Radio-frequency identification, or RFID, is an identification and tracking technology that communicates through the use of radio waves to transfer data between a reader and an electronic tag attached to an object. Radio-frequency identification involves hardware known as readers and tags, as well as RFID software or RFID middleware. RFID tags can be passive, active, or semi-active. These tags broadcast over a portion of the electromagnetic spectrum; the exact frequency is variable and can be chosen to avoid interference with other electronics or among RFID tags and readers.
Active and semi-active RFID tags power their circuits by use of an internal battery. A semi-active tag must rely on a reader to supply the power for broadcasting, while an active tag uses its battery to broadcast to the reader. Active and semi-active tags can be configured with the capability to sense temperature, humidity, movement, and many other variables. Active tags can be read over greater distances and therefore require less infrastructure; however since the tag is more complex, it is more expensive than a passive tag.
Passive RFID tags rely entirely on the reader as their power source. When radio waves from the reader are encountered by a passive RFID tag, the coiled antenna within the tag forms a magnetic field. The tag draws power from it, energizing the circuits in the tag. The tag then sends the information encoded in the tag's memory.
BENEFITS OF RFID
Foremost, RFID lends itself to automation; therefore reducing not only labor costs but the errors associated with human intervention. The time required to conduct an inventory can be reduced by 50% or more, and the time required to manually check shipments and receipts can be eliminated.
When web-based RFID software is real time, logistic chain managers instantly know the location and status of their assets. The software is available to everyone in the logistic chain, factories, customers, and suppliers; however, authority levels may be set to ensure they have access only to appropriate information.
RFID software creates a database which not only tells you what you have and where it is; but also the history of that asset. Analysis of the asset movements can result in more efficient logistics operations, reductions in shrinkage, and more efficient use of that asset. Since the data is also secure, the historical record also serves as a chain of custody for that asset.PASSIVE vs. ACTIVE RFID
The optimum method (Passive vs. Active) is best determined by working with an RFID professional. They will assess your needs and design the most cost effective solution. Often, infrastructure needs can be significantly reduced by a simple evaluation of product flow patterns and the identification of choke points.