Radio Frequency Identification (RFID) uses special data carriers, or tags, to hold data. Readers use RF signals to communicate with the tags.

RFID technologies are a complex family of products that range from extremely basic, short-range devices to extremely sophisticated long-range devices. It is important to understand that not all types of RFID offer the same features, performance and data capacities. While some active (battery assisted) tags, for examples, can be read from100m or more, passive (no battery to boost signal) tags have a much more limited range.

System availability ranges from:

• Low frequency
• Mid frequency
• High frequency
• Ultra-high frequency

Note that frequency ranges are relative terms -- with high simply signifying that it's above mid, and mid is above low.

Generally, range, data transfer rate (DTR), and the dampening effects of overlying materials increase with frequency. Absorption of signal by metal decreases with frequency (although special tags for use on metal are available). Active tags (with batteries to boost signal strength) provide the greatest range.

Depending on the frequency and technology employed, system performance can range from:

• One-bit Electronic Article Surveilance tags to sophisticated read/write systems with up to 4K of addressable memory.
  
• Reading distances of only a few centimeters or up to 30 meters.
  
• Tag read stationary or at 100 kph or more.

International RFID standards now provide for open systems architecture. Standards have been developed, or are being developed for:

• Maritime container ID,
  
• Rail and truck rolling stock ID,
  
• Companion animal tagging,
  
• Manufacturing,
  
• Pallet and returnable container ID, and
  
• Lifetime product ID.

RFID systems are currently being used for:

• Electronic article surveillance (EAS),
  
• Intermodal container identification,
  
• Rail and truck rolling stock identification,
  
• Animal (livestock and domestic) identification,
  
• Automated livestock feeding stations,
  
• Flexible manufacturing (tracking and control),
  
• Cutting tool identification,
  
• Asset identification,
  
• Laundry tracking,
  
• Vehicle identification / access control, and
  
• Automated debit or credit cards (gasoline),
  
• Automated toll collection, and
  
• Personnel identification / access control.

RFID Advantages:

Great flexibility,

• Read/write capabilities or permanent (non-erasable) ID,
  
• Non-contact reading,
  
• Virtual immunity from obscuring paint, dirt, grease, etc., (depending on frequency)
  
• Automatic operation,
  
• Low cost-per-use,
  
• Wide range of tag options,
  
• Range from several centimeters to 100 meters,
  
• Extremely high data integrity, and
  
• Extremely difficult to counterfeit.

RFID Limitations:

• Initial cost of tags or infrastructure,
  
• Possibility of interference in operation by strong EMI from outside sources,
• Security (hacking/skimming) and privacy concerns.