JP2001177325A - Helical antenna and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a helical antenna and its manufacturing method, where the connection between a helical coil and a core wire of a feeding coaxial cable is not required, there is no deviation in a resonance frequency caused by the offset of the connection position between the coil and the coaxial wire, and ease of manufacture process and cost reduction can be attained. SOLUTION: This helical antenna is characterized with a center conductor (14) of a coaxial cable (12) for feeding at the antenna connection side being wound in a spiral form, and the spiral wound part is made to act as an antenna element.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a helical antenna used for, for example, a portable telephone and a method for manufacturing the same.

[0002]

2. Description of the Related Art FIG. 4 is a sectional view showing the structure of a conventional helical antenna of this type. In FIG. 4, 11 is a metal joint, 12 is a coaxial cable, 13 is an outer conductor of the coaxial cable, 14 is a center conductor of the coaxial cable, 19 is a cap, 20 is a main body case, 21 is a bracket (ground), and 22 is a flat. Washers and 23 are nuts. 24 is a helical coil, 25 is a relay board.

As shown in FIG. 4, a core wire 14a of the coaxial cable 12 and a specially provided helical coil 24 are
Electrical connection is established by soldering via the relay board 25.

[0004]

The above-mentioned conventional helical antenna has the following problems. That is, in order to stably and surely connect the core wire 14a of the coaxial cable 12 and the specially provided helical coil 24, the relay board 25 is required. Incidentally, the helical coil 24 specially provided as described above naturally moves unless some fixing means is provided. Because of this,
When the core wire 14a is directly connected to the helical coil 24, the core wire 14a may be disconnected. In addition, the work of soldering the core wire 14a and the helical coil 24 in a free state is extremely poor in workability and requires a long time for connection work.

[0005] When the relay board 25 is provided as shown in the figure, means for fixing the relay board 25 itself is required. For this reason, the structure must be complicated. Moreover, when the core wire 14a and the helical coil 24 are connected, the connection point is likely to be displaced in the length direction.
For this reason, the resonance frequency may be shifted.

An object of the present invention is to provide a helical antenna having the following advantages and a method for manufacturing the same.

(1) There is no need to specially manufacture a helical coil.

(3) There is no need for a relay component between the helical coil and the core of the coaxial cable.

(2) There is no need to perform a soldering operation between the helical coil and the core of the coaxial cable.

(4) A shift in resonance frequency due to a shift in the connection position between the helical coil and the core of the coaxial cable does not occur.

(5) The manufacturing process is simplified, and the cost can be reduced.

[0012]

In order to solve the above-mentioned problems and achieve the object, a helical antenna of the present invention and a method of manufacturing the same are configured as follows.

(1) In the helical antenna according to the present invention, the central conductor on the antenna connection end side of the coaxial cable for feeding is spirally wound, and the spirally wound portion is operated as an antenna element. It is characterized by.

(2) A helical antenna according to the present invention comprises: a cylindrical conductive base having a hollow portion at an axial center; an insulating holder connected to one end of the conductive base and having a spiral groove on an outer peripheral surface; A wire lead-out portion provided on the insulating holder, a power supply coaxial cable inserted into a hollow portion of the conductive base, and an external conductor on an antenna connection end side of the coaxial cable are connected to the conductive base. Means to guide the center conductor on the antenna connection end side of the coaxial cable to the outer peripheral surface of the insulating holder via the wire lead-out portion,
Means for winding around the spiral groove.

(3) The helical antenna according to the present invention is the helical antenna according to the above (2), wherein the helical antenna is placed outside the center conductor wound around the spiral groove of the insulating holder, and has an open end. Fixed (screwed,
(Including integral molding, bonding, etc.).

(4) The helical antenna according to the present invention is the helical antenna according to the above (2), wherein the wire lead-out portion communicates with the hollow portion of the conductive base at the axis of the insulating holder. And a slit cut radially from the axis of the insulating holder so as to open the hollow to the outer peripheral surface of the insulating holder. Features.

(5) The helical antenna according to the present invention is the helical antenna according to the above (2), wherein the wire lead-out portion is connected to a hollow portion of the conductive base so that an axial center of the insulating holder is connected to the hollow portion. It is characterized by comprising only a hollow portion provided through the portion. (6) The helical antenna of the present invention includes the above (1) to
(5) The helical antenna according to (5), wherein the center conductor includes a core of the coaxial cable and an insulating coating covering an outer periphery of the core.

(7) In the method for manufacturing a helical antenna according to the present invention, the coaxial cable for feeding power may be inserted into the hollow portion of the cylindrical conductive base, and the coaxial cable led out to one end of the conductive base may be inserted. A first step of connecting an external conductor to the conductive base, connecting one end of an insulating holder having a spiral groove on an outer peripheral surface to one end of the conductive base,
A second step of guiding a center conductor of the coaxial cable led out to one end of the conductive base to the outside of the insulating holder through a wire lead-out portion provided on the insulating holder; and The center conductor of the coaxial cable guided to the outside of the insulating holder in the second step,
A third step of winding around the spiral groove of the insulating holder, and a bottomed cylindrical cap made of an insulating member outside the center conductor wound on the insulating holder by the third step; And fixing the opening end to the conductive substrate (including screwing, integral molding, adhesion, etc.).
And a step of:

[0019]

(First Embodiment) "Structure" FIG. 1 is a sectional view showing a configuration of a helical antenna 10 according to a first embodiment of the present invention. Reference numeral 11 denotes a metal joint as a conductive substrate. The metal joint 11 is formed in a substantially cylindrical shape, and has a hollow portion 11a having a predetermined diameter through which a coaxial cable described later can be inserted, at an axial center portion. A screw portion 11b is formed on the outer peripheral surface of the metal joint 11. A power supply coaxial cable 12 is inserted through a hollow portion of the metal joint 11.

An outer conductor (braided wire) 13 at the end of the coaxial cable 12, that is, at the end of the antenna connected to the antenna connected to one end (upper end in the figure) of the metal joint 11
Is electrically connected to the metal joint 11 at a point P by caulking or soldering.

A center conductor (in the present embodiment, a state in which a core wire is insulated and coated) 14 of the coaxial cable 12 for feeding is connected to an outer peripheral surface of an insulating holder 15 described later. Spirally wound.

FIGS. 2A to 2F show the insulating holder 1.
5A and 5B are diagrams showing the configuration of FIG. 5, wherein FIG. 5A is a top view and FIG. (C) is a top view in which the insulating holder is rotated by 90 ° from the state of (a), (d) is a side view thereof, and (e) is a bottom view thereof. (F) is a sectional view taken along line FF in (c).

As shown in FIGS. 2A to 2F, the insulating holder 15 is integrally formed of an insulating material made of a hard resin or the like. It has a connecting portion 16 formed of a cylindrical concave portion that can be connected to one end of the metal joint 11 by, for example, press fitting. The outer circumferential surface of the insulating holder 15 is formed with a spiral groove 17 having a semi-circular cross section formed in such a size that the center conductor 14 can be recessed.

The insulating holder 15 is provided with a wire lead-out portion 18. The wire lead-out portion 18 is for leading out the center conductor 14 of the coaxial cable 12 from the vicinity of the connecting portion 16 in the insulating holder 15 to the outer peripheral surface of the holder 15. The wire lead-out portion 18 in the present embodiment is provided with the metal joint 1.
A hollow portion 18a provided at the axis of the insulating holder 15 so as to communicate with the first hollow portion 11a, and the hollow portion 18a is opened from the axis so that the hollow portion 18a is opened to the outer peripheral surface of the insulating holder 15. It comprises a slit 18b cut open in the radial direction and a guide groove 18c for guiding the spiral groove 17 from the slit.

The diameter or width W of each of the cables 18a to 18c is slightly larger than the outer diameter of the coaxial cable 12 so that the coaxial cable 12 can pass through.

Returning to FIG. The central conductor 14 led to the outer peripheral surface of the insulating holder 15 via the wire lead-out portion 18 is wound around the spiral groove 17 of the insulating holder 11. The wound center conductor 1
A cap 19 having a bottomed cylindrical shape integrally formed of an insulating material such as a synthetic resin is covered so as to press the outer surface 4 from outside. The opening of the cap 19 is screwed into a screw portion 11b provided on the outer peripheral surface of the joint 11, whereby the two are integrated.

In FIG. 1, reference numeral 19a denotes a cap 19
, 20 is a main body case, 21 is a bracket (ground), 22 is a metal flat washer, and 23 is a metal nut. These functions will be described later.

[Assembling Method and Mounting Method] The helical antenna according to the first embodiment is assembled according to the steps shown in FIGS. Then, as shown in FIG. 3E, the antenna is mounted on the antenna mounting object.

[First Step] As shown in FIG.
A coaxial cable 12 for power supply is inserted into the hollow portion 11a of the cylindrical metal joint 11, and the outer conductor 13 of the coaxial cable 12 led out to one end side (upper end in the drawing) of the metal joint 11 is connected to the outside. The metal joint 11
On the other hand, electrical connection is made by performing caulking or soldering at point P, for example.

[Second Step] As shown in FIG.
With respect to one end (the upper end in the figure) of the metal joint 11,
One end of the insulating holder 15 having the spiral groove 17 on the outer peripheral surface is connected by means such as press fitting. At this time, the coaxial cable 12 led out to one end of the metal joint 11
(In this embodiment, a conductor in which the outer periphery of the core wire 14a is covered with an insulating coating 14b) 14 is inserted into the hollow portion 18a of the insulating holder 15.

[Third Step] As shown in FIG.
The center conductor 14 of the coaxial cable 12 is
Through the slit 18b, and further to the outer peripheral surface of the insulating holder 15 via the guide groove 18c, and wound around the spiral groove 17.

[Fourth Step] As shown in FIG.
A bottomed cylindrical cap 19 made of an insulating member is covered so as to cover the outside of the center conductor 14 wound around the spiral groove 17 of the insulating holder 15. And this cap 1
The screw part formed at the open end of the screw 9 is screwed to the screw part 11 b formed on the outer peripheral surface of the metal joint 11. As a result, the metal joint 11 and the cap 19 are integrally connected, and the center conductor 14 having a relatively high elasticity in a state where the outer periphery of the core wire 14a is covered with the insulating coating 14b is attached to the insulating holder 15. It will be stably held in the spiral groove 17. Then, the center conductor 14 is safely protected by the cap 19.

The antenna 10 assembled as described above is
For example, when attaching to a main body case 20 of a mobile phone (having a bracket 21 as a ground on the back surface), first, as shown in FIG. Metal joint 11
And the outer peripheral portion of the open end of the cap 19 are inserted. Then, the joining surface (the lower surface in the figure) of the flange portion 19 a projecting from the outer peripheral surface of the opening end of the cap 19 is brought into close contact with the outer surface of the main body case 20.

Next, after a flat washer 22 is fitted on the outer periphery of the metal joint 11 protruding from the back side of the main body case 20, a nut 23 is screwed into a screw portion 11b provided on the outer periphery of the metal joint 11. And tighten. By doing so, the antenna 10 can be stably and reliably attached to the main body case 20.

The outer conductor 13 of the coaxial cable 12 is grounded through the path of the metal joint 11, the nut 23, the flat washer 22, and the bracket 21.

In the present embodiment, the center conductor 14 of the coaxial cable 12 for feeding is spirally wound and the portion is operated as an antenna element, so that there are the following advantages.

(1) It is not necessary to specially manufacture a helical coil.

(2) There is no need for a relay component between the helical coil and the core wire 14a of the coaxial cable 12.

(3) There is no need to solder the helical coil and the core wire 14a of the coaxial cable 12.

(4) A shift in resonance frequency due to a shift in the connection position between the helical coil and the core wire 14a of the coaxial cable 12 does not occur.

(5) The manufacturing process is simplified, and the cost can be reduced. In particular, when the center conductor 14 is wound into a helical coil while the core wire 14a is covered with the insulating coating 14b, the mechanical strength of the center conductor 14 is remarkably excellent, and the man-hour is reduced. Becomes extremely easy.

(Modification) The helical antenna shown in the embodiment includes the following modifications.

A structure in which the central conductor 14 having only the core wire 14a is spirally wound by removing the insulating coating 14b and operated as an antenna.

Only the hollow portion 18a provided so as to penetrate the axis of the insulating holder 15 is used as the wire lead-out portion 18, and the center conductor 14 penetrating the hollow portion 18a is U-turned and wound around the spiral groove 17. Something like that.

The cap 19 is connected to the metal joint 11
Fixed to the body using integral molding or adhesive means.

(Features of Embodiment) [1] In the helical antenna shown in the embodiment, the center conductor (14) on the antenna connection end side of the coaxial cable (12) for feeding is spirally wound. It is characterized in that the spirally wound portion is operated as an antenna element.

[2] The helical antenna shown in the embodiment is connected to a cylindrical conductive base (11) having a hollow portion (11a) at the axial center thereof and one end of the conductive base (11). An insulating holder (15) having a spiral groove (17) on the outer peripheral surface; a wire lead-out portion (18) provided on the insulating holder (15); and a hollow portion (11a) of the conductive base (11). And a means for connecting an outer conductor (13) on the antenna connection end side of the coaxial cable (12) to the conductive base (11); and Means for guiding the center conductor (14) on the antenna connection end side to the outer peripheral surface of the insulating holder (15) through the wire lead-out portion (18) and winding the spiral conductor (17) around the spiral groove (17). And, it is characterized by having.

[3] The helical antenna described in the embodiment is the helical antenna according to the above [2],
It is covered on the outside of the central conductor (14) wound around the spiral groove (17) of the insulating holder (15), and the open end is fixed to the conductive base (11) (screwed, integrally molded). , Including adhesives)
And a bottomed cylindrical cap (19).

[4] The helical antenna described in the embodiment is the helical antenna according to the above [2],
The wire lead-out portion (18) has a hollow portion (18a) provided at the axis of the insulating holder (15) so as to communicate with the hollow portion (11a) of the conductive base (11); A slit (18b) cut radially from the axis of the insulating holder (15) so as to open the portion (18a) to the outer peripheral surface of the insulating holder (15). It is characterized by.

[5] The helical antenna according to the embodiment is the helical antenna according to the above [2],
The wire lead-out part (18) is a hollow part of the conductive base (11).
It is characterized in that it comprises only a hollow portion (18a) penetrating through the axis of the insulating holder (15) so as to be continuous with (11a).

[6] The helical antenna according to the embodiment is the helical antenna according to any one of [1] to [5], wherein the central conductor (14) is a core of a coaxial cable (12).
(14a) and an insulating coating (14
b) is included.

[7] The method for manufacturing a helical antenna described in the embodiment is directed to a method for manufacturing a hollow portion (11) of a cylindrical conductive substrate (11).
a) A power supply coaxial cable (12) is inserted thereinto, and the coaxial cable (12) led out to one end of the conductive base (11).
A first step of connecting the outer conductor (13) to the conductive substrate (11), and an insulating holder (1) having a spiral groove (17) on the outer peripheral surface.
One end of 5) is connected to one end of the conductive base (11), and the center conductor (14a) of the coaxial cable (12) led to one end of the conductive base (11) is insulated by the insulation. Sex holder
A second step of leading out of the insulative holder (15) through the wire lead-out portion (18) provided in (15), and to the outside of the insulative holder (15) by the second step. A third step of winding the guided central conductor (14) of the coaxial cable (12) around the spiral groove (17) of the insulating holder (15); and A bottomed cylindrical cap (19) made of an insulating member is put on the outside of the center conductor (14) wound around the insulating holder (15), and the open end of the cap is placed on the conductive base (11). And a fourth step of fixing (including screwing, integral molding, adhesion, and the like).

[0053]

According to the present invention, a helical antenna having the following advantages and a method for manufacturing the same can be provided.

(1) There is no need to specially manufacture the helical coil.

(3) A relay component between the helical coil and the core of the coaxial cable becomes unnecessary.

(2) It is not necessary to perform the work of soldering the helical coil and the core of the coaxial cable.

(4) A shift in resonance frequency due to a shift in the connection position between the helical coil and the core of the coaxial cable does not occur.

(5) The manufacturing process is simplified, and the cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a configuration of a helical antenna according to a first embodiment of the present invention.

FIGS. 2A to 2F are views showing a structure of an insulating holder of the helical antenna according to the first embodiment of the present invention.

FIGS. 3A to 3D are views showing steps of a method for assembling the helical antenna according to the first embodiment of the present invention, and FIGS.
FIG. 4 is a diagram showing a method of mounting the helical antenna.

FIG. 4 is a sectional view showing a configuration of a helical antenna according to a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Helical antenna 11 ... Metal joint 12 ... Coaxial cable for power supply 13 ... Outer conductor 14 ... Center conductor 15 ... Insulating holder 16 ... Connecting part 17 ... Spiral groove 18 ... Wire lead-out part 19 ... Cap 20 ... Main body case 21 ... Bracket (Grand) 22 ... Flat washer 23 ... Nut

Claims (7)

[Claims] A helical antenna characterized in that a central conductor on an antenna connection end side of a coaxial cable for feeding is spirally wound, and the spirally wound portion is operated as an antenna element. 2. A cylindrical conductive base having a hollow portion at a shaft center, an insulating holder connected to one end of the conductive base and having a spiral groove on an outer peripheral surface, and provided on the insulating holder. A wire lead-out part, a power supply coaxial cable inserted into the hollow part of the conductive base, a means for connecting an external conductor on the antenna connection end side of the coaxial cable to the conductive base, Means for guiding a center conductor on the antenna connection end side to the outer peripheral surface of the insulating holder through the wire lead-out portion and winding the spiral conductor around the spiral groove. 3. A bottomed cylindrical cap which is placed over the center conductor wound around the spiral groove of the insulating holder and whose open end is fixed to the conductive substrate. The helical antenna according to claim 2, wherein: 4. The wire lead-out portion includes a hollow portion provided at an axis portion of the insulating holder so as to communicate with a hollow portion of the conductive base, and the hollow portion is provided on an outer peripheral surface of the insulating holder. The helical antenna according to claim 2, further comprising: a slit cut radially from an axis of the insulating holder so as to be opened. 5. The wire lead-out portion comprises only a hollow portion penetrating through a shaft portion of the insulating holder so as to be continuous with the hollow portion of the conductive base. The helical antenna according to 1. 6. The helical antenna according to claim 1, wherein the center conductor includes a core of a coaxial cable and an insulating coating covering an outer periphery of the core. . 7. A power supply coaxial cable is inserted into a hollow portion of a cylindrical conductive base, and an outer conductor of the coaxial cable led out at one end of the conductive base is connected to the conductive base. Step 1; connecting one end of an insulating holder having a spiral groove on the outer peripheral surface to one end of the conductive base, and connecting the center conductor of the coaxial cable led out to one end side of the conductive base to the A second step of leading out of the insulating holder through a wire lead-out portion provided in the insulating holder; and a step of leading the coaxial cable led out of the insulating holder by the second step. A third step of winding a center conductor around a spiral groove of the insulating holder; and a bottomed bottom made of an insulating member outside the center conductor wound on the insulating holder by the third step. Cylindrical cap Covered with up method of a helical antenna which a fourth step of fixing the open end thereof to said conductive substrate, comprising the.