JPH066121A - Antenna system - Google Patents

Abstract

PURPOSE:To realize the same radiation characteristic for the antenna system as the state that an antenna rod is extracted from the casing of a radio equipment while attaining a nearly circular antenna radiation pattern even when the antenna rod is retracted in the case with respect to the antenna system able to be contained slidably in the case of the radio equipment. CONSTITUTION:In the antenna system in which a metallic rod 1 is skided to be contained in a radio equipment casing 3, a helical antenna 11 is mounted to an upper end of the rod 1 via an insulation material, and only the rod antenna 1 acts like an antenna when the rod 1 is extracted from the case and only the helical antenna 11 acts like an antenna when the rod 1 is contained in the case 3. When the helical antenna 11 is fitted to the upper end of the rod 1 while keeping electric continuity and the rod is contained in the case, only the helical antenna acts like an antenna, and the rod 1 and the helical antenna 11 act like a composite antenna when the rod is extracted from the case 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmitting / receiving antenna for a wireless communication device, and more particularly to an antenna device which can be housed in a housing of a mobile wireless device.

[0002]

2. Description of the Related Art Generally, in a portable radio apparatus for a mobile body, an antenna called a unipole or monopole type antenna having one metal rod with one end as a feeding path is widely used. There is also a structure in which the rod slides so as to be able to be housed in the wireless device housing in order to improve portability.

FIG. 3 is a diagram showing an example of the above.
Is a perspective view showing a state where the metal rod 1 is pulled out from the housing 3 of the wireless device 2, and (b) is a cross-section of the antenna device part showing a state where the rod 1 is slid and housed in the housing 3. In the figure, it is assumed that the rod 1 has a length of λ / 4 (λ = wavelength), which is the most common in a unipole antenna. Here, the coupler 4 is a metal ring that electrically connects the rod 1 and a matching circuit (not shown) in the transmission / reception unit 5, and supports the rod 1 together with the storage sleeve 6 so as to be slidable in the axial direction. And large diameter parts 7 and 8 provided at both ends of the rod 1.
And the movable range of the rod 1 is limited.

In recent years, from the viewpoint of weight reduction and aesthetics, it has become mainstream to form the casing 3 from a non-metallic material such as plastic. Therefore, as shown in FIG. 3 (b), the rod 1 is housed. Some sleeves 6 are made of a non-metallic material so that the antenna can be operated even in such a state. According to this structure, the transmission signal provided from the transmission / reception unit 5 to the coupler 4 via the matching circuit is supplied to the rod 1 and transmitted through the sleeve 6 and the housing 3 to be radiated as a radio wave, while the sleeve 6 and the housing are radiated. The signal transmitted through the body 3 and received by the rod 1 follows the opposite path.

However, in the above-mentioned structure, since the transmitting / receiving unit 5 is generally housed in the metal case for shielding, the transmitting / receiving unit 5 is housed in the housing 3 with the rod 1 housed therein. There is a drawback that the antenna radiation pattern existing across the antenna radiation pattern of the rod 1 and ideally having a circular shape in the horizontal plane orthogonal to the rod 1 is weakened and distorted on the transmission / reception unit 5 side. there were. Also, when the handheld wireless device is gripped and operated, the antenna radiation pattern is distorted because the hand also covers the rod 1.
There is a defect that the radiation efficiency is significantly deteriorated as compared with the state where the rod 1 is pulled out of the housing 3.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in order to eliminate the defects of the conventional antenna device which can be slidably housed in the housing of the wireless device as described above, and even when the antenna rod is housed. An object of the present invention is to provide an antenna device having a substantially circular antenna radiation pattern and realizing radiation characteristics equivalent to those when the rod is pulled out of the housing.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, an antenna device according to the present invention is an antenna device in which a metal rod is slidably housed in a radio device housing, and an insulating member is interposed at an upper end portion of the rod. The helical antenna is fixed by means of the rod so that only the rod functions as an antenna when the rod is pulled out from the housing, and only the helical antenna when housed in the housing, or the upper end of the rod. A helical antenna is electrically fixed to the part, and only the helical antenna functions when the rod is housed in the housing, and the rod and the helical antenna function as a composite antenna when the rod is pulled out from the housing. It is configured as follows.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in detail with reference to the drawings showing the embodiments. 1A and 1B are views showing an embodiment of the present invention, in which FIG. 1A is a perspective view showing a state in which a metal rod 1 is pulled out from a housing 3 of a wireless device 2, and FIG.
FIG. 3 is a cross-sectional view of an antenna device portion showing a state where the antenna device is slid and housed in the housing 3. In this antenna device, a large-diameter portion 7 is formed as a contact metal fitting on the lower end portion of the rod 1, while the upper end is formed. A large-diameter portion 10 made of metal that functions as a second contact fitting through an insulating member 9 having the same diameter as the rod 1
And a helical antenna 11 fixed to the large-diameter portion 10 so as to be conductive. Similar to the rod 1, the helical antenna 11 is formed by spirally forming a conductive wire so as to have a circular antenna radiation pattern characteristic orthogonal to the axial direction at the transmission / reception frequency of the wireless device, and in a housed state. It is covered with a non-metal cover 12 in order to protect the shape from the pressing force when pulling out the rod by picking up the rod with a finger or the impact during carrying.

By configuring as described above, FIG.
In the state where the rod 1 is pulled out from the housing 3 of the wireless device 2 as shown in (a), the transmission signal given from the transmission / reception unit 5 to the coupler 4 is transmitted only to the rod 1 via the large diameter portion 7. While being supplied and radiated as a radio wave, the helical antenna 11 does not function as an antenna at all because it is electrically separated from the rod 1 by the insulating member 9.

On the other hand, in the state where the rod 1 is housed in the housing as shown in FIG. 1 (b), the coupler 4 and the large diameter portion 10 are provided.
Since and are electrically connected to each other, the transmission signal given from the transmission / reception unit 5 to the coupler 4 is supplied only to the helical antenna 11 through the large diameter portion 10 and radiates as a radio wave, and the rod 1 is insulated by the insulating member 9. At coupler 4 and large diameter part 1
It does not function as an antenna because it is electrically separated from 0. That is, only the rod 1 functions as an antenna when the rod 1 is pulled out from the housing, and only the helical antenna 11 functions when housed in the housing. In both cases, the antenna functions when the antenna is exposed from the housing. Therefore, the problem as described above does not occur.

As is well known, the helical antenna generally has a planar antenna radiation pattern characteristic orthogonal to the axial direction as described above by reducing the total length and the circumference of the helix in comparison with the wavelength λ. It is possible to make it extremely shorter than a rod antenna having a length of / 4. Therefore, the portion of the helical antenna projecting from the housing when the rod is housed does not impair the appearance and portability without much difference from the conventional degree of projection.

2 (a) and 2 (b) are sectional views of the antenna device portion showing the second embodiment of the present invention and its modification, respectively, in which the rod 1 and the large-diameter portion 10 are directly connected. It is greatly different from the above-mentioned invention in that it is fixed so as to be conductive. FIG. 2 (a) shows a state in which the rod 1 is housed in the housing, but when the rod is pulled out, the rod 1 and the large-diameter portion 10 are electrically connected and fixed as described above. The transmission signal supplied to the large diameter portion 7 at the lower end of the rod 1 via the coupler 4 is radiated as a radio wave by the rod 1 and the helical antenna 11 functioning as an antenna in combination. It is well known that the antenna having such a structure functions as an antenna having a length of λ / 2 as a whole when the length of the rod 1 is λ / 4 helical antenna 11 corresponding to λ / 4.

On the other hand, in the state in which the rod 1 is housed as shown in FIG. 2A, one end is connected to the ground and the other end of the contact 13 which is elastically biased toward the inside of the sleeve 6 has the sleeve 6 It contacts the large diameter portion 7 through a window 14 provided at the lower end. In such a state, since the impedance between the large diameter portion 7 and the coupler 4, that is, the portion of the rod 1 becomes high impedance, the transmission signal given to the coupler 4 is supplied to only the helical antenna through the large diameter portion 10. Then, the state is almost the same as the state of FIG. 1B in which only the helical antenna exposed to the outside of the housing operates. Here, in order to improve the efficiency when the rod 1 is pulled out, for example, when the length of the rod 1 is set to λ / 2, the contact 13 is set to λ / 4 from the coupler 4.
It may be arranged so as to come into contact with the position (1), that is, substantially the center of the rod 1.

In FIG. 2B, the sleeve 6 is made of metal and is connected to the ground, and a plurality of radial contacts 15 provided at the tip of the large diameter portion 7 at the lower end of the rod 1 are provided in the sleeve 6. It is needless to say that the elastically biased member is shown so as to come into contact with the wall surface, and operates and acts in the same manner as in the case of FIG.

Although the present invention has been described above using the helical antenna in which one conductor is processed into a spiral shape as an example, the present invention is not limited to this.
It is also possible to use another helical antenna such as a wire-wound helical antenna. Further, the coupler has a ring shape so as to slidably support the rod and also has a function of a stopper that prevents the large diameter portions at both ends of the rod from coming into contact with the rod and dropping off the rod. Alternatively, the respective functions may be realized by a plurality of parts. Further, it is needless to say that the rod length may be set as needed and is not limited to that of the embodiment.

[0016]

Since the present invention is configured as described above, in a slidable antenna device for a wireless device, even if the rod of the antenna is housed, the rod of the housing can be accommodated. A substantially circular antenna radiation pattern equivalent to that when it is pulled out is realized, and a remarkable effect is obtained in preventing deterioration of radiation efficiency.

[0017]

[Brief description of drawings]

1A and 1B are respectively a perspective view and a cross-sectional view of an antenna device portion showing a state in which an embodiment of the antenna device according to the present invention is used in a wireless device.

2A and 2B are cross-sectional views showing an embodiment and a modified embodiment of the antenna device according to the second invention, respectively.

3A and 3B are a perspective view and a cross-sectional view of an antenna device portion showing a state in which a conventional antenna device is used in a wireless device, respectively.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Rod 2 ... Wireless device 3 ... Housing 4 ... Coupler 7, 10 ... Large diameter part (contact metal fitting) 9 ... Insulation member 11 ... Helical antenna

Claims (3)

[Claims] 1. An antenna device in which a metal rod is slidably housed in a radio device housing, wherein a helical antenna is fixed to an upper end portion of the rod via an insulating member,
An antenna device, wherein only the rod functions as an antenna when the rod is pulled out from the housing, and only the helical antenna functions when the rod is housed in the housing. 2. A rod-shaped lower end of the helical antenna and a lower end of the rod are provided with contact fittings, respectively, and a metal coupler is provided in the vicinity of the rod through hole of the housing, and the rod is slid. The antenna device according to claim 1, wherein one of the contact fittings is electrically connected to the coupler. 3. An antenna device in which a metal rod is slidably housed in a radio device housing, and a helical antenna is conductively fixed to an upper end portion of the rod, and the rod is housed in the housing. An antenna device characterized in that only the helical antenna is such that the rod and the helical antenna function as an antenna in a combined manner when pulled out from the housing.