Radio Frequency IDentification

What is RFID?

RFID stands for radio frequency identification. It is an automatic identification technology whereby data encoded in an RFID tag or “smart label” is captured by a reader using radio waves. Put simply, RFID is similar to bar code technology but uses radio waves to capture data from tags, rather than scanning the bar codes on a label. RFID does not require the tag or label to be seen to read its stored data—that's one of the key characteristics of an RFID system.

What is an RFID tag?

RFID tags consist of an integrated circuit attached to an antenna—typically a small coil of wires—plus some protective packaging (like a plastic card) as determined by the application requirements. RFID tags can come in many forms and sizes. Some can be as small as a grain of rice. Data is stored in the IC and transmitted through the antenna to a reader. RFID tags are either “passive” (no battery) or “active” (self-powered by a battery). Tags also can be read-only (stored data can be read but not changed), read/write (stored data can be altered or re-written), or a combination, in which some data is permanently stored while other memory is left accessible for later encoding and updates.

What is an RFID reader?

A reader is basically a radio frequency (RF) transmitter and receiver, controlled by a microprocessor or digital signal processor. The reader, using an attached antenna, captures data from tags then passes the data to a computer for processing. As with tags, readers come in a wide range of sizes and offer different features. Readers can be affixed in a stationary position (for example, beside a conveyor belt in a factory or dock doors in a warehouse), portable (integrated into a mobile computer that also might be used for scanning bar codes), or even embedded in electronic equipment such as print-on-demand label printers.

How does RFID work?

Information is read from RFID tags by a reader using radio waves. In passive systems, which are the most common, an RFID reader transmits an energy field that “wakes up” the tag and provides the power for the tag to operate. In active systems, a battery in the tag is used to boost the effective operating range of the tag and to offer additional features over passive tags, such as temperature sensing. Data collected from tags is then passed through familiar communication interfaces (cable or wireless) to host computer systems in the same manner that data scanned from bar code labels is captured and passed to computer systems for interpretation, storage, and action.