JPS5951162B2 - Manufacturing method of laminated waveguide - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a laminate waveguide for microwave transmission.

Waveguides are widely used as microwave transmission lines for UTF, SHF bands, etc. Among them, elliptical waveguides manufactured by arc welding metal tape into a tubular shape are easy to construct and inexpensive. Currently, it is rapidly becoming popular.

However, this method of manufacturing waveguides by arc welding has many drawbacks.

This conventional manufacturing method mainly consists of three steps. In the first step, a long metal tape of a constant width is formed into a cylindrical shape, the overlapping parts are welded, and the cylindrical body is corrugated in a bellows shape. In the second step, the cylinder is formed into an arbitrary cross-sectional shape, such as an ellipse, using rolls or dies, and in the third step, a sheath made of polyethylene or the like is applied as an outer cover to the formed cylinder to complete the process. There is.

Therefore, (1) it is necessary to wind up the product on a drum or the like for each process and send it to the next process, which is inefficient.

(2) Arc welding requires a metal tape thickness above a certain level, which is considerably thicker than the electrically required conductor thickness and is uneconomical; (3) In order to obtain good melting results, e.g. (4) Arc welding equipment is huge and expensive and requires a large installation space; (5) Accurate speed adjustment is required during arc welding. There are quite a few drawbacks, such as requiring a special take-off device and (6) cyclical unevenness is likely to occur because the bellows-like corrugation is applied after being formed into a cylindrical body.

An object of the present invention is to eliminate the above-mentioned drawbacks and to provide a method for manufacturing a laminate waveguide that is continuously manufactured in one step using an adhesive method that does not involve arc welding. A long laminated tape made of a conductive tape with a thermoplastic synthetic resin layer on one side is corrugated in the direction perpendicular to the longitudinal direction, and heated while forming a cylinder with both sides of the tape forming continuous overlapping parts in the longitudinal direction. By melting the thermoplastic synthetic resin layer and adhering the overlapping portions, and molding the cylinder into a bellows-like elliptical cylinder, and further applying a protective coating to a predetermined thickness as an outer layer of the cylinder. This method is characterized by continuous production of waveguides.

The method of the invention will be explained in more detail by means of illustrated embodiments.

FIG. 1 shows the sequential manufacturing means of an embodiment of the method for manufacturing a laminated waveguide according to the present invention, and FIG. 2 shows the sequential products or finished products manufactured by each method. .

Reference numeral 1 denotes a tape drum, around which a laminated tape 2 serving as a raw material is wound.

As shown in FIG. 2a, this laminate tape 2 is made of a thin metal film such as aluminum and has a thickness of 0.20 m.
A thermoplastic synthetic resin layer 4 having a thickness of 0.05 mm, such as an ethylene/vinyl acetate copolymer, is coated on the back side of the conductor tape 3.

This laminate tape 2 is corrugated by a corrugating device 5 made of, for example, a roll, as shown in FIG. 2, and then transferred to a forming device 6.

In the forming device 6, for example, by a belt forming mechanism, the laminate tape 2 is gradually wound around the cylindrical body disposed in the longitudinal direction with the conductor tape 3 inside, using a belt to form the cylindrical body 7.
to form.

At this time, since the laminate tape 2 is extremely thin, it has stretchability, and the difference between the crests and troughs of the corrugations is, for example, about 1 mm, so it can be formed without damaging the corrugations. The laminate tape 2 can be stacked so that both end edges overlap each other.

Next, in the melt bonding device 8, the thermoplastic synthetic resin layer 4 applied to the cylindrical body 7 is melted by heating means, and the overlapped portion 9 is completely bonded as shown in FIG. 2C. do.

At this time, in the melt bonding device 8, a cylindrical center rod (not shown) having an outer diameter slightly smaller than the inner diameter of the cylindrical body 7 is introduced into the cylindrical body 7, so that the overlapping portion 9 Apply sufficient pressure to ensure reliable adhesion.

The cylindrical body 7 having a bellows shape made in this way is
The ellipsoidal body 11 is shaped into an ellipsoidal body 11 as shown in FIG. It is applied to a uniform thickness as shown in Figure e.

The thus manufactured laminate waveguide 14 is transferred to the take-up device 1.
5 and winding it onto a winding drum 16, the laminate waveguide 14 is continuously manufactured in one step.

In the embodiment, the laminate tape 2 was once formed into a cylindrical body 7 by the forming device 6, and then shaped into an elliptical cylinder 11 by the shaping device 10. In contrast, the forming device 6 directly shaped the laminate tape 2 into an elliptical body 11. It is also possible to form it into a cylindrical body 11.

Furthermore, if the inner edge 17 of the laminated tape 2 at the overlapped portion 9 is located on the short axis Y-Y line of the elliptical cross section as shown in FIG. As shown in FIG. 3, the wall current does not cross the inner edge 17, and even if the conductive tape 3 is substantially insulated at the overlapped portion 9, no electromagnetic waves leak there.

Furthermore, if the width d of the overlapping portion 9 is set to one quarter of the wavelength within the tube, the overlapping portion 9 can be considered to be in a short-circuited state with respect to the internal electric field.

Exemplary dimensions of the laminated waveguide 14 manufactured in this way are as follows: the inner diameter of the major axis of the ellipse is 21.3 mm, the inner diameter of the short axis of the ellipse is 9.6 mm, and the width d of the overlapping portion 9 is 9 mm.

Various metals can be used for the conductor tape 3, and the current flowing through the conductor tape 3 is concentrated only in a limited skin thickness from the surface due to the skin effect, and the depth depends on the wavelength and the material of the conductor tape 3. The unit is 10-2 to 10-3 mm at most.

Therefore, there is no need to increase the thickness of the conductor tape 2; rather, the thinner the conductor tape 2, the better the processability and the more economical.

As the thermoplastic synthetic resin layer 4, polyethylene that exhibits melt-adhesive properties when heated, a single layer of polyethylene, a multi-layer layer made of ethylene/ethyl acrylate copolymer, ethylene/vinyl acetate/glycidyl copolymer, etc. may be used. .

The material for the protective coating 13 can be selected from polyethylene, polyvinyl chloride, polypropylene, ethylene, propylene-based rubber plastic compositions, etc., which have appropriate strength and flexibility.

In the present invention, the elliptical shape includes not only a pure ellipse but also an ellipse formed with circular arcs, a circular arc and a straight line, a parabola and a circular arc, or similar shapes of a perfect circle.

As explained above, according to the method for manufacturing a laminated waveguide according to the present invention, the cylinder body is formed by an adhesive method instead of conventional arc welding, so a large amount of equipment cost is not required.
The thickness and material of the conductive tape are also economical.

In addition, by adopting an adhesive method, it is possible to corrugate the laminated tape while it is still flat, resulting in a product that is much lower and more stable than the conventional method of corrugating a cylindrical body. .

Furthermore, with this manufacturing method, everything from the laminated tape to the waveguide can be manufactured in one step, reducing labor costs and
This can greatly contribute to reducing manufacturing costs such as equipment costs.

[Brief explanation of drawings]

The drawings show one embodiment of the method for manufacturing a laminated waveguide according to the present invention, and FIG. 1 is an explanatory diagram showing the sequential manufacturing means, and FIG. 2 shows the products produced at each stage of FIG. 1. 3A is a perspective sectional view of the finished product; FIG. 3A is a perspective sectional view of the waveguide; FIG. 3A is an explanatory diagram showing the state of wall current. Reference numeral 2 is a laminate tape, 3 is a conductive tape, 4 is a thermoplastic synthetic resin layer, 5 is a corrugated device, 6 is a forming device, 7 is a cylindrical body, 8 is a melt bonding device, 9 is an overlapping part,
10 is a shaping device, 11 is an elliptical cylinder, 12 is an extrusion device,
13 is a protective coating, and 14 is a laminate waveguide.

Claims (1)

[Scope of Claims] 1. A long laminate tape made of a conductive tape with a thermoplastic synthetic resin layer provided on at least one side is corrugated in a direction perpendicular to the longitudinal direction, and both side edges are formed into continuous overlapping parts in the longitudinal direction. While forming a cylindrical body, the thermoplastic synthetic resin layer is melted by a heating means, the overlapping portions are bonded, and the cylindrical body is formed into a bellows-like elliptical cylinder, and a protective coating is further applied as an outer layer of this cylindrical body. 1. A method for manufacturing a laminated waveguide, characterized in that the waveguide is continuously manufactured by applying to a predetermined thickness. 2. The inner edge of the overlapping portion is located on the short axis of the elliptical cross section, and the width of the overlapping portion is formed into an elliptical cylinder having a size equal to one-fourth of the wavelength in the pipe, as described in claim 1. A method for manufacturing a laminated waveguide.