RFID – Radio Frequency Identification

&

EPC – Electronic Product Code

Radio Frequency identification is a technology that has been available for decades, originally developed to identify combatants (Aircraft) as “Friend or Foe”. In its simplest form, it is a technology that allows tags (RFID Tags) to be interrogated by a device that is capable of decoding the information encoded on the RFID tag. Examples of where this technology is currently in use are:

• Office security systems utilizing personal badges to verify and track user access to sensitive work spaces

• ‘Pay at the pump’ systems utilizing a RFID tag to verify user and account information.

• Live stock identification – Systems used to monitor and identify individual animals

• Automated vehicle identification system – Toll both tracking systems

Similar to the UPC (Universal Product Code) barcode found on virtually all consumer products, the EPC (Electronic Product Code) will replace, or at the least enhance the ability to track products through the supply chain. The significance of the EPC is that it is a “unique” identification of the item/product, much like a license plate, that can be used to distinguish: 

• Authenticity of the Product

• Unique Lot Number

• Date of Manufacture

• Various data associated with the transport of the item through the supply chain can also be traced.

  • Place of manufacture

  • Product shipment date & information

  • Carrier manifest information & current product location

  • Product receipt information

  • Product sale information

UPC data can only be used to identify the unique product, it does not allow for the tracking of unique item data (license plate) through the supply chain. EPC allows for serialization of product down to the individual item level.

RFID - How Does It Work 

A radio-frequency identification system requires three components:

• A scanning antenna

• A transceiver (interrogator) with a decoder to interpret the data

• A transponder, the radio-frequency tag, that has been pre-programmed with information

The scanning antenna emits a radio-frequency signal that has relatively short range.  When an RFID tag passes through the field of the scanning antenna, it detects the activation signal from the antenna. This ‘wakes up’ the RFID chip, and causes

transmission of the information encoded on the microchip to be picked up by the scanning antenna. The RF radiation provides a means of communicating with the transponder tag ‘RFID chip’, and in the case of passive RFID tags, it provides the RFID device with the energy to communicate back to the transceiver. This is a key part of the technology, ‘passive’ RFID devices do not contain batteries, and can therefore remain usable for very long periods of time. Current estimates are that passive chips will remain viable upwards of twenty years.  ‘Active’ RFID tags on the other hand do contain a battery which limits the effective life span. The trade off being that active tags can be read from a distance of one hundred feet or more, while having a current price of $20.00 per tag. Application requirements will drive the selection of active vs. passive RFID tags. The scanning antennas can be permanently mounted (i.e. shipping door) or be incorporated into a mobile handheld device.   

RFID tags can be read in a wide variety of environments where barcodes or other optically read technologies are ineffective. The tag need not be on the surface of the object and is therefore not subject to wear and tear. The read time is typically less than 100 milliseconds, and large numbers of tags can be read simultaneously rather than item by item. From a productivity stand point, the tag does not need to be located and scanned by a worker, it merely needs to be in proximity to the antenna to be read.

Some common problem with RFID implementations involves reader collision and tag collision. Reader collision occurs when the signals from two or more readers overlap. Since the tag is unable to respond to simultaneous queries, the ‘read’ fails. Systems must be carefully designed to avoid this problem. Tag collision occurs when many tags are present in a small area. Since the read time is very fast data collisions occur. Careful vendor selection in terms of hardware will eliminate this problem.

Additional Links 

EPCglobal, Inc. is one of the companies responsible “for the development of industry-driven standards for the Electronic Product Code™ (EPC) to support the use of Radio Frequency Identification (RFID)”. Their Web site is a wealth of information on RFID and EPC. Also, on the EPCglobal Web site is a Video “The Basics of RFID and EPC Standard Quality - High Quality” which can be used as a primer for the basics of RFID & EPC. Since EPCglobal, Inc. does not allow for companies to directly link to the video, you will have to visit their Web site and locate the link on the “LEFT” side of the home page:  EPCglobal, Inc.