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Mobile Phone Patent Abstract
A mobile phone includes a body and an antenna array that is coupled
to the body.
Mobile Phone Patent Claims
We claim:
1. A mobile phone comprising: a body; a first pair of parallel
dipoles, spaced apart and positioned within the body in order to
focus electromagnetic energy away from a user's head during operation;
and a retractable antenna element wherein the retractable antenna
element being used as a whip antenna while in an extended position
and being forming an antenna array incorporating the first pair
of parallel dipoles while in a retracted position.
2. The mobile phone of claim 1, one of the dipoles of the first
pair of dipoles is a metallic paint or a line of metal.
3. The mobile phone of claim 1 further comprising: a second pair
of parallel dipoles, spaced apart and positioned within the body
in order to focus electromagnetic energy away from the user's head
during operation, the second pair of dipoles orthogonal to the first
pair of dipoles in order to achieve orthogonally polarized electromagnetic
fields during operation.
4. The mobile phone of claim 1 further comprising: a loop antenna
coupled to the body in order to achieve orthogonally polarized electromagnetic
fields during operation.
Mobile Phone Patent Description
FIELD OF THE INVENTION
The present invention relates to mobile phones, and more particularly
to a mobile phone having a directed beam antenna.
BACKGROUND OF THE INVENTION
Mobile phones typically use whip or helix antennas, which have
hemispherical coverage patterns. With a hemispherical pattern, the
mobile phone may be oriented anywhere in azimuth with respect to
the cell site without affecting reception, assuming no blocking
objects are present.
One disadvantage of conventional mobile phones is that the antenna
radiates electromagnetic energy into a user's head equally compared
to other angles. Antenna design must be carefully managed in order
to comply with Specific Absorption Rate (SAR) specifications, which
limit the amount of electromagnetic energy a user's head may receive.
Another disadvantage is that gain in the direction of a user's
head is diminished because of blockage by the head. The energy directed
into the head makes it difficult to meet SAR requirements, and is
to some degree wasted because it is blocked by the head. Conventional
designs employ an external whip antenna and/or an external helical
antenna that each has hemispherical coverage. Some mobile phones
use internal antennas such as the Inverted-F type or microstrip
designs such as a patch or parasitic patch, which have hemispherical
patterns or a dipole-like pattern as illustrated in FIG. 1. FIG.
1 also illustrates an external helical antenna.
FIG. 1 is a diagram illustrating a front view of a conventional
mobile phone 10 with an electromagnetic pattern 12 from a center-fed
dipole 14 located inside the mobile phone 10. The dipole 14 has
a length of approximately L/2, where L is the length of one electromagnetic
wave at the frequency at which the dipole 14 operates.
FIG. 2 is a diagram illustrating a side view of the conventional
mobile phone 10 with the electromagnetic pattern 12 from the dipole
14. Electromagnetic pattern 12 has a null, but in order to align
that null with a user's head during operation the dipole 14 would
have to be rotated 90 degrees. At the frequencies typically used
with mobile phones, a mobile phone housing such a rotated dipole
would be very thick.
Accordingly, what is needed is a mobile phone having a directed
beam antenna that assists in meeting SAR specifications, reduces
wasted energy towards a user's head, and increases energy in other
directions. The present invention addresses such a need.
BRIEF SUMMARY OF THE INVENTION
The present invention provides a mobile phone including a body
and an array antenna that is coupled to the body.
According to a method and system disclosed herein, the present
invention takes advantage of the three dimensions in a mobile phone
to implement a directed beam antenna, for example a Yagi antenna,
also known as Yagi or a Yagi-Uda array. The Yagi antenna includes
two or more parallel dipoles aligned within the body of a mobile
phone to direct energy away from the user, taking advantage of the
three dimensions by placing each dipole at a different distance
from the front (or back) of the phone. Selecting appropriate lengths
for each of the dipoles also assists in directing the energy away
from the user's head during normal use.
BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS
FIG. 1 is a diagram illustrating a front view of a conventional
mobile phone with the electromagnetic pattern from a center-fed
dipole.
FIG. 2 is a diagram illustrating a side view of a conventional
mobile phone with an electromagnetic pattern from a center-fed dipole.
FIG. 3 is a diagram illustrating a two-element antenna array.
FIG. 4 is a diagram illustrating a two-element antenna array.
FIG. 5 is a diagram illustrating a three-element antenna array.
FIG. 6 is a diagram illustrating a radiation pattern for a two-element
antenna array.
FIG. 7 is a diagram illustrating a radiation pattern for a three-element
antenna array.
FIG. 8 is a diagram illustrating a front view of one embodiment
of the invention in a mobile phone.
FIG. 9 is a diagram illustrating a side view of one embodiment
of the invention in the mobile phone from FIG. 8.
FIG. 10 is a diagram illustrating a front view of one embodiment
of the invention in a mobile phone.
FIG. 11 is a diagram illustrating a plan view of the embodiment
of the invention in the mobile phone from FIG. 10.
FIG. 12 is a diagram illustrating a front view of one embodiment
of the invention in the mobile phone from FIG. 10.
FIG. 13 is a flow diagram illustrating one method of implementing
the invention with the mobile phone from FIG. 10.
FIG. 14 is a diagram illustrating a front view of a mobile phone
according to one embodiment of the present invention shown in FIGS.
8,9, 10 and 11.
DETAILED DESCRIPTION OF THE INVENTION
The present invention relates to mobile phones, and more particularly
to a mobile phone having a directed beam antenna. The following
description is presented to enable one of ordinary skill in the
art to make and use the invention and is provided in the context
of a patent application and its requirements. Various modifications
to the preferred embodiments and the generic principles and features
described herein will be readily apparent to those skilled in the
art. Thus, the present invention is not intended to be limited to
the embodiments shown, but is to be accorded the widest scope consistent
with the principles and features described herein.
FIG. 3 is a diagram illustrating one embodiment of the invention
implemented in a two-element antenna array 300 (array 300), or an
array of stacked dipoles, slots, monopoles, patches, parasitic elements,
etc. The antenna is an array of elements positioned and sized to
achieve directivity and consequently gain. One example of an antenna
array is a Yagi antenna, or Yagi array. Antenna array 300 includes
a driven element 310 and a passive (or parasitic) element, or a
director 320. The driven element 310 typically has a length of approximately
L/2, where L is the wavelength of the signal the array 300 is intended
to receive. For example, with a communication frequency of 850 MHz,
L/2 is approximately 3.1 inches, while L/2 at 1900 MHz is approximately
1.4 inches. The driven element 310 may be a center-fed dipole, or
the equivalent of a center-fed, half-wave dipole antenna. The driven
element 310 typically is electrically coupled to circuitry in the
mobile phone.
The director 320 typically has a length slightly shorter than the
driven element 310. FIGS. 3, 4, and 5 provide one example of elements
scaled according to actual designs. The driven element 310 and the
director 320 may be separated by 0.15 L in one embodiment and up
to about 0.5 L (as a guideline, not a limitation). The driven element
310 radiates a signal that is directed, or focused, by director
320. Energy is directed from the driven element 310 to the director
320, in the direction of arrow 330.
The driven and passive elements in an array antenna may be any
conducting material, for example wires, cylinders, and printed traces,
and the dimensions may be reduced, for example by folding the dipoles
(each element may be a dipole) and/or using dielectrics. Alternatively
or in addition to the array antenna, two driven elements, each with
a length of approximately L/2, may be used as stacked dipoles. Also,
the array may be used in multi-band operation, using tuning, traps,
and other multi-band techniques.
FIG. 4 is a diagram illustrating another embodiment of the invention
implemented in a two-element array 400. Array 400 includes a driven
element 410 and a passive element, or a reflector 420. The driven
element 410 typically has a length of approximately L/2, where L
is the wavelength of the signal the array 400 is intended to receive.
The driven element 410 may be a center-fed dipole, or the equivalent
of a center-fed, half-wave dipole antenna.
The reflector 420 typically has a length slightly longer than the
driven element 410. The driven element 410 and the reflector 420
may be separated by 0.15 L in one embodiment and up to about 0.5
L (as a guideline, not a limitation). The driven element 410 radiates
a signal that is reflected by reflector 420. Energy is reflected
from the reflector 420 back to the driven element 410, or towards
the right in FIG. 4.
FIG. 5 is a diagram illustrating one embodiment of the invention
implemented in a three-element array 500. Array 500 includes a driven
element 510 and two passive elements, a director 520 and a reflector
530. The driven element 510 typically has a length of approximately
L/2, where L is the wavelength of the signal the array 500 is intended
to receive or transmit. The driven element 510 may be a center-fed
dipole, or the equivalent of a center-fed, half-wave dipole antenna.
The director 520 typically has a length slightly shorter than the
driven element 510. In array 500, the driven element 510 and the
director 520 may be separated by 0.13 L in one embodiment and up
to about 0.5 L (as a guideline, not a limitation). The driven element
510 radiates a signal that is directed, or focused, by director
520.
The reflector 530 typically has a length slightly longer than the
driven element 510. The driven element 510 and the reflector 530
may be separated by 0.1 L in one embodiment and up to about 0.5
L (as a guideline, not a limitation). The driven element 510 radiates
a signal that is reflected by reflector 530. Energy is reflected
by reflector 530 and directed from the driven element 510 to the
director 520, in the direction of arrow 540. Advantages of an array
antenna include a directional radiation and response pattern, with
a corresponding gain in the radiation and response.
In another embodiment, an array antenna may be configured with
more than three total elements, for example a driven element and
multiple directors with no reflector, or in other configurations.
FIG. 6 is a diagram illustrating a radiation pattern for a two-element
array antenna. Pattern 600 is focused and directed along the 0 degree
axis of an array antenna, or towards the right direction of FIGS.
3 5. A two-element array antenna, for example array 300 or 400 from
FIG. 4 or FIG. 5, has a gain of 5 6 dBi over an isotropic antenna.
FIG. 7 is a diagram illustrating a radiation pattern for a three-element
array antenna. Pattern 700 is focused and directed along the 0 degree
axis of an array antenna, or towards the right in FIGS. 3 5. In
comparison, pattern 710 represents an isotropic pattern while pattern
720 represents a dipole pattern. A three-element array antenna,
for example array 500 from FIG. 5, has a gain of 6 8 dBi over a
conventional isotropic antenna. The more directors an array antenna
has, the greater the forward gain. With respect to both pattern
600 from FIG. 6 and pattern 700 from FIG. 7, the energy is focused
and directed from the driven element to the director, or away from
the reflector, or both. By positioning the driven element and one
or more passive elements in a mobile phone, energy may be directed
away from a user's head, assisting in the SAR requirements and improving
reception from certain angles. Because phones are being made smaller,
their antennas do not extend above a user's head. Also, in a clamshell
design, the antenna is situated near the middle of the phone and
not at the top of the phone. Given that the beam from a non-directional
antenna is blocked in one direction by the user's head, energy in
that direction tends to be wasted.
FIG. 8 is a diagram illustrating a front view of one embodiment
of the invention in a mobile phone 800. The body 802 of mobile phone
800 holds an array 805 that includes elements 810a and 810b, collectively
referred to as 810. In one embodiment, assume element 810a is a
driven element. Element 810a may be approximately L/2 in length
(disregarding techniques and tuning for decreasing dipole length),
with element 810b as a passive element, in this case a director.
The array 805 may be located inside of body 802. FIG. 3 represents
one embodiment of a driven element/director configuration upon which
the array 805 may be modeled.
In another embodiment, assume element 810a is a passive element,
or a reflector. Element 810b may be a driven element approximately
L/2 in length (disregarding techniques and tuning for decreasing
dipole length). FIG. 4 represents one embodiment of a driven element/reflector
configuration upon which the array 805 of FIG. 8 may be modeled.
In both of the above embodiments, the energy from the array 805
is directed upward, as indicated by arrow 820.
FIG. 9 is a diagram illustrating a side view of the embodiment
of the invention in the mobile phone from FIG. 8. In this embodiment,
element 810a is closer to the front of body 802, or closer to the
area that a user's head 900 would typically occupy during use. Element
810b is further from the front, or closer to the back of the body
802 of mobile phone 800. Only the end view of a wire or rod is illustrated
for elements 810 in FIG. 9.
With either element 810a as a driven element and element 810b as
a director, or element 810a as a reflector and element 810b as a
driven element, the energy from array 805 is directed along arrow
910, which is away from user's head 900 during operation. Elements
810 form a line through arrow 910, indicating the direction in which
radiation from array 805 is concentrated, assuming the director/reflector/driven
element arrangement described above. By tilting the array 805 within
the body 802, energy can be directed and focused away from the user.
Some energy is still directed toward the user's head 900 (see FIGS.
6 and 7), but the majority of the energy is directed away from the
user's head 900. The driven element may be located on a circuit
board (not shown), for example, while the passive element may be
located somewhere on the body 802. Many variations on the positioning
of array 805 are available.
FIG. 10 is a diagram illustrating a front view of another embodiment
of the invention in a mobile phone 1000. The body 1002 of mobile
phone 1000 holds an array 1005, which may be located inside of body
1002, that includes elements 1010a, 1010b, and 1010c, collectively
referred to as 1010. If element 1010a is a driven element, then
element 1010a may be approximately L/2 in length (disregarding techniques
and tuning for decreasing dipole length), with element 1010b slightly
shorter and element 1010c slightly longer. In this embodiment, element
1010b is a director and element 1010c is a reflector. FIG. 5 represents
one embodiment of a driven element/director/reflector configuration
upon which the array 1005 may be modeled.
In another embodiment, assume elements 1010a and 1010b are passive
elements, or directors. Element 1010c may be a driven element approximately
L/2 in length (disregarding techniques and tuning for decreasing
dipole length).
In both of the above embodiments, the energy from the array 1005
is directed towards the left, as indicated by arrow 1020. Furthermore,
in both of the above embodiments, element 1010c may function as
a part of the array 1005 while in the down, or retracted position,
and as a whip antenna while in the up, or extended position (see
FIG. 12). The whip may extend above the head, so energy is above
the head. In conventional systems, when the whip is retracted, the
internal antenna is no longer above the head so energy is directed
toward the head. According to the invention, for SAR and gain reasons
it is therefore advantageous for the internal antenna to direct
energy away from the head.
FIG. 11 is a diagram illustrating a plan view of the embodiment
of the invention in the mobile phone 1000 from FIG. 10. In this
embodiment, element 1010c is closer to the front of body 1002, or
closer to the area that a user's head 1100 would typically occupy
during use. Element 1010b is further from the front, or closer to
the back of the body 1002 of mobile phone 1000. Element 1010a is
in between elements 1010b and 1010c. Only the end view of a wire
or rod is illustrated for elements 1010 in FIG. 11.
With either element 1010a as a driven element and element 1010b
as a director and element 1010c as a reflector, or element 1010c
as a driven element and elements 1010a and 1010b as directors, the
energy from array 1005 is directed along arrow 1102, which is away
from user's head 1100 during operation. Elements 1010 form a line
through arrow 1102, indicating the direction in which radiation
from array 1005 is concentrated, assuming the director/reflector/driven
element arrangement described above.
By tilting the array 1005 within the body 1002, energy can be directed
and focused away from the user. Some energy is still directed toward
the user's head 1100 (see FIGS. 6 and 7), but the majority of the
energy is directed away. The driven element may be located on a
circuit board (not shown), for example, while the passive elements
may be located somewhere on the body 1002. Many variations on the
positioning of array 1005 are available.
FIG. 12 is a diagram illustrating a front view of one embodiment
of the invention in the mobile phone 1000 from FIG. 10. Element
1010c is extended from the body 1002 and a mechanism (not shown)
has deactivated the array antenna and is instead applying element
1010c as a whip antenna, providing the benefits of a whip antenna
while extended and the benefits of an array antenna while retracted.
A separate whip antenna may be provided and used aside from an array
antenna (having no overlapping parts).
In another embodiment, as illustrated in FIG. 14, the configurations
of the array antenna in FIGS. 8, 9, 10, and 11 may be combined in
order to provide two antennas with directional beams that are orthogonally
polarized. FIG. 14 is a diagram illustrating a front view of a mobile
phone according to one embodiment of the present invention shown
in FIGS. 8, 9, 10 and 11. Two-or-more-element array antennas 805
and 1005 from FIGS. 8 and 10 may be combined for diversity as shown
in FIG. 14. Additionally, a loop antenna 1401 may be added around
the periphery of the circuit board or the body 1400 to provide spatial
and/or polarization diversity.
FIG. 13 is a flow diagram illustrating one method of implementing
the invention with the mobile phone 1000 from FIG. 10. In block
1300, mobile phone 1000 determines if element 1010c, which is also
a whip antenna, is extended (or alternatively, retracted). A switch,
lever, or other mechanism may be used (not shown).
If the element 1010c is not extended, then in block 1310 the mobile
phone 1000 activates an internal antenna, for example array 1005.
If the element 1010c is extended, then in block 1320 the mobile
phone 1000 activates element 1010c as the whip antenna.
Radiation towards the users head may be reduced by activating the
array antenna when the whip is down, and performance may be increased.
According to the method and system disclosed herein, the present
invention provides a mobile phone with a directed beam antenna.
The present invention has been described in accordance with the
embodiments shown, and one of ordinary skill in the art will readily
recognize that there could be variations to the embodiments, and
any variations would be within the spirit and scope of the present
invention. Furthermore, the preceding Figures are not drawn to scale.
Accordingly, many modifications may be made by one of ordinary skill
in the art without departing from the spirit and scope of the appended
claims.
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