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Mobile Phone Patent Abstract
A folding mobile phone with incorporated antenna is disclosed. A
folding mobile phone comprises a first and second housings connected
by a hinge mechanism each other. A first conductive film is incorporated
with the first housing, and a second conductive film is incorporated
with the second housing. When the mobile phone is in an open position
a monopole antenna is constituted by the first and second conductive
films, when the mobile phone is in a closed position the second
conductive film acts as a ground plane.
Mobile Phone Patent Claims
What is claimed is:
1. A folding mobile phone including a first and second housings
connected by a hinge mechanism each other, said folding mobile phone
comprising:
a first conductive film incorporated with said first housing; and
a second conductive film incorporated with said second housing,
when said first and second housings are in a open position constituting
a monopole antenna together with said first conductive film, and
when said first and second housings are in a closed position acting
as a ground plane.
2. A folding mobile phone according to claim 1, wherein said first
conductive film is a metallic finish on the outside of said first
housing.
3. A folding mobile phone according to claim 1, wherein said first
conductive film is a metallic finish on the inside of said first
housing.
4. A folding mobile phone according to claim 1, wherein said first
conductive film is formed on a PCB.
5. A folding mobile phone according to claim 1, wherein said second
conductive film is a copper sheet formed on a PCB.
6. A folding mobile phone according to claim 1, wherein said second
conductive film is a metallic finish applied to the outside of said
second housing.
7. A folding mobile phone according to claim 1, wherein said second
conductive film is applied to the inside of said second housing.
8. A folding mobile phone according to claim 1, wherein said folding
mobile phone is a dual mode phone for operation in two network frequency
bands.
9. A folding mobile phone according to claim 1, wherein said folding
mobile phone is a tri-mode phone for operation in three network
frequency bands.
10. A folding mobile phone according to claim 8, wherein the two
network frequency bands are GSM 900 and PCN 1800.
11. A folding mobile phone according to claim 9, wherein the three
network frequency bands are DCS 1900, GSM 900 and PCN 1800.
12. A folding mobile phone according to claim 1, wherein said first
conductive film surrounds a viewing window disposed on said first
housing.
13. A folding mobile phone according to claim 1, wherein the area,
in plan, of said first conductive film is greater than two thirds
of the area in plan of said first housing.
14. A folding mobile phone according to claim 13, wherein said
first conductive film is a metallic finish on the outside of said
first housing.
15. A folding mobile phone according to claim 13, wherein said
first conductive film is a metallic finish on the inside of said
first housing.
16. A folding mobile phone according to claim 13, wherein said
first conductive film is formed on a PCB.
17. A folding mobile phone according to claim 13, wherein said
second conductive film is a copper sheet formed on a PCB.
18. A folding mobile phone according to claim 13, wherein said
second conductive film is a metallic finish applied to the outside
of said second housing.
19. A folding mobile phone according to claim 13, wherein said
second conductive film is applied to the inside of said second housing.
20. A folding mobile phone according to claim 13, wherein said
folding mobile phone is a dual mode phone for operation in two network
frequency bands.
21. A folding mobile phone according to claim 13, wherein said
folding mobile phone is a tri-mode phone for operation in three
network frequency bands.
22. A folding mobile phone according to claim 20, wherein the two
network frequency bands are GSM 900 and PCN 1800.
23. A folding mobile phone according to claim 21, wherein the three
network frequency bands are DCS 1900, GSM 900 and PCN 1800.
24. A folding mobile phone according to claim 13, wherein said
first conductive film surrounds a viewing window disposed on said
first housing.
Mobile Phone Patent Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to mobile phones, and more particularly
to folding mobile phones having an incorporated antenna.
2. Description of the Related Art
The design of antennas for mobile phones capable of operation in
more than one frequency band (dual mode or tri-mode) is constrained
by the market demand continually to reduce die overall size of mobile
phones. Preference by many customers for external metallic finishes
on the mobile phone housings can also increase the difficulty of
antenna design.
The volume occupied by the antenna and associated circuitry and
their costs are important factors for a satisfactory design as well
as antenna effectiveness over a sufficiently wide operating bandwidth.
Preferably the antenna will be incorporated into the mobile phone
so that it is not noticeable by the user.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a folding mobile
phone capable of realizing both miniaturization and antenna effectiveness
over a sufficiently wide operating bandwidth.
According to the present invention there is provided a folding
mobile phone including a first and second housings connected by
a hinge mechanism each other, and the folding mobile phone comprising,
a first conductive film incorporated with the first housing, and
a second conductive film incorporated with the second housing, when
the first and second housings are in a open position constituting
a monopole antenna together with the first conductive film, and
when the first and second housings are in a closed position acting
as a ground plane.
In the present invention, a first conductive film is incorporated
with the first housing, and a second conductive film is incorporated
with the second housing, and when the mobile phone is in an open
position a monopole antenna is constituted by the first and second
conductive films, when the mobile phone is in a closed position
the second conductive film acts as a ground plane. Therefore, miniaturization
and antenna effectiveness over a sufficiently wide operating bandwidth
are both realized.
The above and other objects, features and advantages of the present
invention will become apparent from the following description with
reference to the accompanying drawings which illustrate examples
of the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a folding phone in the open position;
FIG. 2 shows a folding phone in the closed position;
FIG. 3 is a plan view of the phone in the open position;
FIG. 4 is a side view illustrating the antenna in the closed position;
FIG. 5 is a plot of antenna reflection coefficient in the open
position;
FIG. 6 is a plot of antenna reflection coefficient in the closed
position; and
FIG. 7 is a matching circuit used in the closed position.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
With reference to FIG. 1, a folding mobile phone of an embodiment
according to the present invention comprising two main housings
1,2 connected by a hinge mechanism. A first housing 1 is the top
section of the mobile phone and a second housing 2 is the bottom
section of the mobile phone. The display screen and keypad would
usually be located in the bottom section of the mobile phone. Conveniently
the top section of the mobile phone will include a window 4 for
providing viewing access to a display screen or direct access to
part of a keypad when the mobile phone is in the closed position.
When the mobile phone is closed a window 4 in the housing (top section)
1 gives visual access to the visual display 5 located in the housing
(bottom section) 2.
The mobile phone is normally used in the open position (normal
position) as shown in FIG. 1, but incoming calls as well as text
and data messages must be received when the mobile phone is in the
closed position (standby position) as shown in FIG. 2. Performance
of the antenna when the mobile phone is in the closed position must
be sufficient to allow the satisfactory reception of the incoming
calls.
The mobile phone operates in dual mode. That is to say it may be
used to communicate with networks operating in either of Ale two
frequency bands GSM 900 and PCN 1800. The GSM system (Global System
for Mobile communications formerly Group Special Mobile) operates
in the band 890 to 900 megahertz and the PCN system (Personal Communications
Network) operates in the band 1710 to 1880 MHz. The mobile phone
incorporating an antenna according to the present invention is not
restricted to dual band use and may be operated in a third band
(Tri-band operation) e.g. DCS 1900 (Digital Cellular Service) operating
around 1900 MHz.
The top section 1 houses a receiver and connecting leads and the
other components necessary for a mobile phone are housed in bottom
section 2. Operation of the mobile phone and incorporation of the
antenna does not depend on the inclusion of window 4.
Various surfaces may have a conductive metallic finish applied
to them. In this example the top surface 21 has applied to it a
metallic finish so as to provide a conductive film 24 as well as
to provide a desired cosmetic appearance. The conductive film 24
is applied to the whole of the top surface 21 except for the window
4 and forms part of the antenna of the mobile phone. If window 4
was not required then conductive film 24 would conveniently be applied
to the whole of the top surface 21. The conductive film 24 has an
overall length of 97.times.10.sup.-3 meters, an overall width of
55.times.10.sup.-3 meters and a thickness of 15.times.10.sup.-6
meters. The dimensions of the window 4 are width 32.times.10.sup.-3
meters and length 26.times.10.sup.-3 meters. The conductive film
24 surrounds the window 4.
For satisfactory results the area, in plan, of the conductive film
24 incorporated with the first housing should be greater than two
thirds of the area, in plan, of the first housing. The area, in
plan, of the first housing should be taken to include the area of
window 4.
Within bottom section 2, a copper sheet (conductive film) 8 having
an area slightly less than the area in plan of bottom section 2
is disposed. The dimensions of copper sheet 8 are 97.times.10.sup.-3
meters length, 55.times.10.sup.-3 meters width and thickness of
15.times.10.sup.-6 meters. Copper sheet 8 is formed as a conductive
film upon a PCB (Printed Circuit Board) by standard manufacturing
techniques and the position of copper sheet 8 is indicated in FIG.
3. The plan view of FIG. 3 illustrates the extent and position of
the two conductive films and the location of the antenna feeding
point 11.
When the mobile phone is in the open position, the conductive film
24 and copper sheet 8 in combination operate as a monopole antenna.
Excitation of the antenna in the normal operating position is via
a coaxial lead at antenna feeding point 11 across the edges of the
two conductive films 8, 24. The antenna in the open position is
not resonant within the frequency bands of operation and has a wide
band response. Resonance is constrained by the width (area) of the
high conductivity film 24.
The wide band performance of the antenna in the open position of
the mobile phone is exhibited in FIG. 5 which is a plot of reflection
coefficient versus frequency for the antenna. The measured attenuations
with reference to 0 dB at the points marked on the plot of FIG.
5 are:
P, -11 dB at the frequency 890 MHz
Q, -10 dB at 960 MHz
R, -9 dB at 1.71 GHz
S, -7 dB at 1.88 GHz
When the mobile phone is closed into the closed position, the conductive
film 24 overlays in parallel spaced relationship the copper sheet
8 as illustrated in FIG. 4. In the closed position, only the conductive
film 24 is fed at antenna feeding point 12 via a matching circuit
as shown in FIG. 7 and the copper sheet 8 acts as a ground plane.
The antenna in the closed position operates in the manner of a patch
antenna.
The switching required when the mobile phone is moved between the
closed and open positions may be effected mechanically by means
of a cam in the hinge mechanism. Alternatively an electronic switch
may be used which would require a logic line to provide an indication
of the open or closed state of the mobile phone. These switching
means are well known in the prior art.
The performance of the antenna in the closed position is shown
in FIG. 6 which is a plot of reflection coefficient versus frequency.
The measured attenuation with reference to 0 dB at the points marked
on the plot of FIG. 6 are:
X-5 dB at the frequency of 890 MHz
Y-2 dB at 960 MHz
Z-4 dB at 1.710 GHz
T-4 dB at 1.880 GHz
In this embodiment the conductive film 24 is shown as applied to
the planar top surface 21 and therefore is itself planar. It has
been found empirically that the conductive film 24 may be applied
to surfaces which depart considerably from the planar without significant
loss of performance for the antenna.
With reference to FIGS. 1 and 2, the conductive film 24 covering
the top surface 21 may be extended to cover the edges 22 of the
housing 1 without significant loss of antenna effectiveness. The
antenna as described can therefore be used with a range of housing
profiles.
A conductive film may be applied to the inside surface of the housing
instead of to the outside surface. By this means an inside profile
of a housing may be directed toward antenna performance whereas
an outside profile of a housing may be dictated by some other feature
such as appearance.
Application of the conductive film to the housing may be by electroplating,
electroless-Plating or other standard techniques. The conductive
films must have a high conductivity, however and this must be taken
into account when specifying the techniques for application and
the materials to be used for the conductive films. The conductive
film incorporated with housing 1 may be formed on a PCB in the same
manner as described above for copper sheet 8.
While a preferred embodiment of the present invention has been
described using specific terms, such description is for illustrative
purposes only, and it is to be understood that changes and variations
may be made without departing from the spirit or scope of the following
claims.
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