U.S. patent application number 17/521632 was filed with the patent office on 2022-03-03 for planar flexible rf tag and charging device.
The applicant listed for this patent is ISOLYNX, LLC. Invention is credited to Alexander T. Farkas.
Application Number | 20220069436 17/521632 |
Document ID | / |
Family ID | |
Filed Date | 2022-03-03 |
United States Patent
Application |
20220069436 |
Kind Code |
A1 |
Farkas; Alexander T. |
March 3, 2022 |
PLANAR FLEXIBLE RF TAG AND CHARGING DEVICE
Abstract
A planar flexible ultra-wide band (UWB) RF antenna includes a
flexible non-electrically-conductive substrate and at least one
antenna patch having electrically conductive metal positioned on
one side of the flexible non-electrically-conductive substrate and
having geometry defining a wirelessly transmitted UWB signal. The
antenna may electrically couple with an RF transmitter circuit
formed on a second side of the flexible substrate and controlled by
a microcontroller circuit, formed on the second side, to transmit a
radio signal. The RF tag may include at least one decoupling
circuit directly electrically connected to the RF antenna and
having a decoupling frequency that is different from a transmitting
frequency of the antenna. The decoupling circuit transfers power
from the antenna when the antenna receives capacitive power from an
external non-electrical contact charger operating at the decoupling
frequency and having at least one plate of similar geometry to the
at least one antenna patch.
Inventors: |
Farkas; Alexander T.;
(Chatham, MA) |
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Applicant: |
Name |
City |
State |
Country |
Type |
ISOLYNX, LLC |
Haverhill |
MA |
US |
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|
Appl. No.: |
17/521632 |
Filed: |
November 8, 2021 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15648315 |
Jul 12, 2017 |
11171405 |
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17521632 |
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62361359 |
Jul 12, 2016 |
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International
Class: |
H01Q 1/22 20060101
H01Q001/22; H01Q 9/28 20060101 H01Q009/28; H02J 50/20 20060101
H02J050/20; H02J 50/00 20060101 H02J050/00; H01Q 21/06 20060101
H01Q021/06; H01Q 1/27 20060101 H01Q001/27 |
Claims
1. A dual-purpose antenna, comprising: first and second antenna
elements that are electrically conductive and configured to: (i)
one or both of transmit and receive a wireless signal at a
transmission frequency, the first and second antenna elements
having a propagation pattern defined by an antenna geometry of the
first and second antenna elements, and (ii) receive a charging
signal capacitively-coupled across a first capacitor formed in part
with the first antenna element and a second capacitor formed in
part with the second antenna element.
2. The dual-purpose antenna of claim 1, the antenna geometry
including: a size and shape of each of the first and second antenna
elements; and a spacing between the first and second antenna
elements.
3. The dual-purpose antenna of claim 1, further comprising a
non-electrically-conductive substrate, the first and second antenna
elements being located on a surface of the
non-electrically-conductive substrate.
4. The dual-purpose antenna of claim 3, the
non-electrically-conductive substrate being flexible.
5. The dual-purpose antenna of claim 1, the first and second
antenna elements comprising metal patches.
6. A wireless device, comprising: the dual-purpose antenna of claim
1; a first decoupling circuit electrically coupled to the first
antenna element and operable to decouple the charging signal at a
charging frequency less than the transmission frequency; and a
second decoupling circuit electrically coupled to the second
antenna element and operable to decouple the charging signal at the
charging frequency.
7. The wireless device of claim 6, further comprising: a first full
wave rectifier half electrically coupled to the first decoupling
circuit; a second full wave rectifier half electrically coupled to
the second decoupling circuit; and a regulator circuit electrically
coupled to outputs of the first and second full wave rectifier
halves to regulate rectified electrical power outputted by the
first and second full wave rectifier halves.
8. The wireless device of claim 7, further comprising a
rechargeable battery for storing energy outputted by the regulator
circuit.
9. A charging device for charging the wireless device of claim 6,
the charging device comprising: a dielectric layer; first and
second metal plates located on the dielectric layer and having a
charger geometry corresponding to the antenna geometry; a variable
oscillator; a first inductor electrically coupled to the first
metal plate and a first output of the variable oscillator; a second
inductor electrically coupled to the second metal plate and a
second output of the variable oscillator; and a microcontroller,
electrically coupled to the variable oscillator, that controls the
variable oscillator to drive the first and second metal plates to
capacitively couple the charging signal to the first and second
antenna elements.
10. The charging device of claim 9, further comprising a current
sensor that is electrically coupled with the microcontroller and
senses current through one or both of the first and second
inductors; wherein the microcontroller, based on the sensed
current, controls the variable oscillator to operate at a resonance
frequency determined in part by the first and second capacitors.
Description
RELATED APPLICATIONS
[0001] This application is a divisional of U.S. patent application
Ser. No. 15/648,315, filed Jul. 12, 2017, which claims priority to
U.S. Provisional Patent Application No. 62/361,359, filed Jul. 12,
2016. Each of these applications is incorporated herein by
reference in its entirety.
BACKGROUND
[0002] Historically, ultra-wide band (UWB) radio-frequency (RF)
tracking tags that operate within the RF tracking space have faced
significant barriers to adoption due to the geometry and weight of
these RF tracking tags that resulted from the need to generate a
propagation pattern (shape and range) necessary for use in large
sporting venues (e.g., a National Football League (NFL) stadium).
Specifically, the need for an antenna with three-dimensional (3D)
geometry and a battery of sufficient power to meet the transmission
needs has resulted in a minimum size and weight of the RF tracking
tag, even when optimized, that is still obtrusive when configured
with athletic equipment. The use of anything other than an 3D
antenna for RF tracking tags has not been considered.
[0003] Given the 3D structure of the antenna and the size and
weight of the battery, the RF tracking tag is made to be
mechanically rigid, typically having a hard enclosure to provide
protection to the antenna, electronics and battery. Although this
enclosure is protective, its rigid nature also makes it fragile
when exposed to bending forces since it breaks rather than
flexes.
[0004] All known microwave patch antennas are driven "single ended"
or "unbalanced" and most have propagation patterns biased
unidirectionally toward the normal axis of the patch. Thus, type of
biased propagation pattern is not suitable for use within RF
tracking tags. Further, RF tracking tag transceiver input and
output circuits are often "balanced" or "differential" or
"complementary" owing to the internal structure of the integrated
circuit technology. Therefore, to use the traditional microwave
patch antenna, a "balun" (balanced-to-unbalanced converter) is
required to translate balanced to unbalanced (single-ended) RF
currents for delivery to the traditional microwave patch antenna.
The balun causes loss that results in reduced transceiver
performance and reduced operational range, or requires additional
power and associated size increase of a battery providing the
power, making the microwave patch antenna even less suitable for
use in RF tracking tags.
SUMMARY
[0005] When using electronic ultra-wide band (UWB) radio-frequency
(RF) tags to track individuals, such as athletes, it is necessary
to make the electronics as small, unobtrusive and robust as
possible, while maintaining performance of the UWB RF tags. The
embodiments hereof include a real-time location system RF Tag that
has a flat, flexible, and waterproof form factor that is ideal for
integration into athletic uniforms, equipment and other clothing.
Embodiments include nonelectrical contact rechargeable battery
system and an antenna with a propagation pattern optimized for
sports tracking. Within the document is also a description of the
external battery charger.
[0006] In one embodiment, a planar flexible UWB RF antenna includes
a flexible non-electrically-conductive substrate and an antenna
patch having electrically conductive metal positioned on one side
of the flexible non-electrically-conductive substrate and having
geometry defining a wirelessly transmitted UWB signal.
[0007] In another embodiment, a planar complementary patch antenna
includes a flexible non-electrically-conductive substrate, first
and second antenna patches positioned apart from each other on one
side of the flexible non-electrically-conductive substrate, and a
differential input having (a) a first feed element electrically
coupled directly to only the first antenna patch and (b) a second
feed element electrically coupled directly to only the second
antenna patch, the differential input being drivable from a
differential output of an RF transmitter circuit to generate a
wireless signal from the complementary patch antenna.
[0008] In another embodiment, a dual-purpose antenna includes a
first electrically conductive metal antenna element and a second
electrically conductive metal antenna element configured such that:
the dual-purpose antenna transmits a wireless signal at
transmission frequency and propagation pattern defined by geometry
of the first and second antenna elements, and the dual-purpose
antenna receives, without electrical contact, capacitive power
across two different capacitors each formed in part by a different
one of the first and second antenna elements.
[0009] In another embodiment, a planar flexible RF tag for use in a
real-time location system includes a flexible substrate, at least
one antenna patch formed on a first side of the flexible substrate,
an RF transmitter circuit electrically coupled to the at least one
antenna patch and formed on a second side of the flexible
substrate, and a microcontroller circuit formed on the second side
and electrically coupled to control the RF transmitter circuit to
drive the at least one antenna patch to transmit a radio
signal.
[0010] In another embodiment, a planar flexible RF tag for use in a
real-time location system includes a flexible substrate, first and
second antenna patches formed as complementary plates on a first
side of the flexible substrate, an RF transmitter circuit
electrically coupled to the first and second antenna patches and
formed on a second side of the flexible substrate, a
microcontroller circuit formed on the second side and electrically
coupled to control the RF transmitter circuit to drive the first
and second antenna patches to transmit a radio signal, and a
battery for powering the RF transmitter circuit and the
microcontroller circuit.
[0011] In another embodiment, a planar UWB patch antenna for
receiving electrical power includes a non-electrically-conductive
substrate, first and second antenna patches positioned on a first
surface of the non-electrically-conductive substrate and having a
geometry to transmit an UWB wireless signal, a first decoupling
circuit directly electrically connected to the first antenna patch
and having a decoupling frequency that is different from a
transmitting frequency of the UWB wireless signal, and a second
decoupling circuit directly electrically connected to the second
antenna patch and having the same decoupling frequency as the first
decoupling circuit. The first and second decoupling circuits
transfer power from the first and second antenna patches when the
first and second antenna patches receive capacitive power from an
external non-electrical contact charger operating at the decoupling
frequency and having two metal plates of similar geometry to the
first and second antenna patches and that are positioned proximate
and aligned with the first and second antenna patches.
[0012] In another embodiment, a charging device for a flexible
planar RF tag that has a rechargeable battery and two antenna
patches includes a dielectric layer, first and second metal plates
formed on the dielectric layer and having geometry corresponding to
geometry of the two antenna patches, a variable oscillator, a first
inductor electrically coupled to the first metal plate and a first
output of the variable oscillator, a second inductor electrically
coupled to the second metal plate and a second output of the
variable oscillator, and a microcontroller electrically coupled to
the variable oscillator. When positioned such that the first and
second metal plates are adjacent and aligned with the two antenna
patches with the dielectric layer therebetween, the microcontroller
is configured to control the variable oscillator to drive the first
and second metal plates and transfer power to the flexible planar
RF tag.
BRIEF DESCRIPTION OF THE FIGURES
[0013] FIG. 1 is a schematic illustrating one exemplary planar
flexible RF tag, in an embodiment.
[0014] FIG. 2 is a perspective view of the planar flexible RF tag
of FIG. 1, in an embodiment.
[0015] FIG. 3 shows a cross section A-A of the planar flexible RF
tag of FIGS. 1 and 2, in an embodiment.
[0016] FIG. 4 is a schematic illustrating one example planar
flexible RF tag, in embodiments.
[0017] FIG. 5 is a schematic illustrating one example charging
device for charging the rechargeable battery of the planar flexible
RF tag of FIG. 4, in an embodiment.
[0018] FIG. 6 is a top view of the planar flexible RF tag of FIG.
4, in an embodiment.
[0019] FIG. 7 shows a cross section B-B of the planar flexible RF
tag of FIGS. 4 and 6 and a cross section of the charging device of
FIG. 5, in embodiment.
[0020] FIG. 8 shows, in cross section, the charging device of FIGS.
5 and 7 positioned to charge the rechargeable battery of the planar
flexible RF tag of FIGS. 4, 6 and 7, in embodiments.
[0021] FIG. 9 shows a propagation pattern for the planar
complementary antenna patches of FIG. 4, in embodiments.
[0022] FIG. 10 is an image showing exemplary layout of the planar
complementary antenna patches of FIG. 4, in one embodiment.
[0023] FIG. 11 shows exemplary positioning of two planar flexible
RF tags of FIGS. 4, 6, and 7 on an American football player to
illustrate exemplary orientation of the planar flexible RF tags
relative to the player, in an embodiment.
[0024] FIGS. 12 and 13 show the player of FIG. 11 on an American
football field illustrating exemplary propagation of transmissions
from the planar flexible RF tags configured with the player, in an
embodiment.
DETAILED DESCRIPTION
[0025] FIG. 1 is a schematic illustrating one exemplary planar
flexible RF tag 100 for use with a real-time location system.
Planar flexible RF tag 100 includes one antenna patch 102 that
electrically connects to a balun 104 that in turn electrically
connects to a differential output 123 of an RF transceiver circuit
122. A rechargeable battery 112 provides power to RF transceiver
circuit 122 and to a microcontroller circuit 120. In one
embodiment, RF transceiver circuit 122 may be implemented as only a
transmitter. Microcontroller circuit 120 controls RF transceiver
circuit 122 via one or more electrical connections. Planar flexible
RF tag 100 includes a connector 114 for charging rechargeable
battery 112, and may further include a charging regulator circuit
110 to regulate electrical power received from connector 114 to
charge rechargeable battery 112.
[0026] In one embodiment, electrical power is regulated prior to
connector 114, wherein charging regulator circuit 110 is omitted.
Antenna patch 102, rechargeable battery 112, microcontroller
circuit 120, RF transceiver circuit 122 and charging regulator
circuit 110 may be enclosed within a permanently sealed enclosure
130 that is waterproof, wherein connector 114 is configured with
enclosure 130 to allow charging of rechargeable battery 112 without
opening of enclosure 130. For example, connector 114 may be a
waterproof type electrical connector that is permanently sealed
within an orifice of enclosure 130, such that enclosure 130 is
waterproof irrespective of whether connector 114 is in use. In
another embodiment, connector 114 is external to enclosure 130,
which is sealed around the electrical connections running between
connector 114 and charging regulator circuit 110 and/or
rechargeable battery 112. In one embodiment, charging regulator
circuit 110 and connector 114 are omitted and rechargeable battery
112 is replaced with a one-time use, long life, flexible
battery.
[0027] FIG. 2 is a perspective view of the planar flexible RF tag
100 of FIG. 1, in an embodiment. Planar flexible RF tag 100 is
shown within a permanently sealed enclosure 130 that is for example
a permanently sealed, thin flexible plastic packaging that allows
for inclusion of planar flexible RF tag 100 into pockets of, and/or
sewn into, clothing, uniform fabric, and other attire of the
individual. For example, enclosure 130 may include provision for
attachment such as areas for sewing, loops, button holes, and the
like. The sealed nature of enclosure 130 allows for operation of
planar flexible RF tag 100 in wet or dirty conditions as well as
being amenable to washing. For example, additional sealing 204 may
be used proximate and/or around connector 114 to prevent ingress of
moisture. Antenna patch 102 and electrical components of planar
flexible RF tag 100 are positioned on a flexible substrate 202 that
is contained by enclosure 130, such that planar flexible RF tag 100
is pliable. In one embodiment, antenna patch 102 is formed of
conductive metal positioned on one side of flexible substrate 202,
which is non-electrically-conductive, and antenna patch 102 has
geometry defining transmission of a wireless UWB signal. The
geometry of antenna patch 102 is selected to transmit the wireless
UWB signal with a propagation pattern suitable for use in a
real-time location system. Although shown as rectangular, the
geometry of antenna patch 102 is selected to obtain the desired
propagation pattern and transmit at a desired frequency. FIG. 2
also shows an orientation reference 210 that is relative to the
physical embodiment of planar flexible RF tag 100. However, planar
flexible RF tag 100 may have no orientation restrictions when
geometry of antenna patch 102 is symmetrical (e.g., square).
[0028] FIG. 3 shows a cross section A-A of the planar flexible RF
tag 100 of FIGS. 1 and 2, in an embodiment. Antenna patch 102 is
positioned on a first side of a flexible substrate 202, and
electrical components 302 including balun 104, charging regulator
circuit 110 (if included), microcontroller circuit 120, and RF
transceiver circuit 122, and rechargeable battery 112 are
positioned on a second side, opposite the first side, of flexible
substrate 202 as shown. Rechargeable battery 112 is flat and
flexible. In one embodiment, rechargeable battery 112 is a thin
flexible rechargeable lithium polymer battery from BrightVolt Inc.
Flexible substrate 202, antenna patch 102, components 302, and
rechargeable battery 112 are all contained within enclosure 130.
Planar flexible RF tag 100 is thus thin and flexible in format
allowing it to be used in place of conventional RF tags and further
where the hard-potted enclosure of conventional RF tags prohibit
their use.
[0029] FIG. 4 is a schematic illustrating one exemplary planar
flexible RF tag 400. Planar flexible RF tag 400 includes two
antenna patches 402(1), (2), each electrically connected to its own
decoupling circuit 404(1), (2) that in turn electrically connects
to its own full wave rectifier half 406 and 407, respectively.
Antenna patches 402(1) and 402(2) cooperate to form a planar
complementary patch antenna 403 that has a differential input 401.
Full wave rectifier halves 406 and 407 each include two Schottky
diodes 408(1)-(4) that are configured as shown in FIG. 4 to form a
full wave rectifier having an output that electrically connects to
a charging regulator circuit 410. Output from charging regulator
circuit 410 electrically connects with a rechargeable battery 412.
Rechargeable battery 412 provides power to a microcontroller
circuit 420 and an RF transceiver circuit 422. In one embodiment,
RF transceiver circuit 422 may implement only the transmitter. RF
transceiver circuit 422 has a differential output 423 that has two
balanced outputs that each connect to a different input of
differential input 401 of planar complementary patch antenna 403.
That is, outputs of RF transceiver circuit 422 each independently
electrically connect to a different one of antenna patches 402(1)
and 402(2). Microcontroller circuit 420 controls RF transceiver
circuit 422 via one or more electrical connections. Antenna patches
402, decoupling circuits 404, full wave rectifier halves 406, 407,
charging regulator circuit 410, rechargeable battery 412,
microcontroller circuit 420 and RF transceiver circuit 422 may be
enclosed within a permanently sealed enclosure 430 that is
waterproof.
[0030] FIG. 5 is a schematic illustrating one example charging
device 500 for charging rechargeable battery 412 of planar flexible
RF tag 400 of FIG. 4. Charging device 500 includes two metal
charging plates 502(1) and 502(2) that are each electrically
coupled to a different output of a variable oscillator 506 via one
of two inductors 504(1) and 504(2). Metal charging plates 502 are
each of a similar size and shape to a corresponding one of antenna
patches 402(1) and 402(2). A frequency of variable oscillator 506
is controlled by a microcontroller 510 based upon a current through
inductor 504(2) that is sensed by a current sensor 512. Since metal
charging plates 502 and planar complementary patch antenna 403 are
balanced, current through inductor 504(1) is assumed to be similar
to current through inductor 504(2) and therefore is not measured.
Variable oscillator 506 operates at a frequency (e.g., in an
unlicensed ISM band--13.53 MHz) that is much lower than the RF
operating frequency of antenna patches 402. Metal charging plates
502 are sized and positioned on a dielectric substrate 514.
[0031] Charging device 500 operates as an external non-electrical
contact charger for charging rechargeable battery 412 of planar
flexible RF tag 400. In one embodiment, metal charging plates 502
have identical geometry to antenna patches 402 and are printed onto
dielectric substrate 514 which functions to separate metal charging
plates 502 from antenna patches 402 during charging. Charging
device 500 has a flat side which is placed in very close proximity
and in registration to antenna patches 402 to form a set of two
"effective" capacitors. The capacitors couple the low frequency RF
currents (herein also referred to as capacitive power) from the
charging device 500 to antenna patches 402 within planar flexible
RF tag 400. Circuitry of charging device 500 includes a matching
set of inductors in series with the effective capacitors formed by
metal charging plates 502, dielectric substrate 514, and antenna
patches 402. The value of these inductors is calculated to be
resonant with the effective capacitors at the charging frequency to
allow for maximum efficiency for transfer of the maximum power and
thereby a lowest time to charge rechargeable battery 412 of planar
flexible RF tag 400. Microcontroller 510 within charging device 500
uses current sensor 512 to sense the AC RF current draw and
adjusts, under closed loop control, the RF frequency of variable
oscillator 506 to the exact resonance frequency for the effective
capacitors.
[0032] FIG. 6 is a top view of the planar flexible RF tag 400 of
FIG. 4, in an embodiment. Planar flexible RF tag 400 is shown
within a permanently sealed enclosure 430 that is for example a
permanently sealed, thin flexible plastic packaging that allows for
inclusion of planar flexible RF tag 400 into pockets of, and/or
sewn into, clothing, uniform fabric, and other attire of the
individual. For example, enclosure 430 may include provision for
attachment such as areas for sewing, loops, button holes, and the
like. The sealed nature of enclosure 430 allows for operation of
planar flexible RF tag 400 in wet or dirty conditions as well as
being amenable to washing. Components of planar flexible RF tag 400
are positioned on a flexible substrate 602 that is contained by
enclosure 430, such that planar flexible RF tag 400 is pliable. In
one embodiment, antenna patches 402 are formed of conductive metal
positioned on one side of flexible substrate 602, which is
non-electrically-conductive, and antenna patches 402 have geometry
defining transmission of a wireless UWB signal. The geometry of
antenna patches 402 is selected to generate the wireless UWB signal
with a propagation pattern (e.g., see FIG. 9) sufficient for use in
a real-time location system. Although shown as rectangular, the
geometry of antenna patches 402 is selected to obtain the desired
propagation pattern and for operation at a desired transmission
frequency. FIG. 6 also shows an orientation reference 610 that is
relative to the physical embodiment of planar flexible RF tag
400.
[0033] FIG. 7 shows a cross section B-B of the planar flexible RF
tag 400 of FIG. 6 and a cross section of the charging device 500 of
FIG. 5, in embodiment. As shown for charging device 500, metal
charging plates 502 are positioned on dielectric substrate 514,
which is for example a circuit board, such that metal charging
plates 502 align with antenna patches 402 of planar flexible RF tag
400.
[0034] For planar flexible RF tag 400, antenna patches 402 are
positioned on a first side of flexible substrate 602, and
components 702 of decoupling circuits 404, full wave rectifier
halves 406, 407, charging regulator circuit 410, microcontroller
circuit 420, and RF transceiver circuit 422, and rechargeable
battery 412 are positioned on a second side, opposite the first
side, of flexible substrate 602 as shown. Rechargeable battery 412
is flat and flexible. In one embodiment, rechargeable battery 412
is a thin flexible rechargeable lithium polymer battery from
BrightVolt Inc. Flexible substrate 602, antenna patches 402,
components 702, and rechargeable battery 412 are all contained
within enclosure 430. Planar flexible RF tag 400 is thus thin and
flexible in format allowing it to be used where the hard-potted
enclosure of conventional RF tags prohibit use.
[0035] FIG. 8 shows, in cross section, the charging device of FIGS.
5 and 7 positioned to charge rechargeable battery 412 of planar
flexible RF tag 400 of FIGS. 4, 6, and 7. Charging device 500 is
positioned over planar flexible RF tag 400 such that metal charging
plates 502 are aligned with antenna patches 402. Where planar
flexible RF tag 400 is sewn into clothing, fabric 802 of that
clothing may be between charging device 500 and planar flexible RF
tag 400. However, the fabric does not prevent charging device 500
from charging rechargeable battery 412 of planar flexible RF tag
400 since no direct electrical contact is required.
[0036] FIG. 9 shows a propagation pattern 900 for the planar
flexible RF tag 400 of FIGS. 4, and 6-8, in embodiments.
Orientation of propagation pattern 900 is shown relative to
orientation reference 610 of planar flexible RF tag 400.
Propagation pattern 900 is suitable for tracking an individual
using a real-time location system.
[0037] FIG. 10 is an image showing exemplary layout of the planar
complementary patch antenna 403 of FIG. 4, in one embodiment. In
this embodiment, antenna patches 402 are each substantially
rectangular, equally sized, and aligned along one edge with spacing
1004 between them. Planar complementary patch antenna 403 also
include two feed elements 1002(1) and (2) that electrically connect
a different one of antenna patches 402 to decoupling circuits 404
(not shown in FIG. 10) and RF transceiver circuit 422 (not shown in
FIG. 10). In one embodiment, the geometry (e.g., width 1006 and
length 1008, spacing 1004 and substantially rectangular shape) of
antenna patches 402 is configured such that planar complementary
patch antenna 403 is resonant at 6.5 GHz and obtains propagation
pattern 900. Manipulating the geometry of the antenna elements
(i.e., antenna patches 402) of planar complementary patch antenna
403 predictably alters shape and range of propagation of radio
waves transmitted therefrom. This facilitates design of planar
flexible RF tag 400 for a particular use.
[0038] FIG. 11 shows exemplary positioning of two planar flexible
RF tags 100/400 of FIGS. 1-4, and 6-8, on an American football
player 1100 to illustrate exemplary orientation of the planar
flexible RF tags relative to the player, in an embodiment. Tags
100/400 may be configured with clothing and/or equipment of player
1100, as described above.
[0039] In particular, each planar flexible RF tag 100/400 is
oriented (see orientation references 610(1) and (2)) such that
transmission power in the forward and backward directions (relative
to player 1100) is greater than the transmission power in the
sideways directions. Thus, less of the transmitted energy is
absorbed by the player's body, since less power is transmitted in
that direction, as compared to a conventional UWB omnidirectional
antenna.
[0040] FIGS. 12 and 13 show player 1100 of FIG. 11 on an American
football field 1200 illustrating exemplary propagation of
transmissions 1302(1) and 1302(2) from planar flexible RF tags
100(1)/400(1) and 100(2)/400(2), respectively, of player 1100.
Plays on the American football field are generally up or down the
field 1200, as opposed to across the field. Thus, players in
general are also facing up and down the length of the field. As
shown, field 1200 is surrounded by a plurality of receivers 1304
(also known as anchors) that are configured to receive
transmissions from planar flexible RF tags 100/400. The receiver
locations and received transmissions are used to determine the
location of the planar flexible RF tags 100/400 within the
operational area that includes field 1200. At least three receivers
1304 are required to receive a particular transmission to enable
location of the corresponding planar flexible RF tag 100/400.
[0041] Transmissions 1302 correspond to propagation pattern 900
(i.e., transmission power of tag 100/400) of FIG. 9, and also
illustrate exemplary blockage by the body of player 1100.
Positioning and orientation of planar flexible RF tags 100/400
(i.e., antenna patches 102/402) determines the shape of
transmission 1302, and its effectiveness at being received by
receivers 1304. By configuring antenna patches 102/402 such that
more power is transmitted in the player's forward/backward
direction (i.e., 90-270 degrees relative to the orientation
reference 610 of the antenna, less power is absorbed by the
player's body. Further, since field 1200 is longer than it is wide,
more receivers 1304 receive each transmission 1302. The advantages
of planar flexible RF tags 100/400 may be used to track other
players and objects and used with other sports without departing
from the scope hereof.
[0042] Advantages
[0043] Planar flexible RF tags 100/400 have at least three main
advantages over prior art RF tags. First, antenna patches 402(1)
and (2) have differential input 401 that may be driven in a
balanced way (differential) allowing direct connection to a
balanced drive input and output of RF transceiver circuit 422
without a balun (balanced-to-unbalanced converter). A conventional
microstrip patch antenna has a ground plane and one (or more serial
or parallel connected) patches that are driven single ended,
thereby requiring the use of a balun device when using a
transmitter with a balanced/differential input/output (which more
transmitting devices are). By including two antennal patches 402
within planar complementary patch antenna 403, and directly
connecting each of the antenna patches 402 to a different connector
of the differential output 423 of RF transceiver circuit 422, the
balun is not required. Although it is known to drive conventional
dipole antennae in a balanced way, it is previously unknown to
drive a pair of microstrip patch antennae in a complementary manner
similar to driving the conventional dipole antennae. Further, since
the balun device is not required and not included, its associated
loss is also not incurred which improves transceiver performance
and range.
[0044] Second, placement geometry (e.g., spacing 1004) of the two
complementary driven antenna patches 402 is configured to allow the
electromagnetic field interaction and propagation pattern 900 to be
sufficient for tracking an individual using an UWB real-time
location system. For example, planar flexible RF tag 400 of FIG. 4
may be configured to periodically transmit a radio signal that
includes identification information, which is received by the UWB
real-time location system, which in turn determines a location of
the tag based upon triangulation. The propagation pattern (e.g.,
propagation pattern 900 of FIG. 9) in this example is biased
transverse to the player's shoulder axis giving better gain in the
down and up field directions and diminishing gain toward the
players neck and sidelines.
[0045] Third, the complementary nature of antenna patches 402 and
the fact that it is a conducting patch lends itself to a second
application crucial to the overall design of planar flexible RF tag
400, which is the battery recharging function. Antenna patches 402
may be considered as simply metal plates. When another,
complementary set of metal plates (e.g., metal charging plates 502
of charging device 500) and a suitable dielectric layer (e.g.,
dielectric substrate 514) is brought within close proximity of the
antenna patches 402, as shown in FIG. 8, then at frequencies much
lower than the microwave operating frequency of antenna patches
402, power is transferred from the metal plates to the antenna
patches. For sufficient power transfer from the metal plates to the
antenna patches, these metal plates match the geometry (e.g., size,
shape, and spacing) of the antenna patches. With suitable
decoupling (as provided by decoupling circuits 404), rectification
(as provided by full wave rectifier halves 406, 407) and charge
management circuits (as provide by charging regulator circuit 410),
this power transfer may be used to charge rechargeable battery 412
without requiring electrical contact. Thus, enclosure 430 need not
be breached or opened to recharge rechargeable battery 412.
[0046] Advantageously, the non-electrical contact battery
recharging may be performed as needed without removal of planar
flexible RF tag 400 from clothing. Alternatively, as with planar
flexible RF tag 100, connector 114 is easily accessed to charge
rechargeable battery 112.
[0047] Since planar flexible RF tag 100/400 is thin (not having 3D
antenna or a thick battery), flexible (having components mounted on
a flexible substrate and a flexible rechargeable battery) and light
weight (the thin efficient operation does not require the use of a
single-use higher powered battery), it is much less obtrusive and
therefore more widely acceptable for use in tracking athletes and
objects in hostile environments.
[0048] The thin profile of planar flexible RF tag 100/400 allows it
to be placed unobtrusively on or in athletic equipment and on or in
athletic clothing. In one embodiment, a lower surface 304/704 of
planar flexible RF tag 100/400 has an adhesive coating that allows
planar flexible RF tag 100/400 to adhere to a surface (e.g., sports
equipment, helmet, clothing, skin of the athlete). In one
embodiment, the adhesive is protected by a removable layer that
allows planar flexible RF tag 100/400 to be applied using a
technique similar to applying a Band-Aid. For example, planar
flexible RF tag 100/400 may be attached to a bicycle to allow a
real-time location system to track the movement of that bicycle and
the rider. In another embodiment, planar flexible RF tag 100/400 is
attached to a lanyard and/or worn like a pendant. Thereby, a golfer
may wear planar flexible RF tag 100/400 around their neck for
example.
[0049] In the configuration shown in FIG. 10, planar complementary
patch antenna 403 generates propagation pattern 900 which is
ideally suited for operation within planar flexible RF tag 400 to
allow a real-time location system to track athletes performing
within a stadium.
[0050] As shown in FIGS. 3, 7, and 8 rechargeable battery 112/412
is thin and flexible, thereby also allowing planar flexible RF tag
100/400 to be flexible. This alone is a considerable advance in
technology for tracking athletes since planar flexible RF tag
100/400, by being flexible and thin, may thereby provide for
easier, less obtrusive placement in athletic equipment and/or
clothing.
[0051] Antenna patch 102 and planar complementary patch antenna 403
reduce the overall thickness of planar flexible RF tag 100/400
since the conventionally used 3D antenna design is not required.
Further, antenna patch 102 and planar complementary patch antenna
403 have reduced fragility since there is no 3D structure mounted
away from the supporting substrate that requires protection.
[0052] Since antenna patch 102 and planar complementary patch
antenna 403 are substantially flat, less protection (as compared to
a more delicate 3D structure) is required and they may even be
deformed (flexed) without significant loss in performance (e.g.,
deviation from propagation pattern 900 of FIG. 9). Thus, unlike
prior art RF tags, planar flexible RF tag 100/400 may utilize
flexible substrate 202/602 to support each of antenna patch 102 and
planar complementary patch antenna 403, components 302/702, and
rechargeable battery 112/412. This flexibility significantly
advances the art of RF tracking systems where prior art UWB RF tags
were built using rigid circuit boards and required hard, thick
housings. In the prior art, these rigid PCBs were required to
support and protect the 3D antenna, and to support the larger,
heavier and non-flexibly battery.
[0053] Historically, UWB tags were designed from discrete
components that were interconnected by etched tracked on a printed
circuit board. At UWB frequencies absolutely everything, including
the etches, affects the performance of the circuit. For this
reason, etches need to be considered components of the UWB and so
having them flexing, stretching and contracting wreaks havoc with
circuit performance. Within planar flexible RF tag 100/400, UWB
components and connectivity may be implemented within an integrated
circuit that attaches to flexible substrate 202/602. Thus, UWB
circuitry itself is not susceptible to bending within planar
flexible RF tag 100/400.
[0054] Since planar flexible RF tag 100/400 is flexible, when
incorporated within athletic equipment, configured within clothing,
or attaches directly to an athlete, inevitable bending of planar
flexible RF tag 100/400 is accommodated through the flexibility
rather than resulting in breakage. Thus, planar flexible RF tag
100/400 is less fragile that prior art RF tags. Thus, this
flexibility also makes planar flexible RF tag 100/400 more
adaptable to the environment, the athlete, the clothing, and/or the
equipment upon which they are mounted on or in.
[0055] Although the embodiments described above and shown in the
figures have one or two antenna patches, further embodiments are
envisioned where multiple antenna patches are coupled together in
one or both of serial and parallel configurations.
[0056] Changes may be made in the above methods and systems without
departing from the scope hereof. It should thus be noted that the
matter contained in the above description or shown in the
accompanying drawings should be interpreted as illustrative and not
in a limiting sense. The following claims are intended to cover all
generic and specific features described herein, as well as all
statements of the scope of the present method and system, which, as
a matter of language, might be said to fall therebetween. In
particular, the following embodiments are specifically
contemplated, as well as any combinations of such embodiments that
are compatible with one another:
[0057] (A) A planar flexible ultra-wide band (UWB) RF antenna
includes a flexible non-electrically-conductive substrate, and an
antenna patch comprising electrically conductive metal positioned
on one side of the flexible non-electrically-conductive substrate
and having geometry defining a wirelessly transmitted UWB
signal.
[0058] (B) In the planar flexible UWB RF antenna denoted as (A),
the UWB signal having a propagation pattern suitable for use in a
real-time location system.
[0059] (C) Either of the planar flexible UWB RF antennae denoted as
(A) and (B), further including a feed element electrically coupled
to the antenna patch and electronic components of a planar flexible
RF tag configured with an object being tracked by the real-time
location system.
[0060] (D) In any of the planar flexible UWB RF antennae denoted as
(A)-(C), the geometry including a size and shape to wirelessly
transmit the UWB signal with a propagation pattern suitable for use
in a real-time location system.
[0061] (E) In any of the planar flexible UWB RF antennae denoted as
(A)-(D), the shape including a rectangle.
[0062] (F) A planar complementary patch antenna includes a flexible
non-electrically-conductive substrate, first and second antenna
patches positioned apart from each other on one side of the
flexible non-electrically-conductive substrate, and a differential
input having (a) a first feed element electrically coupled directly
to only the first antenna patch and (b) a second feed element
electrically coupled directly to only the second antenna patch, the
differential input being drivable from a differential output of an
RF transmitter circuit to generate a wireless signal from the
complementary patch antenna.
[0063] (G) In the planar complementary patch antenna denoted as
(F), the first and second antenna patches transmitting the wireless
signal at transmission frequency and propagation pattern defined by
geometry of the first and second antenna patches.
[0064] (H) In either of the planar complementary patch antennae
denoted as (F) and (G), the geometry defining size and shape of,
and spacing between, the first and second antenna patches to
transmit the wireless signal for use with an ultra-wide band
real-time location system.
[0065] (I) In any of the planar complementary patch antennae
denoted as (F)-(H), the shape of each of the first and second
antenna patches being substantially rectangular.
[0066] (J) A dual-purpose antenna includes a first electrically
conductive metal antenna element and a second electrically
conductive metal antenna element configured such that the
dual-purpose antenna transmits a wireless signal at transmission
frequency and propagation pattern defined by geometry of the first
and second antenna elements, and the dual-purpose antenna receives,
without electrical contact, capacitive power across two different
capacitors each formed in part by a different one of the first and
second antenna elements.
[0067] (K) In the dual-purpose antenna denoted as (J), the geometry
defining size and shape of, and spacing between, the first and
second electrically conductive metal antenna elements to transmit
the wireless signal for use with an ultra-wide band real-time
location system.
[0068] (L) In either of the dual-purpose antennae denoted as (J)
and (K), the first and second electrically conductive metal antenna
elements being formed on a first surface of a
non-electrically-conductive flexible substrate.
[0069] (M) Any of the dual-purpose antennae denoted as (J)-(L),
further including a first decoupling circuit electrically coupled
to the first electrically conductive metal antenna element and
operable to decouple the capacitive power at a first frequency less
than the transmission frequency, and a second decoupling circuit
electrically coupled to the second electrically conductive metal
antenna element and operable to decouple the capacitive power at
the first frequency.
[0070] (N) Any of the dual-purpose antennae denoted as (J)-(M),
further including a first full wave rectifier half electrically
coupled to the first decoupling circuit, a second full wave
rectifier half electrically coupled to the second decoupling
circuit, and a regulator circuit electrically coupled to both the
first and second full wave rectifier halves to condition rectified
electrical power from the first and second full wave rectifier
halves.
[0071] (O) A planar flexible RF tag for use in a real-time location
system includes a flexible substrate, at least one antenna patch
formed on a first side of the flexible substrate, an RF transmitter
circuit electrically coupled to the at least one antenna patch and
formed on a second side of the flexible substrate, and a
microcontroller circuit formed on the second side and electrically
coupled to control the RF transmitter circuit to drive the at least
one antenna patch to transmit a radio signal.
[0072] (P) The planar flexible RF tag denoted as (0), further
including a rechargeable battery for powering the RF transmitter
circuit and the microcontroller circuit.
[0073] (Q) Either of the planar flexible RF tags denoted as (0) and
(P), further including a flexible waterproof enclosure that
encapsulates the at least one antenna patch, the RF transmitter
circuit, and the microcontroller circuit.
[0074] (R) Any of the planar flexible RF tags denoted as (O)-(Q),
further including an electrical connector positioned at least
partially outside the flexible waterproof enclosure for providing
electrical power to recharge the rechargeable battery.
[0075] (S) Any of the planar flexible RF tags denoted as (O)-(R),
further including a regulator circuit formed on the second side of
the flexible substrate, positioned within the flexible waterproof
enclosure, and electrically connected to the electrical connector
and the rechargeable battery, the regulator circuit regulating
charge of the rechargeable battery.
[0076] (T) In any of the planar flexible RF tags denoted as
(O)-(S), the at least one antenna patch having geometry to transmit
the radio signal using ultra-wide band technology.
[0077] (U) In any of the planar flexible RF tags denoted as
(O)-(T), the geometry defining size, shape and spacing of the at
least one antenna patch.
[0078] (V) In any of the planar flexible RF tags denoted as
(O)-(U), the shape being substantially rectangular.
[0079] (W) A planar flexible RF tag for use in a real-time location
system includes a flexible substrate, first and second antenna
patches formed as complementary plates on a first side of the
flexible substrate, an RF transmitter circuit electrically coupled
to the first and second antenna patches and formed on a second side
of the flexible substrate, a microcontroller circuit formed on the
second side and electrically coupled to control the RF transmitter
circuit to drive the first and second antenna patches to transmit a
radio signal, and a battery for powering the RF transmitter circuit
and the microcontroller circuit.
[0080] (X) The planar flexible RF tag denoted as (W), further
including a first decoupling circuit formed on the second side of
the flexible substrate and electrically coupled with one of the
first and second antenna patches, a second decoupling circuit
formed on the second side of the flexible substrate and
electrically coupled to a different one of the first and second
antenna patches, a first full wave rectifier half formed on the
second side of the flexible substrate and electrically coupled to
the first decoupling circuit, a second full wave rectifier half
formed on the second side of the flexible substrate and
electrically coupled to the second decoupling circuit, and a
charging regulator circuit formed on the second side of the
flexible substrate and electrically coupled to both the first and
second full wave rectifier halves to receive power via the first
and second antenna patches from a charging device that does not
have a direct electrical connection to the planar flexible RF
tag.
[0081] (Y) Either of the planar flexible RF tags denoted as (W) and
(X), further including a waterproof and permanently sealed
enclosure.
[0082] (Z) Any of the planar flexible RF tags denoted as (W)-(Y),
further including provision for attachment of the planar flexible
RF tag to one or both of clothing and equipment of an individual to
allow tracking of the individual.
[0083] (AA) In any of the planar flexible RF tags denoted as
(W)-(Z), the waterproof and permanently sealed enclosure being
flexible.
[0084] (AB) Any of the planar flexible RF tags denoted as (W)-(AA),
further including an adhesive formed on an underside of the
waterproof and permanently sealed enclosure to adhere the planar
flexible RF tag to a surface of an object to be tracked.
[0085] (AC) In any of the planar flexible RF tags denoted as
(W)-(AB), the battery being flexible and allowing the planar
flexible RF tag to bend without damage or loss of performance.
[0086] (AD) A planar ultra-wide band (UWB) patch antenna for
receiving electrical power includes a non-electrically-conductive
substrate, first and second antenna patches positioned on a first
surface of the non-electrically-conductive substrate and having a
geometry to transmit an UWB wireless signal, a first decoupling
circuit directly electrically connected to the first antenna patch
and having a decoupling frequency that is different from a
transmitting frequency of the UWB wireless signal, and a second
decoupling circuit directly electrically connected to the second
antenna patch and having the same decoupling frequency as the first
decoupling circuit. The first and second decoupling circuits
transferring power from the first and second antenna patches when
the first and second antenna patches receive capacitive power from
an external non-electrical contact charger operating at the
decoupling frequency and having two metal plates of similar
geometry to the first and second antenna patches and that are
positioned proximate and aligned with the first and second antenna
patches.
[0087] (AE) In the planar ultra-wide band (UWB) patch antenna
denoted as (AD), the geometry defining size, shape and spacing of
the first and second antenna patches to transmit the UWB wireless
signal with a propagation pattern suitable for use in an UWB
real-time location system.
[0088] (AF) A charging device for a flexible planar RF tag that has
a rechargeable battery and two antenna patches, the charging device
includes a dielectric layer, a first and second metal plates formed
on the dielectric layer and having geometry corresponding to
geometry of the two antenna patches, a variable oscillator, a first
inductor electrically coupled to the first metal plate and a first
output of the variable oscillator, a second inductor electrically
coupled to the second metal plate and a second output of the
variable oscillator, and a microcontroller electrically coupled to
the variable oscillator. When positioned such that the first and
second metal plates are adjacent and aligned with the two antenna
patches with the dielectric layer therebetween, the microcontroller
is configured to control the variable oscillator to drive the first
and second metal plates and transfer power to the flexible planar
RF tag.
[0089] (AG) The charging device denoted as (AF), further including
a current sensor electrically coupled with the microcontroller for
sensing current through one of the first and second inductors. The
microcontroller being configured to control the variable oscillator
to operate at a resonance frequency of capacitors formed by the
dielectric layer, the two antenna patches, and the first and second
metal plates to maximize, based upon the sensed current, the power
transferred from the charging device to the flexible planar RF
tag.
* * * * *