|RFID Based Active & Passive Identification Management System
RFID is used to Improve Efficiency, Visibility and Security in the Supply Chain. The technology for RFID tags has developed in two primary channels: active and passive tags. Each type of tag contains a digital identification code on a microchip that can be scanned by a reader — the difference is in how that scanning takes place.
For passive tags, the reader emits a signal that activates the tag, allowing it to speak back to the reader. In contrast, an active tag contains a battery supply that continuously powers the tag, allowing it to emit a signal without having to be activated by the reader.
Active tags, which are also programmable, reusable and store much more data, are thus more expensive — they may cost as much as US$10 or US$50, compared to about US$0.50 for a passive tag. However, since they both have read and write capabilities, the information on the active tag can change. Thus, the tag can give the reader not only an ID number but information on where it has been and how it has been handled. Active tags offer the following benefits:
Each technology, of course, is still evolving. Passive tags may yet conquer some of their current problems. And active tags may yet come down in price, especially with higher volumes of usage.
- They can monitor a container even when there is no reader nearby, which means they can detect tampering, vibration, light, humidity, temperature changes and other environmental fluctuations.
- They may be more reliable because they transmit information over longer distances than passive tags. Where passive tags may require a communication range of three meters or less, active tags can have a range of 100 meters. This allows a single reader to collect information from thousands of tags at once—even when they’re in motion at speeds up to 100 miles an hour.
- They do not suffer from some of the problems currently afflicting passive tags. For example, in retail implementations, the radio signal of passive RFID transmits poorly through liquids and can be distorted by certain types of nearby metal objects.