Glossary Of Rfid Terms -- B

Back channel

See reverse channel.

Backscatter

A method of communication between passive tags (ones that do not use batteries to broadcast a signal) and readers. RFID tags using backscatter technology reflect back to the reader radio waves from a reader, usually at the same carrier frequency. The reflected signal is modulated to transmit data.

Bar code

A standard method of identifying the manufacturer and product category of a particular item. The bar code was adopted in the 1970s because the bars were easier for machines to read than optical characters. The main drawbacks of bar codes main are they don’t, in most cases, identify unique items and scanners have to have line of sight to read them.

Barrier

See Shielding

Base station

An RFID reader that is connected to a host system.

Battery-assisted tag

These are RFID tags with batteries, but they communicate using the same backscatter technique as passive tags (tags with no battery). They use the battery to run the circuitry on the microchip and sometimes an onboard sensor. They have a longer read range than a regular passive tag because all of the energy gathered from the reader can be reflected back to the reader. They are sometimes called "semi-passive RFID tags."

Beacon

An active or semi-active RFID tag that is programmed to wake up and broadcast its signal at a set intervals.

Biometrics

The study of methods to uniquely recognize and authenticate the identity of humans based upon one or more intrinsic physical or behavioral traits (fingerprints, retinal patterns and so forth). Biometric technology offers several advantages over traditional systems. Unlike passwords, biometric traits cannot be lost or forgotten, and are very difficult to copy, share or distribute. Biometric systems can be used in tandem with passwords or tokens, improving existing security systems rather than replacing them.

Bistatic

A bistatic RFID interrogator, or reader, uses one antenna to transmit RF energy to the RFID tag and a different antenna to receive energy reflected back from the tag.