RFID Part-19

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RFIDRadio Frequency Identification


What is RFID?• RFID is a technology, whose origins are found in the

WWII era, that incorporates electromagnetic or electrostatic coupling in the RF portion of the EM spectrum to uniquely identify an object, animal or person. It is also gaining increasing use in industry as an alternative to the bar code.

• Requires a transceiver, antenna, and transponder• Can operate in Passive or Active Modes


What is RFID?

• RF signals transmitted by the transceiver activates the transponder, which transmits data back to the transceiver.• Transponder is powered by EM waves emitted by the

transceiver

• Various frequencies are used depending on the application

• Requires no line-of-sight (like bar-codes)


RFID Applications

• Tracking Books in Libraries• Inventory Tracking

• Walmart required it of their top 100 vendors

• Authorized building access (Prox Cards)• Passports (US passports recently) • AmEx Blue credit card• Prison inmates (embedded)


RFID Applications

• For toll booths (or any “pay for entry” system)• Airport Baggage ID• Car keys, wireless entry and ignition• Animals• Hospital Patients

• Instant history tracking


RFID Standards

• Tracking Animals • ISO 11784 – Specifies the structure of the ID code• ISO 11785 – Specifies how transponder is activated• ISO 14223/1 – Specifies RF code for advanced transponders

• Credit Cards • ISO 15693 – Specifies modulation and coding schemes

• Passports and proximity cards • ISO 14443 – Specifies modulation and coding schemes

• General Frequency bands • ISO 18000 series


Standard RFID Operating Frequencies

• ISO 18000-2• <135 KHz

• ISO 18000-3• 13.56 MHZ

• ISO 18000-4• 2.45 GHz

• ISO 18000-6• 860-960 MHz

• ISO 18000-7• 433 MHZ (active)


ISO 18000-2 ~ 135 kHz

ISO 18000-3 ~ 13.56 MHz

ISO 18000-6 ~ 800-960 MHz

ISO 18000-4 ~ 2.45 GHzISO 18000-7 ~ 433 MHz

Standard RFID Operating Standard RFID Operating FrequenciesFrequencies


ISO 18000-2• Operates at >135 KHz• Inductive• Unaffected by presence of water• Short range (a few centimeters)• Fairly costly because of coil in transponder


ISO 18000-3• Operates at 13.56 MHz• Inductive • Lower cost ~ 35 cents• Thin flexible form factor ( smart label )• Read / write capable• Unaffected by water (but has to be tuned to item)• Mid range, 70 – 125 cms• Two flavors:

• Mode 1 Standard ISO 15693 data rate (26 kb/s) • Mode 2 High speed interface (848 kb/s)


ISO 18000-4• Operates at 2.45 GHz• Propagating• Dual Mode

• Passive Backscatter• Passive tag currently out of fashion

• Active High data rate• Long range in active version (100 m+)

• Affected by water (signal absorbed…microwave)• Read / write capable• Moderate cost• Small antenna


ISO 18000-6 A/B• Operates between 860 – 960 MHz• Propagating• Long range 2-5 meters• Low cost• High data rates• “Frequency agile”• Read / write capable• Relatively large antenna• The future for mass application RFID


ISO 18000-7• Operates at 433 MHz• Active• Long range - many meters• High cost• High data rates• Read / write capable• Manifest tags- DoD


RFID system components


RFID TAGS


•Tags can be attached to almost anything:• Items, cases or pallets of products, high value goods• vehicles, assets, livestock or personnel

•Passive Tags• Do not require power – Draws from Interrogator Field• Lower storage capacities (few bits to 1 KB)• Shorter read ranges (4 inches to 15 feet)• Usually Write-Once-Read-Many/Read-Only tags• Cost around 25 cents to few dollars

•Active Tags • Battery powered• Higher storage capacities (512 KB)• Longer read range (300 feet)• Typically can be re-written by RF Interrogators• Cost around 50 to 250 dollars

RFID RFID tagstags


Tag block diagram

Antenna

Power Supply

Tx Modulator

Rx Demodulator

Control Logic(Finite State machine)

MemoryCells

Tag Integrated Circuit (IC)


RFID tag memory • Read-only tags

• Tag ID is assigned at the factory during manufacturing• Can never be changed• No additional data can be assigned to the tag

• Write once, read many (WORM) tags• Data written once, e.g., during packing or manufacturing

• Tag is locked once data is written• Similar to a compact disc or DVD

• Read/Write • Tag data can be changed over time

• Part or all of the data section can be locked


RFID readers• Reader functions:

• Remotely power tags• Establish a bidirectional data link• Inventory tags, filter results• Communicate with networked server(s)• Can read 100-300 tags per second

• Readers (interrogators) can be at a fixed point such as• Entrance/exit• Point of sale

• Readers can also be mobile/hand-held


Some RFID readers

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Reader anatomy

915MHzRadio

NetworkProcessor

Digital SignalProcessor(DSP)

13.56MHzRadio

PowerSupply


RFID application points

• Assembly Line

Shipping Portals

Handheld Applications

Bill of LadingMaterial Tracking

Wireless


RFID applications• Manufacturing and Processing

• Inventory and production process monitoring• Warehouse order fulfillment

• Supply Chain Management• Inventory tracking systems• Logistics management

• Retail• Inventory control and customer insight• Auto checkout with reverse logistics

• Security• Access control• Counterfeiting and Theft control/prevention

• Location Tracking• Traffic movement control and parking management• Wildlife/Livestock monitoring and tracking


Smart groceries

• Add an RFID tag to all items in the grocery.

• As the cart leaves the store, it passes through an RFID transceiver.

• The cart is rung up in seconds.


Smart groceries enhanced

• Track products through their entire lifetime.


EM-18 RFID MODULE


EM-18 RFID READER


Interfacing with avr

• The RFID module used here gives a 12 byte unique ID of a particular tag in serial RS232 logic level format. Hence a level converter MAX232 is used in between RFID receiver module and microcontroller.


Engineering

RFID Part-19