Multi-band antenna

Details Multi-band antenna Multi-band antenna

2002-12-20

2004-05-11

Ho, Tan (Department: 2821)

Communications: radio wave antennas

Antennas

Microstrip

C343S725000, C343S741000, C343S846000

Reexamination Certificate

active

06734826

ABSTRACT:

CROSS-REFERENCE TO RELATED APPLICATION
The present application is related to one contemporaneously and one previously filed U.S. patent applications having the same title, the same inventors and the same assignee with the invention.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an antenna, and in particular to an antenna fixed in an electronic device for receiving or transmitting signals in two distinct frequency bands.
2. Description of the Prior Art
The development of wireless local area network (WLAN) technology has been attended by the development of devices operating under the IEEE 802.11b standard (in the 2.45 GHz band) and the IEEE 802.11a standard (in the 5.25 GHz band). These devices benefit from a multi-band antenna. U.S. Pat. No. 6,204,819 discloses a conventional multi-band antenna. The multi-band antenna includes a first and second conductive branches
42
,
46
, and is provided for use within wireless communications devices, such as radiotelephones. A first conductive branch
42
has first and second feeds
43
,
44
extending therefrom that terminate at respectively a first and second micro-electromechanical systems (MEMS) switches S
1
, S
2
. The second conductive branch
46
is in adjacent, spaced-apart relationship with the first conductive branch
42
. One end of the second conductive
46
branch terminates at a third MEMS switch S
3
and the opposite end of the second conductive branch
46
is connected to the first conductive branch
42
via a fourth MEMS switch S
4
. The fourth MEMS switch S
4
is configured to be selectively closed to electrically connect the first and second conductive branches
42
,
46
such that the antenna radiates as a loop antenna in a first frequency band. The fourth switch S
4
is also configured to open to electrically isolate the first and second conductive branches
42
,
46
such that the antenna radiates as an inverted-F antenna in a second frequency band different from the first frequency band. However, the switches add manufacturing cost and complexity to the antenna. Furthermore, the three dimensional structure of the antenna occupies a large space, which is counter to the trend toward miniaturization of portable electronic devices.
Hence, an improved multi-band antenna is desired to overcome the above-mentioned disadvantages of the prior art.
BRIEF SUMMARY OF THE INVENTION
A main object of the present invention is to provide a multi-band antenna occupying smaller space.
A multi-band antenna in accordance with the present invention comprises an insulative substrate, a conductive element disposed on the substrate, and a feeder cable connecting with the conductive element. The conductive element includes a ground portion, a radiating portion, a first connecting portion and a second connecting portion. The first and second connecting portions are adapted to connect the ground portion with the radiating portion. The radiating portion comprises a plurality of radiating segments connecting in turn and perpendicularly to each other. The feeder cable is a coaxial cable having an inner core conductor connecting with the radiating portion and a outer shield conductor connecting with the ground portion. The ground portion, a part of the radiating portion, the second connecting portion and the feeder cable form a loop antenna, which operates in a higher frequency band. The ground portion, the radiating portion, the first connecting portion and the feeder cable form a planar inverted-F antenna, which operates in a lower frequency band.
Other objects, advantages and novel features of the invention will become more apparent from the following detailed description of a preferred embodiment when taken in conjunction with the accompanying drawings.


REFERENCES:
patent: 6002367 (1999-12-01), Engblom et al.
patent: 6072434 (2000-06-01), Papatheodoron
patent: 6204819 (2001-03-01), Hayes et al.
patent: 6295029 (2001-09-01), Chen et al.
patent: 6452551 (2002-09-01), Chen
patent: 6476767 (2002-11-01), Aoyama et al.
patent: 6498586 (2002-12-01), Pankinaho
patent: 6535172 (2003-03-01), Hirabayashi
Fang-I Hsu, “Planar Near-Field to Far-Field Transformation and PIFA Antenna Suitable for Wireless LAN”, Paper of Institute of Communication Engineering National Chiao Tung University of Taiwan, 2001, http//datas.ncl.edu.tw/.

Affiliated with

Also associated with

Rating

Multi-band antenna does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Multi-band antenna, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Multi-band antenna will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3250499