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Mobile Phone Patent Abstract
The present invention provides a mobile phone antenna, which comprises
an antenna ground plane, a radiating conducting plate, a feeding
conducting strip, a shorting conducting strip, and a system ground
plane. Using the antenna ground plane as a shielding metal wall,
the present invention advantages itself of making the antenna and
a shielding metal box easier to be integrated without a need for
an isolation distance. The present invention thus makes the best
use of the internal spacing of a mobile phone. This antenna is suitable
for application as an embedded antenna for both folded-type and
bar-type mobile phones. The operating bandwidth of this antenna
can cover the required bandwidth for a Universal Mobile Telecommunication
System operation.
Mobile Phone Patent Claims
What is claimed is:
1. A mobile phone antenna, comprising: an antenna ground plane
having a first long side and a second long side; a radiating conducting
plate installed on the top of and perpendicularly to said antenna
ground plane, and on which there being one feeding point and one
shorting point; one feeding conducting strip installed between said
antenna ground plane and said radiating conducting plate, having
two ends electrically connected to said feeding point on said radiating
conducting plate and to a feeding signal source, respectively, so
that said feeding signal being fed into said radiating conducting
plate; a shorting conducting strip installed between said antenna
ground plane and said radiating conducting plate, having two ends
electronically connected to said shorting point on said radiating
conducting plate and to said antenna ground plane; and a system
ground plane connecting to said second long side of said antenna
ground plane.
2. The mobile phone antenna as claimed in claim 1, wherein said
antenna ground plane further includes a via hole, such that said
feeding conducting strip feeds said feeding signal into said radiating
conducting plate through said via hole.
3. The mobile phone antenna as claimed in claim 1, wherein said
system ground plane is perpendicularly connected to said second
long side of said antenna ground plane, and said system ground plane
is parallel to said radiating conducting plate.
4. The mobile phone antenna as claimed in claim 1, wherein said
system ground plane further comprises: a first sub-ground plane
having a first short side and a second short side; and a second
sub-ground plane, said first short side of said first sub-ground
plane electrically connected to said second sub-ground plane.
5. The mobile phone antenna as claimed in claim 4, wherein said
radiating conducting plate is installed in adjacent to said first
short side of said first sub-ground plane.
6. The mobile phone antenna as claimed in claim 4, wherein said
radiating conducting plate is installed in adjacent to said second
short side of said first sub-ground plane.
7. The mobile phone antenna as claimed in claim 5, wherein said
first sub-ground plane is perpendicularly connected to said second
long side of said antenna ground plane, and said first sub-ground
plane is parallel to said radiating conducting plate.
8. The mobile phone antenna as claimed in claim 6, wherein said
first sub-ground plane is perpendicularly connected to said second
long side of said antenna ground plane, and said first sub-ground
plane is parallel to said radiating conducting plate.
9. The mobile phone antenna as claimed in claim 1, wherein, said
radiating conducting plate, said feeding conducting strip, and said
shorting conducting strip are all installed on a single conducting
plate.
10. The mobile phone antenna as claimed in claim 1, wherein said
radiating conducting plate, said feeding conducting strip, and said
shorting conducting strip are all installed on a dielectric substrate.
11. The mobile phone antenna as claimed in claim 1, wherein said
radiating conducting plate is in the shape of a rectangle.
12. The mobile phone antenna as claimed in claim 1, wherein said
radiating conducting plate is in the shape of an oval.
13. The mobile phone antenna as claimed in claim 1, wherein said
radiating conducting plate is in the shape of a polygon.
Mobile Phone Patent Description
FIELD OF THE INVENTION
The present invention generally relates to an antenna, and more
specifically to a mobile phone antenna.
BACKGROUND OF THE INVENTION
Following the global blooming in mobile communications, various
kinds of handheld communication products have been demanded by wireless
users. One of the major demands is to minimize the product dimensions.
Generally speaking, the dimensions of a communication product can
be effectively minimized by using an embedded antenna inside the
communication product. However, in the existing communication products,
especially those with an embedded antenna, the internal spacing
for antenna is usually very limited. Thus, with this spacing limitation,
how to achieve good antenna performances and good electromagnetic
compatibility with nearby electronic components inside the product
has become one of the major design challenges for the final communication
product.
For conventional planar inverted-F antennas (PIFAs) applied to
mobile phone antennas, the antenna's radiating metal plate is usually
horizontally installed above the top portion of the ground plane.
A feeding metal pin and a shorting metal pin are electrically connected
to and perpendicular to both the radiating metal plate and the ground
plane.
A ROC patent publication No. 519780, "Dual-Band and Multi-Band
Planar Inverted-F Antenna and the Radiating Metal Plate," disclosed
a planar inverted-F mobile phone antenna This mobile phone antenna
comprises one radiating metal plate, one metal ground plane, and
one feeding metal line and one shorting metal pin, which are installed
perpendicularly to the radiating metal plate and the ground plane.
By meandering the resonant path of the radiating metal plate to
achieve dual-band operation, the size of the antenna profile can
thus be minimized. The drawback of this conventional antenna design,
however, is that the antenna is not easy to be integrated with other
circuitry systems and associated components. This conventional antenna
also requires an isolation distance from the shielding metal box
of the radio frequency (RF) circuitry and RF components to reduce
the destructive coupling effects on the antenna performances.
FIG. 1A shows a schematic view of a conventional mobile phone antenna
with a shielding metal box 15. The antenna element for this mobile
phone antenna is a conventional planar inverted-F antenna and mainly
comprises one metal plate 11, one feeding metal pin 12, one shoring
metal pin 13, and one ground plane 14. The feeding metal pin 12
and the shorting metal pin 13 are both perpendicular to and in between
the metal plate 11 and the ground plane 14. The metal plate 11 is
mainly parallel to the ground plane 14. The shielding metal box
15 is affixed to and electrically connected to the ground plane
14. Referring to FIG. 1A, the shielding metal box 15 is away from
the metal plate 11 with an isolation distance d.
FIG. 1B, shows the measured return loss for the mobile phone antenna
in FIG. 1A. The vertical axis represents the return loss in dB;
the horizontal axis represents the operating frequencies. As shown
in FIG. 1B, the measured return loss for the mobile phone antenna
without a shielding metal box 15 is represented by the curve 16.
The corresponding operating bandwidth, determined by 2:1 Voltage
Standing-Wave Ratio (VSWR) or about 9.6 dB return loss, can cover
the Universal Mobile Telecommunication System (UMTS) band. The drawback
of this conventional mobile phone antenna is that with a decrease
in d (that is, by moving the shielding metal box 15 close to the
metal plate 11), the corresponding operating bandwidth is quickly
degraded and thus can not cover the required UMTS band.
Referring to FIG. 1B, curve 161 represents the measured antenna
return loss when the isolation distance d is 21 mm, while curve
162 represents the measured antenna return loss when the isolation
distance d is reduced to 7 mm. To cover the UMTS band, the isolation
distance d between the shielding metal box 15 and the metal plate
11 is usually required to be greater than 7 mm such that the antenna
performances will not be degraded due to the coupling effects between
the antenna and the shielding metal box 15. With this design configuration,
the internal spacing utilization and design flexibility have become
limited for this type of conventional mobile phone antenna
SUMMARY OF THE INVENTION
To overcome the drawback of the conventional mobile phone antenna,
the present invention provides an improved mobile phone antenna.
The mobile phone antenna according to the present invention comprises
one antenna ground plane, one radiating conducting plate, one feeding
conducting strip, one shorting conducting strip, and one system
ground plane.
The antenna ground plane of the present invention has a first long
side and a second long side. The radiating conducting plate, installed
perpendicularly to the antenna ground plane, includes one feeding
point and one shorting point. The feeding conducting strip, installed
between the antenna ground plane and the radiating conducting plate,
has two ends, which is electrically connected to the feeding point
of the radiating conducting plate and the feeding signal source,
respectively, so that the feeding signal can be fed into the radiating
conducting plate. The shorting conducting strip, installed between
the antenna ground plane and the radiating conducting plate, also
has two ends, which is electrically connected to the shorting point
on the radiating conducting plate and the antenna ground plane,
respectively. Finally, the system ground plane is connected to the
second long side of the antenna ground plane.
According to the present invention, the radiating conducting plate,
the feeding conducting strip, and the shorting conducting strip
can all be fabricated by using a single piece of metal sheet and
be formed into a single metal plate. The metal plate is parallel
to the system ground plane of the mobile phone. Alternatively, all
these three elements can be printed on one dielectric substrate.
The system ground plane, according to the present invention, further
comprises the first sub-ground plane and the second sub-ground plane.
The first sub-ground plane includes a first short side and a second
short side. In the first embodiment of the present invention, the
radiating conducting plate is installed adjacent to the first short
side of the first sub-ground plane. In the second embodiment of
the present invention, the radiation conducting plate is installed
adjacent to the second short side of the first sub-ground plane.
Other than this, the rest of the configuration of the second embodiment
is identical to that of the first embodiment. The mobile phone antenna
according to the present invention can be applied to either folded-type
mobile phones or bar-type mobile phones. In the third embodiment
of the present invention, the system ground plane does not include
a second sub-ground plane. Other than this, the rest of the configuration
of the third embodiment is identical to that of the first embodiment.
The mobile phone antenna according to the present invention mainly
utilizes the antenna ground plane as a metal shielding wall to accomplish
a seamless integration between the antenna and the shielding metal
box of the RF module and RF circuitry without the need of an isolation
distance.
The foregoing and other objects, features, aspects and advantages
of the present invention will become better understood from a careful
reading of a detailed description provided herein below with appropriate
reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1A shows a schematic view of a conventional mobile phone antenna,
wherein the mobile phone antenna has a metal shielding box placed
from a distance.
FIG. 1B shows the measured return loss for the conventional mobile
phone antenna shown in FIG. 1A.
FIG. 2A shows a schematic view of a first embodiment of the present
invention.
FIG. 2B shows how the radiating conducting plate, the feeding conducting
strip, and the shorting conducting strip are formed into a single
piece of metal plate, according to the first embodiment shown in
FIG. 2A.
FIG. 3 shows the measured and simulated return loss for the first
embodiment of the present invention.
FIG. 4 shows the measured antenna radiation pattern when the first
embodiment of the present invention operates at 2045 MHz.
FIG. 5 shows the measured antenna gain for the first embodiment
of the present invention.
FIG. 6 shows a perspective view of a variation of the first embodiment
of the present invention by adding a RF shielding metal box.
FIG. 7 shows the measured return loss for the variation of the
first embodiment as shown in FIG. 6.
FIG. 8 shows a schematic view of a second embodiment of the present
invention.
FIG. 9 shows a schematic view of a third embodiment of the present
invention.
FIG. 10 shows variations in shape for the radiating conducting
plate of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 2A illustrates a schematic view of a first embodiment of the
present invention. Referring to FIG. 2A, the mobile phone antenna
comprises one antenna ground plane 21, one radiating conducting
plate 22, one feeding conducting strip 223, one shorting conducting
strip 224, and one system ground plane 23. The antenna ground plane
21 includes one first long side 211 and one second long side 212.
The radiating conducting plate 22 is installed perpendicularly to
the top of the antenna ground plane 21. The radiating conducting
plate 22 includes one feeding point 221 and one shoring point 222.
The feeding conducting strip 223 is installed between the antenna
ground plane 21 and the radiating conducting plate 22. The feeding
conducting strip has two ends, which is electrically connected to
the feeding point 221 on the radiating conducting plate 22 and to
a feeding signal source, respectively, so that the feeding signal
can be fed into the radiating conducting plate 22. The shorting
conducting strip 224, installed between the antenna ground plane
21 and the radiating conducting plate 22, has two ends, which is
connected to the shorting point 222 on the radiating conducting
plate 22 and the antenna ground plane 21, respectively. The system
ground plane 23 is connected to the second long side 212 of the
antenna ground plane 21.
Through a via hole 213 on the antenna ground plane 21, the feeding
conducting strip 223 feeds the feeding signal into the radiating
conducting plate 22. The system ground plane 23 further includes
a first sub-ground plane 231 and a second sub-ground plane 234.
The first sub-ground plane 231 has a first short side 232 and a
second short side 233, which are perpendicularly connected to the
antenna ground plane 21 at the second long side 212 of the antenna
ground plane 21. The first sub-ground plane 231 is parallel to the
radiating conducting plate 22. The radiating conducting plate 22
is installed adjacent to the first short side 232 of the first sub-ground
plane 231. The first sub-ground plane 231 and the second sub-ground
plane 234 can be connected with a flexible printed circuit board
235.
According to the present invention, the radiating conducting plate
22, the feeding conducting strip 223, and the shorting conducting
strip 224 may be made of material like metal. As shown in FIG. 2B,
these three elements may also be fabricated by cutting a single
piece of conducting plate like a single piece of metal sheet. This
single piece of metal plate is parallel to the system ground plane
23 of the mobile phone antenna. Alternatively, the radiating conducting
plate 22, the feeding conducting strip 223, and the shorting conducting
strip 224 may be formed on a dielectric substrate with the standard
printing or etching fabrication process.
According to the present invention, the center operating frequency
of the mobile phone antenna can be determined by adjusting the size
of the radiating conducting plate 22. A good impedance matching
for the antenna can be achieved by properly selecting the size of
the distance between the radiating conducting plate 22 and the system
ground plane 23, as well as the proper selection of the shorting
position for the shorting conducting strip 224.
FIG. 3 illustrates the measured return loss for the first embodiment
of the present invention. Wherein, the vertical axis represents
the return loss in dB, while the horizontal axis represents the
antenna operating frequencies in MHz. The following are the dimensions
used for the experimental mobile phone antenna design. The antenna
ground plane 21 is 40 mm in length and 8 mm in width. The radiating
conducting plate 22 is of a rectangle with 30 mm in length and 18
mm in width. The feeding conducting strip 223 and the shorting conducting
strip 224 have the same length of 2 mm, but have different width
of 1 mm and 0.5 mm, respectively. For the system ground plane 23,
the first sub-ground plane 231 and the second sub-ground plane 234
both have the same dimension of 70 mm in length and 40 mm in width.
The inclined angle between the first sub-ground plan 231 and the
second sub-ground plane 234 is approximately 165.degree..
Referring to FIG. 3, the curve 31 from the measured results shows
agreement with the curve 32 from the simulation. Determined by 2:1
VSWR, the antenna operating bandwidth can well cover the required
for the UMTS band.
FIG. 4 illustrates the measured results of the antenna radiation
patterns, in the planes x-z, y-z, and x-y, respectively, when the
first embodiment of the present invention operates at 2045 MHz.
The results demonstrate a good omnidirectional radiation pattern
in the x-y plane.
FIG. 5 shows the measured results of the antenna gain for the first
embodiment of the present invention, wherein the vertical axis represents
the antenna gain, while the horizontal axis represents the antenna
operating frequencies. According to FIG. 5, the antenna gain level
is about 3.4 dBi within the operating frequencies, which meets the
antenna gain requirement for the UMTS operation.
FIG. 6 shows a perspective view of a variation of the first embodiment
of the present invention by adding a RF shielding metal box. Referring
to FIG. 6, the shielding metal box 15 is affixed to and electrically
connected to the first sub-ground plane 231 of the system ground
plane 23. The shielding metal box 15 is also very close to the antenna
ground plane 21 and the radiating conducting plate 22. The isolation
distance d between the radiating conducting plate 22 and the shielding
metal box 15 may be eliminated. In this case, the dimension of the
shielding metal box 15 is 40 mm in length, 30 mm in width, and 5
mm in height.
FIG. 7 shows measured return loss for the variation of the first
embodiment as shown in FIG. 6. Referring to FIG. 7, the curve 71
for the measured return loss with the isolation distance d of 0.5
mm and the curve 72 for the measured return loss with the isolation
distance d of 7 mm are quite consistent with the cure 32 for the
simulated return loss shown in FIG. 3.
Using the antenna ground plane 21 as a shielding metal wall, the
mobile phone antenna of the present invention can minimize the destructive
coupling effects even with the shielding metal box 15 placed in
very close proximity to both the antenna ground plane 21 and the
radiating conducting plate 22. This thus overcomes the restriction
of a required isolation distance to accomplish an effective integration
of the antenna and the shielding metal box 15 of the RF module and
RF circuitry. Determined by 2:1 VSWR, the corresponding operating
bandwidth can well cover the UMTS band.
FIG. 8 shows a schematic view of the second embodiment of the present
invention. Wherein, the radiating conducting plate 22 is installed
adjacent to the second short side 233 of the first sub-ground plane
231. The rest of the configuration is identical to that for the
first embodiment shown in FIG. 2A.
The mobile phone antenna according to the present invention may
be applied to either folded-type or bar-type mobile phones.
FIG. 9 shows a schematic view of the third embodiment of the present
invention. Wherein, the system ground plane 23 does not include
the second sub-ground plane 234. The rest of the configuration is
identical to that of the first embodiment shown in FIG. 2A.
FIG. 10 shows the variations in shape for the radiating conducting
plate 22 according to the present invention. Examples show that
the shape of the radiating conducting plate 22 can be a rectangle
10a, an oval 10b, and a polygon 10c.
In conclusion, the mobile phone antenna of the present convention
not only eliminates the need of an isolation distance between the
antenna and the shielding metal box, but also accomplishes the ease
for integrating the antenna and the shielding metal box with more
effective utilization of the internal spacing within a mobile phone.
Although the present invention has been described with reference
to the preferred embodiments, it will be understood that the invention
is not limited to the details described thereof. Various substitutions
and modifications have been suggested in the foregoing description,
and others will occur to those of ordinary skill in the art. Therefore,
all such substitutions and modifications are intended to be embraced
within the scope of the invention as defined in the appended claims.
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