LOW POWER REMOTELY POWERED SENSOR NETWORKS AND RFIDS FOR MEDICAL AND TELECOMS APPLICATIONS
POWER AND DATA TRANSMISSION FOR MEDICAL AND TELECOMS APPLICATIONS
CATHERINE DEHOLLAIN
EPFL, LAUSANNE, SWITZERLAND
RFIC.EPFL.CH
5TH JUNE 2015, PAVIA, ITALY
5TH JUNE 2015, PAVIA, ITALY3rd February 2016
Content2
C. Dehollain, EPFL, Lausanne
PART 1: ARCHITECTURES OF REMOTELY POWERED SENSOR NETWORKS
PART 2: PASSIVE TRANSMITTERS FOR REMOTELY POWERED SENSOR NETWORKS
LOW POWER REMOTELY POWERED SENSOR NETWORKS AND RFIDS FOR MEDICAL AND TELECOMS APPLICATIONS
5TH JUNE 2015, PAVIA, ITALY
PART 1: ARCHITECTURES OF REMOTELY POWERED SENSOR NETWORKS
3
C. Dehollain, EPFL, Lausanne
POWER AND DATA TRANSMISSION FOR MEDICAL AND TELECOMS APPLICATIONS
At the boundary between different domains4
New architectures of sensor nodes for wireless communications at short distance Back-scattering/ Load modulation (e.g. RFIDs), Impulse Radio Ultra Wideband (IR UWB),
Super-regenerative transceivers, Direct conversion transceivers. Biomedical field: implants, wearable sensor networks.
Remotely powered wireless circuits Through RF wave by magnetic coupling , electro-magnetic coupling, electro-acoustic
coupling (ultrasound). Rechargeable micro-batteries.
Ultra low-power wireless communications Low supply voltage imposed by advanced technologies, ultra-low current operation
MHz to GHz-range ICs RF models of the transistors and passive elements, parasitic coupling.
Fully integrated solutions RF and Mixed-mode circuits. Circuits in advanced CMOS technologies. Integrated tuning elements, MEMS (Micro Electro Mechanical Systems).
C. Dehollain, EPFL, Lausanne
Data Transfer Methods5
One single frequency for remote power and data communication Simple transmitter in the sensor node (load modulation or backscattering) Interruption of the transfer of power during data transmission Optimisation of the link for power transfer and data communication thanks to
trade-off
Dual frequency approach: one frequency for data communication and another frequency for remote power Power transfer is independent of data communication Extra power is required due to the active transmitter of the sensor node Extra antenna is used for data communication
C. Dehollain, EPFL, Lausanne
Backscattering Modulation in far field6
One single frequency for remote power and data communication Harry Stockman, "Communication by Means of Reflected Power”, 1948 The tag is tracked if the main station (reader or interrogator) is in range Minimization of the power consumption of the tag → Generation of the
carrier at base station and backscattering of the incident wave
C. Dehollain, EPFL, Lausanne
U. Karthaus and M. Fischer, “Fully integrated passive UHF RFID transponder IC with 16.7 μW minimum RF input power,”Solid-State Circuits, IEEE Journal of, vol. 38, pp. 1602–1608, Oct. 2003.J. Curty, Analysis and optimization of passive UHF RFID systems. PhD thesis, EPFL, March 2006.
Load Modulation in near field7
G. Yilmaz, Wireless power transfer and data communication for intracranial neural implants, EPFL, PhD thesis, Dec. 2014.
One single frequency for remote power and data communication
C. Dehollain, EPFL, Lausanne
The carrier is generated in the tag. LC OOK Transmitter. The frequency of the carrier is
determined by the LC tank.
Wireless Active Transmitter for Data Communication8
C. Dehollain, EPFL, Lausanne
Inductive Coupling (Near-Field) Near field region → d < λ/2π Typical frequency bands: 125 kHz, 6.78 MHz, 13.56 MHz Effective operation distance of 10 cm in air Highly sensitive to misalignment between the primary coil and the
secondary coil of the transformer Higher energy efficiency in short distance at d<10 cm
Electro-magnetic Coupling (Far-Field) Far field region: → d > λ/2π Typical frequency bands: 868 MHz, 915 MHz, 2.45 GHz, 5.8 GHz. Effective operation distance up to 15 m in air Higher data rate than the near-field systems
Wireless Remote Powering9
C. Dehollain, EPFL, Lausanne
Single Frequency for Remote Power and Data Communication
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C. Dehollain, EPFL, Lausanne
Dual Frequency for Remote Power and Data Communication
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→ Three fundamental units1. Implantable sensor system2. External base station for data communication and remote powering 3. Long distance data communication for data base and reporting
C. Dehollain, EPFL, Lausanne
Knee prosthesis monitoring by inductive coupling
C. Dehollain, EPFL, Lausanne
O. Atasoy, C. Dehollain, IEEE NEWCAS Conf. 2012, PRIME Conf. 2010, PRIME Conf. 2013, IEEE Trans. on Automation 2013O. Atasoy, PhD thesis n0 5992, EPFL, November 2013
Objectives• Transcutaneous powering by inductive link• Data communication between the
prosthesis and the external reader
Challenges• Low coupling factor of inductive link due to
distance between the two coils and limitedantenna size
• High power requirement (10 to 20 mW)
Goals• Increase of the life expectancy of the
prosthesis• Monitoring of the force, of the movement of
the knee and of the temperature
Swiss SNF NanoTera
Simos Project
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Ultrasonic Remote Powering and Communication13
C. Dehollain, EPFL, Lausanne
European FP7 project: www.ultrasponder.org
F. Mazzilli, C. Lafon, C. Dehollain: EMBC Conf. 2010, ISCAS Conf. 2012, IEEE TBioCas Journal 2014, BioCAS Conf. 2014, IEE Electronics Letters 2016F. Mazzilli, PhD thesis no 5631, EPFL, March 2013
Digestive Track Diagnostic14
CTI Swiss Project
→ Diagnosis of digestive system for:• Constipation• Irritable Bowel Syndrome (IBS)• Gastroparesis
→ 3D trajectory information of the pill through the gastrointestinal track.
→ The pill provides three axis magnetic field for location information.
→ Fully integrated ASIC development enables miniaturization of the pill.
J.L. Merino, C. Dehollain: ICECS 2012, ISMICT 2013, ISCAS 2015
C. Dehollain, EPFL, Lausanne
Passive Memory Tag for High Data Rate15
Goal: to obtain a medium operating range between the interrogator and the passive memory tag for a given RF output power of the interrogator and a high data rate
System Specifications: • Read/write data rate: 10Mbit/s• Distance range: 10 to 20 cm
• VDC < 3V, IDC < 3mA • Data Communication: 2.4GHz ISM)• Remote powering: 0.9GHz (ISM)
European IP Project MINAMI (2006 - 2010)
N. Pillin, N. Joehl, C. Dehollain, M. Declercq, RFID Conf. 2008, PRIME Conf. 2009, IEEE Trans. on Circuits and Systems-I 2010 N. Pillin, PhD thesis no 4616, EPFL, March 2010
C. Dehollain, EPFL, Lausanne
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C. Dehollain, EPFL, Lausanne
Magnetically-Coupled Remote Powering System for Freely Moving Animals
Magnetically-Coupled Remote Powering System for Freely Moving Animals
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• Real-time long-term monitoring Continuous remote powering• Condition of subject is important in order to obtain reliable
measurement results• Conscious Awake (without anesthetized)• Non-stress environment Freely moving
k
L1 L2
Reader Coil
Tag Coil
Reader Side Tag Side
Power
DataReader Tag
General RFID concept Scenario for remotely powered systems
C. Dehollain, EPFL, Lausanne
Specs for Freely Moving Laboratory Rodents18
C. Dehollain, EPFL, Lausanne
Application: Multi-bio sensor monitoring Condition of animal: mobile/awake Fully implantable sensor node Weight: Less than 2 g (less that 10%) Volume: Less than 1 cm3
Maximum power consumption: 2 mW Wireless Power Transfer Remote powering distance: 3 cm Data communication data rate: 100 kbit/s Data communication distance: 40 cm
SIZE FREE MOVE
Remote Powering
Data Comm.
Implantable Bio-Monitoring System19
Conceptual design of battery-less implantable multiple sensor system
Targets • Detection of different drugs• Measurement of pH and temperature• Detection of different endogenous compounds
Problems • Size and weight to be implantable• Low coupling factor due to distance & tissue
Continuous and Long-term monitoringSwiss SNF Sinergia Project
C. Dehollain, EPFL, Lausanne
E. G. Kilinc, F. Maloberti, C. Dehollain: IEEE SM2ACD 2010, ISCAS 2012, BIOCAS 2012, NEWCAS 2013, IWASI 2013, ICECS 2013, BIOCAS 2014, MWSCAS 2014, IEEE Sensors Journal 2014, IEEE TBioCasJournal 2015, IEEE Sensors Journal 2015, Springer book 2016E.G. Kilinc, PhD thesis n0. 6105, EPFL, Feb. 2014
Temperature Measurements20
To monitor local temperature of the brown adipose tissue of the mouse to study its metabolism.
C. Dehollain, EPFL, Lausanne
Metabolism Study21
C. Dehollain, EPFL, Lausanne
Temperature Sensor in Brown Adipose Tissue• Metabolism study• Inflammation • Wireless powered sensor
Temperature sensor
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C. Dehollain, EPFL, Lausanne
Features• Small tip diameter (Ø0.5mm Max.) • High sensitivity• Temperature range: -40˚C to +125˚C• Rapid time constant
Applications• Laboratory animal research• Temperature control for bath shower• DNA research sensors• Medical implants
Sensor Parameters Value
Resistance@+25˚C (kΩ) 100
Response time in liquids (ms) 200
Dissipation constant in still air (mW/˚C)
0.3
Resistive Response (Ω/0.04˚C) 178.5
Micro-BetaCHIP Thermistor Probe
C. Dehollain, EPFL, Lausanne
Thermistor Response Curve23
100K6MCD1, BetaTHERMSensors
Target temperature range: 27 °C to 42 °C Target resolution: 0.05 °C to 0.1 °C
C. Dehollain, EPFL, LausanneC. Dehollain, EPFL, Lausanne
Time-domain Sensor Readout24
The sensor response is directly digitized by a time-domain comparator to achieve ultra-low-power operation.
M. A. Ghanad, M. M. Green, and C. Dehollain: ICECS 2012, A-SSCC 2013, NEWCAS 2013, IEEE Transaction on Circuits and Systems I 2014, IEE Electronics Letters 2014, ISCAS 2015, ESSCIRC 2015M.A. Ghanad, PhD thesis n0. 6253, EPFL, Oct. 2014
C. Dehollain, EPFL, Lausanne
Implemented Data Transmitter25
Spec. Value
Center freq. 868 MHz
Modulation OOKPower 144 uWSupply 1.3 V
Data-rate 1.7 Mbps
Turn on time < 10 nsFreq. drifts < 1 MHzTechnology 0.18 um
LC cross-coupled pair oscillator Frequency determined by C1, C2 and the off-chip inductive antenna Resistive loss compensated by the negative resistance of the two MOS
cross-coupled pairs
Loop Antenna26
is the wave length of the radiated signal
J. Pandey et al., “A fully integrated RF-powered contact lens with a single element display,” Biomedical Circuits and Systems, IEEE Transactions on, vol. 4, pp. 454–461, Dec. 2010.
If it is assumed that the antenna is isotropic, which means that it radiatesthe same intensity in all directions, then the gain of the antenna GT can beapproximated by the efficiency ant
Low-power Implantable Chip
High efficiency semi-active rectifier Time-domain resistance to digital converter Time interleaved sensor readout and data transmission
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C. Dehollain, EPFL, Lausanne
Local Temperature Sensing Implantable Chip28
SensorReadout
DigitalOsci.Rectifier
1480 um
690
um Regu
lato
r
V REF
Gen
.
MOS Cap.
MOS Cap.MOS Cap.
Semi active rectifier with leakage current control. Time-domain sensor readout. Duty cycled free-running oscillator for data communication.Power Consumption is 6X better than the similar reported works.
M. A. Ghanad, M. M. Green, and C. Dehollain, “A Remotely Powered Implantable IC for RecordingMouse Local Temperature with ±0.09 °C Accuracy,” IEEE A-SSCC 2013 (Asian Solid-State Circuits Conference).
C. Dehollain, EPFL, Lausanne
Friis propagation equation29
The Friis equation is valid for far field operation (<< d) n = Path loss exponent = 2 in free space.
Normally n is chosen between 2 to 4 depending on the environment.
d = Distance between the transmitter and the receiver GR = Antenna gain of the receiver GT= Antenna gain of the transmitter PR = Power available at the input of the receiver antenna PT = Transmitter power
Data Communication Frequency Planning30
Wong et al., “A 1 V wireless transceiver for an ultra-low-power SoC for bio telemetry applications,” IEEE Journal of Solid-State Circuits, vol. 43, pp. 1511–1521, July 2008.
Power transfer ratio = 10log (PR/PT)
868 MHz
2400 MHz433 MHz
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C. Dehollain, EPFL, Lausanne
Wireless Power and Data Transfer for Intracranial Epilepsy Monitoring
Intracranial Neural Implants
• Macro iEEG electrodes• 10 mm diameter• 10 mm separation
• Data extraction• Cable bundles• Amplification and
processing outside
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J. Van Gompel et al., Neurosurgical Focus, vol. 25, no. 3, p. E23, Aug. 2008.
Drawbacks of Current iEEG
Risk of Cerebrospinal Fluid (CSF) leakage Risk of CSF infection Reduced patient comfort Short monitoring period
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C. Dehollain, EPFL, Lausanne
Scenario proposed by EPFL
SNF Swiss Project
Wireless Power and Data Transfer for Intracranial Epilepsy Monitoring
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C. Dehollain, EPFL, Lausanne
• EPFL news on 9th Feb 2015: http://actu.epfl.ch/news/monitoring-epilepsy-in-the-brain-with-a-wireless-s/• PhD Thesis n0 6947, Author: Gurkan Yilmaz, EPFL, December 2014.• G. Yilmaz, O. Atasoy, C. Dehollain, «Wireless energy and data transfer for in-vivo epileptic focus localization», IEEE
Sensors Journal 2013, IWASI 2013, NEWCAS 2014, BIOCAS 2014, Microelectronics Journal Elsevier 2014.
Wireless Power Transfer by Magnetic Coupling at 10 MHz10 mW delivered power with 36% power efficiency from 1cmImplanted coil size < 15 x 15 mm235% power efficiency in in-vitro testsPolymer based packaging and modeling of the packagingAt least 1 month of successful in-vitro operation
Wireless Power and Data Transfer for Intracranial Epilepsy Monitoring
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Wireless Data Communication (single frequency approach) Load modulation on the power transfer frequency 1Mbps on 8.4 MHz carrier has been realized (BER < 10-5) 33% power efficiency in in-vitro experiments
Wireless Data Communication (dual frequency approach) A 433 MHz active transmitter has been designed 1.8 Mbps has been realized (BER < 10-5) Base station in discrete components
C. Dehollain, EPFL, Lausanne
in-vitro tests (single frequency)
Transmitterat 433 MHz
0.18um CMOS
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C. Dehollain, EPFL, Lausanne
Far-Field Remotely Powered Wireless Sensor System at 2.45 GHz
Wireless Remotely Powered Sensor System at 2.45 GHz
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C. Dehollain, EPFL, Lausanne
RECTIFIER FOR REMOTE POWERING at 2.45 GHz
Integrated Sensor System39
C. Dehollain, EPFL, Lausanne
O. Kazanc, J.A. Rodriguez-Rodriguez, M. Delgado-Restituto, F. Maloberti, C. Dehollain, IEEE NEWCAS Conf., June 2013
Matching with Programmable Capacitors
Adaptive Impedance Matching40
C. Dehollain, EPFL, Lausanne
Before Calibration After Calibration
O. Kazanc, F. Maloberti, C. Dehollain, IEEE WiSNet Conference, Jan. 2013
Performance Summary41
C. Dehollain, EPFL, Lausanne
Performance Metric Value
Wireless Comm. Freq. 2.45 GHz
VDD (A & D) 1.5 VPower Consumption 20 μW
Data Rate 125 kbits/sSensor Accuracy ~ 0.05 °C
Area 2.25 mm2
• PhD Thesis n0 6152, Author: Onur Kazanc, EPFL, June 2014.• O. Kazanc, F. Maloberti, C. Dehollain: ISMICT 2011, ISCAS 2012, NEWCAS 2013, BioWireless 2012, WiSNet 2013
EMBC 2014.
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C. Dehollain, EPFL, Lausanne
Far-Field Remotely Powered Wireless Sensor System at 868 MHz
Passive UHF RFID Tags43
Capacitive Humidity Sensor Oscillator Based Sensor Readout Back-Scattering Wireless Com. Remote Powering Link
Base Station Base Station Antenna Tag Antenna Rectifier
Low Power Analog Circuitry Supply Generation
Low Drop-Out Voltage Regulator Bandgap Reference
Current Reference
C. Dehollain, EPFL, Lausanne
Rectifier
Modulator
Hum
idity
Sen
sor
Tag IC
MatchingNetwork
POR
Ant
enna
SensorInterface
Electro-Magnetic Remote Powering44
Base Station Antenna Patch Gain = 3.6 dB S11 = -24 dB @ 866 MHz
Tag Antenna Inductively Coupled Meandered Dipole Gain = 1.2 dB Impedance matched to chip impedance
Rectifier Differential Threshold voltage cancellation PCE = 65% measured
-15
-10
-5
0
5
30
60
90
120
150
180 0
PatchTag
vRF+
vRF-
RLCS
CC CCCC
CI VDCCI
CC CCCC
K. Kapucu, C. Dehollain, IEEE ICECS 2013, IEEE RFID-TA 2014
Low Power Sensor Interface45
Capacitive sensor Printed humidity sensor
Sensor readout Supply voltage
Down to 0.8 V Low power
12 µW @ 0.8 V UMC 0.18 µm CMOS
Distance range: 4 m 3.3 W EIRP from the base station
EPFL, Lausanne
PhD Thesis n0 6540, Author: Kerem Kapucu, EPFL, April 2015.K. Kapucu, J.L. Merino, C. Dehollain, PRIME 2013 and ICECS 2013K. Kapucu , C. Dehollain: PRIME 2014, RFID-TA 2014, RFID 2015, IWASI 2015
C. Dehollain, EPFL, Lausanne
LOW POWER REMOTELY POWERED SENSOR NETWORKS AND RFIDS FOR MEDICAL AND TELECOMS APPLICATIONS
5TH JUNE 2015, PAVIA, ITALY5TH JUNE 2015, PAVIA, ITALY
PART 2: PASSIVE TRANSMITTERS FORREMOTELY POWERED SENSOR
NETWORKS
46
POWER AND DATA TRANSMISSION FOR MEDICAL AND TELECOMS APPLICATIONS
Backscattering Data Communication
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C. Dehollain, EPFL, Lausanne
The RF carrier is generated in the interrogator also called reader The tag, also called transponder, modulates and reradiates the RF carrier that is
coming from the interrogator when there is a high impedance mismatch The power consumption of the tag is minimised because it does not include a RF
oscillator to generate the carrier
IncomingWave
BackscatteredModulated
Signal
Interrogator Tag
f0- fD f0 f0+ fD
Principle of the Backscattering Data Communication
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C. Dehollain, EPFL, Lausanne
fo: carrier frequencyfD: data frequency
If Data = Bit “1” Zin = R’ is mismatched to the tag antenna All the power of the RF incoming signal is reflected to the interrogatorIf Data = Bit “0” Zin = R is matched to the tag antenna All the power of the RF incoming signal is absorbed by the tag
R'
R
Data
f0- fD f0 f0+ fD
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C. Dehollain, EPFL, Lausanne
Principle of the Backscattering Data Communication
D A T A
R
R
DATA
Series impedance switcher Parallel impedance switcher
Examples of Input Impedance Switcher50
C. Dehollain, EPFL, Lausanne
IncomingWave
BackscatteredModulated
Signal
Interrogator Tag
DATADemodulator
PowerSplitter
RF Oscillator
RF Band-PassFilter
Mixer
DATADemodulator
PowerSplitter
RF OscillatorRF
Band-PassFilter
Circulator
Mixer
f0- fD f0 f0+ fD
Architecture of the Reader (Interrogator)
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C. Dehollain, EPFL, Lausanne
f0-fc+ fDf0-fc
f0-fc-fD f0+ fc+ fDf0+ fc
f0+ fc-fDf0
D A T AM o d u la to rIm p e d a n ces w itc h e r
IF O s c illa to rM o d u la te dD a ta
Intermediate Frequency (IF) Backscattering Data Communication
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C. Dehollain, EPFL, Lausanne
fo: carrier frequencyfC: IF frequency
fD: data frequency
• Amplitude
The reflection coefficient at the tag-antenna interface can vary in
• Phase
• Two basic binary modulation types are possible: ASK & PSK
• Power available for both tag power supply & for data communication
• Data communication quality (Bit Error Rate: BER)
• They must be compared in terms of
Modulation Types53
C. Dehollain, EPFL, Lausanne
RANT L
matchingAnt. tag
Ri
Ci
I
(switch closed)
Ri (switch open)Tag input
impedance
Reflected power dueTo mismatch at the tag
Time
Dut
y-cy
cle
ASK
stan
dard
ASK
bit
stre
am
Reflected ASK modulated signal
DC
Bit « 1 »: the switch is closedBit « 0 »: the switch is open
ASK Modulation54
C. Dehollain, EPFL, Lausanne
RANT L
React.Ant. tag
Ri
CiB A
C0
1 0 1 0
Tag input impedance at B
Z1
Z0XC + XC'
XL
1
L
1
0
State 1The switch is closed
State 0The switch is open
In B: Absorbed power and reflected power are constant
In A: Voltage at tag input is however not constant
PSK Modulation55
C. Dehollain, EPFL, Lausanne
Bit Error RateBER = 10-4 1 bit is not correct over 10’000
Comparison through the Bit Error Rate (BER)Eb = Average Energy per bitN0 = Noise level at receiver input = Ri / RANT
Q = tag input series quality factor = 1/(Ri.Ci) DC = Modulation Duty Cycle
J.P. Curty, M. Declercq, C. Dehollain, N. Joehl: « Design and Optimization of Passive UHF RFID Systems » , Editor Springer, year 2007, ISBN: 0-387-35274-0.
Performance of ASK / PSK Modulations 56
C. Dehollain, EPFL, Lausanne
BER
Optimal ASK and PSK BER comparison(ASK: DC = 100%, = 1 and PSK: = 1, Qin = 5.6)
Eb /N0
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C. Dehollain, EPFL, Lausanne
Performance of ASK / PSK Modulations
Ref
lect
ion
coef
ficie
nt
Impedance Matching = 0 and = 1
Normalized resistance = Ri / Rant
The input capacitance is equal to a few hundreds fF
Reflection coefficient is close to ±1 according to the position of the switch
RANT L
tag
Ri
Ci
Priority to communication distance
The real part of Ri is very high (»1k) and much higher than Rant
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C. Dehollain, EPFL, Lausanne
Reflection Coefficient
L and Ci resonate at the operating frequency
Reflection coef. = (Ri – Rant) / ( Ri + Rant) = ( – 1) / ( + 1)
Pseudo PSK Modulation
Ri is much larger than RANT
Voltage at rectifier input is higher than in impedance matchingcondition so that the rectifier has enough input voltage to operate
Absorbed power is lower than in impedance matching condition Modulation corresponds to nearly a 180° phase shift of the
reflection coefficient Pseudo PSK Modulation
RANT
L Ri
C
Zin
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C. Dehollain, EPFL, Lausanne
Nor
mal
ized
pow
er w
ave
ampl
itude
%
Time
Power waves for both modulation states
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It is important to take care of direct-coupling effect
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C. Dehollain, EPFL, Lausanne
Basic Architecture of the Reader
osc
DATA RX
IF
RSSI
LNA
DATA TX
PA
C
90°
0°
LNA
AGC
OOK
Amplitude OOK ModulationOOK IQ Demodulation
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C. Dehollain, EPFL, Lausanne
Improved Architecture of the Reader62
Read Range of passive far field RFID systems
• The phase noise of the local oscillator in the reader has an important impact• A model is derived to estimate the read range of passive far-field RFID systems
PRIME Conference, N. Pillin, C. Dehollain, M. Declercq, Cork, July 2009
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C. Dehollain, EPFL, Lausanne
Radar Cross Section
Tag antenna switches between two different Radar Cross Section called RCS: σ1 and σ2
Effective tag antenna RCS is expressed by:
Model
Gt: gain of the antenna of the tag Gr: gain of the antenna of the reader : conversion loss factorσi : effective tag antenna RCS CTx/Rx: coupling factorN (fsb, B): integral of the phase noise on the bandwidth BSNRmin: minimum required SNR at the input of the reader: wave length of the RF signal
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C. Dehollain, EPFL, Lausanne
Measurements
Measurements compared to Model
Measurements were achieved on a laboratory reader/tag system at 900 MHz and 2.45 GHz to verify the model.
PRIME Conference, N. Pillin, C. Dehollain, M. Declercq, Cork, July 2009
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C. Dehollain, EPFL, Lausanne
Radio Regulations
Some regulations are fine for wireless power transfer (high Tx power) Others for communication (large frequency bandwidth)
(1~3.3 W EIRP, 2for indoor use)
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Passive Memory Tag
European IPProject MINAMI
• Contain high capacity non volatile memory• Can store multimedia content• New distribution method for– Videos– Music– Images
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C. Dehollain, EPFL, Lausanne
Compatible with Non Volatile Memory (NVM)FRAM : 7 mW @ 10 MbpsTotal consumption (IC + memory): 10 mWTag IC realized in a standard 0.18um CMOS processRectifier efficiency: 40%
Passive Memory Tag
Read/write data rate: 10 Mbit/sMinimum Distance range: 15 cm
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C. Dehollain, EPFL, Lausanne
Dual Frequency Tag
SPECIFICATIONSDistance Range: 0.15 mData Rate: 10 Mbit/sPower Consumption: 10 mW
Data Rate: 10 Mbit/s Minimum Frequency Bandwidth = 10 MHzRF Frequency for data transmission: 2.4 GHz to 2.485 GHz
Power Consumption: 10 mW Mini Pav = 25 mW for rectifier power efficiency = 0.4
Friis : Peirp = 3.3 W, Gr = 1, d = 0.15 m, f = 868 MHz Pav max = 102 mW: OKFriis: Peirp = 4 W, Gr = 1, d = 0.15 m, f = 2.4 GHz Pav max = 16.2 mW: Not OK
IT IS NECESSARY TO HAVE A DUAL FREQUENCY TAG: 0.87 GHz, 2.4 GHz
PAV S.2
4.GR PEIRP .GR .
2
4d 2
Medium operating range High data rate between the reader and the tag
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Friis propagation equation
C. Dehollain, EPFL, Lausanne
Chapter 7 of PhD thesis, No 4616, N. Pillin, year 2010, EPFL
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C. Dehollain, EPFL, Lausanne
Dual Frequency Tag
Process: UMC CMOS 0.18m Area: 1.5 mm x 1.5 mm
with I/O pads Dual frequency, passive RFID tag
can be read at 10 Mbps at 33 cm Rectifier’s power efficiency: 36% Tag detector/ receiver can operate
at 10 Mbps in read mode
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C. Dehollain, EPFL, Lausanne
Dual Frequency Tag
Chapter 7 of PhD thesis, No 4616, N. Pillin, year 2010, EPFL
• Different backscattering modulation methods have beencompared• ASK Modulation• PSK Modulation• Pseudo-PSK Modulation
• A model has been defined and validated to estimate theread range of passive, far-field RFID systems
• Depending on the specifications, it can be necessary toimplement a dual frequency architecture.
Summary on Backscattering Modulation74
C. Dehollain, EPFL, Lausanne
Summary on remotely poweredsensor networks
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Research spans Circuit development for low power consumption New architectures for wireless systems Utilization of wireless energy sources, i.e. magnetic,
electromagnetic, ultrasound, etc.Aiming scientific innovation and assisting medicine through various applications
Research in RFIDs Implantable Wireless Sensor Systems Radio Frequency Integrated Circuits
C. Dehollain, EPFL, Lausanne
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