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Mobile Phone Patent Abstract
A built-in multi-band mobile phone antenna assembly includes a patch
antenna, a loop antenna disposed adjacent to the patch antenna,
and a parasitic element disposed adjacent to both the patch antenna
and the loop antenna and coupled parasitically to the patch antenna.
Mobile Phone Patent Claims
We claim:
1. A built-in multi-band mobile phone antenna assembly adapted
to be disposed within a mobile phone that is provided with a circuit
board and a grounding plane therein, said antenna assembly comprising:
a patch antenna; a planar loop antenna disposed adjacent to said
patch antenna; and a parasitic element disposed adjacent to both
said patch antenna and said loop antenna and coupled parasitically
to said patch antenna.
2. The built-in multi-band mobile phone antenna assembly as claimed
in claim 1, wherein said planar loop antenna is provided with a
signal feeding point and a grounding point thereon, which are adapted
to be coupled respectively and electrically to the circuit board
and the grounding plane.
3. The built-in multi-band mobile phone antenna assembly as claimed
in claim 1, wherein said patch antenna is provided with a signal
feeding point thereon, which is adapted to be coupled electrically
to the circuit board.
4. The built-in multi-band mobile phone antenna assembly as claimed
in claim 1, wherein said parasitic element is provided with a grounding
point thereon, which is adapted to be coupled electrically to the
grounding plane.
5. The built-in multi-band mobile phone antenna assembly as claimed
in claim 1, wherein said patch antenna is applicable in GSM900 system,
and said loop antenna is applicable in DCS 1800 and PCS 1900 systems.
6. The built-in multi-band mobile phone antenna assembly as claimed
in claim 1, wherein said parasitic element is coplanar with said
patch antenna and said loop antenna.
Mobile Phone Patent Description
BACKGROUNDING OF THE INVENTION
1. Field of the Invention
This invention relates to a mobile phone antenna, and more particularly
to a multi-band mobile phone antenna assembly, which can increase
effectively the bandwidth of the antenna.
2. Description of the Related Art
Recent mobile phones tend to have a compact size and an attractive
appearance. Therefore, built-in type antennas, which are concealed
within mobile phones, have developed rapidly. For example, referring
to FIG. 1, a conventional planar inverted F-shaped antenna (PIFA)
1 is shown to include a metal strip, which is formed with a slot
10 that has an open end 101 and a closed end 102 and which includes
a first antenna portion 11, a second antenna portion 12, a signal
feeding point 13 disposed between the first and second antenna portions
11, 12, and a grounding point 14 disposed adjacent to the signal
feeding point 13. The first antenna portion 11 is a low frequency
antenna, and is applicable in a GSM 900 system. The second antenna
portion 12 is a high frequency antenna, and is applicable in a DCS1800
system. The signal feeding point 13 and the grounding point 14 are
in electrical connection with a circuit board (not shown) in a mobile
phone. The bandwidth and gain of the antenna 1 are proportional
to the size of the antenna 1 and the distance between the antenna
1 and the ground. The size of the conventional PIFA is too small
to have a wide bandwidth.
To overcome this problem, referring to FIG. 2, a parasitic element
2 can be coupled parasitically to the second antenna portion 12
so as to increase the resonant frequency of the latter. As such,
the second antenna portion 12 is applicable in both DCS1800 and
PCS1900 systems. However, the bandwidth of the conventional PIFA
1 is widened only within the high frequency band of the second antenna
portion 12 but not within the low frequency band of the first antenna
portion 11.
SUMMARY OF THE INVENTION
The object of this invention is to provide a built-in multi-band
mobile phone antenna, which can reduce influence on antenna gain
due to distance between the antenna and the ground, and which can
increase the bandwidths of both high and low frequency bands.
According to this invention, a built-in multi-band mobile phone
antenna assembly includes a patch antenna, a loop antenna disposed
adjacent to the patch antenna, and a parasitic element disposed
adjacent to both the patch antenna and the loop antenna and coupled
parasitically to the patch antenna. As such, the influence of the
distance between the antenna and the ground is reduced with respect
to the antenna gain, and the bandwidth of the antenna is widened.
The patch antenna serves as a low frequency antenna. The loop antenna
serves as a high frequency antenna. The bandwidths of the patch
and loop antennas are widened.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other features and advantages of this invention will
become apparent in the following detailed description of a preferred
embodiment of this invention, with reference to the accompanying
drawings, in which:
FIG. 1 illustrates a conventional PIFA;
FIG. 2 illustrates another conventional PIFA modified from that
of FIG. 1; and
FIG. 3 illustrates the preferred embodiment of a built-in multi-band
mobile phone antenna assembly according to this invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIG. 3, the preferred embodiment of a built-in multi-band
mobile phone antenna assembly 3 is shown to include an elongated
planar loop antenna 31, a patch antenna 32, and a parasitic element
33, which is coplanar with the planar loop antenna 31 and the patch
antenna 32.
The planar loop antenna 31 serves as a high frequency antenna,
i.e. half-wave antenna, is applicable in DCS1800 and pcs1900 systems,
and has a signal feeding point 311 and a grounding point 312, which
are disposed respectively at two opposite ends of the planar loop
antenna 31 and which are respectively in electrical connection with
a circuit board 4 and a grounding plane 5 that are installed within
a mobile phone (not shown).
The patch antenna 32 is disposed adjacent to the planar loop antenna
31, serves as a lower frequency antenna, i.e. quarter-wave antenna,
is applicable in a GSM900 system, and has a signal feeding point
321 that is in electrical connection with the circuit board 4 in
the mobile phone. Because the patch antenna 32 has a size and a
shape so as to operate over a quarter-wave frequency band, the influence
on the antenna gain due to the distance between the patch antenna
32 and the ground can be reduced.
The parasitic element 33 is configured as a rectangular flat metal
plate, is disposed adjacent to the planar loop antenna 31 and the
patch antenna 32, is coupled parasitically to the patch antenna
32 so as to increase the bandwidth of the patch antenna 32, and
has a grounding point 331 that is in electrical connection with
the grounding plane 5 in the mobile phone.
With this invention thus explained, it is apparent that numerous
modifications and variations can be made without departing from
the scope and spirit of this invention. It is therefore intended
that this invention be limited only as indicated by the appended
claims. |