as the π-type LC matching circuit, matching between the external circuits connected to the input terminal 201 and the output terminal 202 can be achieved, and as a result, the mismatch loss is reduced. As a result, low loss characteristics can be realized.

FIG. 3 shows the pass characteristics of a directional coupler designed with a pass frequency fo = 5 GHz, a cutoff frequency fs11 = 10 GHz, and a coupling degree of 17 dB. The directional coupler 1
No. 00 was composed of an alumina substrate having a substrate thickness of 0.635 mm and a dielectric constant of 10 formed thereon.

Here, the input terminal 1 at the pass frequency fo
01 and the output terminal 102 is 0.25 dB,
Among them, the coupling loss is 0.09 dB, and the pure loss is 0.09 dB.
It was 16 dB. Since the conventional directional coupler alone has a loss of 0.2 dB (including coupling loss) and the filter loss is about 0.2 dB, the directional coupler 100 according to the first embodiment is a conventional directional coupler. The transmission characteristic was improved by about 0.15 dB as compared with that of FIG. Fs11 (10 GHz:
(Corresponding to the second harmonic), and a suppression amount of 30 dB or more was obtained.

FIG. 4 is a diagram showing a specific configuration example of a wireless communication device to which the directional coupler according to Embodiment 1 of the present invention is applied. In FIG. 4, since the configuration of the directional coupler 100 is the same as that of FIG. 1, the same reference numerals as in FIG. In FIG. 4, a high-frequency signal input to a variable gain amplifier 401 is transmitted from an antenna 403 via a power amplifier 402 and a directional coupler 100. The resistor 404 is an absorption resistor that prevents a part of a reflected wave due to an antenna mismatch or the like from being induced in the coupling terminal 103. The automatic power control circuit 405 monitors a part of the transmission output extracted by the directional coupler 100, and controls the variable gain amplifier 401 so that the transmission output falls within a specified range.
To control the gain.

As described above, by adding the function of the low-pass filter for removing the harmonic spurious to the directional coupler, a smaller size and lower loss characteristics can be achieved as compared with a case where the directional coupler and the low-pass filter are individually realized. Obtainable. By using the circuit configuration of FIG. 1 for the directional coupler, it is possible to achieve both a suppression characteristic at a cutoff frequency and a low loss characteristic at a pass frequency, and to realize a small directional coupler.

(Embodiment 2) Hereinafter, Embodiment 2 of the present invention will be described with reference to FIGS. FIG.
FIG. 9 is a diagram illustrating a configuration example of a directional coupler according to Embodiment 2 of the present invention, which is applied to a directional coupler for monitoring transmission power.

The directional coupler 500 has input terminals 501,
It mainly includes an output terminal 502, a coupling terminal 503, an isolation terminal 504, a main line 505, a sub line 506, an open stub 507, and an open stub 508. The input terminal 501 is connected to the output terminal 502 via the open stub 507, the main line 505, and the open stub 508.
Connected to. The coupling terminal 503 is connected to the main line 505.
Is connected to an isolation terminal 504 via a sub-line 506 electromagnetically coupled to the terminal.

Open stub 507 and open stub 5
08 has a stub length corresponding to a quarter wavelength at two different cutoff frequencies fs21 and fs22. Further, the following description will be made on the assumption that the characteristic impedance of the directional coupler constituted by the main line 505 and the sub line 506 is equal to the impedance of the external circuit.

First, the realization of unnecessary wave suppression at a desired cutoff frequency will be described. In the configuration shown in FIG. 5, the open stub 5
07, the main line 505 is short-circuited by the open stub 508 at the cutoff frequency fs22, so that unnecessary waves at two different cutoff frequencies fs21 and fs22 can be suppressed.

Next, a case will be described in which impedance matching is performed with an external circuit (not shown) connected to the input / output of the directional coupler 500 at the passing frequency. The main line 505 and the open stubs 507 and 508 can be composed of distributed constant elements such as microstrip lines. Generally, the distributed constant element has a frequency characteristic different from that of a lumped constant element such as an inductor or a capacitor. However, if the frequency is limited to a single frequency, the distributed constant element can approximate the lumped constant element with high accuracy.

FIG. 6 shows that the input terminal 501 to the output terminal 5 of the directional coupler 500 in FIG.
Matching circuit 600 approximating up to 02 with a lumped element
Is shown. Here, the input terminal 601 is the input terminal 501 in FIG. 5, and the output terminal 602 is the output terminal 50 in FIG.
2, the inductor 603 is connected to the main line 505 in FIG.
The capacitor 604 is connected to the open stub 5 in FIG.
07. Here, the matching circuit 600 is a π-type LC
Since the configuration is the same as that of the matching circuit, matching between the external circuits connected to the input terminal 601 and the output terminal 602 can be achieved, and as a result, mismatch loss can be reduced and low loss characteristics can be realized. .

FIG. 7 is a diagram showing an example of characteristics of the directional coupler 500. The pass frequency fo = 5 GHz and the cut-off frequency fs21 =
The characteristic simulation results when 10 GHz and fs22 = 15 GHz are shown. As the amount of suppression at the cutoff frequency,
35 dB or more at fs21 (10 GHz: equivalent to 2nd harmonic), fs22
(15 GHz: equivalent to third harmonic), a value of 30 dB or more was obtained.

FIG. 8 is a diagram showing a specific configuration example of a wireless communication device to which the directional coupler according to Embodiment 2 of the present invention is applied. The wireless communication device shown in FIG. 8 is obtained by applying a directional coupler 500 instead of the directional coupler 100 to the wireless communication device shown in FIG. The wireless communication device shown in FIG. 8 has a function of removing spurious signals at two different cutoff frequencies added to the directional coupler as compared with the wireless communication device shown in FIG. 4, so that a better spurious suppression characteristic can be obtained. Obtainable.

(Embodiment 3) Hereinafter, Embodiment 3 of the present invention will be described with reference to FIGS. FIG.
FIG. 9 is a diagram illustrating a configuration example of a directional coupler according to Embodiment 3 of the present invention, which is applied to a directional coupler for monitoring transmission power.

The directional coupler 900 has input terminals 901,
Output terminal 902, coupling terminal 903, isolation terminal 904, main line 905, sub line 906, open stub 907, open stub 908, and open stub 9
09 mainly. The input terminal 901 is connected to the output terminal 902 via the open stub 907, the main line 905, and the open stub 908. The open stub 909 is arranged on the main line 905. The coupling terminal 903 is connected to the isolation terminal 904 via a sub-line 906 electromagnetically coupled to the main line 905.

Open stubs 907, 908 and 909
Has a stub length corresponding to a quarter wavelength at three different cutoff frequencies fs31, fs32 and fs33. In addition,
The main line 905 and the sub line 906 do not have to have the same length.

First, the realization of unnecessary wave suppression at a desired cutoff frequency will be described. In the configuration shown in FIG. 9, the open stub 9
07, the open stub 908 at the cutoff frequency fs32, and the open stub 9 at the frequency fs33.
Since the main line 905 is short-circuited by 09, unnecessary waves at three different cutoff frequencies fs31, fs32, and fs33 can be suppressed.

Next, a case will be described in which impedance matching is performed with an external circuit (not shown) connected to the input and output of the directional coupler 900 at the pass frequency. The main line 905 and the open stubs 907, 908, 909 can be composed of distributed constant elements such as microstrip lines. Generally, the distributed constant element has a frequency characteristic different from that of a lumped constant element such as an inductor or a capacitor. However, if the frequency is limited to a single frequency, the distributed constant element can approximate the lumped constant element with high accuracy.

FIG. 10 shows a matching circuit 10 in which the input terminal 901 to the output terminal 902 of the directional coupler 900 in FIG.
00 is shown. Here, input terminal 1001 is input terminal 901 in FIG. 9, output terminal 1002 is output terminal 902 in FIG. 9, inductors 1003 and 1004 are main line 905 in FIG. 9, capacitor 1005 is open stub 907 in FIG. 1006 corresponds to the open stub 908 in FIG. 9, and the capacitor 1007 corresponds to the open stub 909 in FIG.
Here, since the matching circuit 1000 has the same configuration as the LC multi-stage π-type matching circuit, the input terminal 1001 and the output terminal 100
2 can be matched, and as a result, mismatch loss can be reduced and low loss characteristics can be realized.

FIG. 11 is a diagram showing an example of the characteristics of the directional coupler 900, where Zos31 = 57.7Ω and Zos32 = 41.4.
Ω, Zos33 = 50Ω, pass frequency fo = 5GHz, cutoff frequency
fs31 = 15 GHz, fs32 = 20 GHz, fs33 = 10 GHz, characteristic impedance of main line 905 50Ω, phase angle 13
3.2 degrees shows the simulation results of the simulation characteristics when the open stub 909 is arranged at the midpoint of the main line 905. In addition, Zos31, Zos32,
The Zos 33 is an open stub 907, 90 in FIG.
8 and 909.
Fs31 (15 GHz:
20 dB or more at fs32 (20 GHz: equivalent to 4th harmonic), fs33 (10 GHz: equivalent to 2nd harmonic) at 3rd harmonic)
And obtained a value of 30 dB or more.

FIG. 12 is a diagram showing a specific configuration example of a wireless communication device to which the directional coupler according to Embodiment 3 of the present invention is applied. The wireless communication device shown in FIG. 12 is obtained by applying a directional coupler 900 instead of the directional coupler 100 to the wireless communication device shown in FIG. The wireless communication device shown in FIG. 12 has a function of removing spurious signals at three different cutoff frequencies added to the directional coupler as compared with the wireless communication device shown in FIG. 4, so that a better spurious suppression characteristic can be obtained. Obtainable.

(Embodiment 4) Hereinafter, Embodiment 4 of the present invention will be described with reference to FIGS. FIG. 13 is a diagram illustrating a configuration example of a directional coupler according to Embodiment 4 of the present invention, which is applied to a directional coupler for monitoring transmission power.

The directional coupler 1300 is connected to the input terminal 130
1, output terminal 1302, coupling terminal 1303, isolation terminal 1304, main line 1305, sub line 130
6, open stub 1307, open stub 1308
And a short stub 1309. The input terminal 1301 is connected to the open stub 1307, the main line 13
05, output terminal 130 through open stub 1308
2 is connected. The short stub 1309 is arranged on the main line 1305. Also, a coupling terminal 1303
Is a sub-line 1306 electromagnetically coupled to the main line 1305
Is connected to the isolation terminal 1304 via the.

The open stub 1307 and the open stub 1308 have the same characteristics, and have a stub length corresponding to １ ／ wavelength at a desired cutoff frequency fs11. Also,
The short stub 1309 has a stub length corresponding to a quarter wavelength at a desired pass frequency fo. The following description is based on the assumption that the characteristic impedance of the directional coupler constituted by the main line 1305 and the sub line 1306 is equal to the impedance of the external circuit.

First, the realization of the unnecessary wave suppression at the desired cutoff frequency will be described. In the configuration shown in FIG. 13, from the above equation (1), at the cutoff frequency fs41, the open stub 1307 and the open stub 1308 make the main line 13
Since 05 is short-circuited, unnecessary waves at the cutoff frequency fs41 can be suppressed.

In addition, the short stub susceptance Bos
(f) is a frequency f at which the electrical length of the stub corresponds to a half wavelength.
Bsss (fss) = infinity at = fsss. Therefore, at the frequency fsss, the impedance Zss after the insertion of the short stub is represented by the following equation (2) regardless of the value of the impedance Zip at the stub insertion point, and the circuit is short-circuited.

Zss (fsss) = 1 / [1 / Zip + jBss (fsss)] = 0 Ω (2) Therefore, in the configuration shown in FIG. 13, the main line 1305 is formed by the short stub 1309 in 2fo. Since the short circuit occurs, unnecessary waves at the cutoff frequency 2fo can be suppressed.

Next, a case will be described in which impedance matching is performed with an external circuit (not shown) connected to the input and output of the directional coupler 1300 at the pass frequency. In FIG. 13, the main line 1305, the open stub 130
7, 1308 and the short stub 1309 can be constituted by distributed constant elements such as microstrip lines. Generally, the distributed constant element has a frequency characteristic different from that of a lumped constant element such as an inductor or a capacitor. However, if the frequency is limited to a single frequency, the distributed constant element can approximate the lumped constant element with high accuracy.

FIG. 14 shows a matching circuit 1400 obtained by approximating from the input terminal 1301 to the output terminal 1302 of the directional coupler 1300 in FIG. In FIG. 14, an input terminal 140
1 is connected to the input terminal 1301 in FIG.
13, an output terminal 1302 in FIG. 13, an inductor 1403 in the main line 1305 in FIG. 13, and a capacitor 1404 in the open stub 1307 in FIG.
The capacitors 1405 respectively correspond to the open stubs 1308 in FIG. Since the short stub 1309 has a stub length corresponding to a quarter wavelength at the pass frequency fo, the susceptance becomes zero.
Therefore, the short stub 1309 is ignored in FIG. Here, since the matching circuit 1400 has the same configuration as the π-type LC matching circuit, the input terminal 1401 and the output terminal 1
Matching between external circuits connected to 402 can be achieved, and as a result, mismatch loss can be reduced and low loss characteristics can be realized.

FIG. 15 is a diagram showing an example of characteristics of the directional coupler 1300, where Zos41 = 60Ω, Zss41 = 100Ω,
Pass frequency fo = 5GHz, cutoff frequency fs41 = 10GH
A simulation characteristic result is shown in the case where z, the characteristic impedance of the main line 1305 is 50Ω, the phase angle at fo is 67.4 degrees, and the short stub 1309 is arranged at the middle point of the main line 1305. Note that Zos41 is the characteristic impedance of the line forming the open stub 1307 and the open stub 1308, and Zss41 is the characteristic impedance of the line forming the short stub 1309. Fs41 (1)
(0 GHz: corresponding to the second harmonic) at least 40 dB. In addition, suppression characteristics are obtained even in a low frequency region. In the present design, the open stub 1307 and the open stub 130
8 and the cutoff frequency by the short stub 1309 match. Here, open stub 1
If the electrical lengths of the open stub 1307 and the open stub 1308 are changed,
8 and a cut-off frequency by the short stub 1309, the suppression characteristics can be obtained.

FIG. 16 is a diagram showing a specific configuration example of a wireless communication device to which the directional coupler according to Embodiment 4 of the present invention is applied. The wireless communication device illustrated in FIG. 16 is obtained by applying a directional coupler 1300 instead of the directional coupler 100 to the wireless communication device illustrated in FIG. The wireless communication device shown in FIG. 16 is different from the wireless communication device shown in FIG.
Since a suppression characteristic in a low frequency region can be obtained, a better spurious suppression characteristic can be obtained.

Embodiment 5 Hereinafter, Embodiment 5 of the present invention will be described with reference to FIGS. FIG. 17 is a diagram illustrating a configuration example of a directional coupler according to Embodiment 5 of the present invention, which is applied to a directional coupler for monitoring transmission power.

The directional coupler 1700 is connected to the input terminal 170
1, output terminal 1702, coupling terminal 1703, isolation terminal 1704, main line 1705, sub line 170
6, open stub 1707, open stub 1708
And a short stub 1709. The input terminal 1701 is connected to the open stub 1707, the main line 17
05, output terminal 170 through open stub 1708
2 is connected. The short stub 1709 is arranged on the main line 1705. Also, the coupling terminal 1703
Is a sub-line 1706 electromagnetically coupled to the main line 1705
Is connected to the isolation terminal 1704 via the.

The open stub 1707 and the open stub 1708 have two different cutoff frequencies fs21 and fs22.
Has a stub length corresponding to １ ／ wavelength. The short stub 1709 has a stub length corresponding to a quarter wavelength at a desired pass frequency fo. The following description is based on the assumption that the characteristic impedance of the directional coupler constituted by the main line 1705 and the sub line 1706 is equal to the impedance of the external circuit.

First, the realization of unnecessary wave suppression at a desired cutoff frequency will be described. In the configuration shown in FIG. 17, the main line 1705 is short-circuited by the open stub 1707 at the cut-off frequency fs51 and by the open stub 1708 at the cut-off frequency fs52 according to the above equation (1).
Unwanted waves at two different cutoff frequencies fs51 and fs52 can be suppressed. In the configuration shown in FIG. 17, the short stub 17
Since the main line 1705 is short-circuited by 09, unnecessary waves at the cutoff frequency 2fo can be suppressed.

Next, a case will be described in which impedance matching is performed with an external circuit (not shown) connected to the input and output of the directional coupler 1700 at the pass frequency. The main line 1705, the open stubs 1707 and 1708, and the short stub 1709 can be configured by distributed constant elements such as microstrip lines. Generally, the distributed constant element has a frequency characteristic different from that of a lumped constant element such as an inductor or a capacitor. However, if the frequency is limited to a single frequency, the distributed constant element can approximate the lumped constant element with high accuracy.

FIG. 18 shows a matching circuit 1800 in which the input terminal 1701 to the output terminal 1702 of the directional coupler 1700 in FIG. Here, the input terminal 1801 is shown in FIG.
7 is an input terminal 1701 and an output terminal 1802 in FIG.
7, the inductor 1803 is connected to the main line 1705 in FIG.
17 corresponds to the open stub 1707 in FIG. 17, and the capacitor 1805 corresponds to the open stub 1708 in FIG. The short stub 1709
Has a stub length corresponding to a quarter wavelength at the pass frequency fo, so that the susceptance becomes zero. Therefore, FIG.
8, the short stub 1709 is ignored. Here, since matching circuit 1800 has the same configuration as the π-type LC matching circuit, matching between external circuits connected to input terminal 1801 and output terminal 1802 can be achieved, and as a result, mismatch loss is reduced. As a result, low loss characteristics can be realized.

FIG. 19 is a diagram showing an example of the characteristics of the directional coupler 1700, where Zos51 = 90Ω, Zos52 = 52Ω, Zs
s51 = 100Ω, pass frequency fo = 5GHz, cutoff frequency fs5
1 = 10 GHz, fs52 = 15 GHz, characteristic impedance of main line 1705 50 Ω, phase angle at fo 74.5 degrees, short stub 1709 shows a characteristic simulation result in the case of being arranged at the middle point of main line 1705. . The amount of suppression at the cutoff frequency is fs51 (10 GHz: 2
A value of 40 dB or more was obtained at fs52 (15 GHz: corresponding to third harmonic) at 25 dB or more.

FIG. 20 is a diagram showing a specific configuration example of a radio communication device to which the directional coupler according to Embodiment 5 of the present invention is applied. The wireless communication device shown in FIG. 20 is obtained by applying a directional coupler 1700 instead of the directional coupler 100 to the wireless communication device shown in FIG. The wireless communication device shown in FIG. 20 is different from the wireless communication device shown in FIG.
Since the function of removing spurious at two different cutoff frequencies is added to the directional coupler, better spurious suppression characteristics can be obtained. In addition, since a suppression characteristic in a low frequency region can be obtained, a better spurious suppression characteristic can be obtained.

Embodiment 6 Hereinafter, Embodiment 6 of the present invention will be described with reference to FIGS. 21 to 24. FIG. 21 is a diagram illustrating a configuration example of a directional coupler according to Embodiment 6 of the present invention, which is applied to a directional coupler for monitoring transmission power.

The directional coupler 2100 is connected to the input terminal 210
1, output terminal 2102, coupling terminal 2103, isolation terminal 2104, main line 2105, sub line 210
6, open stub 2107, open stub 210
8, open stub 2109 and short stub 211
It is mainly composed of 0. The input terminal 2101 includes an open stub 2107, a main line 2105, and an open stub 21.
08 to the output terminal 2102. The open stub 2109 and the short stub 2110 are arranged on the main line 2105. Also, the coupling terminal 2103
Is a sub-line 2106 electromagnetically coupled to the main line 2105
Is connected to the isolation terminal 2104 via the.

Open stubs 2107, 2108 and 2
109 is three different cutoff frequencies fs61, fs62 and fs
63 has a stub length corresponding to a quarter wavelength.
The short stub 2110 has a stub length corresponding to a quarter wavelength at a desired pass frequency fo. In addition,
The main line 2105 and the sub line 2106 do not have to have the same length.

First, a description will be given of the realization of unnecessary wave suppression at a desired cutoff frequency. In the configuration shown in FIG. 21, the main line 2105 is short-circuited by the open stub 2107 at the cut-off frequency fs 61, the open stub 2108 at the cut-off frequency fs 62, and the open stub 2109 at the frequency fs 63 according to the above equation (1).
Unwanted waves at three different cutoff frequencies fs61, fs62 and fs63 can be suppressed. In the configuration shown in FIG. 21, the main line 2105 is short-circuited by the short stub 2110 at 2fo according to the above equation (2).
Unwanted waves at the cutoff frequency 2fo can be suppressed.

Next, a case will be described in which impedance matching is performed with an external circuit (not shown) connected to the input / output of the directional coupler 2100 at the pass frequency. Main line 2105, open stubs 2107, 2108, 2
The short stub 109 and the short stub 2110 can be constituted by distributed constant elements such as microstrip lines. Generally, the distributed constant element has a frequency characteristic different from that of a lumped constant element such as an inductor or a capacitor. However, if the frequency is limited to a single frequency, the distributed constant element can approximate the lumped constant element with high accuracy.

FIG. 22 shows a matching circuit 2200 in which the input terminal 2101 to the output terminal 2102 of the directional coupler 2100 in FIG. Here, the input terminal 2201 is shown in FIG.
1 is an input terminal 2101 and an output terminal 2202 in FIG.
1, an inductor 2203,
Reference numeral 2204 denotes the main line 2105 in FIG. 21, and capacitor 2205 denotes the open stub 2107 in FIG.
2206 is an open stub 2109 in FIG.
In addition, the capacitors 2207 correspond to the open stubs 2108 in FIG. 21, respectively. Since the short stub 2110 has a stub length corresponding to a quarter wavelength at the pass frequency fo, the susceptance becomes zero.
Therefore, the short stub 2110 is ignored in FIG. Here, since the matching circuit 2200 has the same configuration as the LC multi-stage π-type matching circuit, matching between the external circuits connected to the input terminal 2201 and the output terminal 2202 can be achieved, and as a result, mismatch loss can be reduced. , Low loss characteristics can be realized.

FIG. 23 shows the directional coupler 2 in FIG.
As a characteristic example of 100, Zos61 = 57.7Ω, Zos62 =
41.4Ω, Zos63 = 50Ω, pass frequency fo = 5GHz, cutoff frequency fs61 = 10GHz, fs62 = 15GHz, fs63 = 2
0 GHz, the characteristic impedance of the main line 2105 is 50Ω,
With a phase angle of 133.2 degrees, the open stub 2109 is arranged at the middle point of the main line 2105, and the short stub 2110 is a simulation characteristic of the directional coupler 2100 arranged between the open stub 2108 and the open stub 2109. Shown in In addition, Zos61, Zos62,
Zos63 is an open stub 2107 in FIG.
This is the impedance of the lines constituting 2108 and 2109. Fs61 (1)
40 dB or more at 0 GHz: 2nd harmonic, fs62 (15 GHz:
A value of 25 dB or more was obtained at fs63 (20 GHz: equivalent to a fourth harmonic) at 25 dB or more at the third harmonic.

FIG. 24 is a diagram showing a specific configuration example of a wireless communication device to which the directional coupler according to Embodiment 6 of the present invention is applied. The wireless communication device shown in FIG. 24 is obtained by applying a directional coupler 2100 instead of the directional coupler 100 to the wireless communication device shown in FIG. The wireless communication device shown in FIG. 24 is different from the wireless communication device shown in FIG.
Since the function of removing spurious signals at three different cutoff frequencies is added to the directional coupler, better spurious suppression characteristics can be obtained. In addition, since a suppression characteristic in a low frequency region can be obtained, a better spurious suppression characteristic can be obtained.

Embodiment 7 Hereinafter, Embodiment 7 of the present invention will be described with reference to FIGS. FIG. 25 is a diagram illustrating a configuration example of a directional coupler according to Embodiment 7 of the present invention, which is applied to a directional coupler for monitoring transmission power.

The directional coupler 2500 has an input terminal 250
1, output terminal 2502, coupling terminal 2503, isolation terminal 2504, main line 2505, sub line 250
6, short stub 2507 and short stub 250
8 mainly. The input terminal 2501 includes a short stub 2507, a main line 2505, and a short stub 25.
08 to the output terminal 2502. Further, the coupling terminal 2503 is connected to the isolation terminal 2504 via a sub line 2506 electromagnetically coupled to the main line 2505.
Connected to.

The short stub 2507 and the short stub 2508 have the same characteristics and have a desired cut-off frequency fs7.
1 has a stub length corresponding to a half wavelength. The main line 2505 and the sub line 2506 do not need to have the same length.

First, the implementation of the unnecessary wave suppression at the desired cutoff frequency will be described. In the configuration shown in FIG. 25, the short stub 2507 and the short stub 2508 use the main line 25 at the cutoff frequency fs71 according to the above equation (4).
Since 05 is short-circuited, unnecessary waves at the cutoff frequency fs71 can be suppressed.

Next, a case will be described in which impedance matching is performed with an external circuit (not shown) connected to the input / output of the directional coupler 2500 at the pass frequency. Main line 2505 and short stubs 2507 and 2508
Can be constituted by a distributed constant element such as a microstrip line. Generally, a distributed constant element is
Although it has a frequency characteristic different from that of a lumped constant element such as an inductor or a capacitor, the lumped constant element can be accurately approximated by a distributed constant element as long as it is a single frequency.

FIG. 26 shows a matching circuit 2600 in which the input terminal 2501 to the output terminal 2502 of the directional coupler 2500 in FIG. Here, the input terminal 2601 is shown in FIG.
5 is an input terminal 2501 and an output terminal 2602 in FIG.
5, the inductor 2603 is connected to the main line 2505 in FIG.
25 corresponds to the short stub 2507 in FIG. 25, and the inductor 2605 corresponds to the short stub 2508 in FIG. Here, the matching circuit 2600
Since the configuration is the same as that of the LCπ type matching circuit, the input terminal 26
01 and an external circuit connected to the output terminal 2602 can be matched. As a result, mismatch loss can be reduced and low loss characteristics can be realized.

FIG. 27 is a diagram showing an example of the characteristics of the directional coupler 2500. Zss71 = Zss72 = 100Ω, pass frequency fo = 5 GHz, cutoff frequency fs71 = 15 GHz, main line 250
5 shows a characteristic simulation result when the characteristic impedance is 50Ω and the phase angle is 98.2 degrees. In addition, Zss
71 and Zss72 are short stubs 2507 and 2508
Is the impedance of the line constituting Fs71 (15 GHz: equivalent to third harmonic)
And obtained a value of 30 dB or more. In addition, suppression characteristics are obtained even in a low frequency region.

FIG. 28 is a diagram showing a specific configuration example of a radio communication device to which the directional coupler according to Embodiment 7 of the present invention is applied. The wireless communication device shown in FIG. 28 is obtained by applying a directional coupler 2500 instead of the directional coupler 100 to the wireless communication device shown in FIG. The wireless communication device shown in FIG. 28 is different from the wireless communication device shown in FIG.
Since a suppression characteristic in a low frequency region can be obtained, a better spurious suppression characteristic can be obtained.

(Eighth Embodiment) An eighth embodiment of the present invention will be described below with reference to FIGS. FIG. 29 is a diagram illustrating a configuration example of a directional coupler according to Embodiment 8 of the present invention, which is applied to a directional coupler for monitoring transmission power.

The directional coupler 2900 has an input terminal 290
1, output terminal 2902, coupling terminal 2903, isolation terminal 2904, main line 2905, sub line 290
6, short stub 2907, short stub 2908
And an open stub 2909. The input terminal 2901 is connected to the short stub 2907 and the main line 29.
05, output terminal 290 via short stub 2908
2 is connected. The open stub 2909 is arranged on the main line 2905. Also, the coupling terminal 2903
Is a sub-line 2906 electromagnetically coupled to the main line 2905
Is connected to the isolation terminal 2904 via the.

The short stub 2907 and the short stub 2908 have the same characteristics and have a desired cut-off frequency fs8.
1 has a stub length corresponding to a half wavelength. Further, the open stub 2909 has a stub length corresponding to １ ／ wavelength at the cutoff frequency fs82. The main line 2905 and the sub line 2906 do not have to have the same length.

First, the realization of unnecessary wave suppression at a desired cutoff frequency will be described. In the configuration shown in FIG. 29, the short line stub 2907 and the short stub 2908 at the cutoff frequency fs81 indicate that the main line 29 has a cutoff frequency fs81.
Since 05 is short-circuited, unnecessary waves at cutoff frequency fs81 can be suppressed. Further, since the main line 2905 is short-circuited by the open stub 2909 at the cutoff frequency fs82 from the above equation (1), unnecessary waves at the cutoff frequency fs82 can be suppressed.

Next, a case will be described in which impedance matching is performed with an external circuit (not shown) connected to the input and output of the directional coupler 2900 at the pass frequency. The main line 2905, the short stubs 2907, 2908, and the open stub 2909 can be composed of distributed constant elements such as microstrip lines.
Generally, the distributed constant element has a frequency characteristic different from that of a lumped constant element such as an inductor or a capacitor. However, if the frequency is limited to a single frequency, the distributed constant element can approximate the lumped constant element with high accuracy.

FIG. 30 shows a matching circuit 3000 in which the input terminal 2901 to the output terminal 2902 of the directional coupler 2900 in FIG. Here, the input terminal 3001 is shown in FIG.
9 is an input terminal 2901 and an output terminal 3002 in FIG.
9, the inductor 3003,
Reference numeral 3004 denotes a main line 2905 in FIG. 29, and inductor 3005 denotes a short stub 2907 in FIG.
29, the inductor 3006 is in the short stub 2908 in FIG.
909 respectively. Here, the matching circuit 30
00 has the same configuration as the LC multi-stage π-type matching circuit,
The matching between the external circuits connected to the input terminal 3001 and the output terminal 3002 can be achieved. As a result, mismatch loss can be reduced, and low loss characteristics can be realized.

FIG. 31 is a diagram showing an example of characteristics of the directional coupler 2900, where Zss81 = Zss82 = 50Ω and Zss83 = 6.
9.1Ω, pass frequency fo = 5GHz, cutoff frequency fs81 = 1
A characteristic simulation result is shown in the case where 5 GHz, cutoff frequency fs = 10 GHz, characteristic impedance of main line 2905 is 50Ω, phase angle is 28.9 degrees, and open stub 2909 is arranged at the center of main line 2905. Note that Zss81 and Zss82 are short stubs 2907 and 2907, respectively.
908 is the impedance of the line constituting Zss8
Reference numeral 3 denotes the impedance of the line forming the open stub 2909. The amount of suppression at the cutoff frequency, fs
81 (15 GHz: equivalent to 3rd harmonic) 35 dB or more, fs82
(10 GHz: equivalent to the second harmonic), a value of 30 dB or more was obtained. In addition, suppression characteristics are obtained even in a low frequency region.

FIG. 32 is a diagram showing a specific configuration example of a radio communication device to which the directional coupler according to Embodiment 8 of the present invention is applied. The wireless communication device shown in FIG. 32 is obtained by applying a directional coupler 2900 instead of the directional coupler 100 to the wireless communication device shown in FIG. The wireless communication device shown in FIG. 32 is different from the wireless communication device shown in FIG.
Since the function of removing spurious at two different cutoff frequencies is added to the directional coupler, better spurious suppression characteristics can be obtained. In addition, since a suppression characteristic in a low frequency region can be obtained, a better spurious suppression characteristic can be obtained.

Embodiment 9 Hereinafter, Embodiment 9 of the present invention will be described with reference to FIGS. FIG. 33 is a diagram illustrating a configuration example of a directional coupler according to Embodiment 9 of the present invention, which is applied to a directional coupler for monitoring transmission power.

The directional coupler 3300 has an input terminal 330
1, output terminal 3302, coupling terminal 3303, isolation terminal 3304, main line 3305, sub line 330
6, short stub 3307, short stub 3308
And an open stub 3309. The input terminal 3301 is a short stub 3307, the main line 33
05, output terminal 330 via short stub 3308
2 is connected. The open stub 3309 is arranged on the main line 3305. In addition, the coupling terminal 3303
Is a sub-line 3306 electromagnetically coupled to the main line 3305
Is connected to the isolation terminal 3304 via the.

The short stub 3307 and the short stub 3308 have two different cutoff frequencies fs91 and fs9.
2 has a stub length corresponding to a half wavelength. The open stub 3309 has a stub length corresponding to a quarter wavelength at the cutoff frequency fs93. The main line 3305 and the sub line 3306 do not have to have the same length.

First, a description will be given of how to realize unnecessary wave suppression at a desired cutoff frequency. In the configuration shown in FIG. 33, the main line 3305 is short-circuited by the short stub 3307 at the cut-off frequency fs91 and the main line 3305 is short-circuited by the short stub 3308 at the cut-off frequency fs92. Unwanted waves at the frequency fs92 can be suppressed.
In addition, since the main line 3305 is short-circuited by the open stub 3309 at the cutoff frequency fs93 according to the above equation (1), unnecessary waves at the cutoff frequency fs93 can be suppressed.

Next, a case will be described in which impedance matching is performed with an external circuit (not shown) connected to the input and output of the directional coupler 3300 at the pass frequency. The main line 3305, the short stubs 3307, 3308, and the open stub 3309 can be constituted by distributed constant elements such as microstrip lines.
Generally, the distributed constant element has a frequency characteristic different from that of a lumped constant element such as an inductor or a capacitor. However, if the frequency is limited to a single frequency, the distributed constant element can approximate the lumped constant element with high accuracy.

FIG. 34 shows a matching circuit 3400 obtained by approximating from the input terminal 3301 to the output terminal 3302 of the directional coupler 3300 in FIG. 33 by a lumped element at the pass frequency fo. Here, the input terminal 3401 is shown in FIG.
3 is an input terminal 3301 and an output terminal 3402 in FIG.
3, an inductor 3403,
Reference numeral 3404 denotes a main line 3305 in FIG. 33, and inductor 3405 denotes a short stub 3307 in FIG.
The inductor 3406 is in the short stub 3308 in FIG. 33, and the capacitor 3407 is in the open stub 3
309 respectively. Here, the matching circuit 34
00 has the same configuration as the LC multi-stage π-type matching circuit,
Matching between external circuits connected to the input terminal 3401 and the output terminal 3402 can be achieved, and as a result, mismatch loss can be reduced and low loss characteristics can be realized.

FIG. 35 is a diagram showing a characteristic example of the directional coupler 3300, where Zss91 = 50Ω and Zss92 = 86.7.
Ω, Zss93 = 69.1Ω, pass frequency fo = 5 GHz, cutoff frequency fs91 = 15 GHz, cutoff frequency fs92 = 20 GHz, cutoff frequency fs93 = 10 GHz, characteristic impedance of main line 3305 50 Ω, phase angle 28.9 degrees, open stub 33
Reference numeral 09 denotes a characteristic simulation result when the main line 3305 is arranged at the middle point. In addition, Zss9
1, Zss92 is the impedance of the line forming the short stubs 3307 and 3308, and Zss93 is the impedance of the line forming the open stub 3309. The amount of suppression at the cutoff frequency is fs91 (1
20 dB or more at 5 GHz: equivalent to 3rd harmonic, fs92 (20 GHz:
A value of 20 dB or more was obtained at fs93 (10 GHz: corresponding to a second harmonic), and a value of 35 dB or more was obtained. In addition, suppression characteristics are obtained even in a low frequency region.

FIG. 36 is a diagram showing a specific configuration example of a radio communication device to which the directional coupler according to Embodiment 9 of the present invention is applied. The wireless communication device shown in FIG. 36 is obtained by applying a directional coupler 3300 instead of the directional coupler 100 to the wireless communication device shown in FIG. The wireless communication device shown in FIG. 36 is different from the wireless communication device shown in FIG.
Since the function of removing spurious at least two cutoff frequencies is added to the directional coupler, better spurious suppression characteristics can be obtained. In addition, since a suppression characteristic in a low frequency region can be obtained, a better spurious suppression characteristic can be obtained.

[0110]

As described above, according to the present invention,
A stub for suppressing high-frequency spurious is arranged at the input and output of the main line of the directional coupler, and impedance matching between the susceptance of the stub and the circuit where the main line is connected to the input and output terminals is performed at the carrier frequency. Even in the wave band to the millimeter wave band, a small size, low loss, and good harmonic spurious suppression characteristics can be obtained.

[Brief description of the drawings]

FIG. 1 shows a configuration example of a directional coupler according to Embodiment 1 of the present invention.

FIG. 2 is a diagram showing a matching circuit of the directional coupler according to the embodiment.

FIG. 3 is a diagram showing characteristics of the directional coupler according to the embodiment.

FIG. 4 is a diagram showing a configuration example of a wireless communication device using the directional coupler according to the embodiment.

FIG. 5 is a diagram illustrating a configuration example of a directional coupler according to Embodiment 2 of the present invention;

FIG. 6 is a diagram showing a matching circuit of the directional coupler according to the embodiment.

FIG. 7 is a diagram showing a characteristic example of the directional coupler according to the embodiment;

FIG. 8 is a diagram illustrating a configuration example of a wireless communication device using the directional coupler according to the embodiment;

FIG. 9 is a diagram showing a configuration example of a directional coupler according to Embodiment 3 of the present invention.

FIG. 10 is a diagram showing a matching circuit of the directional coupler according to the embodiment.

FIG. 11 is a diagram showing an example of characteristics of the directional coupler according to the embodiment.

FIG. 12 is a diagram showing a configuration example of a wireless communication device using the directional coupler according to the embodiment.

FIG. 13 is a diagram showing a configuration example of a directional coupler according to Embodiment 4 of the present invention.

FIG. 14 is a diagram showing a matching circuit of the directional coupler according to the embodiment.

FIG. 15 is a diagram showing a characteristic example of the directional coupler according to the embodiment.

FIG. 16 is a diagram illustrating a configuration example of a wireless communication device using the directional coupler according to the embodiment;

FIG. 17 is a diagram showing a configuration example of a directional coupler according to Embodiment 5 of the present invention.

FIG. 18 is a diagram showing a matching circuit of the directional coupler according to the embodiment.

FIG. 19 is a diagram showing an example of characteristics of the directional coupler according to the embodiment.

FIG. 20 illustrates a configuration example of a wireless communication device using the directional coupler according to the above embodiment.

FIG. 21 is a diagram illustrating a configuration example of a directional coupler according to a sixth embodiment of the present invention.

FIG. 22 is a diagram showing a matching circuit of the directional coupler according to the embodiment.

FIG. 23 is a diagram showing a characteristic example of the directional coupler according to the embodiment.

FIG. 24 is a diagram showing a configuration example of a wireless communication device using the directional coupler according to the above embodiment.

FIG. 25 is a diagram showing a configuration example of a directional coupler according to a seventh embodiment of the present invention.

FIG. 26 is a diagram showing a matching circuit of the directional coupler according to the embodiment.

FIG. 27 is a diagram showing a characteristic example of the directional coupler according to the embodiment.

FIG. 28 illustrates a configuration example of a wireless communication device using the directional coupler according to the above embodiment.

FIG. 29 is a diagram showing a configuration example of a directional coupler according to Embodiment 8 of the present invention.

FIG. 30 is a diagram showing a matching circuit of the directional coupler according to the embodiment.

FIG. 31 is a diagram showing an example of characteristics of the directional coupler according to the embodiment.

FIG. 32 is a diagram showing a configuration example of a wireless communication device using the directional coupler according to the above embodiment.

FIG. 33 is a diagram illustrating a configuration example of a directional coupler according to a ninth embodiment of the present invention;

FIG. 34 is a diagram showing a matching circuit of the directional coupler according to the embodiment.

FIG. 35 is a diagram showing a characteristic example of the directional coupler according to the embodiment.

FIG. 36 is a diagram illustrating a configuration example of a wireless communication device using the directional coupler according to the above embodiment.

[Explanation of symbols]

 105, 2505 Main line 106, 2506 Sub line 107, 108 Open stub 203, 2603, 2604, 2605 Inductor 204, 205 Capacitor 401 Variable gain amplifier 402 Power amplifier 405 Automatic power control circuit 2507, 2508 Short stub

Claims (12)

[Claims] 1. A main line through which a high-frequency signal is transmitted, a sub line electromagnetically coupled to the main line, a first open stub connected to an input side of the main line, and an output side of the main line. A second open stub connected to the first and second open stubs, the first and second open stubs have a stub length that short-circuits at a desired frequency, and the main line and the first and second open stubs A directional coupler, comprising an impedance matching circuit at a pass frequency with an external circuit. 2. The first and second open stubs are short-circuited at different frequencies from each other.
A directional coupler as described. And a third open stub connected to the main line and having a stub length that short-circuits at a different frequency from the first and second open stubs. The directional coupler according to claim 1 or 2, wherein the open stub (3) forms an impedance matching circuit with an external circuit at a passing frequency. 4. A short stub having a stub length connected to the main line and short-circuited at a desired frequency, wherein the main line, the first and second open stubs and the short stub are used to control an external circuit and a pass frequency. 2. An impedance matching circuit according to claim 1, wherein:
A directional coupler as described. 5. The first and second open stubs are short-circuited at different frequencies from each other.
A directional coupler as described. 6. A third stub connected to the main line and having a stub length short-circuited at a frequency different from the first and second open stubs, and a short stub having a stub length short-circuited at a desired frequency. 2. The directional coupling according to claim 1, wherein the main line, the first, second, and third open stubs and the short stub form an impedance matching circuit at a pass frequency with an external circuit. vessel. 7. A main line through which a high-frequency signal is transmitted, a sub line electromagnetically coupled to the main line, a first short stub connected to an input side of the main line, and an output side of the main line. And a second short stub that connects to the main line and the first and second short stubs. The first and second short stubs have a stub length that short-circuits at a desired frequency. A directional coupler, comprising an impedance matching circuit at a pass frequency with an external circuit. 8. The stub of claim 1, wherein the first and second short stubs are short-circuited at different frequencies.
A directional coupler as described. 9. An open stub having a stub length connected to the main line and short-circuited at a desired frequency, wherein the main line, the first and second short stubs, and the open stub provide an external circuit and a pass frequency at the pass frequency. 8. An impedance matching circuit, comprising: an impedance matching circuit;
Or the directional coupler according to claim 8. 10. A variable gain amplifier for variably amplifying an input high-frequency signal and impedance matching of a signal output from the variable gain amplifier.
A radio comprising: the directional coupler according to any one of the above, and an automatic power control circuit that controls a gain of the variable gain amplifier so that a transmission output extracted by the directional coupler falls within a prescribed range. Communication equipment. 11. A step of electromagnetically coupling a main line and a sub-line, and connecting an input side and an output side of the main line with an open stub that short-circuits at a desired frequency to perform impedance matching with an external circuit at a pass frequency. Performing the step of
Transmitting a high-frequency signal to the main line and the open stub. 12. A stub for suppressing high frequency spurious is arranged at the input and output of the main line of the directional coupler, and the impedance matching between the susceptance of the stub and the circuit in which the main line is connected to the input / output terminal at the carrier frequency. The direction coupling method to be performed.