Sensing with UHF RFID: an Overview · 2019-05-07 · Sensing with UHF RFID: an Overview. 6th IEEE...
Transcript of Sensing with UHF RFID: an Overview · 2019-05-07 · Sensing with UHF RFID: an Overview. 6th IEEE...
Pavel Nikitin Intermec Technologies
TU Graz, Austria, May 5, 2011
Sensing with UHF RFID: an Overview
6th IEEE UWB Forum on Sensing and Communications
Slide 2
Outline
Introduction
Wireless Sensing
Bands, low power technologies, battery life
Some UHF RFID Basics
UHF RFID Sensing
On/off sensing
ID modulation
Analog sensing
Dedicated sensors
Conclusions
Slide 3
Quantities of Interest in Sensing
Temperature
Light
Touch
Pressure
Humidity
Position
Activity
Alerts
Health
Slide 4
Unlicensed Wireless Bands in US
433 MHz
Active RFID, DASH7
902-928 MHz (UHF)
UHF RFID, ZigBee
2.4-2.483 GHz (SHF)
WiFi, ZigBee, Bluetooth, ANT
5.725-5.875 GHz (microwave)
WiFi
3.1-10.6 GHz (UWB)
UWB: PSD < 41.3 dBm/Hz, spectrum >500 MHz or 20% of center frequency)
24-24.25 GHz
Automotive radars
61-61.5 GHz (EHF)
Wireless HD
Slide 5
Low Power Wireless Sensor Topology
Radio
EnergySource
Sensors Actuators
EnergyHarvesting
Antenna
MicroControllerInformation
Connectivity
Actions
Energy
Slide 6
Low Power Wireless Technologies
Zigbee
~1 mA average current
Bluetooth Low Energy (BLE)
~0.1 mA average current
ANT
~ 50 uA average current
DASH7 and UHF RFID (battery assisted)
~1 uA average current
Passive UHF RFID
~0.1 uA average current
Slide 7
Coin Cell Battery Lifetime
Coin cell capacities range from 25 mAh to 1000 mAh
CR2330 (~250 mAh) lasts:
~30 years with 1 uA current
~3 years with 10 uA current
~3 months with 0.1 mA current
~2 weeks with 1 mA current
Shelf life: 5 to 10 years Image from http://www.ipanasonic.com
Slide 8
Passive UHF RFID Systems
RFID tag
Chip
1 2
RCS 2
RCS 1
Reader transmits and receives simultaneously
Tag is powered by RF, scatters data back by modulating its impedance
Attractive features: low cost of the tags, long lifetime
Standardized protocol: Gen2 (ISO 18000-6C)
Slide 9
What is Measured in UHF RFID Sensing
On/OFF Sensing
Powered tag presence (read /no read)
ID modulation
Which ID is readable
Analog sensing with tag antenna
Minimum power to read the tag, RSSI and phase of the received tag signal
Dedicated sensors
Tag user data is supplied by specific sensors
Slide 10
Tag signal constellation
-30
-20
-10
0
10
20
30
-30 -20 -10 0 10 20 30I (mV)
Q (m
V) Qac
Iac
Minimum Power, Tag RSSI and Phase
Simple microwave model of the tag
Minimum transmit power to read the tag
Tag signal power at the reader
tagpathtmin PpGGP
ac
ac
2ac
2ac
22path
2tt
IQarctan
IQKpGGPRSSI
mismatch onpolarizati
gain pathgain antenna transm.
ysensitivit taggain rbackscatte
power incident
p
GG
PKP
path
t
tag
inc
Pinc
K Pinc
Slide 11
First RFID Sensing Tag –
The Great Seal Bug (1945)
Eavesdropping device designed by Leon Theremin was built into the Great Seal and given to US ambassador in Moscow in 1945
Backscattered a harmonic of the 330 MHz CW signal, AM modulated by sound
Was discovered only in 1952 by accident by British radio operator
On display in NSA National Cryptologic Museum (Washington, DC)
Images from http://www.spybusters.com/Great_Seal_Bug.html
Slide 12
On/Off Sensing with Tag Antenna
Tag either receives enough power to turn on and respond or not. This allows to sense the environment (material the tag is placed on, etc.)
RFID tag antenna based sensing: Does your beverage glass need a refill? Bhattacharyya, R.; Floerkemeier, C.; Sarma, S.; RFID, 2010 IEEE International Conference on Publication Year: 2010 , Page(s): 126 –
133
Slide 13
Analog Sensing with Tag Antenna
With proper calibration, change in tag signal RSSI and phase (or in the minimum power needed to activate the tag) due to change in tag antenna performance can be related to the change in the environment.
Self-sensing passive RFID: From theory to tag design and experimentation Marrocco, G.; Amato, F.; Microwave Conference, 2009. EuMC 2009. European Publication Year: 2009 , Page(s): 001 –
004
Coupling sensors to UHF RFID tags Huan-Yang Chen; Bhadkamkar, A.; van der Weide, D.W.; Wireless Sensing, Local Positioning, and RFID, 2009. IMWS 2009. IEEE MTT-S Workshop, 2009 , Page(s): 1 –
4
Slide 14
Analog Sensing Example: Proximity Sensor
Reader is mounted on construction equipment
Smart hat emits audible tone when RSSI becomes too high
S. Thomas, J. Teizer, M. Reynolds, SmartHat: A Battery-Free Worker Safety Device Employing Passive RFID Technology", Proceedings IEEE RFID 2011
Slide 15
Analog Sensing: Tag Localization
With proper calibration, tag signal RSSI and phase can be related to the tag position (and, possibly orientation) relative to the reader antenna system
Several methods exist in standard Gen2 UHF RFID:
Markers (readers or tags)
Transmit power control
Antenna beam steering
Tag RSSI based
Tag phase based (time, frequency, spatial domains)
For more information, come to PhD defense “Tag Localization in Passive UHF RFID”
by Daniel Arnitz, TU Graz, May 6, 2011
Slide 16
ID Modulation
Switches (pushed or triggered by change in the environment) connecting ICs with different IDs to the tan antenna
Battery-free wireless identification and sensing Philipose, M.; Smith, J.R.; Jiang, B.; Mamishev, A.; Sumit Roy; Sundara-Rajan, K.; Pervasive Computing, IEEE Volume: 4 , Issue: 1, 2005
, Page(s): 37 –
45
A Cost-Effective UHF RFID Tag for Transmission of Generic Sensor Data in Wireless Sensor Networks Catarinucci, L.; Colella, R.; Tarricone, L.; IEEE Tran. MTT, Volume: 57 , Issue: 5 , 2009 , pp: 1291 –
1296
UHF RFID remote controller, www.favite.com
Image from http://www.favite.com
Slide 17
Custom ICs with Integrated Sensors
A number of custom Gen2 ICs from universities with integrated temperature sensors
A 9 uA, Addressable Gen2 Sensor Tag for Biosignal
Acquisition, Yeager, D.; Fan Zhang; Zarrasvand, A.; George, N.T.; Daniel, T.; Otis, B.P.; Solid-State Circuits, IEEE Journal of, Volume: 45 , Issue: 10, 2010 , Page(s): 2198 –
2209
A System-on-Chip EPC Gen-2 Passive UHF RFID Tag With Embedded Temperature Sensor Jun Yin;
Jun Yi; Law, M.K.; Yunxiao
Ling; Man Chiu Lee; Kwok Ping Ng; Bo Gao; Luong, H.C.; Bermak, A.; Mansun
Chan; Wing-Hung Ki; Chi-Ying Tsui; Yuen, M.; Solid-State Circuits, IEEE Journal of Volume: 45 , Issue: 11, 2010 , Page(s): 2404 –
2420
Slide 18
BAP UHF Gen2 ICs with Serial Interfaces
Direct access to tag memory via serial port interface allows to connect external microprocessor and any sensors to these ICs
Several commercial products:
NXP UCODE (I2C)
IDS SL900A (SPI)
Ramtron
WM72016 (SPI)
EM Microelectronic –
EM4324 (SPI)
Image from http://www.ids-microchip.com
Slide 19
Flexible Architecture: Discrete Tag
Discrete off-the-shelf element based tag with standard low power microcontroller (TI MSP430) and a lot of capabilities (sensing, security, etc.).
Design of an RFID-Based Battery-Free Programmable Sensing Platform, Sample, A.P.; Yeager, D.J.; Powledge, P.S.; Mamishev, A.V.; Smith, J.R.; Instrumentation and Measurement, IEEE Transactions on, 2008 , Page(s): 2608 -
2615
Image from http://ils.intel-research.net
Slide 20
Dedicated Sensing Example with WISP
A separate capacitive touch sensor can be integrated with UHF tag antenna
A capacitive touch interface for passive RFID tags, Sample, A.P.; Yeager, D.J.; Smith, J.R.; RFID, 2009 IEEE International Conference on , Publication Year: 2009 , Page(s): 103 -
109
Best IEEE RFID 2009 conference paper award
Slide 21
Conclusions
The choice of a wireless sensing system requires tradeoffs and depends on things such as:
Number of nodes for peer-to-peer, readers vs tags for master-slave
Desired range
Total cost
Lifetime
Packaging
UHF RFID is attractive due to low tag cost and power consumption
Low power sensing or sensing in close range may use passive mode
More sensors and features and longer range sensing require battery assisted passive mode
Several commercial BAP Gen2 ICs with serial port are available now
Slide 22
Thank You!
Questions or [email protected]
AcknowledgementsRene Martinez and Mike Hansen
(Intermec Technology Office)