Passive tags can cost as little as 15 cents apiece, compared to $20 or more for active tags. However, it is difficult to offer a straight comparison between the two, because the systems do different things.
Active systems identify objects over long distances. Some triangulate on a tag to show you its location within 10 feet or so. You might require 10 RFID readers to cover a distribution yard, for example.
Passive tags identify objects over much shorter distances, and tell you only that a tag is within range of a specific reader. To know, in real time, the location of containers in a distribution yard, you would need hundreds of passive readers. So the tags would be cheaper, but the overall system would be more expensive.
In choosing between active and passive RFID systems, it is not usually a question of cost. Rather, it’s a question of what the system is required to do. Active systems tend to be used to track a relatively small number of large assets over long distances (300 containers in a distribution yard, for instance), whereas passive systems are usually utilized to track smaller, less expensive assets over shorter distances.
We are currently working on a report that will explain the many different types of RFID systems, the strengths and weaknesses of each, and the applications for which they are typically employed.
—Mark Roberti, Editor, RFID Journal
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