Browse Prior Art Database

Directional, Protecting Antennas for Wireless Hand-Held Telephones

IP.com Disclosure Number: IPCOM000123767D
Original Publication Date: 1999-Apr-01
Included in the Prior Art Database: 2005-Apr-05
Document File: 1 page(s) / 44K

Publishing Venue

IBM

Related People

Duan, D-W: AUTHOR

Abstract

Invented are radio frequency antennas for mounting on wireless hand-held telephones that provide high directivity for improved reception and reduce the amount of radiation impinging on a user.

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This is the abbreviated version, containing approximately 76% of the total text.

Directional, Protecting Antennas for Wireless Hand-Held Telephones

   Invented are radio frequency antennas for mounting on
wireless hand-held telephones that provide high directivity for
improved reception and reduce the amount of radiation impinging on a
user.

   Typical antennas used on a wireless hand-held telephone
are monopoles, dipole-helical combinations, slow-wave axial-mode
helix, et.  These antennas are chosen mainly for their compact form
factors.  There are, however, some drawbacks about these antennas.
The most significant one is that these antennas have quite uniform
radiation patterns, which introduces electromagnetic radiation into
the user's head.  This may raise health concerns, particularly for
sensitive areas like the eyes and the brain.  Furthermore, variations
in radiation pattern and reduction in antenna gain due to the
presence of the user's head also deteriorate the quality of the
communication channel.  One way to avoid this problem is to use some
sort of shielding mechanism such as a ground plane.  This,
unfortunately, is impractical because the required size of the ground
plane is too large.

   Invented in this disclosure is a dipole antenna loaded
with loading bars that are parallel to the dipole.  Such "loaded
dipole" may be designed to have a highly directional radiation
pattern, resulting high gain in one direction (for improved
reception), and very low gain in other directions, which minimizes
the amount of radiation that imping...