JPH0432304A - Dielectric line and launcher - Google Patents

Abstract

PURPOSE:To prevent irregular reflection in a dielectric line from being increased at room temperature while the dielectric line is placed at ultra-low temperature with liquid helium or the like by providing a specific core, a clad and a sheath made of a Cu-PET or the like enclosing the clad. CONSTITUTION:An EPTFE (porous tetrafluoroethylene resin) is used for a core 21 in a dielectric body line 10, an EPTFE is used for a clad 22 enclosing the core 21 and the clad 22 is enclosed by a Cu-PET (copper foil and polyester laminate) 30. In this case, the specific dielectric constant of the core 21 is to be 2.1 or below but should be higher than the specific dielectric constant of the clad 22. Moreover, the specific dielectric constant of the clad 22 is to be 2.1 or below but should be lower than the specific dielectric constant of the core 12. Thus, the dielectric line 10 is placed at an ultra-low temperature with liquid helium or the like and the increase in the attenuation due to reflection in the dielectric line 10 placed at room temperature is avoided.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a dielectric line used for transmitting electromagnetic wave energy such as millimeter waves and submillimeter waves, and particularly relates to a dielectric line that is compatible with cryogenic temperatures and is cooled with liquid helium or the like. Regarding body lines.

[Prior Art] Dielectric lines are used in place of metal waveguides as waveguides within and between devices such as millimeter-wave wireless communication devices.

FIG. 11 is a longitudinal cross-sectional view showing a conventional dielectric line 10a.

The dielectric line 10a includes a core 21 made of a dielectric material having a relatively high dielectric constant, and a core 21 coaxially surrounding the core 21 and made of a dielectric material having a relatively low dielectric constant. It is composed of a cladding 22 and a protective layer 23 attached to the outer periphery of the cladding 22, so that electromagnetic wave energy is mainly transmitted within the core 21.

The core 21 is made of porous tetrafluoroethylene resin (hereinafter referred to as r
EPTFEJ) and its dielectric constant is 1.7.
2, the cladding 22 is also made of EPTFE and has a dielectric constant of 1.26, and the protective layer 23 is made of PvC to protect against mechanical stress.

Compared to metal waveguides, the conventional dielectric line 10a has the advantage that it is flexible and can be easily processed and connected between devices.

[Problems to be Solved by the Invention] However, when the conventional dielectric line 10a is cooled with liquid helium or liquid nitrogen in an attempt to place the conventional dielectric line 10a in an extremely low temperature atmosphere, the cladding forming the dielectric line 10a Liquid helium or the like is absorbed into the dielectric line 10a through the gap 22. Thereafter, when the cooled dielectric line 10a is placed at room temperature, the absorbed liquid helium etc. is vaporized within the dielectric line 10m.

When liquid helium or the like vaporizes in the dielectric line 10a, the vaporized helium and nitrogen cause the dielectric line to become
There is a problem that the radio waves in 0a are absorbed and the amount of attenuation in the dielectric line 10a increases.

Furthermore, when liquid helium or the like evaporates in the dielectric line 10a, the characteristics of the dielectric line 10a change.

There is a problem in that the dielectric line 10a cannot serve as a lead wire used for calibration.

Further, in the above conventional example, radio waves are radiated from the end face of the cladding 22 of the dielectric line 10a, and
There is a problem in that the transmission quality is degraded.

Furthermore, in the above conventional example, radio waves are radiated from the circumferential surface of the cladding 22 of the dielectric line 10a, and
There is a problem that the transmission quality in a becomes unstable.

On the other hand, when the dielectric line 10a is cooled with liquid helium or liquid nitrogen as described above, liquid helium etc. enters from the joint between the launcher flange and the waveguide. Gaskets are used at the joints.

However, using this gasket to create a seal requires time and effort, and the reproducibility of sealing is not very high even for experienced personnel.Furthermore, the gasket can only be used once. As a result, unevenness remains on the surface of the gasket, and when it is reused, the VSWR changes due to the unevenness and the return loss increases, so there is a problem that the gasket has to be discarded.

The present invention is applicable to cases where a dielectric line is placed in an extremely low temperature atmosphere using liquid helium or the like, and when it is placed at room temperature.

It is an object of the present invention to provide a dielectric line in which the amount of return loss in the dielectric line does not increase.

Another object of the present invention is to provide a dielectric line that can reduce deterioration in transmission quality due to radiation of radio waves from the peripheral surface of the cladding that constitutes the dielectric line.

A further object of the present invention is to provide a dielectric line that can reduce deterioration in transmission quality due to radiation of radio waves from the end face of the cladding that constitutes the dielectric line.

Furthermore, the present invention eliminates the need to use a gasket at the joint between the launcher's 7 langes and the waveguide when the dielectric line is placed in an extremely low temperature atmosphere such as liquid helium and left at room temperature. Another object of the present invention is to provide a launcher that can reliably seal the joint between the dielectric line and the mode converter.

[Means for Solving the Problems] The present invention provides a core made of EPTFE and having a dielectric constant of 2.1 or less, a cladding made of EPTFE that is lower than the dielectric constant of this core, and a Cu-PET (copper foil and laminate with polyester).

It is composed of AR-PET (a laminate of aluminum foil and polyester), copper foil, aluminum foil, or stainless steel foil, and has an outer cover that encloses a cladding.

In this case, the jacket is wrapped in CPTFE and the core has a square, oval or oblong cross section.

Further, in the present invention, CPTFE is attached to the end face of the cladding.

Further, in the present invention, a space surrounded by the inner surface of the launcher and parallel to its axis is filled with FEP (4-6 fluorinated ethylene resin).

Further, in the present invention, a threaded strain relief and a dielectric line are bonded together with an adhesive.

The present invention comprises a core made of porous tetrafluoroethylene resin and having a dielectric constant of 2.1 or less, and a porous tetrafluoroethylene resin surrounding this core and having a dielectric constant lower than that of the core. In this dielectric line, the cladding is wrapped in a sintered carbon-containing tetrafluoroethylene resin.

[Function] The present invention consists of a core made of EPTFE or the like with a dielectric constant of 2.1 or less, a cladding that surrounds this core and made of EPTFE whose dielectric constant is lower than that of the core, and a cladding made of Cu-PET or the like. Since the dielectric line has an outer cover that surrounds the cladding, the amount of diffused reflection on the dielectric line does not increase when the dielectric line is placed in an extremely low temperature atmosphere such as liquid helium and left at room temperature.

Further, in the present invention, since CPTFE is attached to the end face of the cladding, deterioration in transmission quality due to radiation of radio waves from the end face of the cladding of the dielectric line can be reduced.

Furthermore, in the present invention, the space surrounded by the inner surface of the launcher, which is parallel to its axis, is filled with FEP, and the dielectric line is placed in a cryogenic atmosphere with liquid helium, etc., and then heated to room temperature. When placed inside, the joint between the dielectric line and the mode converter can be reliably sealed without using a gasket at the joint between the flange of the launcher and the waveguide.

Further, in the present invention, since the threaded strain relief and the dielectric line are bonded together with an adhesive, there is no deterioration in transmission quality due to intrusion of liquid helium.

In the present invention, since the cladding is wrapped in sintered carbon-containing tetrafluoroethylene resin, when the dielectric line is placed in an extremely low temperature atmosphere with liquid helium or the like and left at room temperature, liquid helium Intrusion can be prevented and stable transmission quality can be obtained without fluctuations in the amount of attenuation in the dielectric line [Embodiment] FIG. 5 is a diagram showing an embodiment of the present invention.

Note that figures (1) and (2) are a front view and a right side view, respectively.

In the dielectric 10 of this example, EPTFE (porous ethylene tetrafluoride resin) with a dielectric constant of 1.72 is used as the core 21, and EPTFE with a dielectric constant of 1.26 is used as the cladding 22 surrounding this core 21. This cladding 22 is wrapped with Cu-PET (a laminate of copper foil and polyester) 32. The left end of the core 21 in FIG. 1(2) is connected to a metal waveguide via a launcher 17, which will be described later. Further, the cross section of the core 21 is rectangular, and the dielectric constant of the core 21 may be 2.1 or less, but it must be higher than the dielectric constant of the cladding 22. The cladding 22 has a dielectric constant of 2.1 or less. .1 or less, but it must be lower than the dielectric constant of the core z1.

If the dielectric line 10 is placed in an extremely low temperature atmosphere using liquid helium, liquid nitrogen, etc., the characteristics of the dielectric line 10 are measured, and then placed at room temperature, the dielectric line 10
The transmission characteristics at are stable without any change. This consists of an outer sheath and a Cu-PET 30 layer on the outer periphery of the dielectric line 10.
is provided, liquid helium etc. are prevented from entering the core 21 through the minute bubbles in the cladding 22, and therefore the dielectric line 10 due to the gas vaporized in the core 21 and cladding 22 is prevented. It is possible to prevent the amount of fluctuation in the transmission speed from increasing.

Moreover, when the cross-sectional shape of the core 21 is made rectangular as shown in FIG. 1 rather than circular, the plane of polarization is maintained and its characteristics are improved. By the way, instead of making the cross-sectional shape of the core 21Q rectangular, it may be made oval or oval. In particular, if the cross-sectional shape is made oval or oval, the cladding can be tightly wound around the core all around (especially the core 12), it is preferable to adopt an elliptical or oblong cross-sectional shape of the core.

Furthermore, instead of a core made of EPTFE and having a dielectric constant of 2.1 or less, it is made of a mixture of EPTFE and a ferroelectric resin (for example, barium titanate, calcium titanate, titanium oxide) and has a dielectric constant of 2.1. .1 to 5 cores may be used.

Also, instead of Cu-PET30 as the outer covering, Ai
- PET (a laminate of aluminum foil and polyester), copper foil, aluminum foil or stainless steel foil may be used.

FIG. 2 shows carbon-containing tetrafluoroethylene resin (hereinafter rcPTFE) on the outer periphery of Cu-PET 30 in the above example.
FIG. 2 is a diagram showing a dielectric line 11 covered with a dielectric line (referred to as J) 40, in which FIG. 1 (1) is a front view and FIG. 2 (2) is a right side view.

In this example, the CPTFE 40 is sintered (fired) after 374 wraps of a CPTFE tape with a width of about 4C layers. By sintering the CPTFH tape in this way, the CPTFE 40 becomes similar to a continuous tubular body. Has a function. Therefore, liquid nitrogen etc. can be prevented from entering, and when the dielectric line is placed in an extremely low temperature atmosphere with liquid helium etc. and left permanently, the return loss in the dielectric line does not increase. C.P.
The TFE 40 has the function of preventing the radio waves transmitted through the dielectric line 11 from being radiated from the circumferential surface of the cladding 22 to the outside. By absorbing leakage radio waves in this way, the CPTFE 40 improves the transmission quality in the dielectric line 11. The decline can be prevented. In addition, in the conventional dielectric line.

Its outer periphery is coated with PVCl or ETFE, and these PVCl or ETFE are used solely for mechanical protection, and do not have the function of absorbing radio waves as in the above embodiment.

The tape width and number of wraps of the CPTFH may be arbitrarily determined as necessary.

FIG. 3 is a diagram showing a dielectric line 12 according to another embodiment of the present invention, in which FIG. 3(1) is a front view and FIG. 3(2) is a right side view thereof.

This dielectric line 12 has CPTF on the end face of the cladding 22.
E50.5] was attached.

In FIG. 3(1), the CPTFEs 50 and 51 are separated to the left and right with the core 21 as a boundary, and also cover a part of the end surface of the CPTFE 40 provided on the outer periphery of the cladding 22.

By doing so, the CPTFE 50.51 prevents radio waves from being radiated from the end face of the cladding 22, so that the amount of return loss within the dielectric line 12 can be improved.

Note that the CPTFE 50.51 may cover only the end surface of the cladding 22 without covering the end surface of the CPTFE 40.

FIG. 4 is an example developed from the example shown in FIG.
4A and 4B are diagrams showing a dielectric line 13 in which the cladding 22 and all of the end faces of the CPTFE 40 on its outer periphery are covered with CPTFE 52; FIG. 4(1) is a front view, and FIG. 4(2) is a right side view thereof.

The embodiment shown in FIG. 3 has CPTFE50.51 pasted on the end face of the embodiment shown in FIG. 10, which will be described later.
FIG. 5 shows an example (dielectric line 14) in which CPTFE 53, 54 is attached to the end face of the example shown in FIG. 2.

In addition, an example (dielectric line 1
5) is shown in FIG.

Next, the launcher will be explained.

Generally, when electromagnetic waves are radiated from the end of a dielectric line, a metal waveguide or a metal horn is connected to the dielectric line via a connector called a launcher. This is because conventional electromagnetic wave emitting products using metal waveguides etc. can be used, and the phase center during electromagnetic wave emission is difficult to shift. Actually, the launchers are connected to both ends of the dielectric line.

FIG. 7 is a diagram showing an embodiment of the launcher of the present invention.

The launcher 60 shown in FIG. 1 (1) includes a flange 71 connected to a metal waveguide, its bottle 71F, a trumpet-shaped mode converter 72, and the right end (wide-mouthed part) of the mode converter 72.
It has a threaded portion 73 provided at. The threaded portion 73 is engaged with a strain relief 9J shown in FIG. 8, and this strain relief 91 tightens the dielectric line.

7(2) and (3) are a left side view and a right side view, respectively, of the launcher 60 shown in FIG. 7(1).

FIG. 7(4) shows the flange 71 in the launcher 60.
FIG. 7 is an enlarged cross-sectional view showing the joint portion of the mode converter 72 and the mode converter 72. FIG.

In FIG. 7 (4), a space (straight part) S surrounded by the inner surface of the launcher 60 parallel to its axis is filled with FEP (4-6 fluorinated ethylene resin) 80. There is. The straight portion S is a portion S2 where the inclined inner surface of the mode converter 72 and the inner surface parallel to the axis are joined.
This is the portion from 1 to 2 to the end surface S1 of the flange 71 on the metal waveguide side.

FEP80 may be filled over the entire straight portion S, or may be filled only in the central portion of the straight portion S as shown in Fig. 7 (4), or as shown in Fig. 7 (5). The straight part S may be filled up to the end face of the flange 71 on the mode converter 72 side, however,
It is preferable not to fill the end face 51 of the flange 71 which is in contact with the metal waveguide with FEP 80. In other words, if FEP 80 is filled so as to also contact the end face Sl, dust etc. will adhere to the end face Sl. This is because the characteristics deteriorate.

If the dielectric line is placed in liquid helium by filling the silicate part S with FEP80 as described above, even if liquid helium enters from the joint between the metal waveguide and the launcher 60, The FEP 80 can prevent liquid helium from entering the mode converter 72, prevent changes in VswR caused by liquid helium entering, and prevent the adverse effects of deterioration in transmission quality. can. In other words, it is possible to eliminate the use of gaskets, which have conventionally been necessary.

In the embodiment shown in FIG. 7, ETFE (ethylene tetrafluoroethylene) may be used instead of FEP80.

FIG. 8 shows the dielectric line 10 connected to a strain relief 91.
FIG. 3 is an explanatory diagram of a device fixed to a mode converter 72 by means of a method.

In the embodiment shown in FIG. 8, a strain relief 91 is engaged with the threaded portion of the mode converter 72, and an adhesive 90 is filled between the inner surface of the strain relief 91 and the outer periphery of the dielectric line 10. And this adhesive 9
0 is a hardening material, which firmly fixes the strain relief 91 and the dielectric line 10. With this adhesive 90,
The dielectric line IO is firmly joined to the mode converter 72, and the adhesive prevents helium from entering from the circumferential surface of the cladding of the dielectric line 10, thereby stabilizing transmission quality.

FIG. 9 is basically the same as FIG. 8, but shows an example in which the straight portion S of the launcher 60 is filled with FEP 80.

In addition, in the embodiments shown in FIGS. 8 and 9, the dielectric line 1
In place of 0, dielectric lines 10 to 16 may be used.

FIG. 10 is a sectional view showing another embodiment of the dielectric line of the present invention.

The dielectric line 16 of this embodiment uses sintered CPTFE 40 instead of the Cu-PET 30 used in the dielectric line 10 shown in FIG.

In this way, the sintered C
When PTFE 40 is covered, CPTFE 40 prevents liquid nitrogen etc. from penetrating, so if the dielectric line is placed in a cryogenic atmosphere with liquid helium etc. and then left at room temperature, the reflection loss in the dielectric line will decrease. The amount does not increase.

Further, although the cross section of the core 21 is shown as a square in FIG. 10, it may be oval or oval in addition to the square.

[Effects of the Invention] According to claims (1), (2), and (3), when a dielectric line is placed in an extremely low temperature atmosphere with liquid helium or the like and then left at room temperature, liquid helium does not enter. Since radio waves are not radiated from the circumferential surface of the cladding, there is no variation in attenuation in the dielectric line and stable transmission quality can be obtained.

According to claim (4), it is possible to reduce deterioration in transmission quality due to radiation of radio waves from the end face of the cladding of the dielectric line.

According to claims (5) and (6), when the dielectric line is placed in an extremely low temperature atmosphere with liquid helium or the like and then left at room temperature, the junction between the seven flange of the launcher and the waveguide This has the effect that the joint between the dielectric line and the mode converter can be reliably sealed without using a gasket.

According to claims (7) and (8), when a dielectric line is placed in an extremely low temperature atmosphere with liquid helium or the like and left at room temperature, intrusion of liquid helium is prevented, so that The effect is that stable transmission quality can be obtained without fluctuations in the amount of attenuation.

[Brief explanation of drawings]

1 to 6 are explanations of embodiments of the dielectric line of the present invention. FIG. 7 is an explanatory diagram of the launcher of the present invention. FIGS. 8 and 9 are explanatory diagrams of the case where the dielectric line and launcher of the present invention are joined. FIG. 10 is a sectional view showing another embodiment of the dielectric line of the present invention. FIG. 11 is a diagram showing a cross section of a conventional dielectric line. lO~16...Dielectric line, 21.22...EPTFE (porous tetrafluoroethylene resin) 30...Cu-PET (laminate of copper foil and polyester), 40...Sintered CPTFE (carbon-mixed tetrafluoroethylene resin), 50-55... CPTFE (carbon-mixed tetrafluoroethylene resin), 60... launcher 71... flange, 72... mode converter. S...Straight part. 80...FEP (4-6 fluorinated ethylene resin), 90
...adhesive, 91...strain relief. Patent applicant Junkosha Co., Ltd. Arata Kubo for the same agent Figure 7 Screw part Figure 8 Figure 9 Figure 60 Lunch C-'Σ Figure 11 10a Conventional dielectric line ■

Claims (8)

[Claims] (1) A core composed of porous tetrafluoroethylene resin and having a dielectric constant of 2.1 or less; This core is wrapped and composed of porous tetrafluoroethylene resin having a dielectric constant lower than that of the core. A dielectric line comprising: a cladding; an outer sheath that is made of a laminate of copper foil and polyester, a laminate of aluminum foil and polyester, copper foil, aluminum foil, or stainless steel foil and that encloses the cladding; . (2) The dielectric line according to claim (1), wherein the outer jacket is wrapped in carbon-containing tetrafluoroethylene resin. (3) The dielectric line according to claim (1), wherein the cross section of the core is rectangular, elliptical, or oval. (4) The dielectric line according to claim (1), wherein carbon-containing tetrafluoroethylene resin is adhered to the end face of the cladding. (5) In a launcher having a flange connected to a waveguide and a mode converter connected to an end of a dielectric line, the inner surface of the launcher is surrounded by an inner surface parallel to the axis of the launcher. 4-6 fluoroethylene (
A launcher characterized in that it is filled with FEP) resin or ethylenetetrafluoroethylene resin (ETFE). (6) A threaded strain relief that has a threaded part that screws into the threaded part provided on the outer periphery of the mode converter of the launcher and a dielectric line that is connected to the waveguide via the launcher are bonded with adhesive. A dielectric line characterized by being bonded. (7) A core made of porous tetrafluoroethylene resin and having a dielectric constant of 2.1 or less, and a porous tetrafluoroethylene resin surrounding this core that has a dielectric constant lower than that of the core. A dielectric line having a cladding, the cladding being wrapped in a sintered carbon-containing tetrafluoroethylene resin. (8) The dielectric line according to claim (7), wherein the core has a cross section that is rectangular, elliptical, or oval.