JPH08340207A - Antenna system and portable radio equipment - Google Patents

Abstract

PURPOSE: To obtain an antenna having excellent radiation characteristics at the time of applying it to a portable telephone set. CONSTITUTION: A supporting fitting 25 is fixed through a metallic casing 21 of a portable telephone set, a coaxial line 40 with length more than nλ/2 is slidably supported so as to be optionally projected/hidden. A herical antenna 31 with λ/4 electric length is connected to one end of the line 40 and a high frequency signal source 22 is connected to the other end of the line 40 through a coaxial cord 23. Since the antenna 31 is separated from a user's head in the drawn-out state of the line 40 from the casing 21, the deterioration of radiation characteristics can be evaded.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antenna device and a mobile radio device suitable for, for example, a mobile phone.

[0002]

2. Description of the Related Art In a conventional mobile telephone, as shown in FIG. 7, an opening 1 for a receiver (speaker) and a transmitter (microphone) is usually provided on a front surface 10f of a telephone housing 10.
2h and 13h are provided, and a dial key 14 and various function control keys 15 are provided. Further, the liquid crystal display element 16 is arranged at the center of the front surface 10f.

An arc-shaped projecting portion 1 is provided on the left side of the upper portion of the housing 10.
0c is formed to prevent removal during use. An operation knob for function control is arranged so as to contact the peripheral edge of the overhang portion 10c, and when the user holds the housing 10 with the left hand, the thumb drives the peripheral edge of the knob 21 upward or downward. Then, the knob 21 is rotated clockwise or counterclockwise.

A flexible monopole antenna, so-called whip antenna 18, having a length of 1/4 of the wavelength λ corresponding to the transmission / reception frequency can be housed in the top surface 10t of the housing 10 in the housing 10. It is attached to the
The whip antenna 18 is pulled out.

Further, as an antenna for a portable radio device,
A fixed helical antenna having an electric length of approximately λ / 4 (1/4 wavelength) is also used.

Further, an antenna in which a helical antenna is loaded on the tip of a movable whip antenna is also known.

In this antenna, when the whip antenna is housed in the housing, power is supplied to the tip portion of the whip antenna by the fixed power feeding contact, and the helical antenna mainly operates. Further, when the whip antenna is pulled out from the housing, power is supplied to the base of the whip antenna, and the helical portion and the monopole portion form one antenna system, which operates as a so-called top loading whip antenna.

[0008]

By the way, in the field of mobile communication in recent years, due to factors such as an improvement in call quality and an increase in line capacity, the frequency used has become tight and the frequency used is 1 GHz.
The frequency band over is now used.

However, in the 1.5 GHz band, for example, the length of the λ / 4 type monopole antenna is 5 as described above.
When the mobile phone is shortened to about cm and a phone call is made, the monopole antenna approaches the human body, especially the head, and due to the effect, the gain decreases and the radiation characteristics of the antenna deteriorate. There was a problem of doing.

Further, in the λ / 4 type helical antenna,
Since its axial length is shorter than that of the monopole antenna, there is a problem that the influence of the human head becomes larger and the radiation characteristic of the antenna is significantly deteriorated.

On the other hand, in the movable whip antenna having the helical antenna loaded, there is a problem that the input impedance changes between when the antenna is pulled out and when it is stored, and matching is difficult.

In view of the above point, an object of the present invention is to provide an antenna device and a portable radio device capable of avoiding the deterioration of the radiation characteristic of the antenna due to the influence of the human head during use.

[0013]

In order to solve the above-mentioned problems, in the antenna device according to the first invention, one end of a radiation conductor of a predetermined length is used as a feeding point, and this feeding point and the high frequency signal source are formed by a coaxial line. In the connected antenna device,
It is characterized in that a coaxial line in a predetermined range from the feeding point is a supported portion that is slidable.

The second aspect of the present invention is a portable radio apparatus provided with an antenna in which one end of a radiation conductor having a predetermined length is used as a feeding point and the feeding point and a high frequency signal source are connected by a coaxial line. The housing is provided with a supporting means for slidably supporting a coaxial line in a predetermined range from the power feeding point.

[0015]

According to this structure, the coaxial line within a predetermined range is concealed from the feeding point, and the coaxial line within a predetermined range is revealed from the feeding point. In this revealed state, the coaxial line within the predetermined range is revealed. The radiation conductor is moved away from the housing by the amount.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an antenna device and a portable radio device according to the present invention will be described below with reference to FIGS.

The construction of an embodiment of the present invention is shown in FIGS.

In both figures, reference numeral 21 designates a metal shield case (metal case) which is built in the case 10 of the above-mentioned portable telephone, and inside the shield case 21, a signal source is provided. A transmitter circuit (and receiver circuit), represented as 22, is housed.

An opening 24 for inserting the antenna is formed in the upper end portion of the housing 10, and a metal fitting 25 for supporting the antenna is fixed to the opening 24 by, for example, press fitting. A support spring 26 is formed inside the support fitting 25.

In this embodiment, a fixed helical antenna 31 having an electric length of approximately λ / 4 (1/4 wavelength) is used as the antenna, and the helical antenna 31 has an appropriate insulating material over its entire length. Protective case 3
2

Reference numeral 40 denotes a coaxial feed line, which is an inner conductor 4
1 has a tubular outer conductor 43 through the dielectric 42.
To form a coaxial feed line 40 having a predetermined characteristic impedance of, for example, 50Ω.

The helical antenna 31 is connected to one end of the inner conductor 41 of the feed line 40, and the outer conductor 4 is connected.
One end of 3 is fixed to the protective case 32.

The other end of the outer conductor 43 is inserted into the metal member 25 for supporting the antenna and slidably supported by the spring 26, and the other end of the outer conductor 43 is fitted with a retaining metal member 44. Are combined.

The signal source 22 is connected to the other end of the inner conductor 41 of the feed line 40 via a flexible coaxial cord 23. The outer conductor of the coaxial cord 23 is connected to the other end of the outer conductor 43 of the feed line 40.

In this embodiment, when the operating frequency band is, for example, 1.5 GHz, the winding diameter Dh, the number of turns Nh and the pitch Ph of the helical antenna 31 are, for example, Dh = 5 mm; Nh = 5; Ph = It is set as 2 mm 2.

Further, in this embodiment, as shown in FIG. 1, the feed line 40 can be pulled out from the housing 10 for use, and as shown in FIG.
It can be used even if is stored in the housing 10. The length of the power supply line 40 drawn out from the housing 10 is set to an integral multiple of 1/2 of the wavelength λ corresponding to the transmission / reception frequency.

As a result, when the feed line 40 is pulled out from the housing 10, the outer conductor 43 is included in the (2n +
1) It operates as a λ / 4 antenna, and as described above,
Deterioration of antenna characteristics due to the influence of the human head can be avoided, and good call quality can be secured.

Further, when the feed line 40 is housed in the housing 10, it operates as a λ / 4-system helical antenna, so that it is easily affected by the human head, but it remains as it is in a strong electric field. You can call.

At the position where the power feeding line 40 is pulled out from the housing 10 and the position where the power feeding line 40 is housed in the housing 10, there is little change in impedance seen from the coaxial cord 23 side, and matching is achieved. It's easy.

It is desirable that the signal source 22 is arranged in the middle of the stroke of the retaining metal fitting 44 of the power feeding line 40 in order to cope with the drawing and housing of the power feeding line 40 as described above.

Next, another embodiment of the present invention will be described with reference to FIG.

The configuration of another embodiment of the present invention is shown in FIG. In FIG. 3, parts corresponding to those in FIGS. 1 and 2 are denoted by the same reference numerals, and redundant description will be omitted.

In the above embodiment, the coaxial feed line 40 is
Although it is formed with high rigidity by using the tubular outer conductor 43, in the embodiment of FIG. 3, the outer conductor 43f of the coaxial line 40F is formed by closely winding an uncoated conductor in a coil shape. By covering the outside of the coil-shaped conductor 43f with the elastic insulating layer 45, the coil-shaped conductor 43f is made flexible, and the resilience is imparted to the deformation due to an external force. The rest of the configuration is the same as in FIG.

As a result, in the embodiment of FIG. 3, the same effect as that of the embodiment of FIG.
Even if it is removed while 0 is pulled out, it is less likely to be damaged.

The outer conductor 43f of the coaxial line 40F may be a braided uncoated conductor.

Next, still another embodiment of the present invention will be described with reference to FIGS.

The construction of still another embodiment of the present invention is shown in FIGS. In both of these figures, the parts corresponding to those in FIGS.

In FIG. 4 and FIG. 5, the coaxial line 40
A tubular mantle conductor 46 having a length of ¼ wavelength is disposed coaxially with the outer conductor 43 of S. One end 4 of this mantle conductor 46
6a is connected to the outer conductor 43 of the coaxial line 40S on the retaining metal fitting 44 side. Also, this mantle conductor 46
The other end 46b of the protective case 32 is made of an appropriate insulating material between the other end 46b and the outer conductor 43 of the coaxial line 40S.
Is inserted and electrically opened.

Also in this embodiment, the coaxial line 40S is similar to that shown in FIG.
As shown in FIG.
And the position housed in the housing 10, as shown in FIG.

Further, in this embodiment, in order to achieve smooth sliding, a spacer 47 made of an insulating material having the same diameter as the outer conductor 46 is provided. The remaining structure is shown in FIGS. 1 and 2 above.
Is the same as

In this embodiment, the length of the outer conductor 46 is
A so-called spell top is formed by setting the diameter to approximately λ / 4 and appropriately setting the diameter.

As a result, as shown in FIG. 4, at the position where the coaxial line 40S is pulled out from the housing 10, the leakage current from the inside to the outside of the outer conductor 43 is blocked, and the helical antenna 31 due to the leakage current. The deterioration of the characteristics of is prevented.

Then, at the position where the power supply line 40S is pulled out from the housing 10 and the position where it is housed in the housing 10,
Basically, radiation can be done in the same mode, so there is little change in radiation pattern.

Further, as in the embodiment of FIG. 1, the position where the feed line 40S is pulled out from the housing 10 and the housing 10 are different from each other.
At the position housed inside, there is little change in the impedance seen from the coaxial cord 23 side, and matching is easy.

Next, still another embodiment of the present invention will be described with reference to FIG.

The structure of still another embodiment of the present invention is shown in FIG. In FIG. 6, parts corresponding to those in FIGS. 1 to 5 are given the same reference numerals and redundant description will be omitted.

In the embodiment shown in FIGS. 4 and 5, the coaxial feed line 40S has a tubular outer conductor 43 and a jacket conductor 4.
6, the outer conductor 43f and the outer conductor 46 of the coaxial line 40SF are formed in the embodiment of FIG.
f is formed by closely winding an uncoated conductor into a coil,
The outer side of the coil-shaped outer conductor 43f is covered with a spacer 47f made of an elastic insulating material, and the outer side of the coil-shaped outer conductor 46f is covered with an elastic insulating layer 48 to be flexible and deformed by an external force. The resilience is given to the. The other structure is the same as that shown in FIG.

As a result, in the embodiment of FIG. 6, the same effect as that of the embodiment of FIG.
Even if it is removed while 0SF is being pulled out, it is less likely to be damaged.

The outer conductor 43f of the coaxial line 40SF is
As the outer conductor 46f, a braided uncoated conductor may be used.

In each of the above-mentioned embodiments, λ / is used as the antenna.
Although the helical antenna of No. 4 was used, the present invention can be applied to the monopole antenna in exactly the same manner.

[0051]

As described above, according to the present invention, the predetermined range of the coaxial line that feeds one end of the antenna composed of the radiation conductor of the predetermined length is slidably supported by the housing in a hidden manner. Therefore, in the state where the coaxial line in the predetermined range is revealed, the radiation conductor is moved away from the housing by the amount of this coaxial line, and is moved away from the user's head.
Radiation characteristic deterioration is avoided.

[Brief description of drawings]

FIG. 1 is a sectional view showing the configuration of an embodiment of the present invention.

FIG. 2 is a sectional view for explaining the operation of the embodiment of FIG.

FIG. 3 is a perspective view showing a configuration of a main part of another embodiment of the present invention.

FIG. 4 is a cross-sectional view showing the configuration of still another embodiment of the present invention.

FIG. 5 is a cross-sectional view for explaining the operation of the embodiment of FIG.

FIG. 6 is a sectional perspective view showing the configuration of still another embodiment of the present invention.

FIG. 7 is a front view for explaining the present invention.

[Explanation of symbols]

 10 case (non-metal case) 21 shield case (metal case) 22 signal source 23 coaxial cord 25 antenna support metal fitting 31 helical antenna 40, 40S coaxial feed line 40F, 40SF flexible coaxial feed line 45, 48 elastic insulating layer 46,46f mantle conductor

Claims (10)

[Claims] 1. An antenna device in which one end of a radiating conductor having a predetermined length is used as a feeding point and the feeding point and a high-frequency signal source are connected by a coaxial line, and the coaxial line within a predetermined range is slid from the feeding point. An antenna device characterized by being a freely supported portion. 2. The antenna device according to claim 1, wherein the coaxial line in the predetermined range has a required rigidity. 3. The antenna device according to claim 1, wherein the coaxial line in the predetermined range is a coaxial tube. 4. The outer conductor of the coaxial line in the predetermined range is a coil-shaped conductor, and the outside of the coil-shaped conductor is covered with an elastic insulating layer.
The antenna device according to. 5. The antenna device according to claim 1, wherein the outer conductor of the coaxial line in the predetermined range is a braided conductor wire, and the outer side of the braided conductor wire is covered with an elastic insulating layer. 6. A jacket conductor having a length of ¼ wavelength is arranged coaxially with the outer conductor of the coaxial line, and the jacket conductor and the outer conductor are connected at the feeding point side. The antenna device according to. 7. The antenna device according to claim 6, wherein the outer conductor is a conductor tube. 8. The antenna device according to claim 6, wherein the outer conductor is composed of a conductive wire formed in a coil shape, and the outside of the coiled conductive wire is covered with an elastic insulating layer. 9. The antenna device according to claim 6, wherein the outer conductor is composed of a braided conductor wire, and the outer side of the braided conductor wire is covered with an elastic insulating layer. 10. An end of a radiation conductor having a predetermined length is used as a feeding point,
In a portable wireless device including an antenna in which the feeding point and a high-frequency signal source are connected by a coaxial line, a housing is provided with a supporting means for slidably supporting the coaxial line in a predetermined range from the feeding point. A portable wireless device characterized in that