Smart Dust: Unique Low Power
Flexible Sensor Networks
Maryland Sensor Network Group
Neil Goldsman, Martin Peckerar, Quirino Balzano,
Shuvra Bhattacharyya, Reza Ghodssi, Gilmer Blankenship
Dept. of Electrical and Computer Engineering
University of Maryland College Park
Outline: Focus on Hardware for Achieving
Smart Dust Motes and Working Network
1.
2.
3.
4.
5.
6.
Overview
Power Efficient Micro RF Circuits
Digital Low Power Circuits and Networking
Ultra Small Antennas
Energy: Micro Super Capacitor-Battery
Energy Harvesting: RF & RF
Overview: Smart Dust Hardware
Smart Dust Node
• Analog Transceiver
• Microprocessor
~1mm
– Communication and
Sensor Control
– Decision making
• Micro-Battery
• Energy Harvesting
• Micro-Antenna
/power
Smart Dust Particle
Low Power Transceiver
Design
Thomas Salter, Bo Yang, Bo Li,
Yiming Zhai and Neil Goldsman
Work Summary
• Last January 2008 Review:
– Tested 2.2GHz OOK receiver.
• Successfully demodulated digital signal
• Still required DC bias, integration with transmitter, integration with digital control,
and integration with antenna.
– Tested 2.2GHz OOK Transmitter:
• Operated but frequency lower than expected.
• Individual die components operated in accordance with design
– Initial studies for benefits of FSK Transceiver began
• Current February 2009 Review:
– 2.2GHz OOK Receiver and Transmitter fabricated and operating as
designed, communicating proved in test.
– Integrated Transmitter and Receiver onto one chip, PCB test hardware
developed
– Improved isolation of transmitter and receiver
– Designed bias circuits, under fabrication for 2.2GHz OOK receiver
– Designed and fabricated and Tested: 2.2GHz FSK.
– Designed and fabricated 10GHz LNA
– Designed 20GHz FSK, under fabrication.
– Designed 20GHz ASK, under fabrication.
– Fabricated part COTS part custom Transceiver with 2cm footprint
– Initial studies for UWB transceiver began.
Communication between 2.2GHz TX-RX
TX
Layout
Simplified Schematic Drawing
RX
Measured results
Data rate: 20.16kHz (up to 300kHz)
Yellow: RX output, -0.6 ~0.6V, AC
coupling (x5 cable)
Blue: TX fed-in data: 0~0.9V
generated by function generator
2.2 GHz Transceiver with on chip
Power Control switch
TX
Power
rail
Control
Switch
RF Switch
RX
2.2GHz FSK Receiver using Ultra Low Power Mixer
Mixer
Receiver Test Results:
•
•
•
Signal at buffered osc
•
BFSK Input: 2.2GHz+8MHz freq modulation •
8MHz lock-in frequency (limited by signal
generator)
Output of FM receiver.
FM Input: 2.2 GHz FM+1MHz
modulation
20GHz Receivers
20 GHz ASK Receiver, under fabrication
20 GHz FM Receiver, under fabrication
Can detect a 2MHz freq difference in 35MHz
(20.719~20.754GHz) lock-in range
Ultra Low Power
mixer and amplifier
OOK Receiver: Fabrication and Results
• fabricated utilizing 130
nm IBM process
BER vs RF Bias
1.00E+00
1.00E-01
BER
1.00E-02
-83 dBm RF
Signal
Strength
1.00E-03
1.00E-04
-90 dBm RF
Signal
Strength
1.00E-05
1.00E-06
0.38
0.39
0.4
0.41
0.42
LNA Bias Voltage
0.43
0.44
0.45
Improvement Over the Past Year
Prior
Generation
Measurements
Receiver Performance
Sensitivity (BER=10-3)
Power Consumption
Energy per Bit
Data Rate
New
Generation
Measurements
-50 dBm
2.77 mW
2.77
nJ/bit
1 Mbps
Single-Stage LNA Performance
Gain
13 dB
Power Consumption
2.7 mW
Noise Figure
3.4 dB
RF Scavenging Demodulator
Gain vs Voltage
Rectifier
10.6 dB
Power Consumption
0 mW
Baseband
Voltage Gain
Filter Bandwidth (3dB)
Power Consumption
30 dB
1 MHz
.07 mW
Receiver Performance
Sensitivity (BER=10-3)
Power Consumption
Energy per Bit
Data Rate
-90 dBm
1.55 mW
1.5 nJ/bit
1 Mbps
Multi-Stage LNA Performance
Gain
45 dB
Power Consumption
1.5 mW
Noise Figure
3.6 dB
RF Scavenging Demodulator
Gain vs Voltage
Rectifier
17.6 dB
Power Consumption
0 mW
Baseband
Voltage Gain
Filter Bandwidth (3dB)
Power Consumption
30 dB
1 MHz
.05 mW
40 dB more sensitive while consuming almost 50% less power!
Comparison to Other Receiver Designs
Presented in the Literature
Comparison of Low Power Receiver Designs
1.E-06
Energy per Bit (J/bit)
Daly [30]
Porret [15]
1.E-07
More sensitive
This work
Molnar [112]
1.E-08
Better
Less power
1.E-09
1.E-10
0
-20
-40
-60
Sensitivity (dBm)
-80
-100
Prior work by other in the field achieves excellent sensitivity OR very low
power consumption. This work is unique in that it achieves BOTH.
Digital/Low Power Design and
Optimization for the
Maryland Smart Dust Project
Chung-Ching Shen, Roni Kupershtok,
Shuvra Bhattacharyya and Neil Goldsman, with
contributions from William Plishker
February, 2009
Design Flows for the Smart Dust Digital System
Application development
software
Implementation using
C
Implementation using
Verilog
Download hex file to
hardware prototypes
hardware
Design tool
Synopsys Synthesis
Design tool
FPGA Synthesis (Xilinx ISE)
Download binary file to
Xilinx FPGA
ASIC
Compile source code to
generate hex format
output file
Design tool
Verilog Simulator (ModelSim)
FPGA platform
MCU platform
Design tool
IAR Embedded Workbench
Floorplanning
Placement
Routing
Fabrication
Design Summary for the Smart Dust Digital ASIC
Application
– Distributed Line-crossing
Recognition (DLCR)
Design summary
– 8 major modules and12 sub
modules for implementing
DLCR algorithm and TDMA
protocols
– All the modules have been
implemented with VerilogHDL.
– All the modules have been
tested and verified with a
FPGA developing platform.
– I/O interfaces are designed
for interacting with analog
transceiver modules
ReceivePacket
PacketFilter
ClockCounter
Control
PreSync
Unit
Control
S
e
n
s Core
e
TransmitPacket
15
Mixed-signal Integration for the Smart Dust
Digital/Analog ASICs
Analog transceiver modules
Smart dust digital ASIC
RX data
RX control
TX control
TX data
Digital
ASIC
Fabricated Chip for the Smart Dust Digital ASIC
Process: MOSIS AMI 0.5 µm
Voltage: 5 V
Target Freq: 20KHz
Power : 1.2 mW
Chip Size: 2.4 mm2
Pads: 40 (including test pins)
Process: IBM 0.13 µm
Voltage: 1.2 V
Target Freq: 20KHz
Power : 0.014 mW
Chip Size: 1.0 mm2
Pads: 20 (including test pins)
Process: MOSIS AMI 0.5 µm
Chip Size: 2.4 mm2
# of Transistors: ~ 30,000
17
Testing Results for the Smart Dust Digital ASIC
ASIC 0 transmits data to ASIC 1
via wired connection
ASIC 1
ASIC 0: Transmitted data
ASIC 1: Have received data and validated it
ASIC 0
Data validation: ID must be matched as well as parallel bit check
18
Generations for theFabrication
Smart
Dust
Chip design
Mote
Packaging
0.24cm
0.24cm
Smart dust digital ASIC
(microprocessor)
TX
0.2cm
Smart dust transceiver
ASICs
RX
0.2cm
FPGA-MCU
1.2cm
PCB design
MCU
MCU
MCU
19
Power and Size Comparison for Sensor Network
Hardware Systems
SNoW5 [3]
*Power: 73.1mW
Size: 50X85mm
Size
Tmote Sky [2]
*Power: 58.5mW
Size: 32X80mm
SHIMMER [1]
*Power: 54mW
Size: 50X25X12.5mm
Btnode [5]
*Power: 105mW
Size: 58X33mmMica2 [6]
MicaZ [4]
*Power: 88.2mW
*Power: 117mW
Size: 58X32X7mm
Size: 58X32X7mm
Mica2Dot [7]
*Power: 117mW
Size: 25X6mm
Smart
Dust
*Power: 4.8mW
Size: 20X14X12mm
*CPU on, Radio RX/TX on
Power
References
[1] B. Kuris and T. Dishongh. SHIMMER Hardware Guide Rev 10, October
2006. (http://www.eecs.harvard.edu/~konrad/projects/shimmer/)
[2] Moteiv Tmote Sky Datasheet, November 2006. (http://www.moteiv.com/)
[3] M. Baunach, R. Kolla, and C. Muhlberger. Snow5: a modular platform for
sophisticated real-time wireless sensor networking, Institut fur Informatik,
University of Wuerzburg, Technical Report 399, January 2007.
[4] MICAz Datasheet Rev A. Crossbow. (http://www.xbow.com/)
[5] BTnode rev3 Hardware Reference. ETH Zurich.
(http://www.btnode.ethz.ch/)
[6] MICA2 Datasheet Rev A. Crossbow. (http://www.xbow.com/)
[7] MICA2Dot Datasheet Rev A. Crossbow. (http://www.xbow.com/)
21
•
Journal
–
–
•
Publications
C. Shen, R. Kupershtok, S. Adl, S. S. Bhattacharyya, N. Goldsman, and M. Peckerar. Sensor
support systems for asymmetric threat countermeasures. IEEE Sensors Journal, 8(6):682-692,
June 2008.
C. Shen, W. Plishker, D. Ko, S. S. Bhattacharyya, and N. Goldsman. Energy-driven distribution of
signal processing applications across wireless sensor networks. Submitted to ACM Transactions
on Sensor Networks.
Conference
–
–
–
–
–
–
C. Shen, W. Plishker, and S. S. Bhattacharyya. Design and optimization of a distributed,
embedded speech recognition system. Proceedings of the International Workshop on Parallel
and Distributed Real-Time Systems, Miami, Florida, April 2008.
M. Peckerar, C. Shen, S. S. Bhattacharyya, and N. Goldsman. Integrated Multi-layer Design of
Ad-Hoc Smart Small Sensor Networks. Proceedings of the Government Microcircuit Applications
and Critical Technology Conference, Las Vegas, Nevada, March 2008.
C. Shen, W. Plishker, S. S. Bhattacharyya, and N. Goldsman. An energy-driven design
methodology for distributing DSP applications across wireless sensor networks. Proceedings of
the IEEE Real-Time Systems Symposium, Tucson, Arizona, December 2007.
C. Shen, R. Kupershtok, S. S. Bhattacharyya, and N. Goldsman. Design and implementation of a
device network application for distributed line-crossing recognition. Proceedings of the
International Semiconductor Device Research Symposium, College Park, Maryland, December
2007.
C. Shen, R. Kupershtok, S. S. Bhattacharyya, and N. Goldsman. Design techniques for
streamlined integration and fault tolerance in a distributed sensor system for line-crossing
recognition. Proceedings of the International Workshop on Distributed Sensor Systems, Honolulu,
Hawaii, August 2007.
C. Shen, R. Kupershtok, B. Yang, F. M. Vanin, X. Shao, D. Sheth, N. Goldsman, Q. Balzano, and
S. S. Bhattacharyya. Compact, low power wireless sensor network system for line crossing
recognition. Proceedings of the International
22Symposium on Circuits and Systems, New Orleans,
Louisiana, May 2007.
Efficient Antennas for Motes
Dimensions << λ/4
BO YANG, XI SHAO, Q. BALZANO AND
NEIL GOLDSMAN
Work summary
• Last January 2008 Review:
– Fabricated FICA for 2.2 GHz /2.4 GHz with 1.1 mm x 1.1 mm ground
plane.
– Tested 2.2 GHz FICA outdoor.
– Measured FICA performance with in-house designed On-Off Keying
(OOK) receiver
– Developed circuit model of FICA
– Expected 3D integration of transceiver, with lowest form factor in the
world
– Investigation of ground plane size effect under way
• Current February 2009 Review:
– Applied FICA circuit model into system design optimization.
– Measured 916MHz and 2.2GHz FICA radiation pattern in Anechoic
Chamber
– Implemented 3D integrated transceiver, with world’s record low form
factor.
– Tested 20mm x 15 mm x 15 mm radio (including FICA, radio, sensor,
battery, etc.)
Short Review of ESAs
• ESA is:
– a radiating resonator
– compact and efficient
– minimum ohmic losses
– short transmission line
• To Radiate ESA:
– Need large currents and
large e-fields over the small
volume (resonance)
– Need impedance
transformer to feed with 50

– Need low loss materials
• ESA Plusses
– Small volume
– More room for electronics
– Attractive product looks
– High tech impression
– Wide applicability
– Low manufacturing cost
• ESA Minuses
– Adverse reactance (l or
1/c)
– Low radiation resistance
(m)
– Low effiency (ohmic losses)
– Narrow band
– Low gain
– Difficult to match to 50 
An Efficient ESA:
FICA (F-Inverted Compact Antenna)
• Transmision line propagation constant
k=ω√LC
• Helical transmission line (high L)
• Strong coupling to ground (high C)
• Short helix resonant size
• Minimum number of turns
• Embedded reactive impedance
transformer
• Strong electric dipole radiation current
2.45GHz FICA Integrated with a
Mote
Exposed part is the antenna
12mm
3.5mm
4mm
Full transceiver
radio and battery
is enclosed in the
black box.
20mm
Microphone sensor
• The wave length at 2.45GHz is 12.24cm.
• The dimension of 2.45GHz FICA is shown in the photo.
FICA Radiation Pattern
FICA tested in anechoic
chamber, radiation
pattern matches
simulation.
FICA vs. COMPETION
FICA Equivalent Circuit for System
Optimization
FICA Publications
•
Patent:
– B. Yang, F. Vanin, X. Shao, Q. Balzano, N. Goldsman, G. Metze, Low Profile
F-Inverted Compact Antenna (FICA), filed by University of Maryland, Jun.
2007, patent pending.
•
Journal:
– B. Yang, X. Shao, Q. Balzano, N. Goldsman, G. Metze, “916 MHz F-Inverted
Compact Antenna (FICA) for highly integrated transceivers,” Antennas and
Wireless Propagation Letters, to be published.
•
Conference:
– B. Yang, X. Shao, Q. Balzano, N. Goldsman, “ Integration of small antennas
for ultra small nodes in wireless sensor networks,” in IEEE International
Semiconductor Device Research Symposium Dig. (ISDRS), College Park,
MD. USA., Dec. 2007.
– B. Yang, F. Vanin, C. Shen, X. Shao, Q. Balzano, N. Goldsman, C. Davis, “A
low profile 916 MHz F-Inverted Compact Antenna (FICA) for wireless sensor
networks,” in IEEE Antenna and Propagation International. Symposium. Dig.,
pp. 5419-5422, Honolulu, HI. USA., Jun. 9-15, 2007.
– C-C. Shen, R. Kupershtok, B. Yang, F. Vanin, X. Shao, D. Sheth, N.
Goldsman, Q. Balzano, S. S. Bhattacharyya, “Compact, low power wireless
sensor network system for line crossing recognition,” in IEEE International
Symposium on Circuits and Systems (ISCAS), pp. 2506-2509, New Oreland,
LA. USA., May 27 -30, 2007.
CONCLUSION
•
•
•
•
•
Extremely small antenna
High efficiency for size
Bandwidth compatible with theoretical q
Radiation: isotropic as possible
Performance better than or comparable to
larger commercial antennas
433 MHz
Body Antenna
Q. Balzano, Bo Yang, Xi Shao,
Neil Goldsman
Presented in Classified Review
Flexible Thin Film
Battery/Supercapacitor Hybrid
Power Sources
Martin Peckerar, Yves Ngu, Zeynep Dilli, Mahsa
Dornajafi, Kwangsik Choi, Myunghwan Park and
Neil Goldsman
Department of Electrical and Computer
Engineering
University of Maryland
College Park, MD 20742
Project Goals
• To achieve a mechanically flexible power source
that can conform to a range of surface topologies
(electronic packaging material, bridge abutments,
supporting struts, etc.)
• To create a galvanic cell/supercapacitor hybrid
capable of long term, low power level sourcing as
well as power “burst mode” operation
• To create a power supply that is more easily
charged by RF (and mechanical energy
scavenger) sources: e.g. , a cell that recharges at
low (~1V) voltage
• To create an “environmentally safe” power source
to eliminate the toxicity issues associated with
lithium
Negative lead
Negative lead
Filter paper +
electrolyte
Zinc sheet
Gold coated
graphite
Powder mix
Positive lead
Lexan package
Positive lead
Single cell
Double stacked cell
The electrolyte is made of a solution of ethylene glycol, ammonium hydroxide,
boric acid + nitric acid OR phosphorus acid
We Have Successfully Run
Smart Motes with the RuOx
Batteries
We Have Demonstrated LowVoltage RF charging
We Have Demonstrated “BurstMode” Operation
We Have Driven Flexible Electronics
Platforms With the RuOx Cells
Comparison of Thin Film Galvanic
Cells
Conclusions
• WE HAVE DEMONSTRATED:
– A FLEXIBLE THIN-FILM POWER SOURCE WITH
GREATER STORAGE CAPACITY THAN ANY OTHER
APPEARING IN THE LITERATURE
– WE HAVE OPERATED THE “SMART DUST” MOTE IN
FULL T/R MODE FOR OVER 4.5 MINUTES
– THE CELL EXHIBITS INTERESTING “REGENERATION”
BEHAVIOR
– WE HAVE DEVELOPED A LOW VOLTAGE
RECHARGING CELL
– WE HAVE USE OUR CELL TO OPERATE FLEXIBLE
ELECTRONICS
Future
• Ultra Low Power Transceivers
– Ultra Wide Band Radios
– Broad Band Antennas
– Dedicated Signal Processing & Digital Control
• Batteries for Networks
– Planar
– Geometrically Configurable
– Remote Chargeability