U.S. patent application number 13/026299 was filed with the patent office on 2012-03-15 for directional antenna and smart antenna system using the same.
Invention is credited to Min-Chung Wu.
Application Number | 20120062432 13/026299 |
Document ID | / |
Family ID | 45806156 |
Filed Date | 2012-03-15 |
United States Patent
Application |
20120062432 |
Kind Code |
A1 |
Wu; Min-Chung |
March 15, 2012 |
Directional Antenna and Smart Antenna System Using the Same
Abstract
The present invention discloses a directional antenna for a
portable device. The directional antenna includes at least one
antenna, disposed on a side of a display of the portable device,
for utilizing a metal part of the display as a reflector to
generate a directional radiation pattern.
Inventors: |
Wu; Min-Chung; (Hsinchu
County, TW) |
Family ID: |
45806156 |
Appl. No.: |
13/026299 |
Filed: |
February 14, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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61382922 |
Sep 15, 2010 |
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61422660 |
Dec 14, 2010 |
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61425252 |
Dec 21, 2010 |
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Current U.S.
Class: |
343/720 |
Current CPC
Class: |
G01S 5/0252 20130101;
H01Q 1/2258 20130101; H01Q 21/205 20130101 |
Class at
Publication: |
343/720 |
International
Class: |
H01Q 1/44 20060101
H01Q001/44 |
Claims
1. A directional antenna for a portable device, comprising: at
least one antenna, disposed on a side of a display of the portable
device, for utilizing a metal part of the display as a reflector to
generate a directional radiation pattern.
2. The directional antenna of claim 1, wherein two of the at least
one antenna has constructive interference in a far field.
3. The directional antenna of claim 1, wherein the at least one
antenna is disposed on one of a right side, a left side, a top side
and a bottom side of the display of the portable device.
4. The directional antenna of claim 3, wherein the at least one
antenna is series-fed.
5. The directional antenna of claim 4, wherein two of the at least
one antenna have a specific phase difference, such that the two of
the at least one antenna have constructive interference in a far
field.
6. The directional antenna of claim 3, wherein the at least one
antenna is parallel-fed.
7. The directional antenna of claim 3 further comprising a pad,
located at a feeding point of the at least one antenna, for
impedance matching.
8. The directional antenna of claim 3, wherein the at least one
antenna is at least one dipole antenna.
9. The directional antenna of claim 3, wherein the at least one
antenna is at least one folded dipole antenna.
10. The directional antenna of claim 1, wherein the at least one
antenna is disposed on a back side of the display of the portable
device.
11. The directional antenna of claim 10, wherein the at least one
antenna is parallel-fed.
12. The directional antenna of claim 10, wherein the at least one
antenna is series-fed.
13. The directional antenna of claim 12, wherein two of the at
least one antenna have a specific phase difference, such that the
two of the at least one antenna have constructive interference in a
far field.
14. The directional antenna of claim 10, wherein the at least one
antenna is at least one patch antenna.
15. A smart antenna system for a portable device, comprising: a
plurality of directional antennas, each directional antenna
comprising: at least one antenna, disposed on a side of a display
of the portable device, for utilizing a metal part of the display
as a reflector to generate a directional radiation pattern; wherein
all of directional radiation patterns generated by the plurality of
directional antennas substantially form an omni directional
radiation pattern.
16. The smart antenna system of claim 15, wherein two of the at
least one antenna has constructive interference in a far field.
17. The smart antenna system of claim 15, wherein the at least one
antenna is disposed on one of a right side, a left side, a top side
and a bottom side of the display of the portable device.
18. The smart antenna system of claim 17, wherein the at least one
antenna is series-fed.
19. The smart antenna system of claim 18, wherein two of the at
least one antenna have a specific phase difference, such that the
two of the at least one antenna have constructive interference in a
far field.
20. The smart antenna system of claim 17, wherein the at least one
antenna is parallel-fed.
21. The smart antenna system of claim 17, wherein the each
directional antenna further comprises a pad, located at a feeding
point of the at least one antenna, for impedance matching.
22. The smart antenna system of claim 17, wherein the at least one
antenna is at least one dipole antenna.
23. The smart antenna system of claim 17, wherein the at least one
antenna is at least one folded dipole antenna.
24. The smart antenna system of claim 15, wherein the at least one
antenna is disposed on a back side of the display of the portable
device.
25. The smart antenna system of claim 24, wherein the at least one
antenna is parallel-fed.
26. The smart antenna system of claim 24, wherein the at least one
antenna is series-fed.
27. The smart antenna system of claim 26, wherein two of the at
least one antenna have a specific phase difference, such that the
two of the at least one antenna have constructive interference in a
far field.
28. The smart antenna system of claim 24, wherein the at least one
antenna is at least one patch antenna.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefits of U.S. Provisional
Application No. 61/382,922, filed on Sep. 15, 2010 and entitled
"SMART ANTENNA AND SYSTEM USING THE SAME", U.S. Provisional
Application No. 61/422,660, filed on Dec. 14, 2010 and entitled
"SMART ANTENNA SYSTEM", and U.S. Provisional Application No.
61/425,252, filed on Dec. 21, 2010 and entitled "PORTABLE DEVICE
WITH SMART ANTENNA" the contents of which are incorporated herein
by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a directional antenna and
smart antenna system using the same, and more particularly, to a
directional antenna and smart antenna system using the same capable
of utilizing a metal part of a display of a portable device as a
reflector to generate a directional radiation pattern.
[0004] 2. Description of the Prior Art
[0005] Antenna design is crucial to a portable device with wireless
communication function, such as wireless local area network (WLAN)
or other mobile communication systems. In a conventional wireless
communication device, one or a plurality of omni directional
antennas are used to receive radio signals from all directions.
Antenna diversity technique is also used to determine which one or
more omni-directional antennas should be used to receive or
transmit signals. However, the efficiency and gain of omni
directional antennas are not good enough. Hence, there's a need for
an antenna design that provides smarter and better receiving
quality.
SUMMARY OF THE INVENTION
[0006] It is therefore an object of the present invention to
provide a directional antenna and smart antenna system using the
same capable of utilizing a metal part of a display of a portable
device as a reflector to generate a directional radiation
pattern.
[0007] The present invention discloses a directional antenna for a
portable device. The directional antenna includes at least one
antenna, disposed on a side of a display of the portable device,
for utilizing a metal part of the display as a reflector to
generate a directional radiation pattern.
[0008] The present invention further discloses a smart antenna
system for a portable device. The smart antenna system includes a
plurality of directional antennas. Each directional antenna
includes at least one antenna, disposed on a side of a display of
the portable device, for utilizing a metal part of the display as a
reflector to generate a directional radiation pattern. All of
directional radiation patterns generated by the plurality of
directional antennas substantially form an omni directional
radiation pattern.
[0009] These and other objectives of the present invention will no
doubt become obvious to those of ordinary skill in the art after
reading the following detailed description of the preferred
embodiment that is illustrated in the various figures and
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is a schematic diagram of a smart antenna system
according to an embodiment of the present invention.
[0011] FIG. 2A is a schematic diagram of an omni-directional
antenna and a corresponding radiation pattern according to an
embodiment of the present invention.
[0012] FIG. 2B is a schematic diagram of another omni-directional
antenna with a reflector and a corresponding radiation pattern
according to an embodiment of the present invention.
[0013] FIG. 3 is a directional antenna according to an embodiment
of the present invention.
[0014] FIG. 4A is a schematic diagram of the directional antenna
shown in FIG. 3 disposed on a left side of a display of a laptop
according to an embodiment of the present invention.
[0015] FIG. 4B is a schematic diagram a reflection coefficient of
the directional antenna according to an embodiment of the present
invention.
[0016] FIG. 5A is a directional antenna and a corresponding
directional radiation pattern according to an embodiment of the
present invention.
[0017] FIG. 5B is a schematic diagram a reflection coefficient of
the directional antenna shown in FIG. 5A according to an embodiment
of the present invention.
DETAILED DESCRIPTION
[0018] Please refer to FIG. 1, which is a schematic diagram of a
smart antenna system 10 according to an embodiment of the present
invention. The smart antenna system 10 is utilized in a portable
device 12. The smart antenna system 10 includes directional
antennas ANT.sub.1-ANT.sub.4. A directional antenna ANT.sub.x of
the directional antennas ANT.sub.1-ANT.sub.4 includes at least one
antenna. The at least one antenna is disposed on a side of a
display 14 of the portable device 12, and utilizes a metal part of
the display 14 as a reflector to generate a directional radiation
pattern DRP.sub.x. The side of the display 14 can be a left side, a
right side, a bottom side, a top side or a back side (not shown) of
the display 14. All of directional radiation patterns
DRP.sub.1-DRP.sub.4 generated by the directional antennas
ANT.sub.1-ANT.sub.4 substantially form an omni directional
radiation pattern.
[0019] Noticeably, compared with an omni directional antenna, an
ordinary directional antenna has many advantages in a corresponding
directional radiation pattern, such as high gain for desired
signal, long transmission distance, better received signal strength
indication (RSSI), low side lobe for interference, low noise floor,
and low power consumption under the same Equivalent isotropically
radiated power (EIRP) requirement, etc. Therefore, in such a
configuration, the omni directional radiation pattern substantially
formed by the directional radiation patterns DRP.sub.1-DRP.sub.4
has better efficiency than an omni directional radiation pattern
formed by one or a plurality of omni directional antennas. As a
result, the smart antenna system 10 can have better gain and
efficiency.
[0020] In detail, please refer to FIG. 2A and FIG. 2B. FIG. 2A is a
schematic diagram of an omni-directional antenna 20 and a
corresponding radiation pattern DRP according to an embodiment of
the present invention, and FIG. 2B is a schematic diagram of
another omni-directional antenna 22 with a reflector 24 and a
corresponding radiation pattern DRP' according to an embodiment of
the present invention. As shown in FIG. 2A and FIG. 2B, the
omni-directional antenna 22 with the reflector 24 can provide a
directional field DRP'. Therefore, the omni-directional antenna 22
with the reflector 24 can act as a directional antenna, which
provides a larger peak gain than that of omni-directional antenna
20. For example, a dipole antenna with a driver (as shown in FIG.
2A) has a maximum antenna peak gain of 2 dB. If a reflector is
added to the dipole antenna (as shown in FIG. 2B), the peak gain
will be 5 dB, which is twice the gain of the dipole antenna with
the driver.
[0021] In such a situation, please continue referring to FIG. 1. In
order to place the directional antenna ANT.sub.x into a space
between the side of the display 14 and a housing of the portable
device 12, the at least one antenna can utilize the metal part of
the display 14 as the reflector to generate a directional radiation
pattern DRP.sub.x. Noticeably, since a frame of the display 14 is
metal, the metal part can be used as a ground, e.g. for a plane
inverse F antenna (PIFA) antenna used in a conventional notebook,
the metal part is used as the ground to design an omni-directional
antenna. In comparison, in the present invention, the at least one
antenna utilizes the metal part of the display 14 as the reflector
of the directional antenna ANT.sub.x that provides higher gain.
Moreover, the at least one antenna can be further designed to have
constructive interference in a far field for more gain
enhancement.
[0022] For example, please refer to FIG. 3, which is a directional
antenna 30 according to an embodiment of the present invention. The
directional antenna 30 is utilized as the directional antenna
ANT.sub.x, when the directional antenna ANT.sub.x is disposed on
one of the left side, the right side, the bottom side and the top
side of the display 14, where the space is very narrow.
[0023] As shown in FIG. 3, the directional antenna 30 includes at
least one antenna. Take the directional antenna 30 as a series feed
dipole array antenna for example, the directional antenna 30
further includes a feed line, a pad and a two layer substrate for a
top metal and a bottom metal, which can be a FR4 substrate with a
length L3 and a thickness W (e.g. 140 mm and 0.6 mm, respectively).
The at least one antenna is series-fed, and can be a dipole antenna
D1 with a length L1 and a dipole antenna D2 with a length L2,
wherein the length L1 equals to the length L2 (e.g. 50 mm). A
distance d between the dipole antenna D1 and the dipole antenna D2
can be designed, e.g. 70 mm, such that the dipole antenna D1 and
the dipole antenna D2 have a specific phase difference. The feed
line feeds signals in a dual conductor way by feeding the signals
to the dipole antenna D1 and feeding to the dipole antenna D2 with
the specific phase difference, such that the dipole antenna D1 and
the dipole antenna D2 have constructive interference in the far
field. The pad is located at a feeding point for impedance
matching. A fire wire of a co-axial wire is bonded to the feed line
of the bottom metal, while the a wire is bonded to the pad of the
top metal. With this design, the maximum gain of the antenna can be
increased.
[0024] Please refer to FIG. 4A and FIG. 4B. FIG. 4A is a schematic
diagram of the directional antenna 30 shown in FIG. 3 disposed on a
left side of a display 44 of a laptop 40 according to an embodiment
of the present invention, and FIG. 4B is a schematic diagram a
reflection coefficient of the directional antenna 30 according to
an embodiment of the present invention. As shown in FIG. 4A and
FIG. 4B, the directional antenna 30 can utilize a metal part of the
display 44 as a reflector to generate a directional radiation
pattern with an antenna peak gain of 6 dB. Besides, the directional
antenna 30 can have a return loss less than -10 dB between 2.4
GHz.about.2.5 GHz. By the same token, the directional antenna 30
can be disposed on the right side and the top side of the display
44, so as to utilize the metal part of the display 44 as a
reflector to generate directional radiation patterns as well.
[0025] On the other hand, please refer to FIG. 5A, which is a
directional antenna 50 and a corresponding directional radiation
pattern according to an embodiment of the present invention. The
directional antenna 50 is utilized as the directional antenna
ANT.sub.x, when the directional antenna ANT.sub.x is disposed on
the back side of the display 14, where the space is very thin but
broad.
[0026] As shown in FIG. 5A, the directional antenna 50 includes at
least one antenna. Take the directional antenna 50 as a parallel
feed patch array antenna for example, the at least one antenna is
parallel-fed, and can be four patch antennas P1-P4 with similar
size and a parallel feed-in network. The directional antenna 50 can
utilize a metal part of the display 14 as a reflector to generate a
directional radiation pattern with an antenna gain of 8 dB.
Besides, the directional antenna 50 can have a return loss less
than -10 dB between 2.4 GHz.about.2.5 GHz as shown in FIG. 5B,
which is a schematic diagram a return loss of the directional
antenna 50 shown in FIG. 5A according to an embodiment of the
present invention.
[0027] Noticeably, the spirit of the present invention is to
utilize a metal part of a display of a portable device as a
reflector to generate a directional radiation pattern, such that
all directional radiation patterns generated can substantially form
an omni directional patter and thus have better gain and
efficiency. Those skilled in the art shout make modifications or
alterations accordingly. For example, the portable device 12 is
preferably a laptop, but can be a tablet computer, a mobile phone,
etc.
[0028] Besides, the at least one antenna of the directional antenna
30 is not limited to any feeding type, antenna type or number, as
long as the at least one antenna can be disposed on one of the left
side, the right side, the bottom side and the top side of the
display 14, where the space is very narrow, to utilize a metal part
of a display as a reflector to generate a directional radiation
pattern. For example, the at least one antenna of the directional
antenna 30 is not limited to be series-fed, and can be parallel-fed
as well; the at least one antenna of the directional antenna 30 is
not limited to be dipole antenna, and can be folded dipole antenna
or other antenna types.
[0029] On the other hand, the at least one antenna of the
directional antenna 50 is also not limited to any feeding type,
antenna type or number, as long as the at least one antenna can be
disposed on the back side of the display 14, where the space is
very thin but broad, to utilize a metal part of a display as a
reflector to generate a directional radiation pattern. For example,
the at least one antenna of the directional antenna 50 is not
limited to be parallel-fed, and can be series-fed as well, as long
as two of the at least one antenna of the directional antenna 50
have a specific phase difference, such that the two of the at least
one antenna of the directional antenna 50 have constructive
interference in a far field.
[0030] In the prior art, efficiency and gain of omni directional
antennas are not good enough. In comparison, the present invention
utilize the metal part of the display as a reflector to generate
directional radiation patterns, so as to substantially form an omni
directional patter with better gain and efficiency. Moreover, the
present invention provides a series feed dipole array antenna
design for the left side, the right side, the bottom side and the
top side of the display, and a parallel feed patch array antenna
for a back side of the display, so as to generate directional
radiation with higher gain and efficiency.
[0031] Those skilled in the art will readily observe that numerous
modifications and alterations of the device and method may be made
while retaining the teachings of the invention. Accordingly, the
above disclosure should be construed as limited only by the metes
and bounds of the appended claims.
* * * * *