This document discusses RF energy harvesting and wireless power transmission for low-power applications. It describes how microwatts of power transmitted over radio waves can be used to trickle charge batteries or power battery-free devices. Key factors that determine the received power are the power of the RF source, distance from the source, size of the receiving antenna, and transmission frequency. Examples of applications that could benefit from this technology include wireless sensors for industrial monitoring and smart buildings.

1. RF Energy Harvesting and Wireless Power
for Low-Power Applications
Emerging P2100 TX91501 P2110 P2110
Technology Powerharvester® Powercaster® Powerharvester® Powerharvester®
www.powercastco.com
©2012 Powercast Corporation
April 6 2012 1

2. Powercast Technology Overview
• Micro-power over distance using common radio waves
– Microwatts (µW) to low milliwatts (mW)
• Micro-power is useful for: RF Source
Powercast Enabled
– Trickle-charging batteries Devices
– Powering battery-free devices
• Received power is determined by multiple factors:
– Power of RF source
– Distance from RF source
– Size / performance of receiving antenna
– Transmission frequency (e.g. 915MHz)
www.powercastco.com
©2012 Powercast Corporation 2

3. Why RF-based Wireless Power?
Industrial Minimizes Operating Costs
 Eliminates cost to hard wire or replace batteries – e.g. wireless sensors
 Eliminates service downtime caused by depleted batteries
 Reduces battery handling and disposal
OEMs Improved Product Design
 Sealed devices – less expensive enclosures and manufacturing
 Embedded power – eliminate wires, cables, connectors
 Reliability – improved durability, reduced product failures, eliminate ESD
End-Users Convenience and Usability
 Placement flexibility – no charging mats or charging stations
 Transparent charging – no user action required
 Embedded power – eliminate wires, cables, connectors
www.powercastco.com
©2012 Powercast Corporation 3

4. Perspective: Communication vs. Power
RF Sensitivity of Wireless Devices
Power Requirement
mA Communication
uA Wake-up Receiver
0 - nA Power Harvesting
-100 -75 -50 -25 0
Input Power (dBm)
www.powercastco.com
©2012 Powercast Corporation 4

5. RF Power Sources
Intentional Anticipated Unknown
?
www.powercastco.com
©2012 Powercast Corporation 5

6. Average Power Consumption
Recommended Power Profiles
Recommended Profiles for
RF-based Wireless Power
Low-power
Wireless
Sensors
Hours Days Weeks Months Years
Battery Run Time
www.powercastco.com
©2012 Powercast Corporation 6

7. Full Suite of Wireless RF Solutions
Powerharvesters RF
• Modules Transmitters
• Chipset
• License
Evaluation Engineering
Boards Services
Development Kits
www.powercastco.com
©2012 Powercast Corporation 7

8. Powercast Technology Advantages
80
 High efficiency over a broad range
70
 Load resistance
RF to DC Conversion Efficiency
60
 Input power
50
 Recharging current 40
(%)
 No Maximum Power Point Tracking 30
(MPPT) required 20
Example of other solutions
10
 Over 850 MHz operating bandwidth 0
 Essential for ambient energy harvesting -5 0 5
Input Power (dBm)
10 15 20
 Easy scalability for geographic regions P2110 Harvester Efficiency
-3dBm (500uW) Input, 1V Load
using different frequencies 1.2 1.2
Normalized Efficiency
1.0 1
Normalized Efficiency
 Result … 0.8 0.8
 Better performance
0.6 0.6
0.4 0.4
 More power 0.2 0.2
 Simplified design-in 0 0
500
500 700
700
900
900
1100
1100
1300
1300
1500
1500
1700
1700
Frequency (MHz)
Frequency (MHz)
www.powercastco.com
©2012 Powercast Corporation 8

9. Powerharvester® Receivers
Low Volume Applications and Prototyping
 Convert RF input to DC current
Power
 Power/charge management RF
I/O
 Frequency range: 850-950MHz
 RSSI and Data output RF
Power
I/O
 Designed for standard 50Ω antennas Capacitor
P1110 P2110
Continuous Power Output Pulsed Power Output
• RF range: -5.0dBm to 20dBm • RF range: -11.5dBm to 15dBm
• Output voltage: 1.8V to 4.2V • Output voltage: 1.8V to 5.25V
(configurable) (configurable and regulated)
• Range of at least 3 meters • Range of at least 10 meters
www.powercastco.com
©2012 Powercast Corporation 9

10. Powerharvester® Performance Comparison
80
RF-to-DC Conversion Efficiency (%)
P1110 - 915MHz, 3V
70
P2110 - 915MHz, 1.05V Power
60
50
40
30
20
10
Distance
0
-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 10

11. Bandwidth Increases with Received Power
P2110 Harvester Efficiency
-3dBm (500uW) Input, 1V Load
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 11

12. Powerharvester® Chipset / Reference Design
High Volume Applications
 Flexible implementation
 Output from 2 to 5V (higher with custom design)
 Wide tunable range: 1MHz to 6GHz
 RF harvesting down to around -12dBm input
 Same performance as P1110 / P2110
 Estimated BOM: $5-6 @ 3K, $3-5 @100K, <$2 @1M+
 Reference designs available for license
RF Harvesting Circuit
• Powercast chipset (3 custom ICs)
• 20-25 other discrete components
• Small footprint: 0.2 in2 / 1.3 cm2
www.powercastco.com
©2012 Powercast Corporation 12

13. TX91501 Powercaster® Transmitter
6.25” width • 915 MHz center frequency
• FCC and IC certified
• RoHS compliant
• DSSS modulation (power)
• ASK modulation (data)
6.75” • 1W or 3W EIRP
height
– TX91501-1W-ID
– TX91501-3W-ID
• ~60 beam pattern
• Data broadcast (factory-set)
• Plug-and-play installation
1.63” depth • Powers virtually unlimited
number of Powerharvesters
Power Jacks (2) – 5V Status Indicator LED
Back – for tabletop placement Green – Transmitting • Design available for license
Bottom – for wall mounting Red – Fault Condition
www.powercastco.com
©2012 Powercast Corporation 13

14. Lifetime Power® Development Kits
P2110-EVAL-01 P2110-EVAL-02
 Complete system for battery-free  Complete system for wireless battery
wireless applications charging
 Jointly developed with Microchip  Developed in conjunction with Infinite
 Designed for wireless sensing applications Power Solutions
using MiWi protocol  Features IPS THINERGY® Energy Cell
• RF Transmitter (TX91501) • RF Transmitter (TX91501)
• (2) P2110 Evaluation Boards (P2110-EVB) • P2110 Evaluation Boards (P2110-EVB)
• (2) 6dBi Directional Antennas • 6dBi Directional Antenna
• 1dBi Omni-directional Antenna
• (2) 1dBi Omni-directional Antennas
• Battery Charging Board (BAT-EVAL-01)
• (2) Wireless Sensor Boards (WSN-EVAL-01) • THINERGY® Micro-Energy Cell Evaluation Card
• Microchip 16-bit XLP Development Board • Cable for connecting to THINERGY® ADP
• Microchip MRF24J40 PICtail/PICtail Plus • TI eZ430-RF2500 Wireless Development Tool
daughter card
• Microchip PIC-kit 3 programmer/debugger
www.powercastco.com
©2012 Powercast Corporation 14

15. Intentional Transmitter Power
uW Available Power Before Conversion (Estimated)
180
160
140
120
100
80 3W EIRP Transmitter
915MHz
60 6 dBi
Receiver
40 Antenna
20
0
0 5 10 15 20 25 30
Distance (meters)
www.powercastco.com
©2012 Powercast Corporation 15

16. Intentional Transmitter Coverage
Coverage Area – 3W transmitter (TX91501)
@ 60 feet ≈ 1900 ft2
@ 80 feet ≈ 3300 ft2
Average ≈ 2500 ft2
60 ft 80 ft
Effective
range
increases with
improved RF
sensitivity of
the receiver
and antenna
performance
www.powercastco.com
©2012 Powercast Corporation 16

17. Ambient Wi-Fi Power
uW
400 Available Power Before Conversion (Estimated)
350
300 50mW
250
200 0 dBi
150 6 dBi
~4uW Receiver
100 Antenna
50
0
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0
Distance (meters)
www.powercastco.com
©2012 Powercast Corporation 17

18. Applications: High-Function RFID
Harvest additional RF power for enhanced functionality
• Identification
• Sensors
• ePaper display RFID Sensor Tags
• Battery charging
• Low-power radio
RFID • LEDs
Reader • Buzzer
High-Function Tag
ePaper Signs / Labels
Powercast receivers provides 10X the power vs. traditional RFID chips
www.powercastco.com
©2012 Powercast Corporation 18

19. Applications: Wireless Sensors
Building Automation Structural Monitoring Defense Data Centers
Security Industrial Monitoring Energy Management Smart Grid
www.powercastco.com
©2012 Powercast Corporation 19

20. Applications: Bulk Trickle Charging
 Freedom of placement
 Eliminate wires and connectors
 Automatic/transparent charging
 Multiple battery types/chemistry
www.powercastco.com
©2012 Powercast Corporation 20

21. Applications: Consumer Electronics
Mice / Keyboards Game Controllers Media Remotes
Audio / Headsets Health / Fitness Low-power Displays
mWs to 3ft / >100uW to 10ft
www.powercastco.com
©2012 Powercast Corporation 21

22. Wireless Power Calculator
• Quick Power
Estimates
• Available
Online
• Simple to Use
http://www.powercastco.com/power-calculator/
www.powercastco.com
©2012 Powercast Corporation 22

23. For More Information
www.powercastco.com
www.powercastco.com
©2012 Powercast Corporation 23