Radio Frequency Identification 2369

8/3/2019 Radio Frequency Identification 2369

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Radio Frequency Identification

Done by:

Haitham Habli.


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Table of contents

Definition of RFID. Do they need license? RFID vs other identification systems. Classification of RFID systems. Emerge of passive RFID systems. Operation of data transfer in low-frequency simplified

passive RFID tags. What materials RFID tags can be encased in? Backscatter RFID system. RFID Tag Integrated Circuit. Applications of RFID. Summary.


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what is RFID?

Radio frequency Identification is amony the most technicallyadvanced methods of collecting data automatically.

RFID system generally consists of three basic components: atransponder, a reader and host data processing system.

The transponder is the data-carrying device that is attached tothe object that is to be identified.

The reader is used to communicate with the transponders inorder to read or write the data inside the transponders memory.

The RFID system is useless without the ability to share theinformation of the transponders identified by the reader.

Therefore, the host data processing system has connection to theclosed or worldwide network.


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Do they need license?

RFID systems operate in the unlicensed RF bands knownas ISM (Industrial, scientific and Medical).

It is important to note that while ISM devices do not require

a license, they are still subject to signal emission limitsthat vary by country.


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RFID vs other identification systems

Automatic identification systems include barcode systems, opticalcharacter recognition, smart cards and radio frequency identification.

RFID is the most sophisticated systems among them.

At the moment, using barcodes is very widespread application of carrying

identification data with the item. Compared to barcodes, RFID systems dont need the line of sight contact

with the reader. RFID systems is also more stable against the vulnerableenviroment factors like dirt and wearing that barcodes and opticalcharacter recognition labels face.

Biometric body measurements as an identifcation method are onlyavailable for living beings. In smart cards the data stored in the memorycan be protected but they need a galvanic contact in order to be read.


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Few advantages of RFID over barcode

Multiple tag identification is possible.

It does not require the transponder to be in line-of-sight.

RFID can handle environments like moisture, dirt frost etc.

We can combine the RFID functionality with ElectronicArticle Surveillance (EAS).


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Classification of RFID systems.

Various demands on RFID systems can be set due to differentapplications. Therefore, different types of RFID systems exist.

The RFID systems can be classified into different groups by read range,operating frequency, coupling method and the amount of data and energy

supply of the transponder. According to their operating frequency, RFID systems can be divided into

near and afr field systems.125 kHz and 13,56 MHz systems are near fieldsystems whereas 868 MHz, 915 MHz and 2,4 GHz are far field systems.

Near field systems depends on the areas of the antenna coils and their

mutual positions.

In Far field systems an electric field is used in the coupling and theantennas used are usually dipole, folded dipole (omnidirectionalantennas) and microstrip antennas (directional antennas).


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The transponders can either be passive or active.

Active transponder have a power source of their own. It has theadavantage of longer reading distance as no power has to be transmittedwirelessly. They can perform data collection tasks even when no reader is

present. Passive transponders are powered by the energy radiated by the reader.

They are smaller, have lower cost, and require no periodic maintenance.The source of energy to power the passive tags is the magnetic orelectromagnetic field that the reader omitts.

In case of the electromagnatic coupling the reader uses an antenna toradiate an alternating electromagnetic field at a constant frequency. Theantenna of the transponder receives the signal. The rectifier on the ICconnected to the antenna terminals converts the recieved signal to thevoltage that is used to power the electronics in the transponder.


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The communication procedure in RFID systems can be fullduplex (FDX), half duplex (HDX) or sequential.

In FDX and HDX procedure communication fromtransponder is possible when signal from the reader unit is

on. In sequential the communication is handled in turns. It's

disadvantage is that the wireless power transmitted to thetransponder is not continuous and is interrupted when thetransponder is responding.


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Emerge of Passive RFID systems

Passive tags, on the other hand, are very inexpensive; theycan cost as little as 20 cents apiece, and new technologiesare constantly making them cheaper to integrate intocommon materials and products. Because passive tags areinexpensive, they will likely be the basis of most of thegrowth in RFID implementations, so I will examine thetechnology behind passive tags in detail.

In addition to their low cost, passive tags can also be quitesmall. Current antenna technology limits the smallestuseful passive tag to about the size of a quarter. The largerthe tag, the larger the read range.


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Emerge of Passive UHF RFID systems

Passive UHF RFID systems have many features that speakfor using them in supply chain managment and product lifecycle management.

The most important features of them when SCM and PLMare considered are non-line of sight reading and writing oftags, multiple object identification and the ability to readmoving objects, relatively long, over 1 m read ranges,

possibilties to develop low-cost tags and readers for high-volume applications and the ability to provide a uniqueidentifier for each object using EPC code.

Supply chain managment is the mangemnt and control of all materials and information inthe logistics process from acquisition of raw materials to delivery to the end user.


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Simplified view of data transfer in low-frequency

passive RFID tags (the tag is enlarged for clarity).


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Operation of data transfer in low-frequencysimplified passive RFID tags

A passive-tag reader can constantly broadcast its signal or broadcast iton demand. When a tag comes within the readers range, it receives anelectromagnetic signal from the reader through the tags antenna. Thetag then stores the energy from the signal in an on-board capacitor, aprocess called inductive coupling. When the capacitor has built upenough charge, it can power the RFID tags circuitry, which transmits amodulated signal to the reader. That return signal contains theinformation stored in the tag.

The communication between the reader and passive tag uses one of two

methods to modulate the ID signal. Low-frequency (less than 100 MHz)tags pass information by releasing energy from the capacitor to the tagcoils in varying strengths over time, which affects the radio frequencyemitted by the tag.The reader detects these varying waves and can usethese variances to demodulate the code. Figure shows this load

modulation.


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In higher-frequency (greater than 100MHz) tags

In higher-frequency (greater than 100 MHz) tags, the tagtransmits the signal using backscatter, in which the tags circuitchanges the resistance of the tags antenna.

This change in resistance causes a transmission of RF waves,

which the reader can pick up and demodulate. Passive tags typically operate at frequencies of 128 KHz, 13.6

MHz, 915MHz, or 2.45 GHz, and have read ranges of a fewinches to 30 feet.

Frequency choice depends on the systems environment, whatmaterial the signal must travel through, and the systemsrequired read range


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What materials RFID tags can be encased in?

RFID tags can be encased in many materials. Plastics are avery common material for RFID, forming identificationcards for building access, credit cards or bus fares. Tagscan also go on the back of labels printed on standard inkjet printers, for placement on inventory.


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Backscatter RFID system.


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Backscatter RFID system

In the return link from the transponder to thereader, the proportion of incoming RF signal isbackscattered from the transponder antennaback to the reader antenna. The processingcircuit of the transponder changes the RFimpedance of the transponder antenna andcontrols the amount of this scattered field. In thiscase the modulation of the scattered field

contains the identification information. The transponder is identified when the

backscattered field is received and decoded bythe reader unit.


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Backscatter RFID Transponder.


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What happen?

The modulated signal from the base station is received bythe tag transponder.

Voltage induced at the input terminals of the transponderdue to the RF field from the base station. This voltage will

be detected by the RF front end circuit of the chip and thisDC voltage will be used to charge a high capacitor andprovide the necessary bias for the processing circuitry.

The response of the transponder is determined by the

voltage induced on the transponder that exceeds athreshold voltage, which depends on the properties of thedetection circuit attached to the transponder antenna.


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What happen?

The processing circuit on the chip responds tothe base station commands according to theprotocol and provides a change in the in the RFimpedance and hence provides a detectable back

scattered signal to the base station. Depending on the sensitivity of the receiver and

the minimum transponder threshold voltage wecan establish a read /write range from the basestation. Data can be either read from any memorylocation of the chip or can be written to anyspecified location.


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RFID Tag Integrated Circuit Block Diagram


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The basic components in the chip are

EEPROM

RF front end

Analog section Digital Section

Storage device / battery


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Typical chip specifications are:

Ultra low power 5-15 micro-watts during readoperation and 80-120 micro-watts during writeoperation.

Forward and return links use different types ofmodulation schemes.

EEPROM total 128 bytes. System reserved memory 8 bytes.

Tag identifier (ID) 8 bytes. User memory 112 bytes. Operating temperature -40 to 175'C.


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Applications of RFID.

RFID can be widely used in the applications likeretail, transportation, access control, assetmanagement, supply chain, electronic anti theft.

Few promising applications are source tagging, selfcheck out, video rental, parking, auto registration,non-stop toll collection, access control, badge

readers, subway entry, theme parks, warehouseinventory, package handling, parcels, mail, pallets,etc.


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Find on wikipedia more on appliactions

Current uses: Passports

Transport payments

Product tracking Automotive

Animal identification

RFID in inventory

systems Human implants

RFID in libraries

and others applications.

Potential uses: Replacing barcodes

Telemetry

Patient identification
http://en.wikipedia.org/wiki/RFID#Passports#Passportshttp://en.wikipedia.org/wiki/RFID#Transport_payments#Transport_paymentshttp://en.wikipedia.org/wiki/RFID#Product_tracking#Product_trackinghttp://en.wikipedia.org/wiki/RFID#Automotive#Automotivehttp://en.wikipedia.org/wiki/RFID#Animal_identification#Animal_identificationhttp://en.wikipedia.org/wiki/RFID#RFID_in_inventory_systems#RFID_in_inventory_systemshttp://en.wikipedia.org/wiki/RFID#RFID_in_inventory_systems#RFID_in_inventory_systemshttp://en.wikipedia.org/wiki/RFID#Human_implants#Human_implantshttp://en.wikipedia.org/wiki/RFID#RFID_in_libraries#RFID_in_librarieshttp://en.wikipedia.org/wiki/RFID#Replacing_barcodes#Replacing_barcodeshttp://en.wikipedia.org/wiki/RFID#Telemetry#Telemetryhttp://en.wikipedia.org/wiki/RFID#Patient_identification#Patient_identificationhttp://en.wikipedia.org/wiki/RFID#Patient_identification#Patient_identificationhttp://en.wikipedia.org/wiki/RFID#Telemetry#Telemetryhttp://en.wikipedia.org/wiki/RFID#Replacing_barcodes#Replacing_barcodeshttp://en.wikipedia.org/wiki/RFID#RFID_in_libraries#RFID_in_librarieshttp://en.wikipedia.org/wiki/RFID#Human_implants#Human_implantshttp://en.wikipedia.org/wiki/RFID#RFID_in_inventory_systems#RFID_in_inventory_systemshttp://en.wikipedia.org/wiki/RFID#RFID_in_inventory_systems#RFID_in_inventory_systemshttp://en.wikipedia.org/wiki/RFID#Animal_identification#Animal_identificationhttp://en.wikipedia.org/wiki/RFID#Automotive#Automotivehttp://en.wikipedia.org/wiki/RFID#Product_tracking#Product_trackinghttp://en.wikipedia.org/wiki/RFID#Transport_payments#Transport_paymentshttp://en.wikipedia.org/wiki/RFID#Passports#Passports


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summary

They dont need license.

Founding many application in logistics.

RFID is certainly a usefull alternative identification tool inapplications where large data storages are essential.

getting cheaper.

However the important point in the design is the matchingbetween the front end and the input of the tag antenna terminals.A careful matching network design is the key for obtaining the

best performance.


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QUESTIONS ??

Radio Frequency Identification 2369

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