JP2002204113A - Portable telephone antenna - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a portable telephone antenna having a high antenna gain of a coil-like antenna element 20 without varying a dimension of an external shape. SOLUTION: In a portable telephone antenna, a coil-like antenna element 20 is arranged at a distal end of a whip antenna element 10 which can be freely drawn out or housed in a case body of the portable telephone, and is covered with a circular cylindrical top cover 22 and a top cover cap 26 at its distal end. The coil-like antenna element 20 is insert-molded into the top cover 22 made of an insulation resin to match the inside diameter, the top cover cap 26 is formed with a conductive member, an insertion part 26a of the top cover cap 26 is fitted into an inner periphery of the distal end of the top cover 22, and the inner diameter of the distal end of the coil-like antenna element 20 is electrically connected to an outer diameter of the insertion part 26a of the top cover cap 26. Further, a silver metal plating 26b is provided on an outer surface of the top cover cap 26.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antenna for a portable telephone which is provided in a casing of the portable telephone so as to be freely retractable.

[0002]

2. Description of the Related Art An example of a conventional antenna for a portable telephone is shown in FIG.
This will be described with reference to FIG. FIG. 3 is a longitudinal sectional view of a part of an example of a conventional antenna for a mobile phone. In FIG. 3, a whip antenna element 10 is provided in a housing of a mobile phone (not shown) so as to be able to be pulled out and housed, and a coil-shaped antenna element 12 is provided at the tip thereof. The whip antenna element 10 and the coiled antenna element 12 may be electrically connected in a DC or AC manner, or may not be electrically connected in an AC manner. The coil-shaped antenna element 12 is appropriately housed and fixed in a spiral groove 14a provided on the outer periphery of a cylindrical or cylindrical bobbin 14 made of an insulating resin. Further, a cylindrical top cover 16 made of an insulating resin is put on the outside of the bobbin 14, and a top cover cap 18 made of an insulating resin is fitted to a tip end of the top cover 16. In addition, for mobile phone antennas used in certain mobile phone systems,
In order to display this system, silver metal plating 18a or paint is provided on the outer surface of the top cover cap 18.

[0003]

In the above-mentioned conventional antenna for a portable telephone, the top cover cap 18 does not act as an antenna at all. When the silver conductive metal plating 18a is provided on the outer surface, the radiated electric field of the antenna is disturbed by the metal plating 18a, which may deteriorate the antenna characteristics.
In addition, as a standard for a mobile phone system, external dimensions of each part of a mobile phone antenna are generally defined. Therefore,
The physical length of the coiled antenna element 12 is short by the size of the top cover cap 18. This is a factor that lowers the antenna gain of the coil-shaped antenna element 12 and also reduces the resonance bandwidth because the required number of turns is wound with a short physical length.

[0004] The present invention has been made to improve the prior art as described above, and without changing the external dimensions.
An object of the present invention is to provide a mobile phone antenna in which the antenna gain of a coiled antenna element is increased.

[0005]

In order to achieve the above object, an antenna for a portable telephone according to the present invention is provided in a coil shape disposed at the tip of a whip antenna element which can be pulled out and stored in a casing of the portable telephone. An antenna element, wherein the coil-shaped antenna element is covered with a cylindrical top cover and a top cover cap fitted and fixed to a tip of the top cover, wherein the top cover cap is made of a conductive material. The coil-shaped antenna element is formed of a member, and is electrically connected to the top cover cap.

[0006] Then, the top cover and the coiled antenna element made of insulating resin are insert-molded so that the inner diameter of the coiled antenna element matches the inner diameter of the top cover. The insertion part of the top cover cap may be inserted into the inner circumference to electrically connect the coiled antenna element and the top cover cap.

In addition, a cylindrical bobbin made of insulating resin and the coiled antenna element are insert-molded so that the outer diameter of the bobbin and the outer diameter of the coiled antenna element coincide with each other. A fitting portion of the top cover cap may be fitted to the outer periphery of the antenna to electrically connect the coil-shaped antenna element and the top cover cap.

Further, it is possible to provide a silver metal plating or paint on the outer surface of the top cover cap.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIG. FIG. 1 is a vertical sectional view of a part of the first embodiment of the mobile phone antenna of the present invention.

In FIG. 1, a whip antenna element 10 which can be pulled out and housed in a casing of a portable telephone (not shown).
A coil-shaped antenna element 20 is disposed at the tip of. The coil-shaped antenna element 20 is insert-molded integrally with a cylindrical top cover 22 made of an insulating resin so as to have the same inner diameter. The insertion portion 24a of the connection member 24 made of conductive metal provided at the tip of the whip antenna element 10 is fitted into the inner periphery of the lower end of the top cover 22, and the outer diameter of the insertion portion 24a of the connection member 24 and the coil The lower end inner diameter of the antenna element 20 is in contact with and electrically connected. An insertion portion 26a of a top cover cap 26 made of a conductive metal is fitted into the inner periphery of the upper end of the top cover 22, and the outer diameter of the insertion portion 26a of the top cover cap 26 and the inner diameter of the upper end of the coiled antenna element 20 are different. Electrically connected by contact. Furthermore, a silver metal plating 26b such as silver plating or chrome plating is provided on the outer surface of the top cover cap 26 as necessary.

In the first embodiment of the portable telephone antenna having the above structure, the top cover cap 26 is electrically connected to the tip of the coiled antenna element 20, so that the top cover cap 26 functions as an antenna. However, the physical length of the antenna 12 is longer than that of the conventional antenna shown in FIG. 3, and the antenna gain is improved accordingly. In addition, since the top cover cap 26 functions as an antenna, the number of turns to be wound of the coil-shaped antenna element 20 is reduced by that much, and the resonance bandwidth is widened accordingly. Further, in the conventional antenna shown in FIG. 3, the tip of the coiled antenna element 12 is formed at a certain distance from the top cover cap 18, and the physical length of the coiled antenna element 12 is shortened accordingly. On the other hand, in the first embodiment of the present invention,
The tip of the coil-shaped antenna element 20 is disposed so as to overlap with the top cover cap 26 in the length direction, and the physical length of the portion acting as the coil-shaped antenna is increased. Therefore, from this point as well, the pitch width can be expanded, and the resonance bandwidth can be expanded. Moreover, the top cover cap 26
Acts as an antenna, so metal plating 26
Even if b is provided, it does not cause any deterioration in antenna characteristics.

Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 2 is a vertical sectional view of a part of a second embodiment of the antenna for a mobile phone according to the present invention.

In FIG. 2, a whip antenna element 10 which can be pulled out and stored in a housing of a portable telephone (not shown).
A coil-shaped antenna element 30 is disposed at the tip of. The coil-shaped antenna element 30 is integrally insert-molded with a cylindrical bobbin 32 made of an insulating resin so as to have the same outer diameter. And this bobbin 3
The fitting portion 34a of the connecting member 34 made of conductive metal provided at the tip of the whip antenna element 10 is fitted around the lower end of the whip antenna element 2, and the inner diameter of the fitting portion 34a of the connecting member 34 and the coil-shaped antenna element 30 Abuts on the lower end outer diameter to be electrically connected. A fitting portion 36a of a top cover cap 36 made of a conductive metal is fitted around the outer periphery of the upper end of the bobbin 32.
Inner diameter of the fitting portion 36a and the coiled antenna element 3
The upper outer diameter of 0 is in contact with and electrically connected. further,
The bobbin 3 is made of a cylindrical top cover 38 made of insulating resin.
2, the connecting member 34 and the top cover cap 3
6 are disposed with both ends fitted to each other. If necessary, a silver metal plating 36b is provided on the outer surface of the top cover cap 36.

The second embodiment of the mobile phone antenna having such a structure can provide the same effects as those of the first embodiment described above.

In the description of the above embodiment, the top cover caps 26, 36 are made of conductive metal.
The present invention is not limited to this, and may be formed of a resin into which a conductive resin or a conductive metal powder is kneaded, or may be formed of a resin and subjected to metal plating on the entire surface thereof,
What is necessary is just to be formed with the conductive member which can substantially function as an antenna. In addition, the coiled antenna element 2
Reference numerals 0 and 30 are not limited to those formed by insert molding, and a top cover cap made of a conductive metal may be appropriately connected and fixed to the tip of the coil-shaped antenna element by screwing or the like, and may be electrically connected. Further, the elasticity of the coil-shaped antenna element as a coil spring may be used to make the tip end portion elastically contact a top cover cap made of a conductive metal for electrical connection.
Further, any structure may be used as long as the tip of the coil-shaped antenna element can be directly electrically connected to the top cover cap made of a conductive metal.

[0016]

As described above, since the antenna for a portable telephone according to the present invention is constituted, the following special effects can be obtained.

In the portable telephone antenna according to the first aspect of the present invention, the top cover cap made of a conductive member is electrically connected to the tip of the coil-shaped antenna element. Specifically, the physical length of the antenna becomes longer. Thus, the antenna gain can be improved and the resonance bandwidth can be increased.

In any of the antennas for a portable telephone according to the second and third aspects, the coil-shaped antenna element is insert-molded, and a top cover cap made of a conductive member is fitted or fitted into the coil-shaped antenna element. Since the element and the top cover cap are in contact and electrically connected, the overall structure is relatively simple,
In addition, the electrical connection can be made reliably and the antenna characteristics are stable.

In the antenna for a portable telephone according to the fourth aspect, the outer surface of the top cover cap is made silver, so that the antenna can be adapted to the specifications of a specific portable telephone system.

[Brief description of the drawings]

FIG. 1 is a vertical sectional view of a part of a first embodiment of a mobile phone antenna according to the present invention.

FIG. 2 is a vertical sectional view of a part of a second embodiment of the antenna for a mobile phone according to the present invention.

FIG. 3 is a diagram showing a part of an example of a conventional antenna for a mobile phone in a longitudinal section.

[Explanation of symbols]

 Reference Signs List 10 Whip antenna element 12, 20, 30 Coiled antenna element 14, 32 Bobbin 16, 22, 38 Top cover 18, 26, 36 Top cover cap 18a, 26b, 36b Metal plating 24, 34 Connection member 24a, 26a Insertion part 34a , 36a fitting part

Claims (4)

[Claims] 1. A coil-shaped antenna element disposed at a tip of a whip antenna element that can be pulled out and stored in a housing of a mobile phone, wherein the coil-shaped antenna element is a cylindrical top cover and the top cover. In a mobile phone antenna formed so as to be covered with a top cover cap fitted and fixed to the tip of the mobile phone, the top cover cap is formed of a conductive member, and the tip of the coiled antenna element is electrically connected to the top cover cap. An antenna for a mobile phone, wherein the antenna is connected. 2. The antenna for a mobile phone according to claim 1, wherein the top cover and the coiled antenna element made of insulating resin are arranged such that the inside diameter of the coiled antenna element matches the inside diameter of the top cover. Insert molding is performed, and an insertion portion of the top cover cap is inserted into an inner periphery of a tip portion of the top cover so that the coil-shaped antenna element and the top cover cap are electrically connected to each other. Mobile phone antenna. 3. The antenna for a mobile phone according to claim 1, wherein a cylindrical bobbin made of insulating resin and said coiled antenna element have an outer diameter equal to that of said coiled antenna element. And the fitting portion of the top cover cap is fitted around the outer periphery of the tip of the bobbin so that the coil-shaped antenna element and the top cover cap are electrically connected. Mobile phone antenna. 4. The antenna for a mobile phone according to claim 1, wherein an outer surface of said top cover cap is provided with silver metal plating or paint.