Communications: radio wave antennas – Antennas – With radio cabinet
Reexamination Certificate
2000-04-04
2001-11-27
Phan, Tho (Department: 2821)
Communications: radio wave antennas
Antennas
With radio cabinet
C343S846000
Reexamination Certificate
active
06323812
ABSTRACT:
TECHNICAL FIELD
This invention is generally related to antennas and more particularly to antennas for portable communication devices.
BACKGROUND
As improved integrated circuit technology allows portable communication devices, such as transceivers and radiophones, or their combination, to be reduced in size, it is also desirable to reduce the overall length of the antenna structure used with such devices. One style of antennas is the half wave dipole antenna which requires no extensive ground plane to operate. Half wave dipole antennas produce highly desirable and predictable electrical performance. However, these antennas are large and therefore are undesirable for portable applications.
One of the smallest antenna structures frequently used with portable transceivers is a quarter wave length whip antenna which requires an extensive ground plane to operate effectively. A quarter wave whip antenna radiates at acceptable levels below the standards of the halfwave dipole, however with the benefit of reduced length. The much reduced size of portable communication devices has also reduced the size of the available ground plane. Consequently, the ground interacts with a high level of sensitivity to its surrounding environment. The smaller the antenna and ground become, the more the Q of the system increases, making the antenna and frequency bandwidth of operation smaller.
An antenna grounding improvement is therefore desired that can be used with small portable communication products.
REFERENCES:
patent: 4755822 (1988-07-01), Chesebro
patent: 4849765 (1989-07-01), Marko
patent: 4868576 (1989-09-01), Johnson, Jr.
patent: 4876552 (1989-10-01), Zakman
patent: 5539417 (1996-07-01), Terry et al.
patent: 5739791 (1998-04-01), Barefield et al.
patent: 6140977 (2000-10-01), Morales et al.
patent: 6191740 (2001-02-01), Kates et al.
Kopp Markus B.
Perrotta Alessandro
Yeboah Daniel
Garrett Scott M.
Motorola Inc.
Phan Tho
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