How Radio Frequency Identification Technology Works

RFID Basics

Radio Frequency Identification, or RFID technology, is a way of tracking people and objects and storing information about them. In some ways, RFID does the same thing that barcodes do: each RFID tag stores a small amount of information about the product, which can be read and recorded by the scanner. The big difference is that, while a barcode scanner must come within inches of the barcode, an RFID scanner can be hundreds of feet away.

How it Works

The radio frequency identification tag has a small microchip inside it which stores information. When a nearby RFID scanner broadcasts a signal, the tag picks up the signal and broadcasts its information out. The scanner then picks up that information and records encountering that particular chip. This can be used to control access to a building by only allowing people wearing particular chips in, to speed checkout lines by instantly reading every item in a basket, to do inventory at a warehouse and for many other purposes.

Passive RFID

The simplest RFID chips are passive. They have no batteries and can last almost indefinitely. Radio signals are electromagnetic radiation. When a conductor such as an antenna captures part of a radiowave, some of that electromagnetic energy is turned into electricity. That electricity powers passive RFID chips, giving them just enough energy to send a signal back to the RFID scanner.

Active and Semi-Passive RFID

Active RFID chips are used for items that need to broadcast greater distances. While passive chips can broadcast up to 20 feet, active ones can broadcast 100 feet or more. They are powered by small, long-life batteries, which can last for years. Some of them can even be written and rewritten like a computer. Semi-passive RFID chips are halfway between active and passive. They have a battery which powers their circuitry once the scanner sends an "on" signal, but they rely on energy from the scanner to broadcast.

References

• How RFID Works