JPH04119001A - Directional coupler - Google Patents

Abstract

PURPOSE:To extract part of signal power at a coupling terminal connecting to an inner conductor sub-line by connecting a coaxial inner conductor of a waveguide/coaxial line converter and an inner conductor main line and coupling the inner conductor main line and the sub-line coaxially. CONSTITUTION:A power of a signal made incident on an outer conductor tube 13 from an input terminal 16 fetched from an input section 11 via a waveguide/ coaxial line converter 171 is divided to an inner conductor main line 14 and an inner conductor sub-line 15 depending on the coupling quantity of them and extracted at a passing terminal 18 and a coupling terminal 19. The signal extracted at the passing terminal 18 radiates a waveguide at an output section 12 via a waveguide/coaxial line converter 172. A high coupling quantity is obtained regardless of the small size by applying coupling to the signal in the outer conductor tube 13 provided at the outside of a waveguide by means of the coaxial coupling system in the directional coupler in which the waveguide is employed for the input section 11 and the output section 12.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a directional coupler that extracts a portion of a microwave signal (power) traveling in one direction within a waveguide.

In particular, the present invention relates to a directional coupler in which the amount of coupling can be adjusted.

[Conventional technology]

Directional couplers in the microwave band are divided into several types depending on the coupling type.

FIG. 3 is a diagram showing the structure of a cross-shaped directional coupler.

In the figure, a main transmission waveguide 31 and a sub-transmission waveguide 33 having equal long sides are orthogonally crossed, and a cross-shaped slit (coupling hole) 35 is provided on a diagonal of a common wall.

Here, if the openings of the main transmission waveguide 31 are ``■'' and ``■'' and the openings of the sub-transmission waveguide 33 are ``■'' and ``■'', then when the input terminal of the transmission signal is ``■'', the coupling terminal is ``■''.

In addition, in the passage cover-shaped directional coupler, two waveguides couple the same type of coupling holes separated by an odd multiple of 1/4 of the signal wavelength, and cancel waves going in the opposite direction of the sub-transmission waveguide. There is a 1/4 wavelength type and an inversely coupled type in which two coupling holes excite coupled waves of opposite phase, respectively, and cancel out the waves traveling in the forward direction of the sub-transmission waveguide.

A series-parallel type directional coupler couples two waveguides with coupling holes of series operation and parallel operation with equal coupling amount, respectively.
This configuration takes advantage of the fact that the phase relationship between the two is reversed depending on the direction of wave propagation, and there are Bethehall type and other types.

A multi-element coupling type directional coupler has a configuration in which a large number of coupling holes for loose coupling are provided in a common wall of two waveguides whose tube axes are parallel to each other, and there are two types: an H-plane coupling type and an E-plane coupling type.

Such directional couplers, including other types, hole-couple the main transmission waveguide and the sub-transmission waveguide, and transmit a part of the signal traveling in one direction within the main transmission waveguide. The structure is such that it is taken out and transmitted in a predetermined direction of the sub-transmission waveguide.

On the other hand, for coaxial lines, there are a loop coupling type (CM type) and a strip line type directional coupler having a long coupling portion, which are based on the same principle as the series-parallel type directional coupler for waveguides.

FIG. 4 is a diagram showing the structure of a stripline type directional coupler used for coaxial lines.

In the figure, terminals ■ and terminal ■, and terminals ■ and terminal ■ are connected by coaxial inner conductors 41 and 43, respectively. Each terminal■
~■ correspond to openings ■~■ in the waveguide directional coupler shown in FIG. 3, and their functions are almost the same.

[Problem to be solved by the invention]

By the way, in conventional directional couplers in which the main transmission waveguide and the sub-transmission waveguide are hole-coupled, due to their structure, it is unavoidable that they become large, and this tendency becomes even more pronounced as the amount of coupling increases. It was increasing.

Further, in such a conventional directional coupler, it is structurally difficult to create a mechanism for continuously changing the amount of coupling without affecting the signal passing through the main transmission waveguide. Therefore, each conventional directional coupler has a fixed amount of coupling depending on its coupling method.

Furthermore, a directional coupler inserted to take out a part of the signal when measuring or investigating a transmitted signal is unnecessary at other times. However, if the directional coupler is left inserted during purposes other than measurement or investigation, the amount of coupling is fixed and cannot be reduced to zero, so the signal passing through the main transmission waveguide will not be affected. On the other hand, certain losses were unavoidable.

SUMMARY OF THE INVENTION An object of the present invention is to provide a directional coupler that can be miniaturized and that can continuously change the amount of coupling without affecting the signal passing through the main transmission waveguide.

[Means to solve the problem]

The invention according to claim 1 provides a directional coupler in which an input part and an output part are waveguides, and a part of the signal power input to the waveguide is taken out to a coupling terminal. A waveguide/coaxial converter that performs power conversion between a waveguide and a coaxial inner conductor, and a waveguide/coaxial converter that is provided outside the waveguide and has an inner conductor main line and an inner conductor sub line that are parallel to each other inside the waveguide. a coupling circuit constituted by an outer conductor pipe having a coupling circuit configured to connect the coaxial inner conductor of the waveguide/coaxial converter to the inner conductor main line of the outer conductor pipe; Configure by connecting to the coupling terminal.

The invention according to claim 2 is the directional coupler according to claim 1, wherein at least one of the internal conductor main line and the internal conductor sub line of the external conductor pipe is a movable line, and the external conductor line of the external conductor pipe is The movable line adjustment member is configured to contact the movable line from above to adjust the distance between the internal conductor main line and the internal conductor sub line.

According to a third aspect of the invention, in the directional coupler according to the second aspect, an insulating plate is inserted between the internal conductor main line and the internal conductor sub line.

The invention according to claim 4 is the directional coupler according to claim 2 or 3, wherein the movable line adjustment member adjusts the interval between the internal conductor main line and the internal conductor sub line of the coupling circuit to a predetermined coupling. It is configured to include an interval setting mechanism that sets the interval according to the amount.

[For production]

According to the first aspect of the invention, the signal power input to the waveguide is extracted to the external conductor tube via the waveguide/coaxial converter of the coupling circuit. In other words, by connecting the coaxial inner conductor of the waveguide/coaxial converter and the inner conductor main line, and coaxially coupling the inner conductor main line and the inner conductor sub line, the coupling is made to the inner conductor sub line. A portion of the signal power can be taken out to the terminal.

In this way, in a directional coupler where the input and output sections are waveguides, a coaxial coupling method is used within the external conductor tube provided outside the waveguide, thereby achieving a small size and high coupling amount. be able to.

Note that this differs from the directional coupler for coaxial lines shown in FIG. 4 in that the input/output section is a waveguide.

In the invention according to claim 2, at least one of the internal conductor main line and the internal conductor sub line in the external conductor pipe is a movable line,
By using a movable line adjustment member that contacts the movable line to move the movable line from outside the external conductor tube and adjust the interval between each line, the amount of coupling can be continuously varied.

According to the fourth aspect of the invention, the distance setting mechanism enables the movable line adjustment member to set and fix the distance between the internal conductor main line and the internal conductor sub line, and it is possible to easily obtain a desired coupling amount. .

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

FIG. 1 is a diagram showing an embodiment of a directional coupler corresponding to the invention set forth in claim 1.

Note that (a) is a cross-sectional view taken along line AA', and b) is a cross-sectional view taken along line BB'.
FIG.

In the figure, the input section 11 and the output section 12 are formed by waveguides and are connected to the main transmission waveguide.

Inside the rectangular external conductor pipe 13 provided outside this waveguide, an internal conductor main line 14 and an internal conductor sub line 1 are provided.
5 are installed in parallel. The waveguide/coaxial converter 17t on the input section 11 side is connected to both ends of the internal conductor main line 14 via the input terminal 16, and the output section 1 is connected via the pass terminal 18.
The waveguide/coaxial converter 17□ on the second side is connected. A coupled terminal 19 and a non-coupled terminal 20 are connected to both ends of the internal conductor sub-line 15 . A non-reflection terminator 21 is connected to the specific coupling terminal 20 .

Note that the portion where the internal conductor main line 14 and the internal conductor sub line 15 overlap in parallel is usually set to a length corresponding to approximately 1/4 of the signal wavelength, and the narrower the interval, the tighter the coupling becomes.

In addition, the dimensions of the outer conductor tube 13 and the line widths of the inner conductor main line 14 and the inner conductor sub line 15 are set to a predetermined value that minimizes the standing wave ratio (VSWR) seen from each terminal and maximizes the reverse direction loss. Designed to value.

In such a configuration, input from the input unit 11,
Waveguide/coaxial converter 17. The signal input from the input terminal 16 to the external conductor tube 13 via the internal conductor main line 14
The power is divided according to the amount of coupling between the internal conductor sub-line 15 and the internal conductor sub-line 15, and is taken out to the passing terminal 18 and the coupling terminal 19. In addition,
The signal taken out to the pass terminal 18 is emitted to the waveguide of the output section 12 via the waveguide/coaxial converter 17□.

In this way, in a directional coupler in which the input section 11 and the output section 12 are waveguides, the coupling process is performed using the coaxial coupling method within the external conductor tube 13 provided outside the waveguide, thereby making it possible to reduce the size of the directional coupler. A high amount of binding can be obtained.

FIG. 2 is a diagram showing an embodiment of a directional coupler corresponding to the invention according to claims 2 to 4.

In addition, (a) is an AA' cross-sectional view, and (b) is a BB-B cross-sectional view.
(C) is a cross-sectional view taken along line cc'.

Here, the same parts as in FIG. 1 are given the same reference numerals and the explanation will be replaced.

In this embodiment, the internal conductor sub-line 15 inside the external conductor pipe 13
is made of a metal material for springs, and when no load is applied by the insulator rod 23, it moves away from the inner conductor main line 14, and the outer conductor tube 1
Make sure to bend it toward the inner wall of 3. In addition, it is preferable that the amount of coupling with the internal conductor main line 14 can be reduced to almost zero when no load is applied or at a predetermined setting.

The insulator rod 23 , which penetrates one surface of the external conductor pipe 13 and has one end in contact with the internal conductor sub-line 15 , has the other end held by the switch 24 , and its protruding length from the external conductor pipe 13 is 90 degrees from the switch 24 . It has a structure that can be adjusted in two stages by rotation.

That is, when the switch 24 is operated, the internal conductor sub line 15 is pushed down via the insulator rod 23, the distance between it and the internal conductor main line 14 is narrowed, and the amount of coupling is increased. This is a structure in which the pushing force of the inner conductor is released, the distance from the inner conductor main line 14 is widened, and the amount of coupling is reduced.

In this embodiment, the movable line is an internal conductor sub-line 15 with restoring force, the movable line adjustment member is realized by an insulator rod 13 and a switch 24, and the internal conductor sub-line 15 is pressed down by operating the switch 24. However, on the contrary, when there is no load due to the insulator rod 23, the internal conductor sub line 15
is bent so as to approach the inner conductor main line 14 side, and the insulator rod 23 is attached to the inner conductor sub line 15.
It is also possible to have a structure in which it is fixed and pulled back. Furthermore, it is also possible to have a structure in which the internal conductor main line 14 is movable. Moreover, the movable line adjustment member may have a structure that moves the support point of the movable line, such as the internal conductor sub-line 15.

Furthermore, although this embodiment shows a structure in which the amount of coupling is adjusted in two stages using the switch 24, it is also possible to use a switch that allows adjustment in three or more stages. It is also possible to set the amount of coupling steplessly by changing the pressed position of the internal conductor sub-line 15 continuously. In this case, by displaying the binding amount on a scale, it is possible to easily set the binding amount to a predetermined value.

Further, an insulating plate 26 is inserted between the internal conductor main line 14 and the internal conductor sub line 15. This prevents a short circuit with the internal conductor main line 14 even if the movable internal conductor sub line 15 is damaged due to repeated use, and minimizes the effect on the signal passing through the main transmission waveguide. It is something to suppress.

With such a structure, the amount of coupling between the internal conductor main line 14 and the internal conductor sub line 15 can be easily adjusted. Furthermore, by setting the coupling amount to almost zero when the coupling output to the coupling terminal 19 is not required, the loss of the signal passing through the main transmission waveguide is minimized even if the directional coupler is inserted and connected. can be kept to a minimum.

In the embodiments described above, an example of a coaxial coupling method using electric field coupling was shown, but a structure using magnetic field coupling is also possible.

〔Effect of the invention〕

As described above, in the invention according to claim 1, by using the coaxial coupling method of the internal conductor main line and the internal conductor sub line, it is possible to realize a small size and a high coupling amount. That is, a directional coupler with a large coupling amount can be made smaller, the installation space can be used more effectively, and costs can be reduced.

In the invention described in claim 2, the amount of coupling can be easily and continuously changed without affecting the signal passing through the main transmission waveguide. Therefore, it is possible to minimize the loss of the signal passing through the main transmission waveguide, and the directional coupler is always used, except when it is necessary to take out a part of the output, such as during measurement or investigation. It becomes possible to insert it into the main transmission waveguide.

In the invention described in claim 3, even if the movable line is damaged, short circuit between the internal conductor main line and the internal conductor sub line can be prevented, and the influence on the signal passing through the main transmission waveguide in the event of a failure can be minimized. can be kept to a minimum.

In the invention set forth in claim 4, it is possible to easily set the degree of coupling to be variable, and for example, it is possible to prevent the degree of coupling from being increased more than necessary and the loss of signal power passing through the main transmission waveguide from becoming excessive. can.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment of a directional coupler according to the invention according to claim 1. FIG. 2 is a diagram showing an embodiment of a directional coupler corresponding to the invention according to claims 2 to 4. FIG. 3 is a diagram showing the structure of a cross-shaped directional coupler. FIG. 4 is a diagram showing the structure of a strip, seven-brine type directional coupler used for coaxial lines. DESCRIPTION OF SYMBOLS 11... Input part, 12... Output part, 13... External conductor tube, 14... Internal conductor main line, 15... Internal conductor sub line, 16... Input terminal, 17...・Waveguide/coaxial converter, 18... passing terminal, 19... coupling terminal,
20... Non-coupling terminal, 21... Non-reflection terminator, 23
... Insulator rod, 24 ... Switch, 26 ... Insulating plate, 31 ... Main transmission waveguide, 33 ... Sub transmission waveguide, 35 ... Slit, 41.43. ...Coaxial inner conductor. A-A' cross-sectional view (a) B-B' cross-sectional view ('b) Figure A-A' new view (a) B-B' cross-sectional view [c-c' cross-sectional view (e) Figure

Claims (4)

[Claims] (1) In a directional coupler in which the input part and the output part are waveguides, and a part of the signal power input to the waveguide is taken out to a coupling terminal, inside the waveguide, coaxial with the waveguide. Consisting of a waveguide/coaxial converter that performs power conversion with a conductor, and an outer conductor tube that is provided outside the waveguide and has an inner conductor main line and an inner conductor sub line that are parallel to each other inside the waveguide. the coaxial inner conductor of the waveguide/coaxial converter is connected to the inner conductor main line of the outer conductor tube, and the inner conductor sub line of the outer conductor tube is connected to the coupling terminal. A directional coupler featuring: (2) In the directional coupler according to claim 1, at least one of the internal conductor main line and the internal conductor sub line of the external conductor tube is constituted by a movable line, and the movable line is contacted from the outside of the external conductor tube. A directional coupler comprising a movable line adjustment member that adjusts the interval between the internal conductor main line and the internal conductor sub line. (3) The directional coupler according to claim 2, wherein an insulating plate is inserted between the internal conductor main line and the internal conductor sub line. (4) In the directional coupler according to claim 2 or 3, the movable line adjustment member sets the interval between the internal conductor main line and the internal conductor sub line of the coupling circuit to correspond to a predetermined coupling amount. A directional coupler characterized by being equipped with an interval setting mechanism.