Information
-
Patent Grant
-
6480156
-
Patent Number
6,480,156
-
Date Filed
Tuesday, March 27, 200123 years ago
-
Date Issued
Tuesday, November 12, 200221 years ago
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Inventors
-
Original Assignees
-
Examiners
Agents
-
CPC
-
US Classifications
Field of Search
US
- 343 700 MS
- 343 702
- 343 735
- 343 736
- 343 805
- 343 806
- 343 808
- 343 809
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International Classifications
-
Abstract
An inverted-F dipole antenna (1) for an electronic device includes a conductive antenna body (12), an antenna base (11), a connector (14) providing an electrical interface to an RF circuitry, and a cable (13) connecting the antenna body to the connector. The antenna body includes a first and second arms (121), (122) and a U-shaped portion (123) connecting the first and second arms. The antenna base includes an insulative board (111) and a metal sheet (112) attached to one surface of the board. The U-shaped portion of the antenna body is attached to a second surface of the board opposite to the metal sheet. The first arm serves as a radiation device.
Description
FIELD OF THE INVENTION
The present invention relates to an antenna, and particularly to an inverted-F dipole antenna mounted in an electronic device and operating in the ISM (Industry, Science, Medicine) frequency band for communicating with various electronic devices.
BACKGROUND OF THE INVENTION
FIG. 7
illustrates a conventional planar inverted-F antenna (PIFA). The PIFA
10
includes a ground plane
12
, an L
P
×W
P
rectangular radiating patch
14
and a short-circuit plate
16
having a width d
1
which is narrower than the width W
p
of the radiating patch
14
. The short-circuit plate
16
shorts the radiating patch
14
to the ground plane
12
along a null of the TM
100
dominant mode electric field of the radiating patch
14
. The PIFA
10
may thus be considered a rectangular microstrip antenna in which the length of the rectangular radiating patch
14
is reduced by half by the connection of the short-circuit plate
16
at the TM
100
dominant mode null. The short-circuit plate
16
supports the radiating patch
14
at a distance d
2
above the ground plane
12
. The radiating patch
14
is fed by a TEM transmission line
18
from the back of the ground plane
12
, at a point located a distance d
3
from the short-circuit plate
16
. The transmission line
18
has a width d
4
and includes an inner conductor
20
surrounded by an outer conductor
22
. The PIFA
10
is suited for use in personal base stations, handsets and other wireless communication terminals because it has a large bandwidth and can be implemented using an air dielectric as shown in FIG.
7
.
However, in this design, the inner conductor
20
of the TEM transmission line
18
penetrates through the ground plane
12
and connects with the radiating patch
14
and the outer conductor
22
connects with the ground plane
12
. This design makes the assembly more complicated and increases the cost of the antenna. Furthermore, the antenna occupies a large space, so it goes against the trend toward miniaturization of electronic devices.
The present invention is directed to solving the above problems and satisfying the need for a simple antenna of the character described.
BRIEF SUMMARY OF THE INVENTION
A primary object, therefore, of the present invention is to provide an improved antenna which occupies a small space and has a simplified manufacture.
In order to achieve the objects set forth, an inverted-F dipole antenna in accordance with the present invention comprises an antenna body, an antenna base, a connector providing an electrical interface to an RF circuitry and a cable connecting the antenna body with the connector. The antenna body includes two metal arms and a bended wire connecting the two arms. The antenna base includes a rectangular insulative board and a metal sheet attached to one surface of the board. The antenna body is mounted on the antenna base with the bended wire thereof being attached to a second surface of the board opposite to the metal sheet. The cable serves as a RF feeder and one of the metal arms serves as a radiation device.
Other objects, advantages and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1
shows a perspective view of an inverted-F dipole antenna in accordance with an exemplar embodiment of the present invention;
FIG. 2
shows an antenna base of the antenna of
FIG. 1
;
FIG. 3
shows the antenna of
FIG. 1
without the antenna base;
FIG. 4
shows an inverted-F dipole antenna module of the present invention assembled in a desktop computer;
FIG. 5
is a partial, enlarged view of the circled portion labeled V in
FIG. 4
;
FIG. 6
is a graph of experimental data obtained for the inverted-F dipole antenna of
FIG. 1
, disclosing Voltage Standing Wave Ratio (VSWR) varying with frequency; and
FIG. 7
shows a planar inverted-F antenna (PIFA) in accordance with the prior art.
DETAILED DESCRIPTION OF THE INVENTION
Reference will now be made to the drawing figures to describe the present invention in detail.
Referring to
FIG. 1
, an inverted-F dipole antenna
1
in accordance with the present invention comprises an antenna base
11
, an antenna body
12
mounted on the antenna base
11
, a connector
14
providing an electrical interface to an RF circuitry (not shown) and a cable
13
connecting the antenna body
12
with the connector
14
.
Particularly referring to
FIG. 2
, the antenna base
11
includes a rectangular insulative board
111
and a metal sheet
112
attached to one surface of the insulative board
111
.
Particularly referring to
FIG. 3
, the antenna body
12
is formed of a conductive metal wire and includes a U-shaped portion
123
, and a first arm
121
and a second arm
122
respectively extending substantially opposite to each other from opposite extreme ends of the U-shaped portion
123
. In this embodiment, the cable
13
serves as RF feeder of the antenna body
12
and is a coaxial cable. The cable
13
has an inner core wire
131
soldered to one end of the U-shaped portion
123
proximate the first arm
121
, and an outer shield
132
soldered to the other end of the U-shaped portion
123
proximate the second arm
122
. The first arm
121
is the radiation device of the inverted-F dipole antenna
1
.
In assembly, referring to
FIGS. 1
,
4
and
5
, after the cable
13
is attached between the connector
14
and the antenna body
12
, the antenna body
12
is fixed on the antenna base
11
. The U-shaped portion
123
is attached to a second surface of the insulative board
111
opposite to the one surface to which the metal sheet
112
is attached. The first and second arms
121
,
122
extend horizontally in two substantially opposite directions, pointing away from the insulative board
111
, each forming a same angle
0
with the insulative board
111
. The inverted-F dipole antenna
1
is mounted on an enclosure
22
of a desktop computer
2
behind a plastic cover
21
of the desktop computer
2
, with the metal sheet
112
being in electrical contact with a front surface (not labeled) of the enclosure
22
.
Referring to
FIG. 5
, the enclosure
22
is made of a conductive material and serves as a reflective surface for the electromagnetic wave radiated by the antenna
1
. Even if a portion of the antenna base
11
extends out of the enclosure
22
, the metal sheet
112
assists the enclosure
22
to perform as a reflective surface, thereby assuring normal performance of the antenna
1
and making mounting easier. When the inverted-F dipole antenna
1
is operated in the ISM (Industry, Science, Medicine) frequency band of 2.4˜2.5 GHz, the reflection loss thereof is more than 10 dB and the Voltage Standing Wave Ratio (VSWR) is less than 2.0, allowing the desktop computer
2
to operate properly.
In this embodiment, dimensions of the antenna base
11
are B
1
X B
2
X B
3
, wherein the values of B
1
, B
2
and B
3
are 20 mm, 60 mm and 4 mm, respectively. The first and second arms
121
,
122
respectively have a length L
1
of 25 mm. The U-shaped portion has a length L
2
of 13 mm and a width L
3
of 5 mm. The angle θ between the first arm
121
and the antenna base
11
, and between the second arm
122
and the antenna base
11
is 20 degrees. Under these conditions, the experimental data of
FIG. 6
was obtained when the inverted-F dipole antenna
1
was mounted on a desktop computer
2
.
As is shown in
FIG. 6
, the VSWR of the inverted-F dipole antenna
1
is less than 2.0 in the frequency band 2.4˜2.5 GHz.
The experimental data shows that the inverted-F dipole antenna
1
of the present invention can be used with various wireless communication protocols, such as Bluetooth and Wireless LAN. Additionally, an inverted-F dipole antenna
1
of the present invention saves space occupied in an electronic device and is more easily assembled than the prior art planar inverted-F antenna. Understandably, the inverted-F dipole antenna
1
of the invention owns the required electrical characters of the conventional planar inverted-F antenna, i.e., being able to perform 50Ω between the connection points of the inner signal conductor and the outer ground conductor in the frequency band 2.4˜2.5 GHz, while without the clumsy/bumpy contour of the traditional inverted-F antenna and instead with essentially the delicate configuration as the traditional dipole antenna which basically does not meet the aforementioned electrical characters.
It is to be understood, however, that even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and function of the invention, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.
Claims
- 1. An inverted-F dipole antenna for an electronic device, comprising:an antenna body including a first and second metal arms and a flexible conductor connecting the first and second arms; an antenna base including an insulative board and a metal sheet attached to one surface of the board; a connector for providing an electrical interface to an RF circuitry; and a cable connecting the antenna body with the connector; wherein the antenna body is mounted on the antenna base with the flexible conductor being attached to a second surface of the board opposite to the one surface on which the metal sheet is attached.
- 2. The inverted-F dipole antenna as claimed in claim 1, wherein the cable is a coaxial cable serving as a feeder line of the antenna, and comprises an inner core wire soldered to one end of the flexible conductor proximate the first arm and an outer shield soldered to the other end of the flexible conductor proximate the other arm.
- 3. The inverted-F dipole antenna as claimed in claim 1, wherein the first metal arm of the antenna body acts as the radiation device of the antenna.
- 4. The inverted-F dipole antenna as claimed in claim 1, wherein the flexible conductor of the antenna body is U-shaped.
- 5. The inverted-F dipole antenna as claimed in claim 1, wherein the first and second arms extend horizontally in substantially opposite directions and both form a same angle with the board.
- 6. The inverted-F dipole antenna as claimed in claim 1, wherein the inverted-F dipole antenna is mounted on an enclosure of a desktop computer behind a plastic cover of the desktop computer, and the metal sheet of the antenna base is attached to the front surface of the enclosure.
- 7. The inverted-F dipole antenna as claimed in claim 6, wherein the enclosure is made of a conductive material and serves as a reflective surface for electromagnetic waves radiated by the antenna.
- 8. The inverted-F dipole antenna as claimed in claim 1, wherein the inverted-F dipole antenna operates in a frequency band of 2.4 GHz to 2.5 GHz.
- 9. An antenna assembly comprising:a metallic antenna defining a body with two arms extending outwardly and laterally in generally opposite directions, and with a connection portion disposed between said two arms; a cable including an inner signal conductor and an outer grounding conductor connected to the connection portion proximate the two arms, respectively; and a connector positioned at a distal end of said cable away from the antenna; wherein the connection portion performs a specific electrical resistance between the joint points of the inner signal conductor and the outer grounding conductor during high frequency transmission; and wherein said antenna is attached to one face of a base having a metallic sheet on the other opposite face.
- 10. The assembly as claimed in claim 9, wherein said antenna is attached to the base, and said two arms extend away from said base with angles, respectively.
Priority Claims (1)
Number |
Date |
Country |
Kind |
090105621 |
Mar 2001 |
CN |
|
US Referenced Citations (4)
Number |
Name |
Date |
Kind |
2929063 |
Lynn, Jr. |
Mar 1960 |
A |
3683376 |
Pronovost |
Aug 1972 |
A |
5793336 |
Shoemaker et al. |
Aug 1998 |
A |
5966098 |
Qi et al. |
Oct 1999 |
A |