U.S. patent application number 17/511336 was filed with the patent office on 2022-07-21 for loop antennas with selectively-activated feeds to control propagation patterns of wireless power signals.
The applicant listed for this patent is Alister Hosseini, Saman Kabiri, Evangelos Kornaros, Michael A. Leabman. Invention is credited to Alister Hosseini, Saman Kabiri, Evangelos Kornaros, Michael A. Leabman.
Application Number | 20220231541 17/511336 |
Document ID | / |
Family ID | 1000006243748 |
Filed Date | 2022-07-21 |
United States Patent
Application |
20220231541 |
Kind Code |
A1 |
Kabiri; Saman ; et
al. |
July 21, 2022 |
LOOP ANTENNAS WITH SELECTIVELY-ACTIVATED FEEDS TO CONTROL
PROPAGATION PATTERNS OF WIRELESS POWER SIGNALS
Abstract
An example wireless power transmitter includes a ground plate, a
conductive wire offset from the ground plate, and a
signal-conveyance member. The conductive wire of the wireless power
transmitter forms a loop antenna that is configured to radiate a
radio frequency (RF) signal for wirelessly powering a receiver
device. And the signal-conveyance member of the wireless power
transmitter is configured to selectively feed a waveform to a
connection point of a plurality of connection points along the
conductive wire, wherein the waveform, when provided to the
conductive wire, causes the loop antenna to radiate the RF
signal.
Inventors: |
Kabiri; Saman; (Laguna
Nigel, CA) ; Kornaros; Evangelos; (Santa Cruz,
CA) ; Hosseini; Alister; (Phoenix, AZ) ;
Leabman; Michael A.; (San Ramon, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Kabiri; Saman
Kornaros; Evangelos
Hosseini; Alister
Leabman; Michael A. |
Laguna Nigel
Santa Cruz
Phoenix
San Ramon |
CA
CA
AZ
CA |
US
US
US
US |
|
|
Family ID: |
1000006243748 |
Appl. No.: |
17/511336 |
Filed: |
October 26, 2021 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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16296145 |
Mar 7, 2019 |
11159057 |
|
|
17511336 |
|
|
|
|
62643118 |
Mar 14, 2018 |
|
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H02J 50/20 20160201;
H01Q 21/24 20130101; H01Q 25/00 20130101; H01Q 21/064 20130101;
G06K 19/0715 20130101; H01Q 7/00 20130101; H02J 50/23 20160201;
H01Q 13/103 20130101; H01Q 21/28 20130101; H01Q 3/40 20130101; H01Q
1/288 20130101; H01Q 21/245 20130101; H02J 50/10 20160201; H01Q
15/0086 20130101; H02J 7/025 20130101 |
International
Class: |
H02J 50/23 20060101
H02J050/23; G06K 19/07 20060101 G06K019/07; H02J 50/10 20060101
H02J050/10; H01Q 21/24 20060101 H01Q021/24; H01Q 25/00 20060101
H01Q025/00; H01Q 3/40 20060101 H01Q003/40; H01Q 7/00 20060101
H01Q007/00; H01Q 21/28 20060101 H01Q021/28; H01Q 21/06 20060101
H01Q021/06; H01Q 1/28 20060101 H01Q001/28; H01Q 13/10 20060101
H01Q013/10; H01Q 15/00 20060101 H01Q015/00; H02J 50/20 20060101
H02J050/20 |
Claims
1. (canceled)
2. A wireless power transmitter, comprising: a ground plate; a
conductive wire offset from the ground plate, the conductive wire
forming: a loop antenna that is configured to radiate a radio
frequency (RF) signal for wirelessly powering a receiver device; a
signal-conveyance member configured to: selectively feed a waveform
to a connection point of a plurality of connection points along the
conductive wire; wherein the waveform, when provided to the
conductive wire, causes the loop antenna to radiate the RF
signal.
3. The wireless power transmitter of claim 2, wherein the
signal-conveyance member includes a power amplifier.
4. The wireless power transmitter of claim 2, further comprising a
controller configured to: select a respective connection point from
the plurality of connection points based on a location of the
receiver device relative to the plurality of connection points; and
send an instruction to the signal-conveyance member that causes the
signal-conveyance member to feed the waveform to the respective
connection point.
5. The wireless power transmitter of claim 4, further comprising a
communications radio configured to receive a communications signal
from a communications radio of the receiver device, wherein the
controller is further configured to determine the location of the
receiver device relative to the plurality of connection points
based on the communications signal.
6. The wireless power transmitter of claim 4, further comprising a
sensor configured to detect a presence of the receiver device,
wherein the controller is further configured to determine the
location of the receiver device relative to the plurality of
connection points based on information generated by the sensor.
7. The wireless power transmitter of claim 4, wherein the loop
antenna is configured to radiate the RF signal with different
propagation patterns depending on which of the plurality of
connection points is fed by the signal-conveyance member.
8. The wireless power transmitter of claim 7, wherein the loop
antenna is configured to radiate the RF signal with the different
propagation patterns based on a plurality of physical dimensions,
including: a width of the conductive wire; a length of the
conductive wire; a height of the conductive wire; a thickness of
the conductive wire; a shape of the loop antenna; and a magnitude
of an offset between the ground plate and the conductive wire.
9. The wireless power transmitter of claim 7, wherein: the
signal-conveyance member is further configured to feed the waveform
to the connection point when the location of the receiver device is
within a threshold distance from the connection point.
10. The wireless power transmitter of claim 9, wherein: the loop
antenna is configured to radiate the RF signal in a respective
propagation pattern of the different propagation patterns when the
connection point of the plurality of connection points is fed by
the signal-conveyance member, wherein a high concentration of RF
energy in the respective propagation pattern is steered to travel
towards the location of the receiver device.
11. The wireless power transmitter of claim 10, wherein: when the
respective connection point is a different connection point,
distinct from the connection point, of the plurality of connection
points, the signal-conveyance member is further configured to feed
an additional waveform to the different connection point when the
receiver device is located at a different location, distinct from
the location, the different location being within a second
threshold distance from the different connection point.
12. The wireless power transmitter of claim 11, wherein: the loop
antenna is configured, when the additional waveform is fed to the
conductive wire, to radiate an additional RF signal in an
additional propagation pattern of the different propagation
patterns when the different connection point of the plurality of
connection points is fed by the signal-conveyance member, wherein a
high concentration of RF energy in the additional propagation
pattern is steered to travel towards the different location of the
receiver device.
13. The wireless power transmitter of claim 12, wherein the
wireless power transmitter is configured such that in use: the RF
signal radiated in the respective propagation pattern propagates in
a first direction towards the location of the receiver device; the
additional RF signal radiated in the additional propagation pattern
propagates in a second direction towards the different location of
the receiver device; and the second direction is different from the
first direction.
14. The wireless power transmitter of claim 13, wherein the
wireless power transmitter is configured such that in use: the
propagation pattern has a first polarization; the additional
propagation pattern has a second polarization; and the second
polarization differs from the first polarization.
15. The wireless power transmitter of claim 2, wherein: the ground
plate is disposed in a first plane; the conductive wire is disposed
in a second plane; and the second plane is substantially parallel
to the first plane.
16. The wireless power transmitter of claim 15, wherein the second
plane is offset from the first plane by a distance.
17. The wireless power transmitter of claim 15, wherein a portion
of the signal-conveyance member is positioned substantially
perpendicular to the first and second planes.
18. The wireless power transmitter of claim 2, wherein: the
conductive wire comprises a plurality of contiguous segments; and
each of the plurality of connection points is positioned between a
respective pair of segments of the plurality of contiguous
segments.
19. The wireless power transmitter of claim 18, wherein: one or
more first segments of the plurality of contiguous segments have a
first shape; one or more second segments of the plurality of
contiguous segments have a second shape different from the first
shape; and each of the plurality of contiguous segments is
configured to radiate the RF signal when one of the plurality of
connection points is fed by the signal-conveyance member.
20. A non-transitory, computer-readable storage medium storing
instructions that, when executed by a processor associated with a
wireless power transmitter, cause the wireless power transmitter
to: selectively feed, by a signal-conveyance member, a waveform to
a connection point of a plurality of connection points along a
conductive wire, wherein the wireless power transmitter includes: a
ground plate; the conductive wire being offset from the ground
plate, the conductive wire forming a loop antenna that is
configured to radiate a radio frequency (RF) signal for wirelessly
powering a receiver device; wherein the waveform, when provided to
the conductive wire, causes the conductive wire to radiate the RF
signal.
21. A method of manufacturing a wireless power transmitter, the
method comprising: providing a ground plate; coupling a conductive
wire to the ground plate, wherein the conductive wire forms a loop
antenna and is configured to radiate a radio frequency (RF) signal
for wirelessly powering a receiver device; providing a
signal-conveyance member, wherein: the signal-conveyance member is
configured to selectively feed a waveform to a connection point of
a plurality of connection points along the conductive wire, and the
waveform, when provided to the conductive wire, causes the
conductive wire to radiate the RF signal.
Description
RELATED APPLICATION
[0001] This application is a continuation of U.S. patent
application Ser. No. 16/296,145, filed on Mar. 7, 2019, entitled
"Loop Antennas With Selectively-Activated Feeds To Control
Propagation Patterns Of Wireless Power Signals," which claims the
benefit of U.S. Provisional Patent Application Ser. No. 62/643,118,
filed Mar. 14, 2018, entitled "Loop Antennas With
Selectively-Activated Feeds To Control Propagation Patterns Of
Wireless Power Signals," each of which is herein fully incorporated
by reference in its respective entirety.
TECHNICAL FIELD
[0002] The present disclosure relates generally to loop antennas
for wireless power transmission, and more particularly to loop
antennas with selectively-activated feeds to control propagation
patterns of wireless power signals.
BACKGROUND
[0003] Portable electronic devices such as smartphones, tablets,
notebooks and other electronic devices have become a necessity for
communicating and interacting with others. The frequent use of
portable electronic devices, however, uses a significant amount of
power, which quickly depletes the batteries attached to these
devices. Inductive charging pads and corresponding inductive coils
in portable devices allow users to wirelessly charge a device by
placing the device at a particular position on an inductive pad to
allow for a contact-based charging of the device due to magnetic
coupling between respective coils in the inductive pad and in the
device.
[0004] Conventional inductive charging pads, however, suffer from
many drawbacks. For one, users typically must place their devices
at a specific position and in a certain orientation on the charging
pad because gaps ("dead zones" or "cold zones") exist on the
surface of the charging pad. In other words, for optimal charging,
the coil in the charging pad needs to be aligned with the coil in
the device in order for the required magnetic coupling to occur.
Additionally, placement of other metallic objects near an inductive
charging pad may interfere with operation of the inductive charging
pad, so even if the user places their device at the exact right
position, if another metal object is also on the pad, then magnetic
coupling still may not occur and the device will not be charged by
the inductive charging pad. This results in a frustrating
experience for many users as they may be unable to properly charge
their devices.
[0005] Charging using electromagnetic radiation (e.g., microwave
radiation waves) offers promise, but RF charging is typically
focused on far-field charging and not near-field or mid-field
charging where the device to be charged is placed on or near the RF
energy transmitter.
SUMMARY
[0006] Accordingly, there is a need for a wireless charging
solution that (i) radiates energy at a mid-field distance (and
various other distances) to wirelessly deliver power to a receiver,
and (ii) allows users to place their devices at any position on or
near the pad and still receive wirelessly delivered energy. A
method of operating one such example wireless power transmitter is
described below.
[0007] In the following description, references to "mid-field"
transmission refer to radiation of electromagnetic waves by an
antenna (e.g., the loop antenna described herein) for distances up
to approximately a wavelength of an operating frequency of the
antenna (e.g., a wavelength of an operating frequency of 5.8 GHz is
approximately 5.17 centimeters, so the mid-field transmission
distance of the antenna in this example would be approximately 5.17
centimeters). In some embodiments, the operating frequency ranges
from 400 MHz to 60 GHz. For the purposes of the following
description, a mid-field charging pad (or mid-field radio-frequency
charging pad) is a wireless-power-transmitting device that includes
one or more wireless power transmitters, each of which is
configured to radiate electromagnetic waves to receiver devices
that are located within a mid-field distance of the charging pad
(e.g., within 0-5.17 centimeters of the charging pad, if the one or
more wireless power transmitters of the charging pad are using an
operating frequency of 5.8 GHz).
[0008] (A1) In some embodiments, a method of wirelessly charging a
receiver device includes, providing a wireless power transmitter
including (i) a ground plate, (ii) a conductive wire offset from
the ground plate, the conductive wire forming a loop antenna, (iii)
a plurality of feed elements extending from the ground plate to the
conductive wire, each feed element being connected to the
conductive wire at a different position on the conductive wire, and
(iv) a power amplifier connected to one or more feed elements of
the plurality of feed elements. The method further includes
selectively feeding, by the power amplifier, an RF signal to a
respective feed element of the one or more feed elements based on a
location of a receiver device relative to the plurality of feed
elements. The method further includes (i) exciting, by the
respective feed element fed by the power amplifier, the conductive
wire, and (ii) radiating, by the conductive wire, the RF signal for
wirelessly powering the receiver device.
[0009] (A2) In some embodiments of the method of A1, the method
further includes: (i) selecting, by a controller of the wireless
power transmitter, the respective feed element of the one or more
feed elements based on the location of the receiver device relative
to the plurality of feed elements, and (ii) sending, by the
controller, an instruction to the power amplifier that causes the
power amplifier to feed the RF signal to the respective feed
element.
[0010] (A3) In some embodiments of the method of A2, the method
further includes receiving, by a communications radio of the
wireless power transmitter, a communications signal from a
corresponding communications radio of the receiver device.
Moreover, the method further includes determining, by the
controller, the location of the receiver device relative to the
plurality of feed elements based, at least in part, on the
communications signal. In some embodiments, the operations of A3
are performed prior to the operations of A2.
[0011] (A4) In some embodiments of the method of any of A2-A3, the
method further includes detecting, by one or more sensors of the
wireless power transmitter, a presence of the receiver device.
Moreover, the method further includes determining, by the
controller, the location of the receiver device relative to the
plurality of feed elements based on information generated by the
one or more sensors. In some embodiments, determining the location
of the receiver device relative to the plurality of feed elements
is based on a combination of the communications signal and the
information generated by the one or more sensors. In some
embodiments, the operations of A4 are performed prior to the
operations of A2.
[0012] (A5) In some embodiments of the method of any of A1-A4,
radiating the RF signal includes radiating the RF signal from the
conductive wire with different propagation patterns (e.g.,
radiation patterns) depending on which of the plurality of feed
elements is fed by the power amplifier.
[0013] (A6) In some embodiments of the method of A5, the RF signal
is radiated from the conductive wire with the different propagation
patterns, wherein the different propagation patterns are based, at
least in part, on a plurality of physical dimensions of the
wireless power transmitter, including: a width of the conductive
wire; a length of the conductive wire; a thickness of the
conductive wire; a diameter of the conductive wire; a shape of the
loop; and a magnitude of the offset between the ground plate and
the conductive wire.
[0014] (A7) In some embodiments of the method of any of A5-A6, when
the respective feed element is a first feed element of the one or
more feed elements that is connected to the conductive wire at a
first position, the method further includes feeding, via the power
amplifier, the RF signal to the first feed element when the
location of the receiver device is within a first threshold
distance from the first position.
[0015] (A8) In some embodiments of the method of A7, radiating the
RF signal includes radiating the RF signal from the conductive wire
in a first propagation pattern of the different propagation
patterns when the first feed element of the one or more feed
elements is fed by the power amplifier, where a high concentration
of RF energy in the first propagation pattern is steered to travel
towards the location of the receiver device.
[0016] (A9) In some embodiments of the method of any of A5-A8, when
the respective feed element is a second feed element, distinct from
the first feed element, of the one or more feed elements that is
connected to the conductive wire at a second position, distinct
from the first position, the method further includes feeding, via
the power amplifier, the RF signal to the second feed element when
the receiver device is located at a second location, distinct from
the location, the second location being within a second threshold
distance from the second position.
[0017] (A10) In some embodiments of the method of A9, radiating the
RF signal includes radiating the RF signal in a second propagation
pattern of the different propagation patterns when the second feed
element of the one or more feed elements is fed by the power
amplifier, where a high concentration of RF energy in the second
propagation pattern is steered to travel towards the second
location of the receiver device.
[0018] (A11) In some embodiments of the method of A10, the RF
signal radiated in the first propagation pattern propagates away
from the first position in a first direction towards the location
of the receiver device, and the RF signal radiated in the second
propagation pattern propagates away from the second position in a
second direction towards the second location of the receiver
device. In some embodiments, the second direction is different from
the first direction. In some embodiments, the second direction is
the same as the first direction.
[0019] (A12) In some embodiments of the method of any of A8-A11,
the first propagation pattern has a first polarization and the
second propagation pattern has a second polarization. In some
embodiments, the second polarization differs from the first
polarization. In some embodiments, the second polarization is the
same as the first polarization.
[0020] (A13) In some embodiments of the method of any of A1-A12,
the ground plate is disposed in a first plane, the conductive wire
is disposed in a second plane, and the second plane is
substantially parallel to the first plane.
[0021] (A14) In some embodiments of the method of A13, the second
plane is offset from the first plane by a distance.
[0022] (A15) In some embodiments of the method of any of A13-A14,
each of the plurality of feed elements is substantially
perpendicular to the first and second planes.
[0023] (A16) In some embodiments of the method of any of A1-A15,
the one or more feed elements are one or more first feed elements,
and the wireless power transmitter further includes a second power
amplifier connected to one or more second feed elements of the
plurality of feed elements.
[0024] (A17) In some embodiments of the method of any of A1-A16,
the one or more feed elements includes at least two feed elements,
and feeding the RF signal includes feeding the RF signal to the at
least two feed elements upon determining that the location of the
receiver device is between the two feed elements.
[0025] (A18) In some embodiments of the method of any of A1-A17,
the conductive wire includes a plurality of contiguous segments and
each of the plurality of feed elements is positioned between a
respective pair of segments of the plurality of contiguous
segments.
[0026] (A19) In some embodiments of the method of claim A18, one or
more first segments of the plurality of contiguous segments have a
first shape and one or more second segments of the plurality of
contiguous segments have a second shape different from the first
shape.
[0027] (A20) In some embodiments of the method of any of A17-A19,
further including radiating, via one or more (or each) of the
plurality of contiguous segments, the RF signal when one of the
plurality of feed elements is fed by the power amplifier.
[0028] (A21) In some embodiments of the method of any of A1-A20,
the plurality of feed elements is configured to provide the RF
signal to the conductive wire at the different positions.
[0029] (A22) In some embodiments of the method of any of A1-A21,
the RF signal is transmitted at a frequency of 5.8 GHz, 2.4 GHz, or
900 MHz.
[0030] (A23) In some embodiments of the method of any of A7 and A9,
the RF signal has a wavelength, the first and second threshold
distances are within a mid-field transmission distance of the
wireless power transmitter, and the mid-field transmission distance
is within the wavelength of the RF signal from the wireless power
transmitter.
[0031] (A24) In one other aspect, a wireless power transmitter is
provided, and the wireless power transmitter includes the
structural characteristics for a wireless power transmitter
described above in any of A1-A22, and the wireless power
transmitter is also configured to perform the method steps
described above in any of A1-A23.
[0032] (A25) In another aspect, a transmitter pad that includes one
or more of the wireless power transmitters described in any of
A1-A23 is provided. In some embodiments, the transmitter pad is in
communication with one or more processors and memory storing one or
more programs which, when executed by the one or more processors,
cause the transmitter pad to perform the method described in any
one of A1-A23.
[0033] (A26) In yet another aspect, a transmitter pad (that
includes one or more of the wireless power transmitters described
in any of A1-A23) is provided and the transmitter pad includes
means for performing the method described in any of A1-A23.
[0034] (A27) In still another aspect, a non-transitory
computer-readable storage medium is provided (e.g., as a memory
device, such as external or internal storage, that is in
communication with a transmitter pad). The non-transitory
computer-readable storage medium stores executable instructions
that, when executed by a transmitter pad (that includes a plurality
of wireless power transmitters) with one or more processors/cores,
cause the transmitter pad to perform the method described in any
one of A1-A23.
BRIEF DESCRIPTION OF THE DRAWINGS
[0035] The patent or application file contains at least one drawing
executed in color. Copies of this patent or patent application
publication with color drawing(s) will be provided by the Office
upon request and payment of the necessary fee.
[0036] So that the present disclosure can be understood in greater
detail, a more particular description may be had by reference to
the features of various embodiments, some of which are illustrated
in the appended drawings. The appended drawings, however, merely
illustrate pertinent features of the present disclosure and are
therefore not to be considered limiting, for the description may
admit to other effective features.
[0037] FIGS. 1A-1B show diagrams illustrating a representative
transmitter pad in accordance with some embodiments.
[0038] FIG. 2 is a schematic of a representative transmitter in
accordance with some embodiments.
[0039] FIG. 3A is a top view of a representative wireless power
transmitter in accordance with some embodiments.
[0040] FIG. 3B is a cross-sectional view (taken along line
A-A.sup.1) of the representative wireless power transmitter of FIG.
3A in accordance with some embodiments.
[0041] FIG. 4 is a flow diagram showing a method of wirelessly
charging a receiver device in accordance with some embodiments.
[0042] FIGS. 5A-5B show various power distributions from a wireless
power transmitter in accordance with some embodiments.
[0043] FIGS. 6A-6B show various propagation patterns radiating from
a wireless power transmitter in accordance with some
embodiments.
[0044] In accordance with common practice, the various features
illustrated in the drawings may not be drawn to scale. Accordingly,
the dimensions of the various features may be arbitrarily expanded
or reduced for clarity. In addition, some of the drawings may not
depict all of the components of a given system, method or device.
Finally, like reference numerals may be used to denote like
features throughout the specification and figures.
DETAILED DESCRIPTION
[0045] Numerous details are described herein in order to provide a
thorough understanding of the example embodiments illustrated in
the accompanying drawings. However, some embodiments may be
practiced without many of the specific details, and the scope of
the claims is only limited by those features and aspects
specifically recited in the claims. Furthermore, well-known
processes, components, and materials have not been described in
exhaustive detail so as not to unnecessarily obscure pertinent
aspects of the embodiments described herein.
[0046] FIG. 1A is a high-level block diagram of a transmitter pad
100, in accordance with some embodiments. The transmitter pad 100
(also referred to interchangeably herein as a mid-field
radio-frequency (RF) charging pad, mid-field charging pad, or
radio-frequency charging pad) includes components 102. The
transmitter pad 100 is configured to generate electromagnetic
energy (e.g., RF power transmission waves/RF signals) that is
received by a receiver that is placed in proximity (e.g., within a
mid-field distance, such as approximately 12.5 centimeters from the
transmitter pad 100 if the wireless power transmitters of the pad
are currently using an operation frequency of 2.4 GHz) or on top of
the transmitter pad 100. the descriptions herein, RF power
transmission waves are used as a primary illustrative example, but
one or ordinary skill in the art will appreciate in view of these
descriptions that any type of electromagnetic radiation waves may
be used instead in certain embodiments or implementations.
[0047] The components 102 of the transmitter pad 100 include, for
example, one or more processors/cores 104, a memory 106, one or
more transmitter zones 110 (each including respective one or more
wireless power transmitters 300, and an example transmitter 300 is
illustrated in FIGS. 3A-3B), one or more communications components
112, and/or one or more transmitter sensors 114. In some
embodiments, these components 102 are interconnected by way of a
communications bus 108. In some embodiments, the components 102 are
housed within the transmitter pad 100. Alternatively, in some
embodiments, one or more of the components 102 are disposed outside
(e.g., external) the transmitter pad 100. For example, the one or
more processors 104, the memory 106, the one or more communications
components 112, may be external while the respective one or more
transmitters 300 of each respective transmitter zone 100 and the
one or more transmitter sensors 114 may be internal (or some other
combination/arrangement of components).
[0048] In some embodiments, the communication component(s) 112
include, e.g., hardware capable of data communications using any of
a variety of wireless protocols (e.g., IEEE 802.15.4, Wi-Fi,
ZigBee, 6LoWPAN, Thread, Z-Wave, Bluetooth Smart, ISA100.11a,
WirelessHART, MiWi, etc.) wired protocols (e.g., Ethernet,
HomePlug, etc.), and/or any other suitable communication protocol,
including communication protocols not yet developed as of the
filing date of this document.
[0049] In some embodiments, the communications component 112
transmits communication signals to the receiver 120 by way of the
electronic device. For example, the communications component 112
may convey information to a communications component of the
electronic device, which the electronic device may in turn convey
to the receiver 120 (e.g., via a bus).
[0050] In some embodiments, the receiver 120 includes a
communications component configured to communicate various types of
data with the transmitter pad 100, through a respective
communication signal generated by a receiver-side communications
component. The data may include location indicators for the
receiver 120, a power status of the electronic device, status
information for the receiver 120 (e.g., a frequency at which a
wireless-power-receiving antenna of the receiver 120 is tuned, a
polarization of the wireless-power-receiving antenna, etc.), status
information for the electronic device (e.g., a current
battery-charge level for the electronic device), status information
about power waves being transmitted to the receiver 120 by the pad
100 (e.g., an amount of energy the receiver 120 is able to extract
from the power waves).
[0051] In some embodiments, the data contained within communication
signals is used by the electronic device, receiver 120, and/or
transmitter pad 100 for determining adjustments of one or more
characteristics used by any of the transmitters 300 to transmit
power waves. Using a communication signal, the transmitter pad 100
receives data that is used, e.g., to identify receivers 120 on the
transmitter pad 100, identify electronic devices, determine safe
and effective waveform characteristics for power waves, and/or
determine which feed to activate for one or more of the
transmitters 300.
[0052] In some embodiments, the transmitter pad 100 is designed to
lay flat on a surface (e.g., horizontally) while in some
embodiments the transmitter pad 100 is designed to be positioned at
an angle relative to the surface (e.g., substantially vertical). In
some embodiments, a housing for the transmitter pad 100 is shaped
such that the transmitter pad 100 is stable when positioned in a
substantially vertical manner. Moreover, the transmitter pad 100
may include a stand (e.g., kick stand) that extends away from the
transmitter pad 100 to provide additional support.
[0053] In some embodiments, the one or more transmitter sensors 114
are positioned at one or more locations on the transmitter pad 100
(e.g., not specific to any transmitter zone 110). Alternatively, in
some embodiments, a first set sensors of the one or more sensors
114 is part of a first transmitter zone 110-A, a second set sensors
of the one or more sensors 114 is part of a second transmitter zone
110-B, and so on. In such an arrangement, the various sets of
sensors provide respective sensor information to the one or more
processors 104, and the one or more processors 104 use the sensor
information to determine a location of the receiver 120 relative to
the one or more transmitter zones 110.
[0054] Non-limiting examples of transmitter sensors 114 include,
e.g., infrared, pyroelectric, ultrasonic, laser, optical, Doppler,
gyro, accelerometer, microwave, millimeter, RF standing-wave
sensors, resonant LC sensors, capacitive sensors, light sensor,
and/or inductive sensors, and a hall sensor. In some embodiments,
technologies for transmitter sensor(s) 114 include binary sensors
that acquire stereoscopic sensor data, such as the location of a
human or other sensitive object.
[0055] In some embodiments, memory 106 of the transmitter pad 100
stores one or more programs (e.g., sets of instructions) and/or
data structures, collectively referred to herein as "modules." In
some embodiments, memory 106, or the non-transitory computer
readable storage medium of memory 106 stores the following modules
107 (e.g., programs and/or data structures), or a subset or
superset thereof: [0056] information received from receiver 120
(e.g., generated by a sensor of the receiver 120 and then
transmitted to the transmitter pad 100, or generated by a
communications component of the receiver 120 (or the electronic
device coupled thereto) and then transmitted to the transmitter pad
100); [0057] information received from transmitter sensor(s) 114;
[0058] RF power transmission signals generation module for
generating and transmitting (e.g., in conjunction with respective
transmitter(s) 300) RF power transmission signals; and/or [0059] a
characteristic selection module for selecting waveform
characteristics of the RF power transmission signals.
[0060] The above-identified modules (e.g., data structures and/or
programs including sets of instructions) need not be implemented as
separate software programs, procedures, or modules, and thus
various subsets of these modules may be combined or otherwise
re-arranged in various embodiments. In some embodiments, memory 106
stores a subset of the modules identified above. Furthermore, the
memory 106 may store additional modules not described above. In
some embodiments, the modules stored in memory 106, or a
non-transitory computer readable storage medium of memory 106,
provide instructions for implementing respective operations in the
methods described below. In some embodiments, some or all of these
modules may be implemented with specialized hardware circuits that
subsume part or all of the module functionality. One or more of the
above-identified elements may be executed by one or more of the
processor(s) 104. In some embodiments, one or more of the modules
described with regard to memory 106 is implemented on memory of a
server (not shown) that is communicatively coupled to the
transmitter pad 100 and/or by a memory of electronic device and/or
receiver 120. In addition, memory 106 may store other information
such as certain thresholds and criteria, as well as identifiers of
certain receivers.
[0061] Turning to FIG. 1B, a simplified top view of the transmitter
pad 100 is illustrated. FIG. 1B shows a receiver 120 (e.g., a
receiver that is internally or externally coupled to an electronic
device) that is placed on top of the transmitter pad 100 and then
receives energy from one or more of the transmitters 300. In some
embodiments, the receiver 120 includes one or more antennas for
receiving energy (e.g., RF signals) from the transmitter pad 100
and a communications component for receiving communications (or
sending communications) sent by the transmitter pad 100. The
communications component of the receiver 120 may also include
hardware capable of data communications using the variety of
wireless protocols listed above with reference to the communication
component(s) 112.
[0062] The receiver 120 converts energy from received signals (also
referred to herein as RF power transmission signals, or simply, RF
signals, power waves, or power transmission signals) into
electrical energy to power and/or charge an electronic device
coupled to the receiver 120. For example, the receiver 120 uses
power-conversion circuitry to convert captured energy from power
waves (received via a wireless-power-receiver antenna) to
alternating current (AC) electricity or direct current (DC)
electricity usable to power and/or charge an electronic device.
Non-limiting examples of power-conversion circuitry can include
rectifiers, rectifying circuits, voltage conditioners, among
suitable circuitry and devices.
[0063] In some embodiments, the receiver 120 is a standalone device
that is detachably coupled to one or more electronic devices. For
example, the electronic device has processor(s) for controlling one
or more functions of the electronic device and the receiver 120 has
processor(s) for controlling one or more functions of the receiver
120. In some embodiments, the receiver 120 is a component of the
electronic device. For example, processor(s) of the electronic
device control functions of the electronic device and the receiver
120. In addition, in some embodiments, the receiver 120 includes
processor(s) which communicate with processor(s) of the electronic
device. It is noted that the combination of the receiver 120 and
the electronic device is sometimes referred to herein simply as a
"receiver device."
[0064] In some embodiments, the receiver 120 receives one or more
power waves directly from the transmitter pad 100 (and in
particular, from one or more of the transmitter(s) 300). In some
embodiments, the receiver 120 harvests power from one or more power
waves transmitted by transmitter pad 100. As will be discussed in
greater detail below, the one or more power waves are generated at
one or more different positions along a respective conductive wire
202-A of a respective transmitter 300 that is positioned within a
respective transmitter zone 110, and the generated one or more
power waves propagate away from the respective transmitter 300 in a
particular pattern. In some embodiments, the transmitter pad 100 is
a mid-field transmitter that transmits the one or more power waves
within a mid-field distance of its charging surface.
[0065] In some embodiments, after energy is harvested from the one
or more power waves (as discussed in greater detail below),
circuitry (e.g., integrated circuits, amplifiers, rectifiers,
and/or voltage conditioner) of the receiver 120 converts the energy
to usable power (i.e., electricity), which powers the electronic
device associated with the receiver 120 (and/or the usable power is
stored in a battery of electronic device). In some embodiments, a
rectifying circuit of the receiver 120 converts the electrical
energy from AC to DC for use by the electronic device. In some
embodiments, a voltage conditioning circuit increases or decreases
the voltage of the electrical energy as required by the electronic
device, and may produce a constant voltage for providing
electricity in a form required by the electronic device.
[0066] In some embodiments, a plurality of electronic devices may
be positioned on a surface of the transmitter pad 100, each having
at least one respective receiver 120 that is used to receive power
waves from the transmitter pad 100. In some embodiments, the
transmitter pad 100 adjusts one or more characteristics (e.g.,
waveform characteristics, such as phase, gain, amplitude,
frequency, etc.) of the power waves and controls which feeds of
respective transmitters 110 are activated to controllably form
propagation patterns of radio-frequency energy transmitter to each
of the respective receivers 120.
[0067] In some embodiments, the one or more transmitter zones 110
cover all or a portion of a surface area of the transmitter pad
100. The transmitter zones 110 may also form a top surface (i.e., a
charging surface) of the transmitter pad 100. Further, in some
embodiments, the one or more transmitter zones 110 and other
components 102 of the transmitter pad 100 may be encapsulated
within a plastic or other type of covering (e.g., a housing).
[0068] In some embodiments, circuits (not shown) of the transmitter
pad 100, such as a controller circuit and/or waveform generator,
may at least partially control the behavior of the transmitters
110. For example, based on the information received from the
receiver 120 by way of a communication signal (or data gathered by
transmitter sensor(s) 114), a controller circuit (e.g., controller
209, FIG. 2) may determine a set of one or more waveform
characteristics (e.g., amplitude, frequency, direction, phase,
among other characteristics) used for transmitting the power waves
that would effectively provide power to the receiver 120. The
controller circuit may also identify one or more transmitter zones
110 (and transmitters 300 included therein) that would be effective
in transmitting the power waves (e.g., receiver 120 may be
positioned between two transmitter zones 110, and in such a case,
respective transmitters 300 positioned within two transmitter zones
110 may be activated). Upon identifying the one or more transmitter
zones 110 and/or particular transmitters 300 positioned therein,
the controller circuit may also select a respective feed element of
one or more feed elements (e.g., one of the plurality of feed
elements 204-A-204-D, FIG. 2) from each of the transmitters 300
based on a location of the receiver device relative to the
plurality of feed elements. In doing so, the controller circuit may
send an instruction to a power amplifier of the one or more
transmitters 110 that causes the power amplifier to feed an RF
signal to the selected respective feed elements of the one or more
transmitters 110.
[0069] FIG. 2 is a schematic of a representative transmitter zone
110 in accordance with some embodiments. The representative
transmitter zone 110 is an example of one of the transmitter zones
110-A-110-N (FIG. 1B). The components in FIG. 2 are illustrated in
a particular arrangement for ease of illustration and one skilled
in the art will appreciate that other arrangements are possible.
Moreover, while some example features are illustrated, various
other features have not been illustrated for the sake of brevity
and so as not to obscure pertinent aspects of the example
implementations disclosed herein.
[0070] As a non-limiting example, the representative transmitter
zone 110 includes a transmitter 300 (which includes an antenna
element 202, a plurality of feeds 204-A, 204-B, . . . 204-N, and a
power amplifier 206 (or multiple power amplifiers)). The components
of the representative transmitter zone 110 are coupled via busing
108 or the components are directly coupled to one another.
Additionally, the representative transmitter zone 110 includes
switches 208-A, 208-B, . . . 208-N positioned between the power
amplifier 206 and each respective feed 204. In some embodiments,
instead of using switches to couple a single power amplifier 206
with multiple feeds 204, multiple power amplifiers may each be
coupled directly with a single feed 204 (or two power amplifiers
may each be coupled with one or more of the feeds via the switching
arrangement illustrated in FIG. 2). Other configurations of power
amplifiers and feeds are also within the scope of this disclosure,
as one of skill will readily appreciate upon reading the
descriptions herein.
[0071] In some embodiments, the power amplifier(s) 206 and any
switches 208 can be configured as part of the transmitter 300 (not
illustrated) while, in other embodiments, the power amplifier(s)
206 and any switches 208 can be configured as external to the
transmitter 300 and coupled to feeds of an antenna element 202 (as
illustrated in FIG. 2). In some embodiments, power amplifiers 206
may be shared across multiple transmitter zones 110.
[0072] The antenna element 202 is coupled with the plurality of
feeds 204-A, 204-B, . . . 204-N. In some embodiments (as shown in
FIG. 3B), the antenna element 202 is directly coupled with each of
the feeds 204-A, 204-B, . . . 204-N. The antenna element 202 is
used to radiate one or more RF signals that provide wirelessly
delivered power to a receiver 120. In some embodiments, the
radiated one or more RF signals are received by the receiver 120
when the receiver is located anywhere between a top surface of the
transmitter zone 110 and up to a wavelength of an operating
frequency of the transmitter 300 away from the transmitter zone 110
(e.g., the receiver 120 is within a mid-field transmission distance
of the transmitter 300). In some embodiments, the antenna element
202 is a conductive wire forming a loop antenna (e.g., a
substantially contiguous loop antenna). The antenna element 202 may
be made from a suitable material that is capable of conducting the
RF signals.
[0073] Each feed 204 is coupled with the antenna element 202 at a
different position (e.g., positions A-D, FIG. 3A) on the antenna
element 202. For example, the feed 204-A is coupled with the
antenna element 202 at a first position, the feed 204-B is coupled
with the antenna 202 at a second position, and so on. Each of the
plurality of feeds 204-A, 204-B, . . . 204-N provides the one or
more RF signals to be radiated by the antenna element 202 at a
particular position along the antenna element 202 (as explained in
more detail below). Each feed 204 may be made from any suitable
conductive material (e.g., aluminum, copper, etc.).
[0074] The power amplifier is used to selectively provide power to
one or more of the feeds 204-A, 204-B, . . . 204-N by closing one
or more of the switches 208-A, 208-B, . . . 208-N. The power
amplifier 206 may be instructed (e.g., by the controller 209) to
close a respective switch of the one or more of the switches 208-A,
208-B, . . . 208-N depending on a location of the receiver 120
relative to the plurality of feeds 204-A-204-D. Although not shown,
the one or more of the switches 208-A, 208-B, . . . 208-N may be
part of (e.g., internal to) the power amplifier. Operation of the
power amplifier is discussed in further detail below with reference
to the method 400.
[0075] In some embodiments, the power amplifier 206 is coupled with
a power supply (not shown), and the power amplifier 206 draws
energy from the power supply to provide RF signals to one or more
of the feeds 204-A, 204-B, . . . 204-N. Moreover, in some
embodiments (not shown), the power amplifier 206 is coupled with an
RF power transmitter integrated circuit (e.g., the RF integrated
circuit may be part of the transmitter zone 110 or more generally
part of the transmitter pad 100). The RF integrated circuit is
configured to generate a suitable RF signal and provide that RF
signal to the power amplifier 206, and the power amplifier 206 in
turn provides the RF signal to one or more of the feeds 204-A,
204-B, . . . 204-N. In some embodiments, the RF integrated circuit
includes an RF oscillator and/or a frequency modulator that is used
to generate the RF signal so that is appropriate for transmission
to an RF receiver 120 (e.g., the RF signal has an appropriate power
level, frequency, etc. to ensure that a maximum amount of energy is
transferred from the transmitter 300 to the RF receiver 120).
[0076] In some embodiments, the power amplifier 206 is coupled to
an internal or external (with respect to the transmitter pad 100)
controller 209, and in turn is coupled to the one or more
processors 104 (FIG. 1A). In some embodiments, the controller 209
and the one or more processors 104 are not part of a particular
transmitter zone 110 (e.g., the controller 209 is an internal
component of the transmitter pad 100 overall and is in
communication with each of the transmitter zones 110).
Alternatively, in some embodiments, respective controllers 209 and
respective one or more processors 104 are each internally
associated with each of the respective transmitter zones 110. The
controller 209 and the one or more processors 104 are configured to
control operation of the power amplifier 206. For example, the
controller 209 or the one or more processors 104 may select a
respective feed of the feed 204-A, 204-B, . . . 204-N based on the
location of the receiver 120 relative to the feeds 204-A, 204-B, .
. . 204-N. Further, the controller 209 may send an instruction to
the power amplifier 206 that causes the power amplifier 206 to feed
one or more RF signals to the respective feed that was selected
based on the location of the receiver.
[0077] In some embodiments, the controller 209 (or a component
thereof, e.g., the one or more processors 104) uses information
received by the one or more communication components 112 and/or
detected by the one or more transmitter sensors 114 to determine
the location of the receiver 120 relative to the feeds 204-A,
204-B, . . . 204-N. Determining the location of the receiver 120 is
discussed in further detail below with reference to the method
400.
[0078] FIGS. 3A-3B illustrate various views of a representative
transmitter 300 in accordance with some embodiments. The
transmitter 300 is an example wireless power transmitter included
in one of the transmitter zones 110 (FIG. 1A and FIG. 2). As shown,
the transmitter 300 includes a ground plate 210, an antenna element
202, and a plurality of feeds 204-A-204-D. It is noted that the
representative transmitter 300, and its various components, may not
be drawn to scale. Moreover, while some example features are
illustrated, various other features have not been illustrated for
the sake of brevity and so as not to obscure pertinent aspects of
the example implementations disclosed herein.
[0079] The ground plate defines a plurality of openings
212-A-212-D, where each of the plurality of openings 212-A-212-D is
sized to receive and accommodate one of the plurality of feeds 204.
The number of openings corresponds to the number of feeds. In some
embodiments, the ground plate 210 forms a bottom surface of the
transmitter pad 100. The ground plate 210 can be made from various
materials as known by those skilled in the art. As explained below,
the transmitter 300 can include any number of feeds, depending on
the circumstances.
[0080] The antenna element 202 is offset from the ground plate
(e.g., distance (D), FIG. 3B). In such an arrangement, the ground
plate 210 defines a first plane (e.g., a first horizontal plane:
the bottom surface) and the antenna element 202 defines a second
plane (e.g., a second horizontal plane: the top surface) that is
offset from the first plane. A gap is formed between the ground
plate 210 and the antenna element 202.
[0081] Each of the plurality of feeds 204-A-204-D is disposed in a
respective opening of the plurality of openings 212-A-212-D, and
each of the feeds 204-A-204-D connects to the antenna element 202
at a different position along the conductive wire 202-A. In such an
arrangement, the feeds 204-A-204-D support the antenna element 204
along a length of the antenna element 202. For example, with
reference to FIG. 3B, feeds 204-A and 204-B extend through their
respective openings 212-A and 212-B to the antenna element 202, and
in doing so, structurally support the antenna element 202. Each of
the plurality of feeds 204-A-204-D is substantially perpendicular
to the ground plate 210 and the antenna element 202 (e.g., each of
the plurality of feeds 204-A-204-D is disposed along a respective
vertical axis while the conductive plate and antenna element are
disposed along respective horizontal axes/planes). Although four
feeds are shown in FIG. 3A, the transmitter 300 can include any
number of feeds, depending on circumstances (e.g., could be less
than or greater than four feeds).
[0082] In some embodiments, the antenna element 202 includes a
plurality of contiguous segments 202-A-202-D, and each of the
plurality of feeds 204-A-204-D is positioned between a respective
pair of adjacent segments (e.g., positioned between abutting ends
of adjacent segments). For example, a first feed 204-A of the
plurality of feeds 204 is positioned between a third segment 202-C
and a fourth segment 202-D of the plurality of contiguous segments
(i.e., a first respective pair of adjacent segments), a second feed
204-B of the plurality of feeds 204 is positioned between the
fourth segment 202-D and a first segment 202-A of the plurality of
contiguous segments (i.e., a second respective pair of adjacent
segments), and so on. In such an arrangement, each of the plurality
of feeds 204-A-204-D is mechanically (and electrically) coupled
with two segments.
[0083] In some embodiments (not illustrated), a shape of each
segment in the plurality of contiguous segments 202-A-202-D is
substantially the same (e.g., each is rectangular or some other
shape). In some embodiments, a shape of at least one segment in the
plurality of contiguous segments 202-A-202-D differs from shapes of
other segments in the plurality of contiguous segments 202-A-202-D.
For example, segments 202-B and 202-D have a first shape (e.g., a
rectangle) and segments 202-A and 202-C have a second shape that
differs from the first shape. It is noted that various combinations
of shapes can be used to form the contiguous segments of antenna
element 202, and the shapes shown in FIG. 3A are merely
examples.
[0084] FIG. 3B is a cross-sectional view (taken along line A-A') of
the representative transmitter 300 of FIG. 3A in accordance with
some embodiments. Feeds 204-A and 202-B are directly coupled with
two segments of the antenna element 202 (although not shown, feeds
204-C and 204-D have the same arrangement). As shown in the
magnified view 311, the fourth segment 202-D is directly coupled
with the feed 204-B at a first connection point 312 and the first
segment 202-A is directly coupled with the feed 204-B at a second
connection point 314 (the other feeds are connected to respective
segments in an analogous fashion). In such an arrangement, when the
power amplifier 206 feeds an RF signal to the feed 204-B, the RF
signal travels along the feed 204-B and then travels through the
segments 202-A to 202-D of the antenna element 202.
[0085] Depending on which one of the feeds 204 is selected to be
fed by the power amplifier 206, the antenna element 202 is
configured to radiate RF energy with different propagation patterns
and concentrations. In some circumstances, a high concentration of
the radiated RF energy is created at a mid-field distance from the
selected feed(s). In some instances, the "high concentration" of RF
energy includes approximately 50 percent of the radiated energy,
although greater and lesser percentages can be achieved. For
example, with reference to FIG. 5A, when the power amplifier 206
feeds an RF signal to feed 204-C (shown schematically in FIG. 5A),
a high concentration of energy radiated by the transmitter 300 is
created at a mid-field distance D.sup.1 from the antenna 202. A
similar result is shown in FIG. 5B for activation of the feed
204-D.
[0086] In some embodiments, by activating one of the feeds (e.g.,
the feed 204-D in the above example), impedance changes may be
introduced at each of the feeds that are not activated (e.g., the
feeds 204-A, 204-B, and 204-C are not activated in the above
example, thereby introducing impedance along the antenna element at
respective points where these feeds contact the antenna element
202). The selective activation of different feeds may also help to
steer a direction along which the RF energy radiates away from the
transmitter 300. For example, as shown in FIG. 6A, when only feed
204-C is activated, then the RF energy radiates away from the
transmitter 300 in a substantially right-moving direction (from a
viewpoint facing the top surface of the transmitter 300 or a top
surface of a transmitter zone 110 in which the transmitter 300 is
positioned). As another example, as shown in FIG. 6B, when only
feed 204-D is activated, then the RF energy radiates away from the
transmitter 300 in a substantially left-moving direction (from a
viewpoint facing the top surface of the transmitter 300 or a top
surface of a transmitter zone 110 in which the transmitter 300 is
positioned). In this way, the transmitter 300 is configured in such
a way that radiation of the RF energy may be controlled to ensure
that a higher concentration of RF energy reaches a targeted
receiver 120 (which may be positioned up to a wavelength away from
the transmitter 300 or the transmitter zone 110 in which the
transmitter 300 is positioned).
[0087] The connection point arrangement illustrated in FIG. 3B is
merely one possible arrangement of the antenna element 202 and the
feeds 204. In an alternative embodiment, each feed 204-A-204-D may
be directly coupled with the antenna element 202 at a single
connection point. In this alternative embodiment, the antenna
element 202 is not divided into a plurality of contiguous segments
but is instead a continuous antenna element 202. Each feed
204-A-204-D, in this alternative embodiment, is only connected to
the continuous antenna element 202 at a respective second
connection point, and each respective second connection point is at
a different position along the conductive wire of the antenna
element 202.
[0088] As explained in greater detail below with reference to FIG.
4, the antenna element 202 is configured to radiate an RF signal
(or multiple RF signals) with different propagation patterns
depending on which of the plurality of feed elements 204 is fed by
the power amplifier 206 (FIG. 2). In some instances, physical
dimensions of the antenna element 202 (and other physical
dimensions of the transmitter 300) dictate (or at least partially
dictate) the resulting propagation patterns. The physical
dimensions include but are not limited to a width (W) of the
antenna element 202, a length (L3) of the antenna element 202, a
height (L1) of the antenna element 202, a length (L2) of one or
more segments of the antenna element 202, a thickness (T) of the
antenna element 202, a shape of the antenna element 202, and a
magnitude (D) of the offset between the ground plate 210 and the
antenna element 202.
[0089] In some embodiments, a value for each of the physical
dimensions is defined according to a wavelength (.lamda.) and a
frequency of the one or more RF signals to be radiated by the
antenna element 202. The transmitter pad 100 can include
transmitters 300 that are dimensioned to cause transmission of RF
signals at frequencies ranging from one or more of 400 MHz
(.lamda.=0.75 meters) to 60 GHz (.lamda.=0.005 meters), depending
on the application. Accordingly, when operating at a frequency of
900 MHz (.lamda.=0.333 meters), the width (W) of an example antenna
element 202 of a transmitter 300 is approximately 0.005994 meters
(i.e., approximately 6 mm), the height (L1) of the example antenna
element 202 is approximately 0.0333 meters (i.e., approximately 33
mm), the length (L3) of the example antenna element 202 is
approximately 0.11655 meters (i.e., approximately 116.5 mm), a
length (L2) of segment 202-B and segment 202-D of the example
antenna element 202 is approximately 0.04995 meters (i.e.,
approximately 50 mm), a magnitude (D) of the offset between the
ground plate 210 and the example antenna element 202 is
approximately 0.02331 meters (i.e., approximately 23.3 mm), a
length (L.sub.F) of each feed 204 of the example antenna element
202 is approximately 0.02731 meters (i.e., approximately 27.3 mm).
Moreover, a height and a length of the ground plate 210 of the
example antenna element 202 can be 0.04995 meters (i.e.,
approximately 50 mm) and 0.14985 meters (i.e., approximately 150
mm), respectively. In some embodiments, the thickness (T) is either
equal to or less than the width (W) of the example antenna element
202. One skilled in the art will appreciate that the dimensions
above are merely one example. Various other dimensions are
possible, depending on the circumstances.
Method of Operation
[0090] FIG. 4 is a flow diagram showing a method of wireless power
transmission in accordance with some embodiments. Operations (e.g.,
steps) of the method 400 may be performed by a controller of a
transmitter pad (e.g., controller 209 of transmitter pad 100, FIG.
2), the transmitter pad including one or more transmitter zones
(e.g., transmitter zones 110, FIGS. 1A-1B; which each include
respective one or more transmitters 300, FIG. 3A). At least some of
the operations shown in FIG. 4 correspond to instructions stored in
a computer memory or computer-readable storage medium (e.g., memory
106 of the transmitter pad 100, FIG. 1A).
[0091] The method 400 includes providing (402) a wireless power
transmitter (e.g., transmitter 300, FIG. 3A) including (i) a ground
plate (e.g., ground plate 210, FIG. 3A), (ii) a conductive wire
(e.g., antenna element 202, FIG. 3A) offset from the ground plate,
the conductive wire forming a loop antenna, (iii) a plurality of
feed elements (e.g., feeds 204-A-204-D, FIG. 3A) extending from the
ground plate to the conductive wire, each feed element being
connected to the conductive wire at a different position on the
conductive wire (e.g., positions A-D, FIG. 3A), and (iv) a power
amplifier (e.g., power amplifier 206, FIG. 2) connected to one or
more feed elements of the plurality of feed elements. In some
embodiments, the ground plate includes a plurality of openings
(e.g., openings 212-A-212-D, FIG. 3A), and each of the plurality of
feeds is disposed in a respective opening of the plurality of
openings (e.g., as shown in FIGS. 3A and 3B). Structural aspects of
the wireless power transmitter are discussed in further detail
above with reference to FIGS. 3A and 3B.
[0092] In some embodiments, the method 400 further includes
selecting (404), by a controller (e.g., controller 209 or a
component thereof, such as one or more processors 104, FIG. 2) of
the wireless power transmitter, a respective feed element of the
one or more feed elements based on a location of a receiver device
relative to the plurality of feed elements. For example, with
reference to FIG. 3A, if the receiver device is located nearest
feed element 204-A relative to the other feed elements 204-B-204-D,
then the controller selects the feed element 204-A. In some
circumstances, the receiver device is located between two or more
of the plurality of feed elements. In such circumstances, the
method 400 may include selecting, by the controller, at least two
feed elements based on a location of the receiver device relative
to the plurality of feed elements. Further, the controller may
select all of the plurality of feed elements in some instances.
[0093] In some embodiments, the method 400 further includes sending
(406), by the controller, an instruction to the power amplifier
that causes the power amplifier to feed the RF signal to the
respective feed element. For example, with reference to FIG. 2, if
the respective feed element is feed 204-A, then the controller 209
sends an instruction (e.g., via busing 108) that causes the power
amplifier to close the switch 208-A, and in turn feed the RF signal
to the feed 204-A.
[0094] In some embodiments, the wireless power transmitter includes
a communications radio (e.g., communications component 112, FIG.
1A), and the method 400 further includes receiving a communications
signal from a corresponding communications radio of the receiver
device. Further, the controller (or a component thereof) may
determine the location of the receiver device relative to the
plurality of feed elements based on the communications signal
(e.g., using information included with or indicated by the
communications signal). In some embodiments, the receiving and the
determining are performed prior to the selecting (404) and the
sending (406). In some embodiments, the controller determines the
location of the receiver device relative to the plurality of feed
elements based on signal strength of the communication signal,
triangulation, and/or response time (e.g., the receiver device
timestamps the communication signal when sent which is then
compared against a timestamp of the communication signal when it is
received at the wireless power transmitter). Additional location
determining techniques can also be used.
[0095] In some embodiments, the wireless power transmitter includes
one or more sensors (e.g., transmitter sensors 114, FIG. 1A), and
the method 400 further includes detecting, via the one or more
sensors, a presence of the receiver device. Further, the controller
(or a component thereof) may determine the location of the receiver
device relative to the plurality of feed elements based on
information generated by the one or more sensors. In some
embodiments, the detecting and the determining are performed prior
to the selecting (404) and the sending (406). In some embodiments,
the one or more sensors include one or more of a pressure sensor,
an infrared sensor, an electromagnetic sensor, an acoustic sensor,
a capacitive sensor, a light sensor, an inductive sensor, and a
hall sensor. As an example, a light sensor may detect a change in
light near the wireless power transmitter when the receiver device
is positioned on or proximate to the wireless power transmitter. In
another example (in addition to or separated from the previous
example), an infrared sensor may detect a change in temperature
near the wireless power transmitter when the receiver device is
positioned on or proximate to the wireless power transmitter. In
some embodiments, information collected from multiple sensors can
be used to determine the location of the receiver device.
[0096] In some embodiments, each of the plurality of feeds is
associated with a respective sensor (e.g., the respective sensor is
positioned near (or perhaps on) the feed and the respective sensor
takes readings near the feed). In this way, readings from each of
the sensors can be compared (e.g., by the one or more processors
104), and the controller may determine the location of the receiver
device relative to the plurality of feed elements based on the
comparing. For example, if a largest change in light occurs at feed
204-A relative to changes in light occurring at the other feeds,
then the controller can determine that the receiver device is
located closest to the feed 204-A.
[0097] In some embodiments, the controller determines the location
of the receiver device relative to the plurality of feed elements
using two or more forms of information (e.g., signal strength in
combination with a thermal imaging data, or some other combination
communications-based and sensor-based information).
[0098] The method 400 further includes selectively feeding (408),
by the power amplifier, an RF signal to the respective feed element
of the one or more feed elements based on the location of a
receiver device relative to the plurality of feed elements. For
example, with reference to FIG. 3A, a first feed element 204-A of
the one or more feed elements 202-A-202-D is connected to the
conductive wire 202 at a first position (e.g., position A) and a
second feed element 202-B, distinct from the first feed element
202-A, of the one or more feed elements 202-A-202-D is connected to
the conductive wire 202 at a second position (e.g., position B). In
such a configuration, the power amplifier: (i) may feed the RF
signal to the first feed element when the location of the receiver
device is within a threshold distance from the first position, and
(ii) may feed the RF signal to the second feed element when the
location of the receiver device is within the threshold distance
from the second position. In some embodiments, feeding the RF
signal to the one or more feed elements includes feeding the RF
signal to two of the plurality of feed elements upon determining
that the location of the receiver device is between the two feed
elements.
[0099] In some embodiments, the selective-feeding operation (408)
is performed in response to the power amplifier receiving the
instruction from the controller.
[0100] The method 400 further includes (i) exciting (410), by the
respective feed element fed by the power amplifier, the conductive
wire and then (ii) radiating (412), by the conductive wire, the RF
signal for wirelessly powering the receiver device. The conductive
wire may radiate the RF signal from the conductive wire with
different propagation patterns depending on which of the plurality
of feed elements is fed by the power amplifier. For example, the
conductive wire radiates the RF signal from the conductive wire in
a first propagation pattern of the different propagation patterns
when a first feed element of the one or more feed elements is fed
by the power amplifier. In this example, a high concentration of
radiated RF energy in the first propagation pattern is created at a
mid-field distance away from the feed 204-C. In some instances, the
"high concentration" of RF energy includes approximately 50 percent
of the radiated energy, although greater and lesser percentages can
be achieved. Also, a concentration of RF energy in the first
propagation pattern forms around the first feed element and the
first propagation pattern propagates away from the first feed
element in a first direction (or a set of first directions) towards
the location of the receiver device. To illustrate, with reference
to FIG. 5A, a high concentration of radiated RF energy 504 is
created at a mid-field distance (e.g., distance D.sup.1) away from
the feed 204-C. Moreover, with reference to FIG. 6A, the resulting
propagation pattern 600 of RF energy from feeding the RF signal to
the feed 204-C moves substantially rightward to cause the RF energy
to travel towards the location of a receiver device, which in this
example would be positioned at the mid-field distance. In this way,
the method 400 allows for selectively activating individual feed
elements of a loop antenna to ensure that RF energy is propagated
in such a way that a sufficiently high concentration of the RF
energy is optimally propagated towards a location of a receiver
device.
[0101] In another example, the conductive wire may radiate the RF
signal in a second propagation pattern of the different propagation
patterns when a second feed element of the one or more feed
elements is fed by the power amplifier. In this example, a high
concentration of RF energy in the second propagation pattern is
created at a mid-field distance away from the feed 204-D. Also, a
concentration of RF energy in the second propagation pattern forms
around the second feed element and the second propagation pattern
propagates away from the second feed element in a second direction
(or a set of second directions) towards a location of the receiver
device. To illustrate, with reference to FIG. 5B, a high
concentration of RF energy 514 is created at a mid-field distance
away from the feed 204-D (e.g., distance D.sup.2). Moreover, with
reference to FIG. 6B, the resulting propagation pattern 610 from
feeding the RF signal to the feed 204-D causes movement of the RF
energy in a substantially leftward direction to cause the RF energy
to travel towards a second location of the receiver device, which
in this example would be positioned at the mid-field distance.
[0102] In some embodiments, the wireless power transmitter is
configured such that in use the first propagation pattern has a
first polarization and the second propagation pattern has a second
polarization. In some embodiments, the second polarization differs
from the first polarization.
[0103] In some embodiments, the different propagation patterns are
based, at least in part, on a plurality of physical dimensions of
the wireless power transmitter. The plurality of physical
dimensions may include but is not limited to: (i) a width of the
conductive wire (e.g., width (W), FIG. 3A), (ii) a length of the
conductive wire (e.g., length (L3), FIG. 3A), (iii) a height of the
conductive wire (e.g., height (L1), FIG. 3A), (iv) a thickness of
the conductive wire (e.g., thickness (T), FIG. 3B), (v) a shape of
the loop, and (vi) a magnitude of the offset between the ground
plate and the conductive wire (e.g., offset (D), FIG. 3B). Physical
characteristics of the conductive wire (e.g., the antenna element
202) are discussed in further detail above with reference to FIGS.
3A and 3B.
[0104] In some embodiments, the conductive wire includes a
plurality of contiguous segments (e.g., segments 202-A-202-D, FIG.
3A), and each of the plurality of feed elements is positioned
between a respective pair of adjacent segments of the plurality of
contiguous segments (e.g., feed 204-A is positioned between
segments 202-C and 202-D). Further, in some embodiments, one or
more first segments of the plurality of contiguous segments have a
first shape and one or more second segments of the plurality of
contiguous segments have a second shape different from the first
shape. In some embodiments, each of the plurality of contiguous
segments radiates the RF signal when one of the plurality of feed
elements is fed by the power amplifier. The plurality of contiguous
segments is discussed in greater detail above with reference to
FIGS. 3A-3B.
[0105] FIGS. 5A-5B show various power distributions from a
transmitter (e.g., transmitter 300, FIG. 3A) in accordance with
some embodiments. In FIG. 5A, when a feed 204-C is activated (e.g.,
fed by the power amplifier 206), the feed 204-C excites the antenna
element 202 and the antenna element 202 radiates an RF signal
having the illustrated power distribution 503. The power
distribution 503 illustrates concentrations of the RF signal at a
mid-field distance (D.sup.1) from the antenna element 202. As
shown, the RF signal has a high concentration 504 at the mid-field
distance (D.sup.1) from the antenna element 202 (and more
particularly, the feed 204-C). In FIG. 5B, when a feed 204-D is
activated (e.g., fed by the power amplifier 206), the feed 204-D
excites the antenna element 202 and the antenna element 202
radiates an RF signal having the illustrated power distribution
513. As illustrated in the power distribution 513, the RF signal
has a high concentration 514 at a mid-field distance (D.sup.2) from
the antenna element 202 (and more particularly, the feed 204-D). In
some instances, a "high concentration" includes approximately 50
percent of the radiated RF energy.
[0106] FIGS. 6A-6B show various propagation patterns 600 and 610
radiating from a transmitter in accordance with some embodiments.
The propagation patterns 600 and 610 shown in FIGS. 6A-6B
correspond to the power distributions shown and described in FIGS.
5A-5B. For example, the propagation pattern 600 results from the
feed 204-C being activated and the propagation pattern 610 results
from the feed 204-D being activated. As described above with
reference to the method 400, the transmitter is configured such
that a concentration of RF energy in a first propagation pattern
may propagate in a first direction (or a first set of directions)
and a concentration of RF energy in a second propagation pattern
may propagate in a second direction (or a second set of
directions). For example, the propagation pattern 600 points
substantially to the right, at least for portions of the
propagation pattern 600 having a high concentration of RF energy,
whereas the propagation pattern 610 points substantially to the
left, at least for portions of the propagation pattern 610 having a
high concentration of RF energy. Accordingly, when a receiver 120
is positioned, e.g., to the right of the transmitter, and is within
a predefined distance from the transmitter (e.g., within a
mid-field distance from the transmitter), the transmitter can
selectively activate one of its feeds to direct RF energy to the
right of the transmitter.
[0107] In some embodiments, the transmitter dynamically adjusts a
shape and/or direction of the propagation patterns 600 and 610 by
changing one or more characteristics of the RF signal. For example,
the one or more characteristics may include but are not limited to
frequency, gain, amplitude, and phase. In doing so, with reference
to the propagation pattern 600, the transmitter may adjust one or
more of the one or more characteristics so that the propagation
pattern 600 points more right or less right (or perhaps more up or
down, or a combination thereof). The transmitter may adjust the
shape and/or direction of a propagation pattern depending on a
location of the receiver 120 relative to the one or more feeds of
the transmitter. Additionally, the physical dimensions of the
transmitter impact the resulting propagation patterns 600 and 610
(e.g., an antenna element having a first width (W) may tend to
create a first propagation pattern and an antenna element having a
second width (W) may tend to create a second propagation pattern
different from the first propagation pattern). The various other
dimensions discussed above with reference to FIGS. 3A-3B may also
impact the resulting propagation patterns 600 and 610.
Method of Fabrication
[0108] A method of fabricating a wireless power transmitter (e.g.,
transmitter 300, FIG. 3A) includes providing a ground plate (e.g.,
ground plate 210, FIG. 3A) and removing material from the ground
plate to define one or more openings (e.g., holes) in the ground
plate (e.g., openings 212-A-212-D). The one or more openings being
sized to receive feed elements (e.g., feeds 204-A-204-D). In some
embodiments, the removing is performed using a drilling operation.
The method further includes disposing/attaching a feed in each of
the one or more openings such that the wireless power transmitter
includes one or more feeds. In some embodiments, each of the feeds
is mechanically and/or chemically (e.g., using an adhesive)
attached to its respective opening. The one or more feeds are
substantially perpendicular to the ground plate and extend away
from the ground plate, as shown in FIG. 3B. The method further
includes attaching an antenna element (e.g., antenna element 202)
to the one or more feeds. In some embodiments, the antenna element
is mechanically and/or chemically attached to the feeds. Connection
points between the antenna element and feed elements are discussed
in further detail above with reference to FIG. 3B. The antenna
element may be offset from the ground plate by a distance (e.g.,
magnitude (D) of the offset, FIG. 3B). In some embodiments, the
antenna element is substantially parallel to the ground plate.
[0109] In some embodiments, one or more wireless power transmitters
are fabricated using the method above, and grouped together to form
a transmission pad 100 (i.e., an array of wireless power
transmitters). In some embodiments, the ground plate may be a
single ground plate used by the one or more wireless power
transmitters. Alternatively, in some embodiments, each of the one
or more wireless power transmitters has a distinct ground plate. An
array of wireless power transmitters may be formed by positioning
each of the wireless power transmitters within respective
transmitter zones, and then interconnecting components of each of
the transmitter zones with a common controller for the transmitter
pad.
[0110] The terminology used in the description of the invention
herein is for the purpose of describing particular embodiments only
and is not intended to be limiting of the invention. As used in the
description of the invention and the appended claims, the singular
forms "a," "an," and "the" are intended to include the plural forms
as well, unless the context clearly indicates otherwise. It will
also be understood that the term "and/or" as used herein refers to
and encompasses any and all possible combinations of one or more of
the associated listed items. It will be further understood that the
terms "comprises" and/or "comprising," when used in this
specification, specify the presence of stated features, steps,
operations, elements, and/or components, but do not preclude the
presence or addition of one or more other features, steps,
operations, elements, components, and/or groups thereof.
[0111] The foregoing description, for purpose of explanation, has
been described with reference to specific embodiments. However, the
illustrative discussions above are not intended to be exhaustive or
to limit the invention to the precise forms disclosed. Many
modifications and variations are possible in view of the above
teachings. The embodiments were chosen and described in order to
best explain the principles of the invention and its practical
applications, to thereby enable others skilled in the art to best
utilize the invention and various embodiments with various
modifications as are suited to the particular use contemplated.
* * * * *