Communications: radio wave antennas – Antennas – With radio cabinet
Reexamination Certificate
2000-01-03
2002-05-14
Le, Hoanganh (Department: 2821)
Communications: radio wave antennas
Antennas
With radio cabinet
C343S895000
Reexamination Certificate
active
06388625
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an antenna device achieving desirable transmission and reception in two or more frequency bands, and which is used in mobile communication apparatus such as cellular phones.
BACKGROUND OF THE INVENTION
FIG. 14
shows one example of a conventional antenna device used in mobile communication apparatus such as cellular phones. In
FIG. 14
,
102
is a transmission and reception unit, and surrounding it is a main housing
101
. On the top of the main housing
101
are a pair of antenna coils
103
and
104
which are disposed integrally on the inside of a common housing
110
.
The two antenna coils
103
and
104
are disposed on the same axis. The antenna coil
103
placed on the top is connected to a transmission unit
105
of the transmission and reception unit
102
via a duplex filter
107
. The antenna coil
104
placed at the bottom is connected to a reception unit
106
of the transmission and reception unit
102
via the duplex filter
107
.
The electrical lengths of the two antenna coils
103
and
104
are designed such that the electrical lengths of the top antenna coil
103
and bottom antenna coil
104
are respectively a quarter of the transmission frequency and reception frequency of the transmission and reception unit
102
.
The antenna coil
103
for transmission is disposed above the antenna coil
104
for reception. By positioning the antenna coil
103
further from metallic parts or other similar parts of the apparatus, better transmission can be obtained.
The two antenna coils
103
and
104
share a common feed line
108
to the duplex filter
107
. The length of a transmission feed line portion
108
a
of the transmission antenna coil
103
, which extends via the reception antenna coil
104
is open in the reception band, and is connectable with the duplex filter
107
in the transmission band. In
FIG. 14
,
109
is a second reception antenna.
Therefore, when the reception antenna coil
104
is used, the transmission antenna coil
103
does not place any load on the junction point, thus only the reception antenna coil
104
is driven. The antenna coils
103
and
104
are designed to match at
50
ohms so that impedance matching is not required.
With the above-mentioned conventional construction however, when trying to obtain the optimal impedance properties of the antenna, relative positions of the two antenna coils can not be changed and possible range for impedance adjustment is limited since the two antenna coils are both supplied with electricity and fixed.
Therefore, when the impedance for the antenna terminals of the duplex filter is changed due to a design change of a high frequency circuit inside the apparatus, the antenna device itself requires a design modification to deal with changed impedance. As such, rapid countermeasures to the design change of the apparatus are difficult to implement.
To mass-produce the device, the two antenna coils must be disposed, maintaining their relative positions precisely so that dispersion of the impedance of the antenna device does not occur. At the same time, the two antenna coils must be electrically connected to the high frequency circuit inside the apparatus. Thus, with this construction it is difficult to mass-produce the device productively.
The present invention aims at providing antenna devices and mobile communication apparatus using the devices, which allow an easy and wide-ranging adjustment of the impedance properties of the antenna as well as mass production of related products with good yield.
SUMMARY OF THE INVENTION
An antenna device of the present invention includes a) a spiral-shaped first antenna element of which one end is open and the other end is electrically connected with a high frequency circuit inside of a communication terminal; and b) a second antenna element having both ends being open, and which is insulated from and disposed on either outer or inner surface of the first antenna element. The impedance properties of an antenna can be adjusted by changing the disposing position of the second antenna element. Desired impedance properties can be gained just by changing the disposing position. A wide range adjustment of the impedance properties is also possible. Moreover, the construction of the antenna device is remarkably simple, thus its mass-production is easy.
REFERENCES:
patent: 5559524 (1996-09-01), Takei et al.
patent: 5828342 (1998-10-01), Hayes et al.
patent: 5923305 (1999-07-01), Sadler et al.
patent: 5982330 (1999-11-01), Koyanagi et al.
patent: 5999142 (1999-12-01), Jang
patent: 6069592 (2000-05-01), Wass
patent: 6107970 (2000-08-01), Holshouser et al.
patent: 3-236612 (1991-10-01), None
patent: 5-275919 (1993-10-01), None
patent: 9-2476828 (1997-09-01), None
patent: 10-22730 (1998-01-01), None
patent: 10-32410 (1998-02-01), None
Japanese language search report for Int'l Appln No. PCT/JP99/01284 dated Jun. 15, 1999.
Fukushima Susumu
Oohara Masahiro
Yuda Naoki
Le Hoang-anh
Matsushita Electric - Industrial Co., Ltd.
Ratner & Prestia P.C.
LandOfFree
Antenna device and mobile communication unit does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Antenna device and mobile communication unit, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Antenna device and mobile communication unit will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2894926