RFID tag
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An RFID tag is a microchip combined with an antenna in a compact package. The packaging is structured to allow the RFID tag to be attached to an object to be tracked. RFID stands for radio frequency identification. The tag's antenna picks up signals from an RFID reader or scanner and then returns the signal, usually with some additional data (like a unique serial number or other customized information). RFID tags can be very small - the size of a large rice grain. Others may be the size of a small paperback book. RFID tags can be either active or passive.[1]
Types of RFID Tags
- Main article: see active tag or passive tag
- Active tag: An active RFID tag is powered by an internal battery, which provides part or all of the tag's power. The batteries used in active tags can be replaceable or sealed into the unit. These tags can also be connected to an external power source.
- Passive tag: A passive RFID tag does not contain a battery. The RFID reader supplies the power for a passive tag.[1]
Frequencies
Most RFID tags operate at either 13 MHZ or 900 MHZ, although other frequencies are used. Each has its relative advantages.
- 13 MHZ (HF) tags are generally better at penetrating liquids and are usually used for access control such as in security cards and wristbands. The read range at this frequency is about 3 feet or 1 meter.
- 900 MHZ (UHF) tags operate better when reading multiple tags simultaneously, and thus are generally the tag type of choice for inventory purposes. The read range at this frequency is about 3-10 feet or more depending on what type of reader, interrogator or access point is used.[2]
