JP4154556B2 - Helical antenna and manufacturing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a helical antenna and a manufacturing method thereof.
[0002]
[Prior art]
Currently, in the United States, digital radio broadcasting (frequency, about 2.3 GHz) using an artificial satellite (broadcast satellite) is about to start. And development of a digital radio receiver for receiving this digital radio broadcast is underway.
[0003]
There are two types of digital radio receivers. One is a type that directly receives radio waves from an artificial satellite, and the other is one that receives radio waves that are broadcast with a frequency shifted from a ground station that has received radio waves from the satellite. . Hereinafter, only a digital radio receiver of a type that directly receives radio waves from an artificial satellite will be described.
[0004]
A digital radio receiver of a type that directly receives radio waves from an artificial satellite is assumed to be mounted on an automobile. And when the antenna is attached outside a vehicle, it is common to make it a stick-shaped antenna.
[0005]
Digital radio broadcast signals radiated from broadcasting satellites are circularly polarized waves, and a helical antenna is well known as a stick-shaped antenna for receiving circularly polarized waves. The helical antenna is characterized in that its shape is simple, its dimensions are reasonable, and it can have high gain.
[0006]
The specific structure of a helical antenna is a helical wire (helix) wound around an insulating cylindrical or cylindrical (hereinafter simply referred to as “cylindrical”) member such as plastic. By making the same as the wavelength, circularly polarized radiation is possible in the axial direction. That is, the helical antenna configured in this way can receive circularly polarized waves arriving along the axial direction.
[0007]
In order to improve the gain of the helical antenna, the number of turns of the spirally wound conducting wire may be increased. In addition, in a circularly polarized antenna, four spirals are used and the phase is matched by a phase shifter. However, it is very difficult to wind a plurality of conducting wires spirally around a cylindrical member. Therefore, a conventional helical antenna is manufactured by printing a plurality of conductor patterns on an insulating sheet and winding the insulating sheet on which the conductor pattern is printed around a cylindrical member.
[0008]
[Problems to be solved by the invention]
However, in the conventional method of printing a plurality of conductor patterns on an insulating sheet, each conductor pattern printed on the insulating sheet is in a state of being divided, and each conductor pattern is accurately accurately wound around a cylindrical member. There is a problem that it must be wound continuously so that it takes time and cost.
[0009]
Therefore, an object of the present invention is to provide a helical antenna that can be easily manufactured at low cost and a manufacturing method thereof.
[0010]
[Means for Solving the Problems]
According to the present invention, in the method for manufacturing a helical antenna having at least one helical conductor (11), the space formed between the inner cylinder (21) and the outer cylinder (31) arranged concentrically. A straight copper wire (11) is disposed inside, and the copper wire is held and fixed at a position away from the one end by a predetermined distance, and a jig for holding the other end of the copper wire is attached to the inner cylinder and The copper wire is wound around the inner cylinder by rotating it with the central axis of the outer cylinder as the center of rotation, and then the space is filled with an insulating resin (12). A method for manufacturing a helical antenna is obtained.
[0011]
In addition, according to the present invention, a helical antenna manufactured by the manufacturing method described above can be obtained.
[0013]
In addition, the code | symbol in the said parenthesis is attached | subjected in order to make an understanding of this invention easy, It is only an example, and of course is not limited to these.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0015]
1A and 1B show a helical antenna (four-phase feeding helical antenna) according to an embodiment of the present invention. FIG. 1A is a partial perspective view of the vicinity of the tip of the helical antenna. As shown in FIG. 1 (a), in this helical antenna, the four copper wires 11 wound in a spiral form a wall defined by the inside of the cylindrical insulating resin 12 (inner peripheral surface and outer peripheral surface). Inside). Here, the four copper wires 11 are arranged at equal intervals in the circumferential direction of the cylindrical insulating resin 12 as shown in FIG.
[0016]
Next, the method for manufacturing the helical antenna of FIG. 1 will be described with reference to FIGS.
[0017]
First, four copper wires 11 having substantially the same length are prepared, and as shown in FIG. 2, the outer periphery of the inner cylinder (mold) 21 is arranged at a position equally divided into four, and from one end (lower end) thereof. It is held and fixed at a position separated by a predetermined distance. Here, one end of the copper wire 11 is inserted into a hole having a predetermined depth formed in a base 22 fixed to one end of the inner cylinder 21 so as to be held and fixed. The height of the inner cylinder 21 is lower than the copper wire 11 by a predetermined length in the state shown in FIG.
[0018]
Next, as shown in FIG. 3, an outer cylinder (mold) 31 is arranged concentrically with the inner cylinder 21. As a result, a portion excluding both ends of the copper wire 11 is disposed in a space formed by the inner cylinder 21 and the outer cylinder 31. The height of the outer cylinder 31 is substantially equal to that of the inner cylinder 21.
[0019]
Next, using a dedicated jig (not shown), the other end (upper end) of the copper wire 11 is held, and the dedicated jig is rotated with the central axes of the inner cylinder 21 and the outer cylinder 31 as the center of rotation. With this rotation, the dedicated jig is moved closer to the inner cylinder 21 and the outer cylinder 31. As a result, as shown in FIG. 4, the copper wire 11 is deformed so as to be wound around the inner cylinder 21 (spirally) in the space between the inner cylinder 21 and the outer cylinder 31. At this time, the portion inserted into the hole formed in the pedestal 22 of the copper wire 11 is not deformed and is used as an output portion after completion.
[0020]
Thereafter, an opening (upper side in the drawing) of the space formed by the inner cylinder 21 and the outer cylinder 31 is closed using a dedicated jig in which the copper wire 11 is spirally deformed. The heights of the inner cylinder 21 and the outer cylinder 31 are determined so that the copper wire 11 has a spiral shape with a predetermined pitch in this state.
[0021]
Next, an insulating resin is injected into a space formed between the inner cylinder 21 and the outer cylinder 31. For example, the insulating resin is injected between the copper wires 11 (four locations) so that the resin is properly filled between the copper wires 11.
[0022]
Finally, if the dedicated jig, the outer cylinder 31, and the inner cylinder 21 are removed, a helical antenna as shown in FIGS. 5A and 5B can be obtained.
[0023]
In the above-described embodiment, the description has been made in the case of using a copper wire, but other metal wires may be used.
[0024]
In the above-described embodiment, the four-phase feeding helical antenna including four copper wires has been described. However, the number of wires may be any number as long as it is one or more.
[0025]
Moreover, in the said embodiment, although the manufacturing method using the inner cylinder fixed to the base, the outer cylinder separate from it, and the exclusive jig | tool which is not illustrated was demonstrated, it is not restricted to this, Metal If the deformed wire can be sealed (insert molding) in the resin after the wire is deformed in a spiral shape, other jigs, devices, and the like may be used.
[0026]
【The invention's effect】
According to the present invention, the structure of the helical antenna is such that the helical conductor is sealed inside the cylindrical insulator, so that the manufacturing can be facilitated and the cost can be reduced.
[0027]
Further, according to the present invention, the wire is spirally deformed in a space formed between the inner cylinder and the outer cylinder arranged concentrically, and in the space formed by the inner cylinder and the outer cylinder. Since the insulating resin is filled, the helical antenna can be manufactured easily and at low cost.
[Brief description of the drawings]
FIG. 1A is a partial perspective view of a helical antenna according to an embodiment of the present invention, and FIG. 1B is a top view of the helical antenna shown in FIG.
2 is a diagram for explaining a method of manufacturing the helical antenna shown in FIG. 1; FIG.
3 is a diagram for explaining a process following the manufacturing process illustrated in FIG. 2. FIG.
4 is a diagram for explaining a process following the manufacturing process illustrated in FIG. 3. FIG.
5A is a perspective view showing the completed helical antenna after the step shown in FIG. 4, and FIG. 5B is a cross-sectional view taken along line AA in FIG. 5A.
[Explanation of symbols]
11 Copper wire 12 Insulating resin 21 Inner cylinder 22 Base 31 Outer cylinder

Claims (2)

In the method for manufacturing a helical antenna having at least one spiral conductor, with disposing the linear copper wire in a space formed between an inner cylinder and an outer cylinder disposed concentrically, copper wire Is held and fixed at a position away from the one end by a predetermined distance, and a jig for holding the other end of the copper wire is rotated about the center axis of the inner cylinder and the outer cylinder to rotate the copper wire. A method for manufacturing a helical antenna, comprising: winding an inner cylinder to form a spiral, and then filling the space with an insulating resin. A helical antenna manufactured by the method for manufacturing a helical antenna according to claim 1.

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