Communications: radio wave antennas – Antennas – With radio cabinet
Reexamination Certificate
2000-08-07
2002-03-26
Le, Hoanganh (Department: 2821)
Communications: radio wave antennas
Antennas
With radio cabinet
C343S895000, C343S725000
Reexamination Certificate
active
06362792
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an antenna apparatus and a portable radio set, and more particularly, is suitably applied to a cellular telephone.
2. Description of the Related Art
At present, such kind of the cellular telephone is miniaturized and reduced in weight for improvement of portability. Thus, in the antenna apparatus installed in the cellular telephone, a retracting/pulling type of whip antenna is actively developed. Such kind of the cellular telephone is exemplified by that configured as shown in
FIGS. 1A and 1B
.
The cellular telephone
1
of such configuration is configured by installing a whip antenna apparatus
3
in a housing case
2
made of such nonconductive material as a synthetic resin.
The antenna apparatus
3
has an antenna part
6
in which a telescopic antenna
4
made of a conductive, rod-like wire material and a helical antenna
5
formed by winding helically the conductive wire material are installed. The antenna part
6
is retractably and pullably installed along with a direction (hereafter, retracting direction,) in which the antenna part
6
is pushed into the inside of the housing case
2
shown by an arrow A in the top end
2
A of the housing case
2
, and on the contrary, a direction (hereafter, pulling direction,) in which pulled out from the inside of the housing case
2
to outside.
In the antenna part
6
, a first feeding member
7
made of the conductive material and having a projected part
7
A is electrically and mechanically connected to the bottom end of the telescopic antenna
4
, and a connecting part
8
made of nonconductive material is mechanically connected to the top end of the telescopic antenna
4
.
A second feeding member
9
made of the conductive material is electrically and mechanically connected to the bottom end of the helical antenna
5
and the second feeding member
9
is mechanically connected to the connecting part
8
. According to this, in the antenna part
6
the telescopic antenna
4
and the helical antenna
5
are mechanically connected by the connecting part
8
and electrically insulated.
The telescopic antenna
4
is covered with an antenna cover
10
for the rod and the helical antenna
5
is retracted in the cap-like antenna cover
11
for the helix to prevent direct touch with a human body.
On the other hand, the inside of the housing case
2
contains a circuit substrate (not illustrated,) in which various circuit elements such as a transmission and reception circuit
12
and a matching circuit
13
are implemented, and a shield case (not illustrated,) made of the conductive material covering the circuit substrate, as a grounding member.
Inside the top end
2
A of the housing case
2
, an antenna feeding terminal
14
, made of the conductive material, electrically connected to the matching circuit
13
is installed, and the antenna feeding terminal
14
is electrically connected to only any one of the telescopic antenna
4
or the helical antenna
5
in retracting and pulling out the antenna part
6
.
Practically in the antenna apparatus
3
, in pushing the antenna part
6
in, the antenna cover
11
for helix is pushed to a retracting direction to contact to the top end
2
A of the housing case
2
, the telescopic antenna
4
is retracted in the inside of the housing case
2
to house it and then, the second feeding member
9
is electrically connected to the antenna feeding terminal
14
.
In the antenna apparatus
3
, the helical antenna
5
is worked as the antenna by feeding the helical antenna
5
sequentially through the transmission and reception circuit
12
, the matching circuit
13
, the antenna feeding terminal
14
, and the second feeding member
9
.
Here in the antenna apparatus
3
, the telescopic antenna
4
is adapted to no work as the antenna by electrically insulating from the antenna feeding terminal
14
in the connecting part
8
.
In contrast, in the antenna apparatus
3
, the second antenna cover
11
is pinched to pull to a pulling direction in a status in which the telescopic antenna
4
is retracted inside of the housing case
2
followed in pulling out the telescopic antenna
4
from the top end
2
A of the housing case
2
to outside, and then the projected part
7
A of the first feeding member
7
contacts with the antenna feeding terminal
14
to connect electrically the first feeding member
7
to the antenna feeding terminal
14
.
In the antenna apparatus
3
, the telescopic antenna
4
is worked as the antenna by feeding the telescopic antenna
4
sequentially through the transmission and reception circuit
12
, the matching circuit
13
, the antenna feeding terminal
14
, and the first feeding member
7
.
Here in the antenna apparatus
3
, the helical antenna
5
is adapted to no work as the antenna by electrically insulating from the antenna feeding terminal
14
in the connecting part
8
.
When the telescopic antenna
4
and the helical antenna
5
are worked respectively as antennae, impedance of the telescopic antenna
4
and the helical antenna
5
are matched to that of the unbalanced transmission line
16
using the matching circuit
13
.
The shield case functions as a ground against various circuit elements and also functions as an electric shielding plate to prevent invasion of stray components of an electric wave of an external noise and the electric wave radiated from the antenna part
6
into various circuit elements implemented on the circuit substrate.
According to this, in the cellular telephone
1
, in pulling the antenna part
6
, the telescopic antenna
4
is pulled outside from the housing case
2
, a transmission signal consisting of a high frequency signal is sent from the transmission and reception circuit
12
to the telescopic antenna
4
through the matching circuit
13
, the transmission signal is sent to a base station (not illustrated) through the telescopic antenna
4
, and also signal consisting of a high frequency signal, which is sent from base station and received by the telescopic antenna
4
, is sent to the transmission and reception circuit
12
through the matching circuit
13
.
In the cellular telephone
1
, in retracting the antenna part
6
, the telescopic antenna
4
is retracted inside the housing case
2
to prevent loss of portability thereof, in this status the transmission signal is sent from the transmission and reception circuit
12
to the helical antenna
5
through the matching circuit
13
, the transmission signal is sent to the base station through the helical antenna
5
, and also signal, which is sent from base station and received by the helical antenna
5
, is sent to the transmission and reception circuit
12
through the matching circuit
13
.
In the cellular telephone
1
with such configuration, for example, the unbalanced transmission line
15
comprising a microstrip line formed on the circuit substrate is installed, the telescopic antenna
4
or the helical antenna
5
is electrically connected to the transmission and reception circuit
12
sequentially through a hot side of the unbalanced transmission line
15
and the matching circuit
13
, and also the ground side of the unbalanced transmission line
15
is grounded to the shield case.
Therefore, in the cellular telephone
1
, as shown in
FIG. 2A and 2B
, when the telescopic antenna
4
or the helical antenna
5
is supplied an electric power from the transmission and reception circuit
12
sequentially through a hot side of the unbalanced transmission line
15
and the matching circuit
13
to work the telescopic antenna
4
or the helical antenna
5
as the antenna, a leak current i
1
flows from the ground side of the unbalanced transmission line
15
to the shield case
16
, showing that the shield case
16
works as the antenna.
However, in the cellular telephone
1
, there is a problem that because the shield case
16
works as the antenna, when a user hold the housing case
2
, a hand of the user covers over the shield case
16
through the housing case
2
, and as a result, an antenna p
Ito Hiroki
Kanayama Yoshiki
Sawamura Masatoshi
Le Hoang-anh
Maioli Jay H.
LandOfFree
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