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Mobile Phone Patent Abstract
A retractable antenna unit for a mobile phone including an antenna
housing provided in the casing of the mobile phone, a helical antenna
installed in the antenna housing, a whip antenna having an upper
end provided with a knob and a lower end provided with a stopper,
the stopper being also provided with a feeder part, and a metal
tube for supplementing the length of the helical antenna when the
whip antenna is completely retracted into the antenna housing, or
serving to extend the operational length of the whip antenna when
the whip antenna is completely extended from the antenna housing,
whereby the wave feed position of the whip antenna is raised when
the whip antenna is completely extended from the antenna housing.
Mobile Phone Patent Claims
What is claimed is:
1. A retractable antenna unit for a mobile phone, comprising:
a helical antenna positioned in an upper portion of an antenna
housing of the mobile phone;
a whip antenna having an upper end provided with a knob and a lower
end provided with a stopper, said stopper being also provided with
a first wave feeder part; and
a metal tube having the whip antenna slidingly positioned therein,
and forming a tubular antenna having a second wave feeder part in
an upper portion thereof, the tubular antenna being positioned in
a lower portion of the antenna housing and connected to said helical
antenna for supplementing the operational length of said helical
antenna when said whip antenna is completely retracted, or serving
to extend the operational length of said whip antenna when said
whip antenna is completely extended by contacting said first feeder
part of said whip antenna to the second feeder part of the tubular
antenna.
2. The retractable antenna recited in claim 1, further comprising
an antenna housing for housing said helical antenna, said metal
tube, and said whip antenna when said whip antenna is in a retracted
position.
3. The retractable antenna recited in claim 1, wherein said metal
tube has the lower end provided with a conductive threaded antenna
fitting for fixing said metal tube into a mobile phone casing.
4. The retractable antenna as recited in claim 3, wherein said
threaded antenna fitting is integrally formed with said metal tube.
5. The retractable antenna recited in claim 1, wherein said helical
antenna has its lower end closely contacting the upper end of said
metal tube.
6. The retractable antenna recited in claim 1, wherein the upper
end of said helical antenna is bent inward so as to improve the
coupling effect between said helical antenna and said whip antenna.
7. An antenna unit for a mobile phone comprising:
a first antenna having an upper end provided with a knob and a
lower end provided with a stopper, said stopper also having a wave
feeder part, the first antenna having an operable length defined
by a distance between the knob and the stopper, the operable length
including at least one insulated portion configured to prevent coupling
in a retracted position, the first antenna being movable between
the retracted position and an extended position;
a second antenna positioned in fixed spaced relation to the mobile
phone to couple with the first antenna in the extended position,
and the second antenna being positioned in apposition with the insulated
portion of the first antenna in the retracted position; and
a third antenna defining a longitudinal hole for the positioning
of the first antenna and being configured to be connected with the
first antenna in the extended position and configured to be connected
with the second antenna when disconnected with the first antenna
in the retracted position.
8. The antenna unit of claim 7, wherein the second antenna is a
helical antenna.
9. The antenna unit of claim 7, wherein the third antenna is a
tubular antenna.
Mobile Phone Patent Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a compact mobile phone, and more
particularly a retractable antenna unit provided in a mobile phone
operating in a low frequency band.
2. Description of the related art
A mobile phone, such as a cellular phone, is typically provided
with a whip or helical antenna, whose length is .lambda./4 or 3.lambda./4,
where .lambda. is the wavelength of the received signal in accordance
with the operating frequency. If a whip antenna is used, it must
be in a extended position to maximize efficiency during calls, making
it less compact and therefore, inconvenient for the user to carry.
On the other hand, a helical antenna has a short physical length,
and hence does not bring about such inconvenience. However, the
efficiency of a helical antenna is low when compared to that of
a whip antenna, due to its short physical height. Therefore, due
to the helical antenna's degraded performance when compared to the
whip antenna, it is desirable to have an antenna with a relatively
longer physical height, such as the whip antenna.
In this view, a retractable antenna has been developed which combines
a whip and helical antenna to realize the advantages of both types
of antenna. Such an antenna is well disclosed in U.S. Pat. No. 5,479,178.
Referring to this patent, when a mobile phone stands by to receive
a call, the whip antenna may be retracted into the casing of the
mobile phone, utilizing only the helical antenna for receiving incoming
calls. When communication is established, the whip antenna may be
completely extended from the casing to improve communication quality
for the duration of the call.
However, such a retractable antenna would only be sufficient for
the end if the body of the mobile phone is long enough to fully
receive the retracted length of the whip antenna. Moreover, there
is a trend toward making mobile phones more compact, especially
with the current state of development of VLSI (very large system
integration) technology, making space in a mobile phone's casing
a premium. Further, when retracting the whip antenna into the casing,
it must be decoupled from the wave feeding point. However, if the
space for retracting the whip antenna into the casing is lacking,
it becomes impractical to achieve complete decoupling.
Consequently, space is one of the key factors limiting the design
of an antenna. Therefore, a need exists for a retractable antenna
unit combining a whip antenna with a helical antenna, wherein the
whip antenna of length .lambda./3 or 3.lambda./4 can be completely
retracted into a compact mobile phone while the helical antenna
remains projected outside of the casing.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a
retractable antenna unit for a compact mobile phone, having a metal
tube contacted with and supplementing the length of the helical
antenna, the metal tube also supplementing the length of the whip
antenna while extended.
It is another object of the present invention to provide a retractable
antenna unit with a metal tube to increase space for housing the
whip antenna in a retracted position and achieve complete decoupling
of the whip antenna, for a mobile phone operated in a low frequency
band.
According to an embodiment of the present invention, a retractable
antenna unit for a mobile phone includes an antenna housing, a helical
antenna installed in the antenna housing, a whip antenna having
an upper end provided with a knob and a lower end provided with
a stopper, the stopper being also provided with a feeder part, and
a metal tube for supplementing the length of the helical antenna
when the whip antenna is completely retracted into the antenna housing,
or serving to extend the physically effective length of the whip
antenna when the whip antenna is completely extended from the antenna
housing, whereby the wave feed position of the whip antenna is raised
when the whip antenna is completely pulled out from the antenna
housing.
BRIEF DESCRIPTION OF THE ATTACHED DRAWINGS
The above and other objects, features, and advantages of the present
invention will become more apparent in light of the following detailed
description of an exemplary embodiment thereof taken in conjunction
with attached drawings in which:
FIG. 1 is a perspective view for illustrating a flip type mobile
phone provided with the antenna unit of the present invention;
FIG. 2 is a partial cross sectional view of the antenna housing
portion of a mobile phone illustrating the whip antenna of the present
invention retracted into the casing of the mobile phone;
FIG. 3 is a partial cross sectional view illustrating the whip
antenna of the present invention completely extended from the casing;
and
FIG. 4 is a perspective view for illustrating the retractable antenna
unit provided with a metal tube according to the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Turning now to the drawings, in which like reference numerals identify
similar or identified elements throughout the several views, and
the detailed descriptions of elements not directly relating to the
invention are omitted for clarity.
FIG. 1 shows a flip-type mobile phone, wherein the antenna unit
of the invention is incorporated. Note however, the antenna of the
present invention can be used with other types of mobile phones.
The casing of the flip-type mobile phone comprises a body 300, flip
350, and hinge mechanism 2a for connecting the flip to the body.
The flip 350 may be opened away or closed toward the body 300, pivoting
about the central axis A1 of the hinge mechanism 2a. Mounted on
the top right side of the body 300 is an antenna unit 200, beneath
which the keypad (not shown) is located. The microphone 312 is mounted
below the key pad and an car piece (not shown) is mounted on the
upper part of the folder 350, including a speaker. The LCD (not
shown) is provided below the ear piece. The LCD displays the operational
information including the data input through the key pad.
The antenna of the present invention will now be described with
reference to FIGS. 2 and 3. A metal tube 30 is employed to supplement
the overall physical length of the whip antenna, which is limited
by the compact height of the mobile phone. The metal tube 30 serves
to extend both the operational length of the helical part 101 of
the helical antenna 10, when the whip antenna 20 is retracted into
the casing (body) of the mobile phone, and the operational length
of the whip antenna 10, when the whip antenna 20 is fully extended
from the casing of the mobile phone. Namely, the helical antenna
10 comprises the helical part 101 and the metal tube 30, and the
metal tube 30 also serves to supplement the length of the whip antenna
20 when the whip antenna 20 is completely extended from the casing.
Hence, by adjusting the lengths of the helical part 101 and metal
tube 30, the overall storage space in the mobile phone will increase
to accommodate the desired length whip antenna 30, making the addition
of metal tube 30 advantageous for a compact size mobile phone operated
in a low frequency band.
The added space provided by the metal tube 30 allows the whip antenna
to completely retract into the casing of a compact mobile phone,
making it possible to store an antenna of length 0.25 .lambda.,
for instance, even in a low frequency band CDMA (Code Division Multiple
Access) and GSM (Global System for Mobile Communication) system.
The problems of the prior art are overcome by substituting the metal
tube 30 for a potion of the helical antenna, so that the helical
antenna 10 and whip antenna 20 each have an overall length of 0.25
.lambda., for instance, while providing enough storage space for
retracting a whip antenna of sufficient length to maximize efficiency.
Referring to FIG. 2, when the whip antenna 20 is completely retracted
into the casing, the helical antenna 10, comprising the helical
part 101 and metal tube 30 serves as the effective antenna. The
metal tube 30 is integrally formed with a threaded antenna fitting
40 and inserted into an antenna housing 400, which is mounted on
the body 300 of the mobile phone by means of the antenna fitting
40. The knob rod 202 of the whip antenna must be insulated to a
length sufficient to prevent coupling between the antenna fitting
40 and helical part 101, since, when completely retracted, the knob
rod 202 is positioned throughout the helical part 101, metal tube
30 and antenna fitting 40.
Referring to FIG. 2, reference symbol L1 represents the physical
operational length of the helical part 101, and L2 the length of
the metal tube 30 projected from the casing, so that the total operational
length L3 of the helical antenna 10 is L1+L2, while the whip antenna
20 is completely retracted into the casing.
Referring to FIG. 3, when fully extended from the casing, the whip
antenna 20 has the stopper 205 contacting the upper end of the metal
tube 30, so that its operational length is supplemented by the length
L2 of the metal tube 30. L2 represents the length of the metal tube
projected from the casing, and L4 the length of the extended whip
antenna 20, so that the total operational length L5 of the whip
antenna 20 is L2+L4. Accordingly while, completely extended from
the casing, the whip antenna 20 has an effective length of L5. Thus,
the metal tube 30 is commonly used by both the helical antenna 10
and whip antenna 20.
FIG. 4 illustrate s the structure of the antenna unit in more detail.
The whip antenna 20 is designed to be retracted into or extended
from the casing while the helical antenna 10 is fixedly installed
in the antenna housing 400. The whip antenna 20 has an antenna knob
201 at the upper end, and a stopper 205 at the lower end. The stopper
205 is provided with a first wave feeding a metal part 204. The
metal tube 30 and antenna fitting 40 serve as a second wave feeding
metal part corresponding to the first wave feeding metal part 204.
The upper end 301 of the metal tube 30 is partially opened while
the lower end fully opened (not shown). The whip antenna 20 may
be retracted or extended through the cylindrical space of the second
wave feeding metal. When the whip antenna is fully extended from
the casing, the first wave feeding metal part 204 contacts the upper
end 301 of the metal tube 30. On the contrary, while the whip antenna
is fully retracted into the casing, the knob rod 202 of the whip
antenna 20 is positioned throughout the inside of the helical antenna
10 and the second wave feeding metal part, namely, the metal tube
30 and antenna fitting 40. Additionally, the upper end 101a of the
helical part 101 may be bent to reduce the space between the surface
of the whip antenna 20 and the helical part 101, and thereby improving
the coupling action between the whip antenna 20 and the helical
part 101. Thus, the invention substitutes a metal tube for part
of the helical antenna to supplement the physical length of the
whip antenna for a compact mobile phone operated in a low frequency
band.
While the present invention has been described in connection with
specific embodiments accompanied by the attached drawings, it will
be readily apparent to those skilled in the art that various changes
and modifications may be made thereto without departing from the
scope and spirit of the present invention as defined by the appended
claims.
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