UHF RFID TAGS

RFID (Radio Frequency Identification) is a technology used for electronic and wireless identification of objects, humans and animals


RFID System



Carrier Frequencies


Refers to the property of radio waves used to transmit data


RFID systems may use a particular frequency band depending on:


  • Application

  • Legislature

  • Cost considerations


Frequency and bandwidth


  • Frequency is of primary importance when determining data transfer rates (bandwidth)

  • The higher the frequency, the higher the data transfer rate

Range and Power


  • The range that can be achieved in an RFID system is determined by

  • The power available at the reader

  • The power available within the tag

  • The environmental conditions and structures


Material Propagation


  • The absorption rate for water and other non- conductive substances is lower by a factor of 100 000 at 100 kHz than it is at 1 GHz

  • LF systems are primarily used due to their high propagation of substances


Electromagnetic Interference


  • Electromagnetic Interference - Interference caused when the radio waves of one device distort the waves of another.

  • Cells phones, wireless computers and even robots in factories

  • can produce radio waves that interfere with RFID tags.

  • EI is likely to be an issue for UHF systems


Tags Characteristics


• Means by which transponder is powered

• Data carrying options

• Data read rates

• Programming options

• Physical forms

• Costs


Active and Passive


• Active tags


◦ Powered by an internal battery

◦ Finite lifetime (because of battery)

◦ Greater range

◦ Better noise immunity

◦ Higher data transmission rates


• Passive tags


◦ Operate without battery

◦ Derive power from the field generate by the reader

◦ Less expensive

◦ Unlimited life

◦ Require more powerful readers

◦ Orientation sensitivity


Data Carrying


◦ An identifier

▪ 1bit – 128 bits


◦ Portable data files

▪ Example: 64 K


Data Programming


• Read-only

◦ Cheap


• Write once read many


• Read/write

◦ Expensive


Inventory tracking


• RFID tag data capacity is big enough that any tag will have a unique code, while current bar codes are limited to a single type code for all instances of a particular product.


• The uniqueness of RFID tags means that a product may be individually tracked as it moves from location to location, finally ending up in the consumer's hands. This may help companies to combat theft and other forms of product loss.

• the visibility provided by RFID allows an accurate knowledge on the inventory level by eliminating the discrepancy between inventory record and physical inventory.


◦ In an academic study performed at Wal-Mart, RFID reduced Out of Stocks by 30 percent for products selling between 0.1 and 15 units a day.


• It has also been proposed to use RFID for POS store checkout to replace the cashier with an automatic system which needs no barcode scanning. However, this is not likely to be possible without a significant reduction in the cost of current tags


Some Application

  • Warehouse Management

  • Asset Management

  • library tracking

  • transportation payments

  • pallet tracking

  • airline baggage tracking