Communications: radio wave antennas – Antennas – Spiral or helical type
Reexamination Certificate
1998-11-02
2001-10-02
Wong, Don (Department: 2821)
Communications: radio wave antennas
Antennas
Spiral or helical type
C343S702000, C343S7000MS
Reexamination Certificate
active
06297784
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a cellular telephone antenna, and more particularly to a bi-frequency cellular telephone antenna which uses two coils to form a bi-frequency antenna structure.
Conventional cellular telephones are specifically designed for a particular frequency. There are disclosed a variety of advanced cellular telephones with bi-frequency antenna capable of matching GSM900 and GSM1800.
FIGS. 1 and 2
show a bi-frequency antenna for a cellular telephone according to the prior art. This structure of bi-frequency antenna uses a conductive plate
10
instead of a winding. The conductive plate
10
is made of a thin sheet of metal by stamping, having a wave-like vertical section
11
, and a wave-like horizontal section
12
. When the conductive plate
10
is made, it is adhered to the periphery of a shaft
13
. Because the stamping die for making the conductive plate
10
is of high precision, the cost is high. Further, adhering the conductive plate
10
to the periphery of the shaft
13
is not an easy job.
SUMMARY OF THE INVENTION
It is the main object of the present invention to provide a bi-frequency cellular telephone antenna which is simple and inexpensive. According to the present invention, the bi-frequency cellular telephone antenna comprises a shaft fastened to a cellular telephone, an insulative barrel fastened to the shaft at a top side, a first coil for a first frequency mounted inside the insulative barrel, and a second coil for a second frequency mounted around the periphery of the insulative barrel.
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patent: 4772895 (1988-09-01), Garay et al.
patent: 5168278 (1992-12-01), Morita
patent: 5436633 (1995-07-01), Liu
patent: 5469177 (1995-11-01), Rush et al.
patent: 5493311 (1996-02-01), Itoh et al.
patent: 5754146 (1998-05-01), Knowles et al.
patent: 5990848 (1999-11-01), Annamaa et al.
patent: 6016130 (2000-01-01), Annamaa
patent: 6097340 (2000-08-01), Chang
patent: 6163300 (2000-12-01), Ishikawa et al.
Auden Techno Corp.
Dougherty & Troxell
Vo Tuyet T.
Wong Don
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