RFID

June 17, 2009Dr. Erick C. Jones

University of Nebraska-Lincoln

ContentsContents

• RfSCL Lab Introduction

• RFID Overview– Applications

– How It Works• Readers

• Antennas

• Tags

– Challenges

• Questions

RfSCL Lab RfSCL Lab IntroductionIntroduction

RfSCL Facility RfSCL Facility

• Mission: – “Providing integrated solutions in logistics and

other data driven environments through automatic data capture, real world prototypes, and analysis”

• Equipment– Active and Passive Tags/Readers and

software (Matrics, Alien, Samsys), Hytrol conveyor and GCS WMS, HP5555 Mobile Active Reader and Software, RF Code Active tags, SAVI Active Tags and Reader (WMRM/WORM)

RfSCL Team (Fall 2009)RfSCL Team (Fall 2009)• Faculty

– Dr. Erick C. Jones (Director)– Dr. Mike Riley (Associate Director)

• Graduate Students– Dwight Mosbey (DM)- PhD – Liyuan Zhang(LZ),- PhD – Casey Richards(CR), -PhD – Maurice Cavitt(MC)- PhD – Jonathan Carlson(JC), – Nancy Kong(NK), – Jian (Hank) Han(JH) , – Bode Alabi (BA)– Rama Thummalapalli (RT), – Jairo De Jesus(JD)

• Undergraduates– As many as I can “afford”

RfSCL LayoutRfSCL Layout

7

RfSCL FacilityRfSCL Facility

Plan PredictDefine

Measure

Analyze

Identify

Perform

Design Optimize Verify

RfSCL Research Methodology RfSCL Research Methodology DFSS-ResearchDFSS-Research

Measure – Set up accurate metricsMeasure – Set up accurate metrics

Analyze – Current SituationAnalyze – Current Situation

Identify – Relevant TechnologyIdentify – Relevant Technology

Design – New Technology from knowledge Design – New Technology from knowledge

Optimize – Test in live situation and improveOptimize – Test in live situation and improve

Verify – Validate technology in live situationVerify – Validate technology in live situation

PredictPredictPredictPredict

PerformPerformPerformPerform

Define – Clear problem definitionDefine – Clear problem definitionPlanPlanPlanPlan

RfSCL DFSS-ResearchRfSCL DFSS-Research Process StepsProcess Steps

RfSCL Multi Disciplinary RfSCL Multi Disciplinary Approach in RFID ResearchApproach in RFID Research

• Applied Research will be attracted to the lab if presented as unified Multi Disciplinary Team on RFID Research

•RFID has 3 components

•Data Acquisition (IE,CE, CM, AgEng)

•Data Transmissions (EE, Communications)

•Database Management (CIS, MIS)

• A robust applied Research project will incorporate these three components which is best addressed using an multi Disciplinary Team

RfSCL Multi Disciplinary RfSCL Multi Disciplinary Approach VisionApproach Vision

Reader

Tag

AntennaRadio Frequency

Power InductionData reading and writing to the

ICElectrical EngineeringElectrical Engineering

CommunicationCommunicationEngineeringEngineering

Frequency

Computer ScienceComputer Science

Interface ProgramTag ID Mapping

Data Storage and Retrieve

Cattle Tracking (Agriculture Eng.Agriculture Eng.)Warehouse Management (Industrial EngIndustrial Eng.)

ApplicationsApplications

RFID integrated with Supply ChainRFID integrated with Supply Chain(EPC Global )(EPC Global )

RfSCL Supply Chain Logistics RfSCL Supply Chain Logistics Research DefinitionsResearch Definitions

• Applied Research• Facility/Transportation Network Modeling• Warehouse/Manufacturing layout design• WMS/LES/TMS&ERP System integrations• RFID & Barcode systems integration for inventory

“visibility”

• Theoretical Research Models• Mathematical modeling inventory policies • Stochastic modeling of SC networks• Algorithm development for systems which minimize

material handling functions

RfSCL RFID RfSCL RFID Research DefinitionsResearch Definitions

• Applied Research• RFID & Barcode integration into WMS and ERP systems • RFID test of EPC/ISO specs & integration including

Military UID• RFID in industrial application such as conveyors and

automated sorters such as tilt tray sortation• RFID testing of consumables in NASA Space Center

storage containers

• Theoretical Research Models• RFID integration into GPS/GIS• RFID antennae/integrated circuit manufacturing process

design • Alternate active tag standard development

Previous ProjectsPrevious Projects• Supply Chain

• Supply Chain Network modeling for a city government.• Strategic Master Plan for Logistics Operations and Local Company

in including Logistics System Analysis

• RFID• Comparative study: RFID Vs. UCC 128 Barcodes• Cost analysis for implementing RFID in Libraries.• RFID impact on enforcing the use of collaborated tools at a defense

manufacturer• Integration of RFID and GIS system for ticket/seat location• Cost reduction of tags through micro manufacturing process design• Applying RFID technology to comprehensive sports timing in a

marathon• RFID testing of consumables in NASA Space Center storage

containers• Integration of Animal ID into systems for Cattle Tracking• RFID in the Operating Room and Patient tracking• RFID in Construction• RFID economics of automated checkout for retail companies

Current Projects Current Projects (Fall 2009)(Fall 2009)

RFID• Imbedded RFID License Plates (DOT)• ROW Underground RFID tags (TxDOT)• RFID RTLS (NASA)

Logistics• Corporate Supply Chain Analysis• Grain Terminal Network Analysis

www.unl.edu/rfscl

RFID RFID OverviewOverview

Applications of RFID

• Secure Access Control

• Inventory Tracking

• Exxon/Mobil Speedpass

• Electronic Toll Collecting

• Animal Tracking

• Smart Shelves

• Electronic Article

Surveillance (EAS)– clothing stores, libraries – 2 - 10 MHz, up to 80 inches

between gates

How RFID Systems Work

1. The antenna of the interrogator (reader) emits radio signals – EM field transmitted can be continuous– Antennas come in a variety of shapes/sizes

• Can be built-in or external• Circular polarization of reader antenna allows any tag antenna orientation

– Range: 1 inch to 100+ feet

2. Transponders (tags) respond with their unique code– Microchip / Integrated Circuit– Antenna: copper or aluminum coil– Encapsulating material: glass or polymer

3. Reader receives and decodes tag

information and sends it to a computer

via standard interfaces– Fixed or portable– Software available to filter data and monitor the network

Reader/InterrogatorReader/Interrogator

Reader

• A device that captures and processes tag data then passes the digital data to a computer system

• Readers are also known as:– Interrogators– Reader/Writers– Couplers

• Reader function:– supply power to passive and semi-active tags– provide command data to tags– capture returned tag signals and process into a digital bit stream– output data to another output device or to a computer system– write data to the tag

Reader

• Electronics containing a

small radio and

computer with memory

• Transmits radio waves

that are received by the

Tag

• Decodes information

received as radio waves

from the Tag

Reader

In operation, the reader has a very simple purpose:

read the tag(s) in its field and pass appropriate data to a host

• A reader passes the following information to a host:– Tag ID– Timestamp– Antenna ID– Reader ID

• Data is output from the reader by various interface methods

• The host software receiving the reader data makes decisions on what

data is logged into the supply chain enterprise software

Reader

• Readers can be mounted in configurations of:– portal: dock door– conveyor: slow or fast– multi-antenna: portals and conveyors– single antenna: hand held

• Control – Externally triggered

• photo-diode

• network

• PLC

– Continuous operation

• Operation Setup– Reader is configured for the target application– Multi-options during setup

Reader

In Summary:

Readers are radio frequency devices that:

• Transmit and Receive RF signals

• Contain a control unit to execute commands

• Incorporate an interface to transfer data

• Another way to look at a reader other than its immediate

functionality, is that a reader is a node on a network

receiving, aggregating, filtering and transmitting data

Antenna

What is an Antenna?

An antenna is a transducer that converts radio frequency electric

current to electromagnetic waves that are then radiated into space.

• An antenna is said to be vertically polarized (linear) when its electric

field is perpendicular to the Earth's surface.  An example of a vertical

antenna is a broadcast tower for AM radio or the "whip" antenna on

an automobile.

• Horizontally polarized (linear) antennas have their electric field

parallel to the Earth's surface.  Television transmissions in the USA

use horizontal polarization.– Passive RFID Tags are sensitive to polarization effects.

Antenna

• Antennas are designed to resonate (allow the radio wave to be

received) at the desired frequency for LF and HF RFID• UHF antennas reflect the radio wave with a length of ~ ½ a

wavelength

Antenna

• The Perfect Antenna

• Picks up desired signal

• Efficient use of energy

• Filters out undesired signals

• Space envelope is minimum

• Structurally light and strong

• Withstands high wind loads

TagsTags

TagsTags

Barcode identification RFID identification

• A scanner reads reflected light from barcodes and then discerns a sequence of numbers• The numbers are arranged according to a prescribed format, like UPC or EAN, and describe attributes about the item.

• Upon power and command from a reader, the RFID tag emits data, and the reader discerns a sequence of numbers• The numbers are arranged according to a prescribed format, such as EPC’s 96-bit, which also describes attributes about the item.

Data

Power & Commands

0101011010101011

TagsTags

• 639382 = manufacturer’s identification number• 00039 = item number or Stock Keeping Unit, SKU• 3 = check digit to validate correct scanning of code

UPC code EPC-96 bit code

• The EPC code contains: code type, near infinite companies, the UPC SKU, and item’s S/N

TagsTags

4 Essential Physical Components of a Tag

•IC (Integrated Circuit, silicon)•Interconnect media, conductive•Antenna•Substrate

conductive adhesive or solder

antenna connectionsIC

paper or plastic acting as the antenna carrier

• logic• modulator• receiver• transmitter• memory

TagsTags

A Tag’s Micro-chip is a very small package for low cost RFID labels

TagsTags

125 kHz 13.56 MHz 860-950 MHz

• Inductive• 20-70 feet of wire• 50-2,000 turns

• Inductive• Planar or wire• 3-20 turns

• Backscatter• Planar foil or conductive ink

TagsTags

Tag Success FactorsTag Success Factors

•Orientation vs. reader antenna type•Multi-path UHF signals: direct & reflected•Noisy environments: Electro-Magnetic Interference•Moving vs. static tags: time in antenna field

Orientation and location of the tag on an item is critical to maximize success

TagsTags

1. There are several different types of tags at many different frequencies

2. The two main differences in tags are their frequency and their type

3. These type differences are: – Passive: All power comes from reader– Semi Active: Battery assisted power for the IC operation– Active : Battery power assists IC & transmit power

TagsTags

Tags & PowerPassive Tags: <5m

– All power comes from reader– Read distance is constrained by power from reader– Most common and inexpensive tags: >95% of market– epc-Global’s: Class 0+, Class 1, and Class1-Gen 2

(Semi) Active Tags: 10m to <200m– Battery assisted power for the IC operation– IC kept in “stand-by” until reader detected– IC wakes-up and transmits at normal, passive levels– epc-Global’s Class 3 tags, enables sensors, ~Q2’06

Active Tags: 10m to <1000m– Battery power assists IC & transmit power– epc-Global’s Class 4 tags, ~2007– Range is increased for all freqs, and up to 1km for specialized

applications such as U.S. DOD

Active Tagat 2.45GHz

Active vs. Passive Tags

• Active Tags – Battery powered – would require periodic replacement/recharging– Typically read/write, up to 1MB of memory– Greater range (30 meters possible with UHF)– Limited operational life: depends on operating temp. and battery– Ultra Wide Band (UWB) systems use time difference of arrival of transmitted pulses to

triangulate position

• Passive Tags – Powered by energy transmitted by reader– Typically read only, 32 – several Kbytes of memory– Virtually unlimited lifetime, lighter, smaller, and cheaper – 13.56 MHz tags powered by inductive coupling

• EM field emitted by the reader creates a voltage drop in the coil• Tag modulates the signal (amplitude/frequency/phase) and sends its unique code back to the

reader– UHF tags (915 MHz and 2.45 GHz) powered by propagation coupling

• Similar to 13.56 MHz tags, but since signal travels greater distances, field strength decreases with distance (depends on tag orientation and other factors)

Frequency

13.5MHz 915MHz 2.4GHz

RFID Challenges

• Lower Frequencies– Lower cost tags– Higher performance around metals and liquids

• Higher Frequencies– More prone to reflection, refraction, and diffraction– High data transfer rate– Longer read ranges– Interference less of a problem with high frequencies

• Frequency Hopping Spread Spectrum (FHSS) can be used to avoid interference

• Common RFID Frequencies (ISM Band)– 13.56 MHz

• Range up to ~1.5 m with credit card sized tag– 915 MHz

• Typical range up to ~3 m– 2.45 GHz

• Typical Range up to ~5 m • BCR operates at this frequency

RFID Challenges, cont.

• Range– Longer range with larger antenna, higher power, frequency, and

cost– Limited by environmental conditions and metal obstacles

• Standards– ISO – some standards for some frequencies, e.g. ISO 15693 and

ISO 18000 – EPC – Auto-ID Center's Electronic Product Code could replace

the UPC as the standard for UHF; 64, 96, 128 bits of information is stored in a specified format, allowing for billions of unique serial numbers

– Performance of ISO and EPC-compliant tags should be similar, but sticking to standards increases flexibility of technology in the future

RFID Standards RFID Standards

• Standardizing RFID–Similar to universal product code (UPC) for

barcodes.–International Standards Organization (ISO)

42

Questions?Questions?AnnouncementsAnnouncements

• RFID in Logistics is in publication

• Currently working on book with CRC: Taylor Francis

“RFID/AIT in Military Logistics”

Erick C. Jones, PhD, PE, CSSBBAssociate Professor

Industrial and Management Systems EngineeringUniversity of Nebraska – Lincoln

(402) 472-3695, ejones2@unl.edu