|
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| United States Patent Application |
20100321270
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| Kind Code
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A1
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|
Pan; Bo
; et al.
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December 23, 2010
|
High Gain Multiple Planar Reflector Ultra-Wide Band (UWB) Antenna
Structure
Abstract
Multiple out-of-plane planar reflectors can be used to build a
receive/transmit high-gain directional antenna. The driver portion and
the first reflector of the antenna are formed within a metal layer of a
PWB. A plurality of sets of reflector plates can be placed on the PWB, on
a non-conductive low-dielectric constant material coating both opposing
planar surfaces of the PWB, or on the opposing sidewalls of the product
housing unit. The metal layer in the PWB is placed between the reflector
plates. The plates can have either a parallel or non-parallel orientation
to each another. This greatly increase the received power and thus
increases the operating range of a low-power UWB system, as well as
significantly improves wireless data transmission throughput. This
antenna is applicable for USB communications systems.
| Inventors: |
Pan; Bo; (Irvine, CA)
; Battaglia; Frederic; (Irvine, CA)
; Li; KuangYu; (Irvine, CA)
; Yan; Ran-Hong; (Irvine, CA)
; Sun; Kuan Loek; (Irvine, CA)
|
| Correspondence Address:
|
THADDEUS GABARA
62 BURLINGTON ROAD
MURRAY HILL
NJ
07974
US
|
| Assignee: |
Wionics Technologies, Inc.
Irvine
CA
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| Serial No.:
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488509 |
| Series Code:
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12
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| Filed:
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June 19, 2009 |
| Current U.S. Class: |
343/837; 343/700MS |
| Class at Publication: |
343/837; 343/700.MS |
| International Class: |
H01Q 5/00 20060101 H01Q005/00; H01Q 19/10 20060101 H01Q019/10; H01Q 1/38 20060101 H01Q001/38 |
Claims
1. A multi planar antenna comprising:a metallic driver plate patterned in
a metal layer of a PWB;a first reflector plate patterned in the metal
layer of the PWB and isolated from the driver plate;at least one set of
reflector plates comprising:an upper reflector plate placed above the
metallic driver plate; anda lower reflector plate placed below the
metallic driver plate; wherein the driver and all reflector plates can
assume any polygon shape, and all plates are isolated from one another.
2. The apparatus of claim 1, wherebythe first reflector plate comprises a
portion of a PCB board ground.
3. The apparatus of claim 1, wherebythe upper and lower reflector plates
in the set are symmetrically positioned with respect to the metal layer
of the PWB.
4. The apparatus of claim 1, wherebythe plates are substantially parallel
to one another.
5. The apparatus of claim 3, wherebythe staggering between the sets of
reflector plates occurs along a main beam direction.
6. The apparatus of claim 3, wherebyeach set of reflector plates can be
offset in a perpendicular direction from the main beam direction.
7. The apparatus of claim 1, further comprising:a non-conductive
low-dielectric constant material deposited on both opposing planar
surfaces of the PWB; wherebythe upper and lower reflector plates are
placed on the opposing planar surfaces of the material.
8. The apparatus of claim 1, further comprising:a product housing unit
supporting the PWB;the PWB is placed between opposing sidewalls of the
product housing unit; wherebythe upper and lower reflector plates are
attached to the opposing sidewalls.
9. The apparatus of claim 1, further comprising:a transceiver coupled to
the driver plate that allows a communication protocol to be used, wherein
the communication protocol is Ultrawide-band (UWB) wireless, WiMedia,
MB-OFDM, 802.11a/b/g/n, 802.16, WiMAX, 802.15 or WPAN.
10. The method of improving the gain of an antenna by using multiple
planar reflectors comprising the steps of:pattering a metallic driver
plate in a metal layer of a PWB;pattering a first reflector plate in the
metal layer of the PWB;isolating the driver plate from the first
reflector plate;positioning at least one set of reflector plates where
the set comprises an upper reflector plate placed above the metallic
driver plate, and a lower reflector plate placed below the metallic
driver plate;whereinthe driver and all reflector plates can assume any
polygon shape, andall plates are isolated from one another.
11. The method of claim 10, wherebythe first reflector plate comprises a
portion of a PCB board ground.
12. The method of claim 10, wherebythe plates are substantially parallel
to one another.
13. The method of claim 10, wherebythe upper and lower reflector plates
are symmetrically located about the first reflector plate forming a first
set of reflector plates.
14. The method of claim 10, further comprising:depositing a layer of
non-conductive low-dielectric constant material on the top and bottom
planar surfaces of the PWB; wherebythe upper and lower reflector plates
are placed on the opposing planar surfaces of the material.
15. The method of claim 10, further comprising:supporting the PWB within a
product housing unit;attaching the upper and lower reflector plates to
the opposing sidewalls; andpositioning the PWB between the upper and
lower reflector plates.
16. The method of claim 10, further comprising:staggering the placement of
the sets of reflector plates along a main beam direction.
17. The method of claim 10, further comprising:offsetting the placement of
the sets of reflector plates from the main beam direction.
18. A method of adjusting a parameter of a multi planar antenna comprising
the steps of:patterning a driver plate in a first metal layer of a
PWB;patterning a first reflecting plate in another portion of the first
metal layer of the PWB;a means for forming a plurality of sets of
reflector plates; anda means for positioning these sets of reflector
plates with respect to a main beam direction to adjust a parameter of the
antenna.
19. The method of claim 18, further comprising:staggering the sets of
reflector plates along the main beam direction; oroffsetting the sets of
reflector plates from the main beam direction; therebyadjusting the
parameter.
20. The method of claim 19, wherebythe parameter is gain, the beam
direction or the angular coverage.
Description
BACKGROUND OF THE INVENTION
[0001]Antennas are one of the components in a wireless system
infrastructure that are used to transfer information between two
different points in space. The antenna is a transducer that transforms
currents and voltages in circuits into electric and magnetic fields in
free space and vice-versa. These electric and magnetic fields propagate
in free space; in addition, these fields can be modulated to carry
information. Wireless signals carry information that is launched/captured
into/from free space by an antenna.
[0002]Some examples of UWB (Ultra-Wideband) antennas that are used in the
field include a dipole whip or rod, a printed PCB (Printed Circuit Board)
wide dipole/monopole, or a ceramic omni-directional UWB antenna. Several
different examples are provided. FIGS. 1a through 1c illustrate different
examples of printed PCB dipole UWB antennas using different shapes for
the dipole portion of the antenna. Typically, a solid metallic plane or
surface is perpendicular to the axis of the main radiation beam. In FIG.
1a, a dipole 1-1a uses ovals 1-2a and 1-3a for the dipole elements. The
dipole is a center fed driven structure as indicated by 1-4a where the
structure is balanced and consists of the two conducting co-planar ovals
1-2a and 1-3a. The transceiver (not shown) would be connected to the
center 1-4a of the antenna (in addition, a switch, an integrated
transceiver IC, and/or a tuning network may be inserted between these
components).
[0003]An example using rectangular elements for the UWB dipole 1-1b is
illustrated in FIG. 1b. The center feed 1-4b is connected to the
rectangular dipoles 1-2b and 1-3b. Triangular elements 1-2c and 1-3c are
the dipole elements which are fed by the feed point 1-4c as indicated in
FIG. 1c. Several different polygon shapes were illustrated in FIG. 1a
through 1c indicating that the dipole elements can have various polygon
shapes. However, the final dipole element needs to be optimized in shape
and size for proper UWB operation.
[0004]Another antenna type can include a planar reflector (usually formed
from an antenna ground) can be designed to form quasi-Yagi antenna
structures in PCBs. An example is illustrated in FIG. 2a which depicts a
double sided PWB. The metallization on the top side is the solid color
while the cross-hatched pattern is the metallization on the bottom side
of the PWB.
[0005]Although not indicated, the PWB could be a multi-layer board. The
additional layers can be patterned into reflector plates to form multiple
reflectors for the Multiple Planar Reflector Ultra-Wide Band (UWB)
Antenna.
[0006]FIG. 2a shows a patterned layout that is used to form a quasi-Yagi
antenna 2-1. A PWB 2-2 has a dipole 2-3 and a director 2-4 that is formed
on the same top side of the board. The cross-hatch area is the ground
plane reflector 2-5 formed on the bottom side of the board. The feed
point 2-6 identifies where the transceiver would be connected.
[0007]FIG. 2b shows a patterned layout that is used to form a different
quasi-Yagi antenna 2-7. A PWB 2-2 has a dipole 2-3 but in this case the
director is eliminated. A ground plane formed on the bottom side below
the Yagi feedpoint 2-6 that is cross-hatched becomes part of the
reflector 2-5. The feed point 2-6 identifies where the transceiver would
be connected.
[0008]FIG. 2c illustrates a dipole antenna 2-8 on a PWB 2-11. The two
metallic rectangular sections 2-9 and 2-10 form the dipole elements.
[0009]In FIG. 2d, the structure 2-12 as indicated in Lin et al., U.S. Pat.
No. 7,064,728, is an ultra-wideband dipole antenna 2 in accordance with a
first preferred embodiment of the invention comprising a generally
axially disposed first outer metal sleeve 20 having a closed face 201 at
a top end thereof opposite its open bottom end, and a hole 202 through
the closed face 201; a generally axially disposed intermediate metal
sleeve 22 dimensioned to be surrounded by the first outer metal sleeve
20, the intermediate metal sleeve 22 having a closed face 221 at a top
end thereof opposite its open bottom end, and a hole 222 through the
closed face 221; a generally axially disposed second outer metal sleeve
23 above the first outer metal sleeve 20, the second outer metal sleeve
23 having a closed face 231 at a bottom end thereof opposite its open top
end; a conductive interconnection 24 having a bottom end 241 extended
through the hole 202, a feed point location 243 at the bottom end 241,
and a top end 242 electrically connected to the closed face 231; and an
inner coaxial conductor 25 surrounded by the intermediate metal sleeve
22, the coaxial conductor 25 including a central conductor 251
electrically connected to the feed point location 243 and an outer
grounding sleeve 252 surrounding the central conductor 251 and
electrically connected to edges of the hole 222.
[0010]In addition, there is the three-dimensional parabolic reflector
antenna. The parabolic surface focuses the reflected incoming energy into
a focal point or emits outgoing energy from the focal point to the
parabolic surface forming a narrow beam emitted from the antenna. The
transceiver is positioned at the focal point to receive or transmit a
desired signal. The parabolic antenna is bulky, heavy and costly.
[0011]A desirable feature would be to increase the directivity of an
antenna without necessarily increasing the cost or weight of the system.
A need of building a high-gain directional antenna for the receive and
transmit paths of a transceiver is highly desirable. This greatly
increases the received/transmitted powers and thus increases the
operating range of a low-power wireless system. Another benefit is that
the wireless data transmission rate can be improved providing higher
signal bandwidths.
BRIEF SUMMARY OF THE INVENTION
[0012]This invention relates to the idea of using multiple planar
reflectors to build a high-gain directional antenna for the
receive/transmit paths to improve the quality of the wireless link. It is
important to note that designing a high-gain directional antenna to
receive a particularly weak signal, also implies that the antenna will
transmit a stronger signal in the high gain direction in the same given
frequency range of operation. The maximum EIRP (effective isotropically
radiated power) also known as maximum transmitted power is specified by
FCC (Federal Communications Commission). The EIRP sets the upper limit of
the power radiated in any spatial direction from a UWB system. The
maximum UWB power levels allowed by the FCC provide marginal received
power levels during the reception of video over short distances. With
this transmit EIRP limit, a high-gain antenna is not required for the
transmit chain since the power level coupled into the antenna has to be
reduced to get the same amount of power radiated into space. The
effective power spatial density remains the same. However, it would be
desirable to increase the gain of antenna to increase the power of the
received signals. On the receive chain, for the same spatial power
density presented to the antenna, a high gain antenna couples more power
into the receiver IC. Designing a high gain omni-directional antenna is
possible but will be very challenging. Meanwhile, for many application
scenarios, an omni-directional transmit/receive antenna is not necessary.
The other method to get a high gain antenna is to asymmetrically
distribute the radiation patterns. An asymmetrically antenna would
increase the received power levels for certain directions. Thus, the
receiver at these points can receive higher power levels and improve the
bit error rate of the USB wireless link.
[0013]The design of the asymmetrical antenna is achieved by altering the
physical attributes of the system. Some of the physical attributes can be
implemented in the PWB, in the regions surrounding the PWB and on the
sidewalls of the housing unit. The modification of the physical
attributes can be done at very low cost. When the transmit/receive paths
shares the same physical antenna, the transmit power would need to be
backed off to accommodate a high gain antenna for EIRP limit set by FCC.
This brings additional advantage in that a potential transmit power
reduction may be possible using the high gain antenna. This greatly
increases the operating range of a low-power wireless system,
significantly improves the wireless data transmission throughput, and
saves power at the transmitter.
[0014]An embodiment of the high-gain directional antenna uses a driver
plate located within a PWB and at least two reflector plates located on
either side of the first plate in the PWB. All three plates are
non-intersecting. The reflector plates can be considered to be
out-of-plane with the first plane forming the multiple planar reflector
antenna structure. The reflector plates can be parallel or non-parallel
to the first plate. These reflector plates can be mounted to the
sidewalls of the unit and be parallel to each other, can be attached to a
foam containing non-conductive low-dielectric constant material that is
deposited on the sidewalls, can be positioned on foam to have a wedge
shape or be parallel to one another. In some cases, the non-parallel
sidewalls can offer an improved performance for this inventive technique.
Several embodiments of antennas using several multiple planar reflector
plates embodying this inventive aspect to form high-gain directional
antennas will be provided.
[0015]In another aspect of the invention provides a method of improving
the gain of an antenna by using multiple planar reflectors comprising the
steps of: pattering a metallic driver plate in a metal layer of a PWB;
pattering a first reflector plate in the metal layer of the PWB;
isolating the driver plate from the first reflector plate; positioning at
least one set of reflector plates where the set comprises an upper
reflector plate placed above the metallic driver plate, and a lower
reflector plate placed below the metallic driver plate; wherein the
driver and all reflector plates can assume any polygon shape, and all
plates are isolated from one another.
[0016]In another aspect of the invention provides a method that further
comprises depositing a layer of non-conductive low-dielectric constant
material on the top and bottom planar surfaces of the PWB; whereby the
upper and lower reflector plates are placed on the opposing planar
surfaces of the material.
[0017]In another aspect of the invention provides a method that further
comprises supporting the PWB within a product housing unit; attaching the
upper and lower reflector plates to the opposing sidewalls; and
positioning the PWB between the upper and lower reflector plates.
[0018]In another aspect of the invention provides a method that further
comprises staggering the placement of the sets of reflector plates along
a main beam direction or offsetting the placement of the sets of
reflector plates from the main beam direction to improve the gain of an
antenna by using multiple planar reflectors.
[0019]In another aspect of the invention provides a method adjusting a
parameter of a multi planar antenna comprising the steps of: patterning a
driver plate in a first metal layer of a PWB; patterning a first
reflecting plate in another portion of the first metal layer of the PWB;
a means for forming a plurality of sets of reflector plates; and a means
for positioning these sets of reflector plates with respect to a main
beam direction to adjust a parameter of the antenna.
[0020]In another aspect of the invention provides a method that further
comprises staggering the sets of reflector plates along the main beam
direction; or offsetting the sets of reflector plates from the main beam
direction; thereby adjusting the parameter of gain, the beam direction or
the angular coverage.
[0021]In another aspect of the invention describes a multi planar antenna
apparatus that comprising: a metallic driver plate patterned in a metal
layer of a PWB; a first reflector plate patterned in the metal layer of
the PWB and isolated from the driver plate; at least one set of reflector
plates comprising: an upper reflector plate placed above the metallic
driver plate; and a lower reflector plate placed below the metallic
driver plate; wherein the driver and all reflector plates can assume any
polygon shape, and all plates are isolated from one another.
[0022]In another aspect of the invention describes a multi planar antenna
apparatus that further comprises a non-conductive low-dielectric constant
material deposited on both opposing planar surfaces of the PWB; whereby
the upper and lower reflector plates are placed on the opposing planar
surfaces of the material.
[0023]In another aspect of the invention describes a multi planar antenna
apparatus that further comprises a product housing unit supporting the
PWB; the PWB is placed between opposing sidewalls of the product housing
unit; whereby the upper and lower reflector plates are attached to the
opposing sidewalls.
[0024]The design criteria for the antenna can be segregated from the
design criteria of the transceiver. This provides a flexibility of
selecting the most cost effective 3.sup.rd party design for the
transceiver since the transceiver can be a plug and play unit. Of course,
the transceiver can be formed using discrete components on a PCB,
packaged in an integrated circuit chip that was fabricated in a high tech
facility and connected to the PCB, or any other combination of packaging
and mounting techniques that can be used to build the components of a
wireless system infrastructure known in the art.
[0025]All reflector and driver plates are shaped as polygons. A polygon is
a shape defined as a plane figure that is bounded by a closed line path.
Thus a triangle, a square, a rectangle or an octagon can be considered a
polygon. In some case, one or more sides of the polygon may be
substituted with a curved line, in any case, this shape with at least one
curved line will still be called a polygon. The polygons can have a
finite thickness. For example, polygons stamped out of metal plates would
have the thickness of the metal plate.
[0026]A set of reflector plates is formed when a first and a second
reflector plate are either symmetrically or asymmetrically placed about a
center plane forming a set of out-of-plane reflector plates or simply a
set of reflector plates. This invention proposes to use several discrete
metal surfaces that are placed in a given relationship with respect to
the axis of main radiation beam to improve the gain of the antenna.
Compared with a three dimension scheme for traditional reflector-based
antennas, this invention reduces manufacturing/assembly complexity and
cost significantly, while demonstrating similar antenna gain by
optimizing the shapes, dimensions, and positions of these discrete
partial reflectors that are claimed in this invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027]Please note that the drawings shown in this specification may not be
drawn to scale and the relative dimensions of various elements in the
diagrams are depicted schematically and not to scale.
[0028]FIG. 1a shows an oval UWB dipole antenna.
[0029]FIG. 1b shows a rectangular UWB dipole antenna.
[0030]FIG. 1c shows a triangular UWB dipole antenna.
[0031]FIG. 2a illustrates a PWB artwork illustrating the various
components of a quasi-Yagi antenna using a director.
[0032]FIG. 2b illustrates a PWB artwork illustrating the various
components of a quasi-Yagi antenna without a director.
[0033]FIG. 2c illustrates a PWB artwork illustrating the various
components of a UWB dipole antenna.
[0034]FIG. 2d illustrates a 3D artwork illustrating the ultra-wideband
antenna.
[0035]FIG. 3a depicts a cross-view 3-D perspective of a high gain multiple
planar reflector antenna structure in accordance with the present
invention.
[0036]FIG. 3b depicts a cross-view 3-D perspective of a high gain
asymmetrical multiple planar reflector antenna structure in accordance
with the present invention.
[0037]FIG. 3c depicts a cross-view 3-D perspective of a high gain multiple
planar reflector antenna structure with two sets of reflector plates in
accordance with the present invention.
[0038]FIG. 4a presents a top view perspective of FIG. 3a of the high gain
multiple planar reflector antenna structure in accordance with the
present invention.
[0039]FIG. 4b presents a top view perspective of FIG. 3b of the high gain
asymmetrical multiple planar reflector antenna structure in accordance
with the present invention.
[0040]FIG. 4c depicts the top view perspective of FIG. 3c where another
set of reflector plates are added to the high gain multiple planar
reflector antenna structure in accordance with the present invention.
[0041]FIG. 5a shows an omni-directional radiation pattern for a
traditional UWB antenna.
[0042]FIG. 5b illustrates the radiation patterns of the high gain multiple
planar reflector UWB antenna structure in accordance with the present
invention.
[0043]FIG. 6a shows a product housing unit that supports and contains the
PWB.
[0044]FIG. 6b illustrates the addition of the out-of-plane reflector
plates to the inside sidewalls of the product housing unit in accordance
with the present invention.
[0045]FIG. 7a depicts a PWB.
[0046]FIG. 7b depicts a PWB with a portion of the front and back surfaces
covered with a foam that cures into a non-conductive low-dielectric
constant material.
[0047]FIG. 7c illustrates the addition of the out-of-plane reflector
plates to the foam in accordance with the present invention.
[0048]FIG. 7d depicts a PWB front and back surfaces covered with a foam
that cures into a non-conductive low-dielectric constant material.
[0049]FIG. 7e illustrates the addition of the out-of-plane reflector
plates inside the foam in accordance with the present invention.
[0050]FIG. 7f illustrates the addition of the out-of-plane reflector
plates to the outside of the foam in accordance with the present
invention.
[0051]FIG. 8a depicts a side view 8-1 of the driver and reflector plates
of FIG. 4a in accordance with the present invention.
[0052]FIG. 8b shows a side view 8-2 of the offset between sets of
reflector plates of FIG. 4b in accordance with the present invention.
[0053]FIG. 8c illustrates a side view 8-5 of the staggering between two
sets of reflector plates of FIG. 4c in accordance with the present
invention.
[0054]FIG. 9a presents a top view perspective of a high gain multiple
planar reflector antenna structure with an in-plane top and bottom plate
in accordance with the present invention.
[0055]FIG. 9b depicts a side view of the driver, reflector, top and bottom
plates of FIG. 9a in accordance with the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0056]FIG. 3a illustrates a side perspective for one embodiment of an
antenna 3-1 that uses reflectors both in and out-of-plane. A Cartesian
coordinate axis 3-6 is provided. The transceiver (not shown) would be
coupled to a driver plate 3-2. The remaining in-plane element is a
reflector plate 3-3. These two elements are in the xz plane with y=0. In
addition, the main beam direction 3-7 is depicted and indicated the
direction of increased power intensity. A first out-of-plane reflector
plate 3-4 is located in the negative y region or below the xz plane. The
second out-of-plane reflector plate 3-5 is located in the positive y
region or above the xz plane. The in-plane reflector plate 3-3 and the
driver plate 3-2 are isolated from each other; that is, the electrical
impedance between these two conductor plates are Mega .OMEGA.'s or
higher. This isolation can occur when the metal layer used to form the
reflector and driver plates is partitioned into at least two separate
metallic segments isolated by the dielectric forming the PWB. The view
from the top 4-1 will be shown in FIG. 4a.
[0057]FIG. 3b depicts a side perspective for another embodiment of an
antenna 3-8 that uses reflectors both in and out-of-plane. A first
out-of-plane reflector plate 34 is located in the negative y region or
below the xz plane. The second out-of-plane reflector plate 3-5 is
located in the positive y region or above the xz plane. This structure is
almost identical to the structure in FIG. 3a except that the reflector
plate 3-4 is asymmetrically placed when compared to the reflector plate
3-5. The plate 3-4 is shifted a distance 3-9 in the main beam direction.
This tends to steer the beam out of the PWB plane. The view from the top
4-5 will be shown in FIG. 4b.
[0058]FIG. 3c shows a side perspective for one embodiment of an antenna
3-10 that uses two sets of reflectors. The first set of reflector plates
3-5 and 3-4 are in the same position as in FIG. 3a. The second set of
reflector plates 3-11 and 3-12 are added to the structure of FIG. 3a. The
view from the top 4-8 will be shown in FIG. 4c.
[0059]FIG. 4a presents the top view perspective 4-1 of FIG. 3a. The
Cartesian coordinate axis 3-6 that was provided in FIG. 3a is
re-orientated for this perspective view and illustrated in 4-4. The
dotted line 4-3 presents the edge wise view of the in-plane 4-3 that
contains the driver plate 3-2. The reflector plate 3-3 is also in the
in-plane 4-3. Referring to coordinate 4-4, the driver and reflector
plates are in the xz plane where y=0. The reflector plates 3-5 and 3-4
are the out-of-plane reflectors, for example, both plates 3-5 and 3-4 are
a distance 4-2 from the in-plane 4-3. The out-of-plane reflector plates
can come in sets. For example, 3-5 and 3-4 comprise a first set; that is,
the position of the second out-of-plane reflector plate 3-5 can be
determined by mirror imaging the first out-of-plane reflector plate 3-4
about the plane 4-3 that contains the in-plane reflector plate 3-3 and
the driver plate 3-2. Superimposing the second out-of-plane 3-5 over this
image forms the set of out-of-plane reflector plates 3-5 and 3-4. In
other words, the upper and lower reflector plates are symmetrically
located about the first reflector plate forming a first set of
out-of-plane reflector plates. The set of out-of-plane reflector plates
will also be referred to as a set of reflector plates. A side view 8-1
will be shown in FIG. 8a.
[0060]FIG. 4b illustrates the top view perspective 4-5 of FIG. 3b. The
structure in FIG. 4b is similar to the structure in FIG. 4a except that
the reflector plate 3-4 which should be in the dotted line position
identified by 3-4a is instead re-positioned as 4-7. In other words, the
reflector plate 4-7 is displaced from the symmetrical position at 3-4a.
The total displacement distance is composed of the Manhattan distances of
4-6 and 3-9. The distance 3-9 was illustrated earlier in FIG. 3b. The two
plates 3-5 and 4-7 now have an asymmetrical structure. This type of
structure can be used to steer the beam out of the PWB plane. A side view
8-2 will be shown in FIG. 8b.
[0061]Sometimes it is not possible to get equal separation between the two
out-of-plane reflector plates and the driver plate. Asymmetric reflector
placement offers the ability to compensate for the lack of equal
separation. Asymmmetry reflector placement can be used to steer the beam
away or toward the plane containing the driver plate (the in-plane).
Thus, asymmetry reflector placement has two uses: 1) to steer the beam
away from the in-plane intentionally when there is equal separation; and
2) steer beam back to the in-plane when equal separation is not possible
due to a mechanical limitation. Asymmetric reflector placement is one
tool that offers flexibility in beam steering.
[0062]FIG. 4c illustrates the top view perspective 4-8 of FIG. 3c. FIG. 4c
illustrates the situation where an additional set of reflector plates
3-12 and 3-11 have been added to the previous configuration that was
shown in FIG. 4a. The positioning of the additional set is staggered 4-9
from the position of the first set. In addition, the positioning of the
additional set can be offset from the position of the first set. The
offset is the displacement difference measured in a direction (not shown)
that is perpendicular to the staggered 4-9 direction. A side view 8-5
will be shown in FIG. 8c
[0063]FIG. 5a shows the radiation pattern 5-1 of a traditional
omni-directional pattern for a UWB antenna. The Cartesian coordinate axis
3-6 that was provided in FIG. 3a is re-orientated for this perspective
view and illustrated in 5-3. FIG. 5b illustrates the radiation pattern
5-2 simulated when using the inventive structure that improves the gain
of the UWB antenna. There is a higher gain in the negative x-direction.
Note that the orientation of the physical antenna as given in FIG. 3a
also depicts the main beam direction 3-7. The increased gain in FIG. 5b
is in the direction of the main beam along the negative x-direction.
[0064]FIG. 6a depicts an outside view 6-1 of the product housing unit 6-2.
The housing unit has six sides where the sides 6-4 and 6-5 are opposing
sidewalls. The PWB 6-3 is placed approximately between the two opposing
sidewalls 6-4 and 6-5 where the PWB and the two opposing sidewalls in
this case are parallel to one another as shown in FIG. 6a. However, the
housing unit could also be constructed with a trapezoidal or wedge shape
such that the sidewalls are not parallel to one another but lie on the
edges of a sliced pie wedge. Secondly, the sidewalls can also include any
internal walls placed inside the housing unit. The context of the meaning
of sidewalls is extended to include the above definitions. The PWB 6-3 is
mounted inside of the unit 6-2. The PCB board ground (not shown) is
located inside the PWB 6-3 and can be used as the center partial
reflector.
[0065]FIG. 6b illustrates an embodiment where the antenna structure 6-6
uses the PCB board ground as the center partial reflector and a set of
two metal plates 6-7 and 6-8 as additional reflector plates that are
attached to the inside of the sidewalls of the product housing as
depicted in FIG. 6b. The plates can be attached to the sidewalls by using
an adhesive, a foam or a indentation formed in the sidewall to mate and
surely hold the plate to the sidewall. The copper plates can be parallel
to the ground plane of the PWB as shown, or can be formed to have a
wedged shape structure by appropriate positioning the plates on the foam
prior to curing.
[0066]FIG. 7a depicts a PWB 7-1. A ground plane 7-2 is illustrated in FIG.
7a. Foams that contain other non-conductive low-dielectric constant
materials 7-4 and 7-5 can be applied to a fraction of the overall area of
the top and bottom sides of the PWB 7-1 as illustrated in FIG. 7b and
cured. Partial reflector plates 7-9 and 7-10 can be placed on the foam or
material during curing as indicated by 7-8 in FIG. 7c. These reflector
plates, although shown as rectangles, can be of any polygon shape as
defined earlier. The partial reflector plates can be made using copper
plates or other metal plates. These plates do not intersect the ground
plane of the PCB surface. The partial reflectors can be stamped from
metal sheets by using an L-shape, U-shape, or any other form that can be
manufactured. Different shapes of planar reflector plates can be stamped
out that can be used to adjust antenna performance.
[0067]Foams that contain other non-conductive low-dielectric constant
materials 7-4 and 7-5 can be applied to the entire top and bottom sides
7-12 and 7-13 of the PWB 7-1 forming the structure 7-11 as illustrated in
FIG. 7d and cured. Partial reflector plates 7-15 and 7-16 can be placed
in the foam or material during curing as indicated in the structure 7-14
in FIG. 7e. The partial reflector plates can be made using copper plates
or other metal plates. These plates do not intersect the ground plane of
the PCB surface. The partial reflectors can be stamped from metal sheets
by using an L-shape, U-shape, or any other form that can be manufactured.
Different shapes of planar reflector plates can be stamped out that can
be used to adjust antenna performance.
[0068]Partial reflector plates 7-18 and 7-19 can be placed on the cured
foam or material as indicated in the structure 7-17 in FIG. 7f. The
partial reflector plates can be made using copper plates or other metal
plates. These plates do not intersect the ground plane of the PCB
surface. The partial reflectors can be stamped from metal sheets by using
an L-shape, U-shape, or any other form that can be manufactured.
Different shapes of planar reflector plates can be stamped out that can
be used to adjust antenna performance.
[0069]FIG. 8a illustrates a view 8-1 in FIG. 4a. The numbers if used
earlier correspond to the same item. The plate 3-2 is the driver plate
while plate 3-3 can be located in the ground plane of the PWB. The plate
3-5 is in front of the plate 3-4 (being hidden) while the plate 3-9 is in
front of plate 3-10 (also being hidden). The plates 3-5 and 3-4 together
form the first set of reflector plates. Plate 3-5 is in front of the
ground plane of the PWB just as much as the plate 3-4 (not shown) is
behind the ground plane of the PWB. In addition, the shape of both of
these plates 3-5 and 3-4 are mirror images of one another. The additional
set of reflector plates is formed by reflector plates 3-9 and 3-10.
[0070]FIG. 8b shows a view 8-2 where offsets have been applied to the
first and additional sets of reflector plates. The offset of the first
set of reflector plates 3-5 and 3-4 is indicated as the offset distance
8-3. The additional set of reflector plates 3-9 and 3-10 are offset in
the negative direction 8-4. The offset can be measured with respect to a
point on the ground plane of the PWB.
[0071]FIG. 8c illustrates a view 8-5 where staggering have been applied to
the first and additional sets of reflector plates. The staggering of the
first set of reflector plates 3-5 and 3-4 is indicated as the stagger
distance 8-6. The additional set of reflector plates 3-9 and 3-10 are
staggered in the by the same stagger distance 8-6. The stagger distance
is measured with respect to one of the corners of the ground plane of the
PWB.
[0072]The mechanism of introducing offset or staggering between multiple
reflectors along the main beam direction to further improve gain. The
mechanism of varying spacing and offset of multiple reflectors also
adjusts and steers the beam direction and the angular coverage. In
addition, the out-of-plane metal plates can be used to focus the
elevation of the beam. The physical dimensions and positions of the
plates in the antenna can be designed to adjust one or more parameters of
the antenna. Some of these parameters that can be adjusted include the
gain, the beam direction or the angular coverage. The proper selection of
the dimensions and positions of the plates can be used to achieve optimum
performance. The reflector is longer than the driver antenna, this helps
collect some EM energy scattered into the direction of the top and bottom
edge of the reflector and re-focus it back to the main beam direction;
secondly, metal reflectors can be placed on the top and bottom of the
driver antenna to further reflect energy back to the main beam.
[0073]FIG. 9a illustrates a side perspective for one embodiment of an
antenna 9-1 that uses reflectors both in and out-of-plane. A Cartesian
coordinate axis 3-6 is provided. The transceiver (not shown) would be
coupled to a driver plate 3-2. The remaining elements are an in-plane
reflector plate 3-3 and the two additional top and bottom reflector
plates 9-2 and 9-3. These four elements are in the xz plane with y=0. A
first out-of-plane reflector plate 3-4 is located in the negative y
region or below the xz plane. The second out-of-plane reflector plate 3-5
is located in the positive y region or above the xz plane. The in-plane
reflector plate 3-3, the driver plate 3-2, the two reflector plates 9-2
and 9-3 are all isolated from each other; that is, the electrical
impedance between all four conductor plates are Mega .OMEGA.'s or higher.
This isolation can occur when the metal layer used to form the reflector
and driver plates is partitioned into at least four separate metallic
segments isolated by the dielectric forming the PWB.
[0074]FIG. 9b illustrates a view 9-4 in FIG. 9b. The numbers if used
earlier correspond to the same item. The plate 3-2 is the driver plate
while plates 3-3, 9-2 and 9-3 can be located in the ground plane or in
segmented metal areas of a metal layer in the PWB. The plate 3-5 is in
front of the plate 3-4 (being hidden) while the plate 3-9 is in front of
plate 3-10 (also being hidden). The plates 3-5 and 3-4 together form the
first set of reflector plates. The plates 9-2 and 9-3 form a top and
bottom reflectors. Plate 3-5 is in front of the ground plane of the PWB
just as much as the plate 3-4 (not shown) is behind the ground plane of
the PWB. In addition, the shape of both of these plates 3-5 and 3-4 are
mirror images of one another.
[0075]Finally, it is understood that the above description are only
illustrative of the principle of the current invention. It is understood
that the various embodiments of the invention, although different, are
not mutually exclusive. In accordance with these principles, those
skilled in the art may devise numerous modifications without departing
from the spirit and scope of the invention. For example, the techniques
of the invention can be practiced in the wireless arena which can include
the security, entertainment, business, and gaming industries. It can also
be practiced in different wireless standards such as WiMedia MB-OFDM;
802.11a/b/g/n; 802.16 WiMAX; 802.15 WPAN, etc.
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