RFID

Radio Frequency Identification (RFID) is an AIDC technology.

RFID tags consist of a silicon microchip (integrated circuit) attached to an antenna. A tag inlay consists of a silicon microchip attached to an antenna and mounted on a plastic or other thin film substrate.

RFID systems can be categorized by the frequency band within which they operate and their power source.

Major RFID vendors include:

Frequency

RFID systems typically operate in one of the following frequency bands: low frequency (LF), high frequency (HF), and ultra-high frequency (UHF).

Radio frequency

RFID at a lower frequency has a shorter read range and slower data read rate, but increased capabilities for reading near or on metal or liquids. At higher frequencies, it generally has faster data transfer rates and longer read ranges than lower frequency systems, but more susceptibility to interference.

Type Band Frequency used Range Transfer rate Interference Use
LF 30 to 300 KHz 125 KHz < 10 cm Low Low Access control
HF 3 to 30 MHz 13.56 MHz 10 cm to 1 m Medium Medium NFC, payment, public transport
UHF 300 MHz to 3 GHz 900 to 915 MHz*1 1 to 10 m High High UHF Gen 2*2

*1 While systems complying with the UHF Gen 2 standard may use the 860 to 960 MHz band, systems in most countries operate between 900 and 915 MHz.

*2 Passive only.

UHF is the fastest growing segment of the RFID market.

UHF

  • Single Gen 2 standard
  • 60 times more efficient than the HF band
  • 20x the range and speed of HF
  • Tags are 2-3 times cheaper

LF and HF

  • Multiple competing standards

Power

RFID systems can be categorized as active, passive or battery-assisted passive.

Active RFID

In active RFID systems, tags have their own transmitter and power source. Usually, the power source is a battery. Active tags broadcast their own signal to transmit the information stored on their microchips. Active RFID systems typically operate in the ultra-high frequency (UHF) band and offer a range of up to 100 m.

For this reason they are typically used with large objects such as shipping containers and rail cars. To date, most RFID systems in the container industry are active.

There are two main types of active tags: transponders and beacons.

Transponders are "woken up" when they receive a radio signal from a reader, power on and respond by transmitting a signal back. This behaviour conserves battery life.

Beacons are used in real-time locating systems, in order to track the precise location of an asset continuously. Unlike transponders, beacons are not powered on by the reader’s signal. Instead, they emit signals at pre-set intervals. Depending on the locating accuracy required, beacons can be set to emit signals every few seconds, or once a day. Each beacon’s signal is received by reader antennas that are positioned around the perimeter of the area being monitored, and capture the tag’s data and position.

Passive RFID

In passive RFID systems, the RFID tag uses the signal transmitted from the reader to power on and reflect a signal back.

Passive RFID systems can operate in the low frequency (LF), high frequency (HF) and ultra-high frequency (UHF) radio bands. Their ranges are limited by the power of the tag’s backscatter (the radio signal reflected from the tag back to the reader). Because passive tags do not require a power source or transmitter, and only require a tag chip and antenna, they are cheaper, smaller, and easier to manufacture than active tags.

Due to the benefits just listed, and the presence of a strong standard, passive RFID is extremely popular in many industries.

Battery-Assisted Passive (BAP) RFID

BAP tags use an integrated power source (usually a battery) to power on the chip so that all of the energy captured from the reader can be used for backscatter.

Standards

Passive UHF RFID is currently the only type of RFID to be regulated by a single global standard. This is the GS1 EPCglobal UHF Gen 2 standard (ISO/IEC 18000-6:2010), or just UHF Gen 2.

Active RFID has not benefited from any standard and existing systems have been very much proprietary. This is being addressed by ISO/IEC 18000-7:2014 and the Dash 7 Alliance.

The implications of ISO 18000-7 to the container industry are significant. A tag on a container could be read by all supply chain partners around the world using a common frequency and protocol.