Overview of radio frequency identification

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Overview of radio frequency identification

Countless business applications, from product manufacturing to end-customer sales, can

benefit from radio frequency identification (RFID). With RFID, logistics becomes more

effective, stock handling is easier, traceability is guaranteed, cloning and counterfeiting can

be avoided, antitheft protection is enabled, and warranty problems can be easily eliminated.

What is radio frequency identification (RFID)?

RFID technology uses radio communications to uniquely identify items, such as goods,

people, or animals. It enables automated collection of information on identified items

independently from their position, without the need of a direct optical link or human

intervention. RFID also liberates the user from harsh or dirty environment concerns that

restrict other automatic identification solutions such as barcodes. On top of that, RFID is

used as a bi-directional data carrier since it allows information attached to the item to be

written and updated on the fly.

What does a RFID system consist of?

An RFID system consists of several components including one or multiple contactless

memory tags (or transponders), attached to the items to be labeled, identified, and traced,

and handheld or fixed contactless read/write reader station units or coupling devices

exchanging data with the transponder(s) by means of RF signals.

Contactless memory tags

Contactless memory tags (transponders) are the backbone of the RFID system since

they contain data that allow the items to be identified. A contactless memory tag is made of

a non-volatile memory associated with a radio frequency communication block, performing

RF signal modulation, demodulation, power supply regulation, and an antenna. A

transponder can be read-only (ROM), one-time-programmable (OTP), or read/write

(EEPROM), and it can be embedded in various package formats (inlays, cards, etc.).

The reader

The reader (or reader station unit) is connected to an antenna that transmits and receives

the radio frequency signal from and to the transponder(s). The reader sends an RF signal to

the transponder’s antenna. This signal generates a voltage that is rectified and provides a

power source to the transponder. The power transfer from the reader to the transponder is

performed through an inductive coupling between the two coils in 125 kHz and 13.56 MHz

systems. For ultra-high frequencies (UHF), the electric field generated by the reader is used

to power the tag. In other words, the transponder does not need a dedicated power supply.

Passive and active tags

Two main families of transponders exist: Passive (battery-less) and Active. Adding a battery

can bring several advantages, such as improvement of the reading range or continuous

monitoring of temperature and pressure etc., but adds an extra cost. During the reader-

transponder communication, the RF signal generated by the reader is modulated according

to the data to be sent. In the transponder-reader direction, no modulation is applied on the

reader RF signal and the communication is done through load modulation in inductive

coupling systems. The reader interfaces with the RFID system control host through a serial

interface such as RS232, RS422/485, or USB.