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INTRODUCTION:
RFID is an acronym for radio frequency identification: the use of wireless communications to establish the identity of a physical object. For the reader who is unfamiliar with the technology and business of RFID, there are many good introductions to RFID already available on the web; links are provided below to some of them. The purpose of this document is to go into some more depth on how such devices actually work. We focus here on passive transponders (tags): that is, tags with no power source other than the radio frequency power provided by the interrogating device (reader). The discussion is also specific to tags and readers operating at high enough frequencies that significant radiation occurs: for typical antenna sizes, operating frequencies over about 200 MHz ensure radiative coupling.
RFID Defined:
Radio Frequency Identification (RFID) uses a semiconductor (microchip) in a tag or label to store data.
Data is transmitted from, or written to the tag or label when it is exposed to radio waves of the correct frequency and with the correct communications protocols
RFID Is:
• A proven process improvement enabler
o Process innovation
• A highly capable technology when intelligently implemented
o Package development
o Factory automation
• A technology that will evolve and continue to improve
What is the purpose of RFID?
RFID allows data to be transmitted by a product containing an RFID tag microchip, which is read by an RFID reader. The data transmitted can provide identification or location information about the product, or specifics such as date of purchase or price.
What is the advantage of using RFID technology?
No contact or even line-of-sight is needed to read data from a product that contains an RFID tag. This means no more checkout scanners at grocery stores, no more unpacking shipping boxes, and no more getting keys out of your pocket to start your car. RFID technology also works in rain, snow and other environments where bar code or optical scan technology would be useless.
Will RFID replace UPC bar code technology?
Probably not, at least not soon. Besides the fact that RFID tags still cost more than UPC labels, different data capture and tracking technologies offer different capabilities. Many businesses will likely combine RFID with existing technologies such as barcode readers or digital cameras to achieve expanded data capture and tracking capabilities that meet their specific business needs.
RFID Applications:
- Livestock tracking
- Automotive immobilizer
- Contactless payments
- Anti-theft
- Library books
- Speedpass
- Control Access
- Production/Inventory tracking
RFID Standards:
ISO 15693 ¡V Smart Labels
ISO 14443 ¡V Contactless payments
ISO 11784 ¡V Livestock
EPC ¡VRetail
ISO 18000 ¡V various frequencies, various applications
RFID Operating Frequencies:
Low Frequency ¡V LF (125 ¡V 134 kHz)
Applications: Access control, livestock, race timing, pallet tracking, automotive immobilizers, pet identification
- Inductively coupled devices, electro-mechanical field
- Antenna coil has many turns
- Read range (near contact to 1 meter)
- Memory usually a UID
- Limited data rate due to a lower bandwidth
High Frequency ¡V HF (13.56 MHz) ¡V Smart Labels
Applications: Supply chain, wireless commerce, ticketing, product authentication, clothing identification, library book identification, smart cards
- Inductively coupled devices
- Fewer antenna turns than LF device
- Read range from proximity to ¡Ó 1.5 meters
- Higher data transfer rate than LF
Ultra-High Frequency ¡V UHF (860-960 MHz)
Applications: Supply chain, tool tags, RTLS, EPC case and pallet
- RF communication uses propagation coupling
- Smaller reader antenna design than LF or HF
- Read distance (1 m ¡V 10 m)
- High data transfer rate
- More complex reader electronic components
Transponder Characteristics:
RFID tags are tiny microchips with memory and an antenna coil, thinner than paper and some only 0.3 mm across. RFID tags listen for a radio signal sent by a RFID reader. When a RFID tag receives a query, it responds by transmitting its unique ID code and other data back to the reader.
Tag Types:
- Active Tags: Battery powered, long read range
- Semi-active: Battery power to preserve memory
- Passive Tags: Low-cost, no battery required, medium read range
Active RFID Tags:
Active RFID tags, are called transponders because they contain a transmitter that is always ¡§on¡¨, are powered by a batter, about the size of a coin, and are designed for communications up to 100 feet from RFID reader. They are larger and more expensive than passive tags, but can hold more data about the product and are commonly used for high-value asset tracking. Active tags may be read-write, meaning data they contain can be written over.
Semi-Active RFID Tags:
Semi-active tags contain a small battery that boosts the range and preserves memory.
Passive RFID Tags:
Passive tags can be as small s 0.3 mm and don¡¦t require batteries. Rather, they are powered by the radio signal of a RFID reader, which ¡§wakes them up¡¨ to request a reply. Passive RFID tags can be read from a distance of about 20 feet. They are generally read-only, meaning the data they contain cannot be altered or written over.
Tag Packing Formats:
- Weatherproof or environment-proof enclosure
- Pressure Sensitive Label
- Laminated card
- Embedded in packaging or product
Transponder Examples:
- 32 mm and 23 mm capsule transponder
- ½ inch key head transponder
- Smart Labels (Clear and Adhesive
- Circular transponders