Introduction to RFID

The abbreviation RFID stands for Radio Frequency Identification. This technology is used to identify an item, follow its path of movement and calculate distances thanks to a special tag that emits radio waves, which is attached or built into the device. RFID technology is used to read the tag even if it is not in a direct line of sight and can also penetrate thin layers of materials (paint, snow, etc.).

The radio frequency tag (transponder,or RFID tag) is made up of a chip linked up to an antenna, which are both enclosed in a label (RFID Tag or RFID Label). It is read by a device which captures and transmits the information.

There are 3 categories of RFID tags:

• Read-only tags, that cannot be modified.
• Write once, read many tags.
• Read, rewritable tags.

However, there are two major families of RFID tags:

• Active tags linked to an in-built energy source (battery, battery cell, etc.). Active tags have improved portability, but an a higher cost and also have a restricted lifespan.
• Passive tags use energy that is created at short distance by the radio signal from the transmitter. These tags are cheaper and generally smaller and also have a practically endless lifespan. On the down side, they require a specific amount of energy from the reader to work.

Examples of functional applications:

• Tracing gas cylinders (Air Liquide, AGA),
• Package tracking (WalMart),
• Tracking of hired out industrial clothing (Elis),
• Animal identification: replaces tattooing (Ordicam),
• Book administration in libraries
• Bogie and wagon identification (SNCF).

RFID implementations follow different standards depending on the functionality required and the area where it is used (ex.: transmission frequency or required power).

RFID can be used to address many different needs. It is well suited to intra-company and logistical areas. The main difficulties that face RFID standards are currently being addressed: cost of the tag (over €0.10 each for the cheapest), anti-collision measures to avoid multiple tags being read at the same time, reading the tags through liquids, slow adoption of standards, re-evaluation of old procedures, security and ethical issues.

The RFID tag shall be the media used for the EPC (Electronic Product Code) which will be used for "the electronic product tracking network". It is planned to have unique identification of all products (sequentially coded tags) and link it to a shared data network on the Internet. EPC has been pushed by the big global players in commerce and information systems. It was developed by the MIT (Massachusetts Institute of Technology). In France, EPC Global France developed by GS1-France (formerly Gencod-Ean France) is responsible for development and promoting of the standard.

Article co-written by Eric Schuler, of www.arvensys.com and Jean-François Pillou.