JPH07105653B2 - Directional coupler - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a directional coupler which is arranged in a transmission path of high frequency power and which can change detection power based on incident power, that is, change coupling degree. .

[Prior Art] Conventionally, when high-frequency power is supplied to a load, for example, an antenna via a transmission line, the incident power signal is divided, or the passing power is measured and monitored, and the characteristics of the antenna, for example,
A directional coupler is used for measuring reflected power (standing wave ratio) based on the junction state of impedance.

It is known that such a directional coupler has a configuration in which a secondary line (detection line) which is closely parallel to the primary line (center conductor) of the coaxial structure is arranged at a relatively low frequency. On the other hand, in a relatively high frequency band, a matrosstrip line structure, a structure including two waveguides in which a probe is arranged in a coupling hole, and the like are adopted.

Power in the directional coupler derived the secondary line on the basis of the incident power (P _i) (p _i), i.e., the degree of coupling (C) is represented by the following formula (1).

C = ₁₀ log ₁₀ P _i / p _i [dB] (1) [Problems to be solved by the invention] However, in the above-described conventional directional coupler, the degree of coupling (C) is constant. That is, the secondary line and the like are arranged in a fixed length and in a fixed state in consideration of the passing frequency and the passing power. Therefore, the degree of coupling (C) is constant, and in such a state, there is a drawback that a wide range of frequencies and passing electric power cannot be dealt with.

The present invention has been made in view of the above point, and provides a directional coupler capable of coping with a wide range of frequencies and passing powers by deriving the power related to the coupling degree by changing it to a desired value. The purpose is to

[Means for Solving the Problems] In order to solve the above problems, in the directional coupler of the present invention, the directional coupler is arranged in a transmission path through which high-frequency power passes and derives detection power proportional to incident power. In the directional coupler, a first end to which the incident power signal is input and an in-phase end that is derived by forming the incident power signal with a phase difference of 180 ° and 1
A first end having an 80 ° phase difference end and a second end including a separation end;
And a first end of the primary line is connected to the in-phase end of the first 180 ° hybrid coupler and has a second end and is substantially parallel to the primary line. A 6 dB directional coupler including a secondary line having first and second ends formed therein; a first end connected to a 180 ° phase difference end of the first 180 ° hybrid coupler; The incident power signal of 180 ° phase difference supplied to the first end is derived by being formed into a signal of 180 ° phase difference having the same phase as the signal and a signal of 270 ° phase difference further shifted by 90 °. A 90 ° phase difference coupler having an in-phase end and a second end including a 90 ° phase difference end and a separation end, a first end to which a load is connected, and a second line of the temporary line of the 6 dB directional coupler. A first end composed of an in-phase end connected to each other, a 180 ° phase difference end connected to the same phase end of the 90 ° phase difference coupler, and a separation end; And a end, and in-phase and 180
A second 180 ° hybrid coupler which combines the incident power signals formed in the phase difference of ° and is led out to the first end, and is connected to each of the separated ends of the first and second 180 ° hybrid couplers. Connected between the 90 ° phase difference end of the 90 ° phase difference coupler and the second end of the secondary line of the 6 dB directional coupler. The level of the incident power having the phase difference of 270 ° derived is changed and supplied to the second end of the secondary line of the 6 dB directional coupler, and the secondary line is supplied based on the incident power of the phase difference of 270 °. And a variable means for varying and deriving the detection power of the 90 ° phase difference derived from the first end of the.

[Operation] In the directional coupler of the present invention configured as described above, the directional coupler is connected to one of the 180 ° hybrid couplers having the same phase and the 180 ° phase difference. A coupler is provided, the detected power based on the incident power is derived with a 90 ° phase difference, and a 90 ° phase difference coupler that forms the same phase and a 90 ° phase is provided on the other transmission line. do it,
The 180 ° phase difference and 270 ° phase difference power signals are derived. Here, the 270 ° phase difference power signal is changed and applied to the directional coupler, whereby the detected power derived from the directional coupler based on the incident power, that is, the power related to the coupling degree is changed. Is derived.

[Embodiment] Next, an embodiment of the directional coupler according to the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 shows the configuration of the first embodiment, and FIGS.
The frequency-coupling degree and frequency-insertion loss characteristics of the first embodiment are shown in the figure. Further, FIG. 4 shows a second embodiment, and FIGS. 5 and 6 show characteristics of frequency-coupling degree and frequency-insertion loss. In addition, in order to avoid complication in the text and screen, common reference numerals are given to common components, and detailed description is omitted.

In FIG. 1, reference numeral 10 is, for example, a phase inversion type 180 ° hybrid coupler, and the 180 ° hybrid coupler 10 has an incident power signal (hereinafter referred to as incident power as necessary) P _i. Is provided with a first end T ₁ . Further, the second end A is composed of respective output ends from which incident powers P _a1 and P _a2 obtained by dividing the incident power P _i into the same phase and 180 ° phase difference are derived, and a separation end from which the incident power P _a3 is derived. (hereinafter, shown respectively in the second end _{a 1, a 2, a 3} ) it has a.

The first end T ₁ covers the whole and has a metal frame B ₀ having a shielding function.
A transmitter (not shown) such as a coaxial plug seat fixed to the
Etc., the incident power P _i is supplied via a coaxial transmission line.

Here, a 6 dB directional coupler 12 is connected to the second end A _{1 from} which the incident power P _a1 is derived. The 6 dB directional coupler 12 is composed of a primary line 12a and a secondary line 12b, each having a first end _12a1 ,
12b ₁ and second ends 12 a ₂ and 12 b ₂ are formed, and the first end 12 b ₁ is connected to the output terminal T ₂ .

Next, the 3 dB hybrid coupler 14 is connected to the second end A _{2 from} which the incident power P _a2 is derived. Further incident power P
A non-reflective termination (dummy load) 17, which is means for impedance matching and power absorption, is connected to the second end A _{3 from} which a ₃ is derived. The 3 dB hybrid coupler 14 has a first end T ₃ to which the incident power P _a2 is input, and an output end from which the incident power P _b1 and P _b2 divided into the same phase and a 90 ° phase difference are derived. It has a second end B (hereinafter referred to as second ends B ₁ , B ₂ and B _{3 respectively} ) which is a separation end from which the electric power P _b3 is derived.

The second end B ₁ has a 180 ° hybrid coupler 22 to be described later.
Are connected. Furthermore, for example, one end of a variable attenuator 16 such as a rotary waveguide attenuator is connected to the second end B _2, and the other end is the second end of the secondary line 12b of the 6 dB directional coupler 12. It is connected to the two ends 12 _b2 . In this case, drive means 18 for operating an electric rotation mechanism (not shown) of the variable attenuator 16 is also provided. The driving means 18 may be manual means. Here, a non-reflective terminal 20 which is an impedance matching and power absorbing means is connected to the second end B ₃ of the separation end.

Next, a 180 ° hybrid coupler 22 having the same structure and function as the 180 ° hybrid coupler 10 is provided. The 180 ° hybrid coupler 22 uses a coaxial plug seat, and has a first end connected to a load, for example, an antenna (not shown) to which the transmission power P ₀ is transmitted via a coaxial power feed line or the like. T ₄ and the 6 dB directional coupler 12
Connected to the second end 12 _a2 of the primary line 12a of
A second end C including an input end and a separation end connected to the second end B ₁ of the hybrid coupler 14 (hereinafter, respectively referred to as the second end C ₁ ,
C ₂ and C ₃ ).

In this case, the above-mentioned components are impedances, for example,
Of course, they are configured to match 50Ω, and each is connected.

Next, the operation of the embodiment configured as described above will be described.

First, the incident power P _i is input to the first end T ₁ of the 180 ° hybrid coupler 10 and the in-phase incident power P _a1 is derived to the second end A ₁ . Further, the incident power P _a2 and the incident power P _a3 in which a phase difference of 180 ° is formed at the second ends A ₂ and A ₃ are derived.

The incident power P _a1 is the primary line 12a of the 6 dB directional coupler 12.
After being fed to the first end 12 _a1 of the through the second end 12 _a2 180
Input to the second end C ₁ of the hybrid coupler 22. In this case, the power input to the second end C ₁ of the 180 ° hybrid coupler 22 is in phase with the incident power P _i .

On the other hand, the incident power P _a2 derived from the second end A ₂ of the 180 ° hybrid coupler 10 is the first end of the 3 dB hybrid coupler 14.
Entered in T ₃ . Then, the incident power P _b1 having a phase difference of 180 ° (in phase with the power P _a2 ) from the power P _a1 at the second end B ₁ is derived and supplied to the second end C ₂ of the 180 ° hybrid coupler 22. It

Therefore, as described above, power having the same phase as the incident power P _a1 is input to the second end C ₁ of the 180 ° hybrid coupler 22,
Also, the power P _b1 having a phase difference of 180 ° with the incident power P _a1 is input to the second end C ₂ , and the transmission power P is transmitted from the first end T _4.
It is sent to the load (not shown) as ₀ .

The non-reflective terminal 26 is connected to the second end C ₃ to absorb the power and to match the impedance.

On the other hand, the power P _a2 is applied to the second end B ₂ of the 3 dB hybrid coupler 14,
Power P with 90 ° phase difference (phase difference between power P _a1 and 270 °)
_b2 is derived and this power P _b2 is supplied to the variable attenuator 16. The variable attenuator 16 controls the level of power supplied to the second end 12 _b2 of the secondary line 12 b of the 6 dB directional coupler 12. Here, the drive means 18 to which the control signal C _s is input causes the electric rotation mechanism (not shown) to operate, and the degree of attenuation of the variable attenuator 16 is controlled.

The drive signal S _d supplied to the second end 12 _b2 of the secondary line 12 b of the 6 dB directional coupler 12, that is, the drive signal S _d having a phase difference of 270 ° from the incident power P _a1 is a 6 dB directional coupler. 12 secondary tracks 1
It is derived in phase with the first end 12 _b1 of 2b, that is, with a phase difference of 270 ° from the incident power P _a1 . On the other hand, the power P supplied by the 6 dB directional coupler 12 to the first end 12 _a1 of the primary line 12 a
_The power having a phase difference of 90 degrees from _a1 , that is, the power related to the coupling degree of the 6 dB directional coupler 12 is the second end 12 of the secondary line 12b.
This power is derived from _b1 and has a phase difference of 180 ° with the drive signal S _d having a phase difference of 270 °, and therefore cancels each other.

Therefore, the incident power detection derived via the output terminal T ₂ based on the level of the power attenuated by the variable attenuator 16 and supplied to the second end 12 _b2 of the secondary line 12 b of the 6 dB directional coupler 12 is detected. The level of the signal D _S can be made variable, that is, the coupling degree (C) can be made variable by the attenuation degree of the variable attenuator 16.

The incident power detection signal D _s is supplied to the measuring means, where the incident power P _i is measurable signal, for example, after being converted into a DC voltage, it is supplied to a meter equipped with a power corresponding scale, a digital display means, or the like. It is made visible.

The characteristics of frequency-coupling degree and the measurement results of frequency-insertion loss in actual operation of this embodiment are shown in FIGS. 2 and 3, respectively.
Shown in the figure. In the measurement results, FIG. 2 and FIG.
As can be easily understood from the figure, good frequency characteristics are obtained.

Next, a second embodiment will be described. The second embodiment is
3 dB hybrid coupler 1 constructed in the first embodiment
In place of 4, a 6 dB directional coupler 15 is provided. The 6 dB directional coupler 15 includes a primary line 15a and a secondary line 15a.
b and _{consists of} first end 15 _a1 , 15 _b1 and second end 1 respectively
5 _a2 and 15 _b2 are formed, the first end 15 _{a1 of which} is connected to the second end A ₂ of the 180 ° hybrid coupler 10. Furthermore, the first end 15
_b1 is connected to the variable attenuator 16, a second end 15 _a2 and 15 _b2 is connected to the second end C ₂ and reflection-free termination 20 of each 180 ° hybrid coupler 22.

The rest of the configuration and operation are the same as in the first embodiment, so a description thereof will be omitted.

The frequency-coupling degree characteristics and the frequency-insertion loss measurement results in actual operation of the second embodiment are shown in FIGS. 5 and 6, respectively. In the measurement result, good frequency characteristics are obtained, as can be easily understood from the figure.

Although the variable attenuator 16 is used in the above embodiment,
The present invention is not limited to this, and for example, adopting a variable amplifier to increase or decrease the drive signal S _d to expand the variable range of the incident power detection signal D _s is also included in the present invention.

[Effects of the Invention] As described above, according to the directional coupler of the present invention, two
A directional coupler for deriving a detected power signal having a 90 ° phase difference based on the incident power is arranged in one transmission line connecting between the 180 ° hybrid couplers. Further, a 90 ° phase difference coupler for deriving a 90 ° phase difference power signal is arranged on the other transmission line to form a transmission line, and the 270 ° phase difference power signal derived from the 90 ° phase difference coupler is The value is changed and applied to the directional coupler, and the value of the detected power signal obtained from the directional coupler is changed.

As a result, the electric power related to the coupling degree is derived while being changed to a desired value, and it is possible to cope with a wide range of frequencies and passing electric power.

[Brief description of drawings]

FIG. 1 is a block diagram showing a first embodiment of the directional coupler according to the present invention, and FIG. 2 is a frequency related to the operation of the embodiment shown in FIG.
FIG. 3 is a characteristic diagram of coupling degree, and FIG. 3 is a frequency related to actual operation of the embodiment shown in FIG.
FIG. 4 is a characteristic diagram of insertion loss, FIG. 4 is a configuration diagram showing a second embodiment of the directional coupler according to the present invention, and FIG. 5 is a frequency related to actual operation of the embodiment shown in FIG.
FIG. 6 is a characteristic diagram of coupling degree, and FIG. 6 is a frequency related to actual operation of the embodiment shown in FIG.
It is a characteristic view of insertion loss. 10 …… 180 ° hybrid coupler, 12 …… 6dB directional coupler 14 …… 3dB hybrid coupler, 16 …… Variable attenuator 20 …… Reflective termination, 22 …… 180 ° hybrid coupler P _i …… Incident power, P ₀ ...... Transmission power

Claims (3)

[Claims] 1. A transmission line through which high-frequency power passes,
In the directional coupler that derives the detected power proportional to the incident power, the first end to which the incident power signal is input, and the in-phase end that is derived by forming the incident power signal with a phase difference of 180 ° 1
A first end having an 80 ° phase difference end and a second end including a separation end;
And the first end of the primary line is connected to the in-phase end of the first 180 ° hybrid coupler, and the first line has a second end and is substantially parallel to the primary line. A 6 dB directional coupler including a secondary line having first and second ends formed therein, a first end connected to a 180 ° phase difference end of the first 180 ° hybrid coupler, and The incident power signal having the 180 ° phase difference supplied to the first end is formed into a signal having a 180 ° phase difference having the same phase as that of the signal and a signal having a 270 ° phase difference which is further 90 ° phase out of the signal. A 90 ° phase difference coupler having the same phase end and a second end including a 90 ° phase difference end and a separation end, a first end to which a load is connected, and a second end of the temporary line of the 6 dB directional coupler. , A 180 ° phase difference end connected to the same phase end of the 90 ° phase difference coupler, and a separation end. And a end, and in-phase and 180
A second 180 ° hybrid coupler which combines the incident power signals formed at a phase difference of ° and is led to a first end, and is connected to each of the separate ends of the first and second 180 ° hybrid couplers. Connected between the 90 ° phase difference end of the 90 ° phase difference coupler and the second end of the secondary line of the 6 dB directional coupler. The level of the incident power having the phase difference of 270 ° derived is changed and supplied to the second end of the secondary line of the 6 dB directional coupler, and the secondary line is supplied based on the incident power of the phase difference of 270 °. A directional coupler comprising: variable means for varying and deriving the detection power of the 90 ° phase difference derived from the first end of the. 2. The directional coupler according to claim 1, wherein the variable means is a variable attenuator or a variable amplifier. 3. The directional coupler according to claim 1, wherein 90
The directional coupler characterized in that the phase difference coupler is a 3 dB hybrid coupler or a 6 dB directional coupler.