JPH06303013A - Antenna - Google Patents

Abstract

PURPOSE:To provide an antenna which can be contained while keeping a basic characteristic of a shape memory alloy and to provide the antenna rich in conductivity while keeping the basic characteristic of the shape memory alloy. CONSTITUTION:The antenna is the one for sending/receiving a radio wave and has a shape memory alloy made tube at least to its part of the antenna. One embodiment 10 of the antenna has 1st, 2nd and 3rd cylinders 11-13 whose aperture differs from each other and the cylinders 11-13 are shape memory alloy tubes. Or the antenna of the other embodiment is provided with the shape memory alloy made tube and a good electric conductor.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an antenna for communication equipment,
In particular, it relates to an antenna of mobile communication equipment.

[0002]

2. Description of the Related Art Conventionally, shape memory alloys (TiNi alloy, C
It is well known that the uZnAl alloy ...) Shows a remarkable shape memory effect accompanying the reverse transformation of the martensitic transformation.

It is also well known that in the matrix phase of this reverse transformation, good superelasticity is exhibited.

By the way, since a superelastic spring made of a shape memory alloy has a movability of about 7% due to extension strain, unlike a stainless wire, a piano wire, etc., it has an advantage that it can be used as a spring material without forming a coil shape. have. This linear spring material made of shape memory alloy has been put to practical use for catheter guide wires and the like. In addition, this spring material has been put into practical use with the merits of preventing deformation and improving the shape retention of the core metal of a brassiere, the core metal of a corset, and the like.

On the other hand, it has already been proposed to use a shape memory alloy for an antenna member for communication equipment, and a shape memory element for recovering the deformation upon use by putting it in hot water and an element utilizing superelasticity which hardly causes deformation. Has been put to practical use. As a member used in these elements, a single wire made of a Ti-Ni alloy having a diameter of about 1 mm or a crushed material having a thickness of about 0.7 mm is mainly used.

[0006]

Originally, it is desirable that the antenna for transmitting and receiving radio waves be long when used and small when housed.

However, when the shape memory alloy is used as a single wire, it is difficult to adopt a mechanism such as folding. In addition, the function of shape memory alloys is superelasticity during normal use, which makes them difficult to bend and more difficult to store.

[0008] Further, the frequency of use of mobile communication devices (cell phones) which have been frequently used recently is gigahertz or a high frequency band close to it, so that a material having relatively poor conductivity such as a Ti-Ni alloy is used. It is designed to be used.

However, it is originally desirable that the radio wave transmitting / receiving antenna has high conductivity, and high conductivity is indispensable for equipment in a low frequency region.

As described above, a method of plating the Ti-Ni alloy with Cu or the like in order to enhance the conductivity of the antenna is conceivable. However, the Ti-Ni alloy may become brittle or the plating may be peeled off repeatedly. There is.

Therefore, a first technical object of the present invention is to provide an antenna that maintains the basic characteristics of the shape memory alloy and is easy to store.

A second technical object of the present invention is to provide an antenna that maintains the basic characteristics of the shape memory alloy and is highly conductive.

[0013]

According to the present invention, there is provided an antenna for transmitting and receiving radio waves, characterized in that at least a part of the antenna is provided with a shape memory alloy tube.

According to the present invention, in the antenna,
An antenna is obtained which has a plurality of metal tubes having different diameters, and at least one of the plurality of metal tubes is the shape memory alloy tube.

Further, according to the present invention, there is obtained an antenna characterized in that the antenna is provided with the shape memory alloy tube and a good conductive material.

Here, in the present invention, it is preferable that the good electric conductor comprises a Cu wire helical pitch coil inserted into the shape memory alloy tube.

Further, as the shape memory alloy applicable to the shape memory alloy tube of the present invention, not only the Ti-50.5 at% Ni alloy described in the next embodiment but also 49 to 51 is used.
At% Ni TiNi alloy and TiNiX (eg,
X = Fe, Si, Cu, Co, Cr, V, Nb, Al
Examples of alloys are not limited to these.

[0018]

Embodiments of the present invention will be described below with reference to the drawings.

(Example 1) T obtained by the high frequency melting method
After processing i-50.5 at% Ni into a solid billet,
Made into a cylinder by machining.

Next, by hot working and cold working, the outer diameter is 2.3 mm-the inner diameter is 2.0 mm, the outer diameter is 1.7 mm-the inner diameter is 1.4 m.
Tubes of m, outer diameter 1.1 mm-inner diameter 0.9 mm were obtained. Each of these tubes was cut into a length of 50 mm, heat-treated at 400 ° C for about 15 minutes, then cooled by liquid nitrogen into a stainless steel thin pipe having a length of 5 mm, press-fitted, and left at room temperature to remove the tube. Restoration with stainless steel was performed by shape recovery. These ends were subjected to predetermined processing and combined to form an antenna as shown in FIG.

The antenna 10 shown in the partial perspective view of FIG.
The tip portion 14 having the cylinder 14a as the top portion is the first cylinder portion 1 made of a shape memory alloy cylinder having a different diameter.
1, a second tubular portion 12, and a third tubular portion 13 are provided.
One ends 11a, 1 of the first and second tubular portions 11, 12, 13
2a and 13a are formed to be narrowed inward. Further, tongue-shaped leaf springs 11b and 12b are provided on the end portion 14b of the tip end portion 14 on the first cylinder portion 11 side and the outer circumferences of the other ends of the first and second cylinder portions 11 and 12, respectively. ing. These tips 1
4, first tubular portion 11, second tubular portion 12, third tubular portion 13
Are nested together.

This antenna 10 was measured for its 10R bending recovery property and pull-out strength at 20 ° C. In addition, as a comparative example, a stainless steel tube antenna having the same size as the above tube was also used. As a result, the shape memory alloy antenna according to Example 1 of the present invention was almost completely restored to 10R bending, could be stored in a length of 50 mm, and could withstand a repetition of 1000 times or more. Moreover, each joint showed a strength of 20 kg or more when pulled out. On the other hand, the antenna made of the tube made of the stainless steel of the comparative example could not be housed because the composition was deformed by bending once.

In the first embodiment, the nested rod antenna is shown, but a rod antenna formed of one long shape memory alloy tube or a Yagi antenna using the shape memory alloy tube is of course also present. Included in the invention.

(Example 2) By the same method as in Example 1, a shape memory alloy tube having an outer diameter of 2.3 mm and an inner diameter of 1.8 mm was obtained, and the length thereof was 150 mm. A Cu wire helical pitch coil (hereinafter referred to as Cu wire coil) having a diameter of 1.7 mm is inserted into this inner diameter surface, and the antenna 2 as shown in FIG.
It was set to 0. As shown in FIG. 2, in the antenna 20, the Cu wire coil 22 is inserted into the shape memory alloy tube 21, and the shape memory alloy tube 2 is formed by the resin cap 23.
Seal both ends of 1 and pierce this cap 23,
Both ends 22a and 22b of the u-wire coil 22 are formed by drawing them out of the shape memory alloy tube 21. Here, the Cu wire coil 22 is used for transmitting and receiving radio waves, and the shape memory alloy is used as an elastic material for keeping the antenna 20 as a mold.

According to the antenna 20 of the second embodiment, the length of the Cu wire is changed in accordance with the frequency band used for mobile communication, that is, the pitch of the Cu wire coil 22 is changed so that the same antenna shape can be obtained. Correspondence is possible.

Although the shape memory alloy tube of the second embodiment is hollow except for the Cu wire coil 22, it may be filled with a liquid or resin having an insulating property, if necessary.

[0027]

As described above, according to the present invention, it is possible to provide an antenna that maintains the basic characteristics of the shape memory alloy and is easy to store.

Further, according to the present invention, it is possible to provide an antenna which maintains the basic characteristics of the shape memory alloy and is highly conductive.

[Brief description of drawings]

FIG. 1 is a perspective view showing a part of an antenna according to a first embodiment of the present invention.

FIG. 2 is a partially cutaway perspective view showing an antenna according to a second embodiment of the present invention.

[Explanation of symbols]

 10, 20 Antenna 11 1st cylinder 12 2nd cylinder 13 3rd cylinder 21 Shape memory alloy tube 22 Cu wire coil 23 Cap

Claims (6)

[Claims] 1. An antenna for transmitting and receiving radio waves, comprising at least a part of a shape memory alloy tube. 2. The antenna according to claim 1, further comprising a plurality of metal tubes having different diameters, and at least one of the plurality of metal tubes is the shape memory alloy tube. Characteristic antenna. 3. The antenna according to claim 1 or 2, wherein the shape memory alloy tube is a Ti—Ni-based alloy that exhibits superelasticity at a use environment temperature. 4. The antenna according to claim 1, further comprising the shape memory alloy tube and a good conductive material. 5. The antenna according to claim 4, wherein the good electric conductor comprises a Cu wire helical pitch coil inserted into the shape memory alloy tube. 6. The antenna according to claim 4 or 5, wherein the shape memory alloy tube is a Ti—Ni-based alloy that exhibits superelasticity at an operating environment temperature.