Passive Wireless Sensor Tags and High-Function RFID tags are enabled by RF Power Harvesting from RFID infrastructure or other dedicated RF power transmitters.

1. RF-Powered, Passive
Wireless Sensor Tags and
High-Function RFID
Sensors Expo 2012
Chicago, IL (USA)
www.powercastco.com
©2012 Powercast Corporation 1

2. RFID Opportunity Overview
• Basic tags are low-cost and pervasive
• RFID chips are designed for range
• High function tags are limited by power
• Add-on power harvesting provides
significantly more power for tags
• More Power Greater Function,
Higher Value
www.powercastco.com
©2012 Powercast Corporation 2

3. RF Power Sources
Intentional Anticipated Unknown
?
www.powercastco.com
©2012 Powercast Corporation 3

4. Perspective: Communication vs. Power
RF Sensitivity of Wireless Devices
Communication
Power Requirement
mA
Passive RFID
uA Wake-up Receiver
Mobile phones,
0 - nA 802.15.4/ZigBee, Power Harvesting
WiFi, Active RFID
-100 -75 -50 -25 0
Input Power (dBm)
www.powercastco.com
©2012 Powercast Corporation 4

5. Powerharvester® Receivers
 Convert RF input to DC current RF
Power
I/O
 Power/charge management
 Frequency range: 850-950MHz RF
Power
I/O
 RSSI and Data output Capacitor
P1110 P2110
• Continuous Power Output • Pulsed Power Output
• Input power: -5 to 20 dBm • Input power: -12 to 15 dBm
• Output voltage: up to 4.2V • Output voltage: up to 5.25V
www.powercastco.com
©2012 Powercast Corporation 5

6. Powerharvester® Chipset / Reference Design
Features / Performance
 Output from 2 to 5V (higher with custom design)
 Wide tunable range: 1MHz to 6GHz
 RF harvesting down to around -12dBm input
 Small footprint: 0.2 in2 / 1.3 cm2
 Low BOM Cost
RF Harvesting Circuit
• Powercast chipset (3 custom ICs)
• 20-25 other discrete components
www.powercastco.com
©2012 Powercast Corporation 6

7. RFID Tag Power Requirements
Power
Sensors
Computation
Screen Update
Memory Access
ID read
ID Memory High-Function
Tag Tag Tag
www.powercastco.com
©2012 Powercast Corporation 7

8. Power Harvesting for High-Function RFID
Sensor
High-Function Tag Tags
• Identification
• Sensors Biometric
• Processing Proximity
• Biometrics Cards
• Bi-stable displays
• Battery charging
• Low-power radio
RFID / Access Control • LEDs
Reader ePaper
• Audio
Signs / Labels
Powercast receivers provide 10X power efficiency vs. RFID chips
www.powercastco.com
©2012 Powercast Corporation 8

9. RF-power for Bi-Stable Displays
Color Indicators Small Displays Large Displays
Sources: adt GmbH, Vanguard ID Systems, Tego, Pervasive Displays
www.powercastco.com
©2012 Powercast Corporation 9

10. 850MHz Bandwidth
P2110 Normalized Efficiency
-3dBm (500uW) Input
1.2
1
Normalized Efficiency
0.8
0.6 ±20% over 850MHz
0.4
0.2
0
500 700 900 1100 1300 1500 1700
Frequency (MHz)
www.powercastco.com
©2012 Powercast Corporation 10

11. Wide Input Power Range for Short & Long Distance
80
P1110 - 915MHz, 3V
RF-to-DC Conversion Efficiency (%)
70
P2110 - 915MHz, 1.05V Power
60
50
40
30
20
10
Distance
0 Anticipated RFID range
-12 -10 -8 -6 -4 -2 0 2 4 6 8 10 12 14 16 18 20
Input Power (dBm)
www.powercastco.com
©2012 Powercast Corporation 11

12. Harvested Power @ 915MHz
60
P1110 - 915MHz, 3V
50
Harvested Power (mW)
40
30
20 Anticipated RFID range
10
0 P2110 - 915MHz, 1.05V
-12 -10 -8 -6 -4 -2 0 2 4 6 8 10 12 14 16 18 20
Input Power (dBm)
www.powercastco.com
©2012 Powercast Corporation 12

13. Harvested Power @ 915MHz
1
P1110 - 915MHz, 3V
0.8
Harvested Power (mW)
0.6
0.4
0.2
P2110 - 915MHz, 1.05V
0
-12 -11 -10 -9 -8 -7 -6 -5 -4 -3 -2 -1 0 1 2
Input Power (dBm)
www.powercastco.com
©2012 Powercast Corporation 13

14. P1110/P2110 Hybrid for RFID
Charge Time for Sustained 3V Regulated Output
16
14
12
Charge Time (sec)
10
8
0dBi Rx antenna @ 2m
6
0.35mW 1dBi Rx antenna @ 1m
4
2
1.8mW
0
-8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9 10
Input Power (dBm)
Charge time based on 4W RFID reader charging 1000uF capacitor
www.powercastco.com
©2012 Powercast Corporation 14

15. Passive Wireless Sensor Tag Demo
P2110 RF Powerharvester
Radio module
Super
Cap
Microcontroller
Sensors
Temp/Humidity/Light
www.powercastco.com
©2012 Powercast Corporation 15

16. Productized PWST
Operated at 80 feet
from 3W Tx with
Omni-Directional 6dBi directional Rx
Rx antenna antenna
(WSN-1002) (WSN-1001)
www.powercastco.com
©2012 Powercast Corporation 16

17. Sensor Tag Development Tool
Credit card
Programming
form factor
interface
Charging Silicon Labs
capacitor Wireless MCU
915MHz
RF Powerharvester Data Antenna
915MHz
Power Antenna
www.powercastco.com
©2012 Powercast Corporation 17

18. 915MHz(ft.) vs. AverageSensor Tag
Distance
(UHF) Current Delivered (uA)
10000
Charge Current @ 4.0V
1000
Average Current (uA)
100
Average current (uA)
4.0
10
1
2uA @ 15 feet
from 3W Tx
0.1
0 2 4 6 8 10 12 14 16 18
Distance (ft)
Distance (ft.)
www.powercastco.com
©2012 Powercast Corporation 18

19. 13.56MHz (HF RFID) – Efficiency
45
1.2V
40
35
30
Efficiency (%)
1V 2V
25
20
>25% Conversion Efficiency for
harvested power before voltage boost
15
10
Based on preliminary designs
5
using P2110 circuit architecture
0
-10 -5 0 5 10 15
Input Power (dBm)
www.powercastco.com
©2012 Powercast Corporation 19

20. 13.56MHz (HF RFID) – Harvested Power
7 Preliminary designs support charging
2V
6 range of inches to several feet
Harvested Power (mW)
5
1.2V
4
1V
3
2
1
0
-6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9 10 11 12
Input Power (dBm)
www.powercastco.com
©2012 Powercast Corporation 20

21. Summary
• Great opportunities for
high-function RFID
• RF power harvesting is a
key enabler
• Core RF circuit design can
support HF and UHF
www.powercastco.com
©2012 Powercast Corporation 21

22. Powercast Resrouces
• Documentation
– http://www.powercastco.com/resources/
• Wireless power calculator (Excel)
– http://www.powercastco.com/power-calculator/
• Videos and Presentations
– http://www.youtube.com/powercastco
– http://www.slideshare.net/powercast
Emerging P2100 TX91501 P2110 P2110
Technology Powerharvester® Powercaster® Powerharvester® Powerharvester®
www.powercastco.com
©2012 Powercast Corporation 22