Tech Primer
An RFID system comprises two components basically – an RFID reader and an RFID tag. The RFID reader is really the transmitter in an RFID system. The reader generates the signal that drives the reader’s antenna which creates the appropriate radio wave. This radio wave may be received by an RFID tag, which in turn ‘reflects’ some of the energy it receives in a particular way (based on the identity of the tag). Whilst this reflection is going on, the RFID reader is also acting as a radio receiver, so that it can detect and decode the reflected signal in order to identify the tag.
The main types of RFID system include passive tag RFID, semi-passive tag RFID and active tag RFID. Passive tag type has no battery in the tag; semi-passive tag type has battery in it to power the internal circuitry during communication but is not used to generate radio waves, active tag type uses battery for their entire operation.
Currently there are four operation bands can be used by RFID, including Low Frequency (LF), High Frequency (HF), Ultra High Frequency (UHF), and Super High Frequency (SHF) or Micro-Wave. The typical Frequency of LF is 125/134.2 kHz, the transmission range is under 0.5m, and the operation principle is Near Field or inductive Coupling. The typical Frequency of HF is 13.56M Hz, the transmission range is up to 1.5m, and the operation principle is Near Field or inductive Coupling. The typical Frequency of UHF is 433 MHz or 865 – 956MHz, the transmission range is up to up to 100m for 433 MHz 0.5 to 5m for 865-956 MHz, and the operation principle is Far Field or back-scattering. As for Microwave, the typical Frequency is 2.45 or 5.85 GHz, the transmission range is up to 10m, and the operation principle is Far Field or back-scattering.
The major applications of RFID System are based on the used frequency of RFID system, usually, the LF RFID system is used for Immobilizer, animal ID, container ID, tool ID, and electronic burglary-proof lock, HF RFID system is used for Smart Labels, Contact-less travel cards, Access & Security, and electronic burglary-proof lock (electronic remote door lock controller).UHF RFID system is used for container ID, logistics, moving vehicle ID, electronic ID, warehouse and logistics, electronic burglary-proof lock. Microwave RFID system is used for moving vehicle toll.
Other Resources
- ISO standard of RFID
- EPCglobal standard of RFID
- RFID Journal website
- RFID update
- RFID courses
- How RFID Works
Glossary:
| RFID | Radio-frequency identification, using of an object (typically referred to as an RFID tag) applied to or incorporated into a product, animal, or person for the purpose of identification and tracking using radio waves. |
| LF | Low Frequency, in RFID, it means the 125/134.2 kHz. |
| HF | High Frequency, in RFID, it means the13.56MHz |
| UHF | Ultra High Frequency, in RFID, it means 433 MHz or 865 – 956MHz |
| Microwave | also named Super High Frequency(SHF), In RFID it means 2.45 or 5.85 GHz |
| Active Tag | It use batteries for their entire operation, and can therefore generate radio waves proactively |
| Passive Tag | There is no battery at the tag. Instead, the tag uses the energy of the radio wave to power its operation, much like a crystal radio |
| Semi-Passive Tag | The battery powers the internal circuitry of the tag during communication, but is not used to generate radio waves Ethernet. |