JPH11150405A - Directional coupler and method for adjusting degree of coupling - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily adjust the degree of coupling in a parallel 2-wire directional coupler where two signal transmission lines made of a metal conductor are placed in parallel. SOLUTION: Metal conductors 1, 2 are placed in parallel, the surroundings of the two metal conductors 1, 2 are covered by dielectric bodies 3, 4, the gap between two metal conductors 1, 2 is filled with dielectric material 5 with the same dielectric constant as that of the dielectric bodies 3, 4, and an insulation film 6 that is easily obtained is added between the two metal conductors 1 and the dielectric material 5, so as to facilitate the adjustment of the coupling degree without deteriorating the power resistance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a parallel two-wire directional coupler in which two metal conductor signal transmission lines are arranged in parallel and a method of adjusting the degree of coupling.

[0002]

2. Description of the Related Art As a conventional directional coupler, a directional coupler in which two transmission lines 10 are arranged on a microstrip substrate 9 shown in FIG. 7 or two dielectric substrates 1 shown in FIG.
There were a triplate type directional coupler in which two transmission lines 13 were sandwiched between 1 and 12, and a parallel two-line directional coupler in which two metal conductors 14 were arranged and coupled in parallel. . Reference numeral 7 denotes a housing, and 8 denotes a cover.

[0003] The former two are small and are disclosed in JP-A-63-2860.
As disclosed in Japanese Patent Application Laid-Open No. 07-207207 and Japanese Patent Application Laid-Open No. 9-18207, it is easy to adjust the degree of coupling, but there is a drawback that transmission loss is larger than the latter.

The latter has a lower loss than the former,
As shown in FIG. 1, two metal conductors 1 and 2 and two metal conductors 1 and 2
Since the gap between the two is completely covered with the dielectrics 3 to 5,
It was difficult to adjust the distance between the two conductors 1 and 2, and the degree of coupling could not be easily adjusted.

[0005]

When power is distributed or combined, low loss is desirable. Therefore, a parallel two-wire directional coupler as shown in FIG. 1 is effective.
In order to improve power durability, the gaps between the two conductors 1 and 2 and between the conductors 1 and 2 are all filled with dielectrics 3 to 5. Therefore, the adjustment of the coupling degree has no other choice but to change the thickness of the dielectric 5 filling the gap between the conductors 1 and 2 or insert a thinner dielectric further between the conductor 1 and the dielectric 5.

In order to replace the dielectric 5, since the conductor 1 is soldered at both ends, the dielectric 5 filling the gap between the conductors 1 and 2 is removed, and the dielectric 5 having a different thickness is inserted. Was difficult.

Even if a thin dielectric is further inserted, it is difficult to process the thin dielectric. In particular, in the case of a dielectric such as Teflon, sufficient dimensional accuracy cannot be obtained for processing a material having a certain thickness to obtain an arbitrary thickness. Therefore, it was necessary to prepare several types of dielectrics 5, remove the soldering of the conductor 1 many times, and replace and adjust the dielectrics 5.

Accordingly, the present invention provides a technique capable of easily adjusting the degree of coupling of the conventional parallel two-line directional coupler.

[0009]

According to the present invention, there is provided a parallel two-wire directional coupler in which two signal transmission lines of metal conductors are arranged in parallel. A structure in which an insulating film is covered with a dielectric, a gap between the two metal conductors is filled with a dielectric having the same dielectric constant as the dielectric, and an insulator film is inserted between the dielectric between the metal conductors and the metal conductor. There is a characteristic in that. In that case, an insulator film can be inserted between any one of the two metal conductors and the dielectric between the two metal conductors. Also,
It is preferable to use a thinner insulator film than the thickness of the dielectric between the metal conductors. The thickness of the insulator film is preferably in the range of 0.05 to 0.2 mm. On the other hand, in the method of the present invention, two signal transmission lines of metal conductors are arranged in parallel, the periphery of the metal conductors is covered with a dielectric, and the gap between the two metal conductors is set to the same dielectric constant as the dielectric. A method of adjusting the degree of coupling of a parallel two-line directional coupler filled with a dielectric, wherein an insulator film thinner than the dielectric between the metal conductors is inserted between the dielectric between the metal conductors. In this way, the degree of binding was adjusted. In that case, one of the two metal conductors
The degree of coupling can also be adjusted by inserting the insulating film between the book and the dielectric between the two metal conductors.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. In the following embodiments, a combiner using a parallel two-line directional coupler having a 3 dB coupling will be described as an example.

In the present embodiment, as shown in FIG. 2, in a parallel two-wire directional coupler in which two signal transmission lines of metal conductors 1 and 2 are arranged in parallel, the two metal conductors 1 and 2 The surroundings are covered with dielectrics 3 and 4 and two metal conductors 1 and 2
The gap between them is filled with a dielectric 5 having the same dielectric constant as the dielectrics 3 and 4, and an insulator film 6 is inserted between the dielectric 5 between the metal conductors 1 and 2 and the metal conductor 1. . In that case, an insulator film 6 can be inserted between the metal conductor 2 and the dielectric 5 between the metal conductors.

That is, in the present embodiment, in the conventional parallel two-line directional coupler as shown in FIG. 1, as shown in FIG. The degree of coupling can be easily adjusted simply by inserting a.

The insulator film 6 used is 0.05 to
With a thickness of about 0.1 mm, the conductor 1 can be inserted without removing the soldering, so that the degree of coupling can be easily adjusted.

FIG. 3 is a circuit diagram of a two-input one-output combiner to which the present invention is applied, and FIG. 4 is a mounting diagram thereof. In these figures, IN1 and IN2 indicate input sections, OUT indicates an output section, L indicates a conductor length, and w indicates a conductor width. The conductor length L to be coupled is given by the following equation.

L = (λ0 / 4−w / 4) / √εr [mm] λ0: wavelength of coupled microwave [mm] w: conductor width [mm] εr: relative permittivity of dielectric

The dielectrics 3, 4, and 5 are made of polyethylene terephthalate (trade name: Teflon (Er = 2.1));
FIG. 5 shows the insertion loss characteristics when the thickness of each of them is 0.5 mm. Teflon 0.5 mm is the same as the material thickness and can be provided without processing the thickness.

Here, in order to reduce the deviation of the insertion loss depending on the signal path, the conventional method has been to replace the dielectric 5. In this method, the solder of the conductor 1 is removed, the dielectric 5 is replaced, and the conductor 1 is soldered again.

According to the present invention, a thin insulator film 6 is inserted between the conductor 1 and the dielectric 5 to have an effect of equivalently changing the distance between the conductors 1 and 2, and the characteristics of insertion loss can be adjusted. I did it. FIG. 6 shows the insertion loss characteristics when the 0.1 mm insulating film 6 is added.

The insertion loss characteristics are as shown in FIG. 5 when the insulator film 6 is not provided. However, only by inserting the insulator film of 0.1 mm, the insertion loss characteristics are as shown in FIG. The degree of coupling can be easily adjusted without removing the soldering of the conductor.

The latter has a smaller deviation due to the signal path, and can be adjusted as an ideal 3 dB coupler. Since the material of the insulator film 6 to be used can be easily obtained, and it is sufficient that the dimensions are not strictly given and the size to cover a part to which the conductors 1 and 2 are coupled is sufficient. You don't have to. The combined loss is 0.1 dB or less in the L, S, and C bands.

Further, the present directional coupler can be provided as a coupler for high power durability, and there is no deterioration in power durability due to the addition of the insulating film 6.

[0022]

As described above, according to the present invention, in a parallel two-wire directional coupler in which two metal conductor signal transmission lines are arranged in parallel, the periphery of the two metal conductors is covered with a dielectric,
The gap between the two metal conductors is filled with a dielectric having the same dielectric constant as that of the dielectric, and a thin insulator film is inserted between the dielectric between the metal conductors and the metal conductor. Can be easily adjusted without deteriorating the coupling degree of the parallel two-line directional coupler.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a conventional parallel two-wire directional coupler in which a conductor is filled with a dielectric.

FIG. 2 is a sectional view of a parallel two-line directional coupler according to the present invention.

FIG. 3 is a circuit diagram of a 3 dB synthesizer having two inputs and one output.

FIG. 4 is a mounting diagram of a 3 dB synthesizer having two inputs and one output.

FIG. 5 is an insertion loss characteristic diagram for the structure shown in FIG.

6 is an insertion loss characteristic diagram for the structure shown in FIG.

FIG. 7 is a cross-sectional view of a conventional directional coupler using a microstrip substrate.

FIG. 8 is a sectional view of a conventional triplate directional coupler.

FIG. 9 is a cross-sectional view of a conventional parallel two-line directional coupler when a conductor is not filled with a dielectric.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1, 2 Conductor 3, 4, 5 Dielectric 6 Insulating film 7 Case 8 Cover 9 Microstrip board 10 Conductor 11, 12 Dielectric 13 Conductor 14 Conductor

Claims (6)

[Claims] 1. A parallel two-wire directional coupler in which two metal conductor signal transmission lines are arranged in parallel, the periphery of the two metal conductors is covered with a dielectric, and a gap between the two metal conductors is provided. Is filled with a dielectric having the same dielectric constant as the dielectric, and an insulating film is inserted between the dielectric between the metal conductors and the metal conductor. 2. One of the two metal conductors,
2. The directional coupler according to claim 1, wherein an insulator film is inserted between the two metal conductors and the dielectric. 3. The insulator film according to claim 1, wherein said insulator film is thinner than a thickness of a dielectric between said metal conductors.
Or the directional coupler according to 2. 4. The insulating film has a thickness of 0.05 to 0.05.
It is the range of 0.2mm, The claim 1 characterized by the above-mentioned.
4. The directional coupler according to any one of 3. 5. A signal transmission line comprising two metal conductors arranged in parallel, a circumference of the metal conductors is covered with a dielectric, and a gap between the two metal conductors is formed by a dielectric having the same dielectric constant as the dielectric. A method for adjusting the degree of coupling of a parallel two-line directional coupler filled with, between the dielectric between the metal conductor and the metal conductor,
Adjusting the degree of coupling by inserting an insulating film thinner than the dielectric between the metal conductors,
A method for adjusting the degree of coupling of the directional coupler. 6. One of the two metal conductors,
The method for adjusting the degree of coupling of a directional coupler according to claim 5, wherein the degree of coupling is adjusted by inserting the insulating film between a dielectric between two metal conductors.