JPS6265501A - Antenna element and its manufacture - Google Patents

Abstract

PURPOSE:To reduce the cost by forming a thermoplastic resin made internal layer by the extruding method and sticking a long conductor strip to the surface of the inner layer so as to be nearly in contact with both long ridges thereby forming a conductor layer and providing a thermoplastic resin made outer layer finally by the extrusion method so as to attain automation. CONSTITUTION:An extruder 10 extrudes a thermoplastic resin mixed with glass short fibers to form the inner layer 4 continuously. Carbon fibers are arranged in the lengthwise direction, molded by a thermoplastic resin and the width is made somewhat longer than the circumferential length of the inner layer 4 in the strip 18, the strip 18 approaches the inner layer 4 to be a circular- arcuate form as the extrusion is progressed, the thermoplastic resin is molten at the exit and stuck to the inner layer 4 to surround it to form a conductive layer 8. The inner layer 4 stuck with the conductive layer 8 is fed to the extruder 26, where the thermoplastic resin is stuck around the conductor layer 8 to form the outer layer 6. The incorporated layers are cooled and cured completely, and the result is cut off to a proper length as an antenna element.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an antenna element used, for example, as a waveguide element of a Yagi antenna, and a method for manufacturing the same.

<Prior Art> Conventionally, some of the above-mentioned antenna elements have an annular layer made of carbon fiber prepreg embedded in the flesh of a tubular body made of glass fiber reinforced polyester resin, for example. In addition, as a manufacturing method for such an antenna element, a glass fiber reinforced polyester resin is wrapped around a mandrel, a carbon fiber prepreg is wrapped on top of that, a reinforced polyester resin prepreg is further wrapped on top of that, and this is heated and cured. , the mandrel was pulled out, the surface was polished and painted.

<Problems to be solved by the invention> However, such an antenna element requires winding and polishing three times, making it difficult to automate manufacturing and increasing costs. There was a point. Further, there was a problem in that the length of the antenna element was determined by the length of the mandrel, the width of the work bed, etc.

Means for Solving the Problems> The antenna element that solves the problems has a ring-shaped conductive layer embedded inside a tubular body made of thermoplastic resin concentrically with the tubular body. The conductive layer is formed into an annular shape with both longitudinal edges of the elongated conductive band substantially in contact with each other.

In this method of manufacturing an antenna element, an inner layer made of a tubular body made of thermoplastic resin is first formed by an extrusion method. Next, a conductive layer is formed by attaching an elongated conductive strip having a width substantially equal to the circumferential length of the inner layer so that both longitudinal edges thereof are substantially in contact with the surface of the inner layer. Finally, an outer layer made of thermoplastic resin is provided on the outer surface of this conductive layer by extrusion.

Embodiment The antenna element of this embodiment has a tubular body 2, as shown in FIG. This tubular body 2 consists of an inner layer 4 and an outer layer 6, the inner layer 4 being made of a resin made by mixing short glass fibers with a thermoplastic resin such as nylon or polyester, and the outer layer 6 as described above. It is made in-house from thermoplastic resin.

An annular conductive layer 8 is buried concentrically between the inner layer 4 and the outer layer 6. This conductive layer 8 is made of long carbon fibers aligned in the same direction and molded from the above-mentioned thermoplastic resin. 9.1 The conductive layer 8 is formed into an annular shape with both longitudinal edges overlapping each other.

Such an antenna element can be manufactured using an apparatus as shown in FIG. In the figure, an extruder 10 extrudes a thermoplastic resin mixed with short glass fibers to continuously mold the inner layer 4. This extruded inner layer 4 is inserted into the center hole 14 of the conductive layer applicator 12.

Reference numeral 16 denotes a drum, around which a band-shaped body 18 serving as the conductive layer 8 is wound. This band-shaped body 18 is made of carbon fibers aligned in the length direction and hardened with thermoplastic resin, and its width is made somewhat longer than the circumferential length of the inner layer 4. This strip 18 is pulled out from the drum 16 and introduced into the guide groove 20 of the conductive layer adhering tool 12. 22 and 24 are rollers for pulling out the strip 18.

As shown in FIG. 3, this guide groove 20 is almost straight on the inlet side at a position above the center hole 14, but as shown in FIG. 1
4 and has an arc shape, and as shown in FIG. 5, the outlet contacts the center hole 14 and is located so as to surround it. Therefore, the inner layer 4 to which the conductive groove conductive layer 8 is attached on the entrance side is
It is fed into an extruder 26 where the thermoplastic resin is applied to the conductive layer 80 times to form the outer layer 6. Here, since the inner layer 4 is not completely cured, the inner layer 4 and the outer layer 6 are integrated with the conductive layer 8 interposed therebetween. Therefore, the inner layer 4
and the outer layer 6 are never separated.

After being extruded from the extruder 26, this integrated product is cooled and completely hardened, and then cut into appropriate lengths to form antenna elements.

In the above embodiment, long carbon fibers aligned in the length direction and hardened with synthetic resin were used as the conductive layer 8, but metal nets and short carbon fibers may also be arranged non-directionally. Carbon fiber mats hardened with synthetic resin, metal-plated fiber cloth, etc. can also be used.

Effect> As described above, according to the antenna element and the method for manufacturing the same according to the present invention, since the conductive layer is formed as an annular body by overlapping the longitudinal edges of the conductive strip, the inner layer can be formed by extrusion. Since the conductive layer can be formed after the formation by the method and the outer layer can be further formed by an extrusion method, automation is possible and costs can be reduced. Moreover, since the extrusion method is used, the length of the antenna element can be set to any desired length.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is a cross-sectional view of one embodiment of the antenna element according to the present invention, FIG. 2 is a partially cutaway side view of one embodiment of the apparatus used for manufacturing the antenna element according to the present invention, Figures 3 to 5
The figures are cross-sectional views at different positions of the conductive attachment tool of the same embodiment. 2... Tubular body, 4... Inner layer, 6... Outer layer, 8
...conductive layer. Patent applicant DIEX Antenna Co., Ltd. Agent
Tetsu Shimizu and 2 other names Tei 5, 12

Claims (2)

[Claims] (1) It includes a tubular body made of thermoplastic resin, and an annular conductive layer buried concentrically with the tubular body in the flesh of the tubular body, and this conductive layer is arranged on both sides of a long conductive strip. An antenna element characterized by having an annular shape with longitudinal edges almost touching each other. (2) An inner layer made of a tubular body made of thermoplastic resin is formed by an extrusion method, and both longitudinal edges of a long conductive strip having a width approximately equal to the circumference of this inner layer are almost in contact with each other. A conductive layer is formed by adhering to the surface of the inner layer as shown in FIG.
A method for manufacturing an antenna element, which comprises providing an outer layer made of thermoplastic resin on the outer surface of the conductive layer by extrusion.