Radio Frequency Identification Systems: Active And Passive Rfid Tags
Active and Passive RFID Tags:
There are primarily two types of RFID tags. One is active and the other is passive. An active tag is powered using internal battery, where a passive tag gets energized using a the power from a tag reader. A passive RFID tag will not have a battery or any kind of power source by itself. It extracts the required energy from a reader. Hence, a passive RFID tag reader must be able to emit stronger electromagnetic signals, and in return, identify very weak signals from the passive RFID tag.
Given below are the primary differences between a Passive and Active RFID tags:
| Passive RFID | Active RFID | |
|---|---|---|
| Power Source | External (Reader provided) | Internal (Battery) |
| Tag Readability | Only within the area covered by the reader, typically up to 3 meters. | Can provide signals over an extended range, typically up to 100 meters.. |
| Energization | A passive tag is energized only when there is a reader present. | An active tag is always energized. |
| Magnetic Field Strength | High, since the tag draws power from the electromagnetic field provided by the reader. | Low, since the tag emits signals using internal battery source. |
| Shelf Life | Very high, ideally does not expire over a life time. | Limited to about 5 years, the life of a battery. |
| Data storage | Limited data storage, typically 128 bytes. | Can store larger amounts of data. |
| Cost | Cheap | Expensive |
| Size | Smaller | Slightly bulky (due to battery) |
