What is RFID?
The term Radio frequency identification, or RFID, describes technologies that use radio waves to automatically identify people or objects. A unique identification number is stored on a microchip which is attached to an antenna. The chip and the antenna together form an RFID tag. The antenna enables the chip to transmit the identification information to a reader. The reader converts the radio waves reflected back from the RFID tag into digital information that can then be downloaded on to computers which processes it into meaningful information for the user.
How does an RFID system work?
An RFID system comprises of tags and readers (or interrogators). An active RFID tag is battery-powered and regularly broadcasts a signal which is picked up by a reader. A passive RFID tag obtains power from the electromagnetic field created by the reader and uses it to power its microchip’s circuits. The chip then modulates the waves that the tag sends back to the reader. In both types of system the reader converts the signals into digital data which in turn is downloaded to a computer to process it.
Do RFID and radio waves pose any health risks?
RFID uses radio waves which are the lowest-energy, lowest-frequency and longest-wave length electromagnetic waves. The waves emitted by RFID readers are similar to those that your radio would receive.
What is the difference between passive and active RFID?
Active RFID systems use self-powered RFID tags that continuously broadcast their own signal. Active RFID tags are commonly used as “beacons” to accurately track the real-time location of. Active tags provide a much longer read range than passive tags, typically up to 40 metres, but they are also more expensive. They are useful for tracking high-value goods that need to be scanned over long ranges. Find out more about active RFID.
Tags in passive RFID systems are powered by the electromagnetic energy transmitted from the RFID reader. Applications for passive RFID tags include access control, device tracking, supply chain management, smart labels, and more. The lower cost per tag makes using passive RFID systems economical for many applications. Tags are often used in the form of labels which means they can be used to carry printed information like on an asset label. Find out more about passive RFID.
Why is RFID better than using bar codes for some applications?
RFID can have distinct advantages over using traditional bar codes. The main difference between the two is bar codes use line-of-sight technology. This means the scanner has to "see" a bar code, one at a time to read it and it also needs to be lined up in a certain way. Radio frequency identification, on the other hand, can work through barriers, i.e. curtains in a nursing environment and many items can be read at the same time.
Also standard bar codes do not normally identify a unique item but just an item type. An RFID tag has a unique identifier which can carry information about a specific item, for example to track when its next scheduled maintenance is due.
What is the difference between low-, high-, and ultra-high frequencies?
Just like your radio is tuned in to different frequencies to receive different channels, RFID tags and readers have to be tuned to the same frequency to communicate with one another. The most comment frequencies used in RFID systems are low- (around 125 KHz), high- (13.56 MHz) and ultra-high frequency, or UHF (850-900 MHz). Radio waves act differently at different frequencies, so it is important to choose the right frequency for your application.
How do I know which frequency is right for my application?
There are many different factors which impact on the choice of the best frequency. These include characteristics of the objects to which tags are attached like their water or metal content. Price and required read range often also influence this decision. We can help you choose the right frequency for your application.
What read range can you achieve with a typical RFID tag?
Read ranges vary greatly. The read range of passive tags depends on the frequency of operation, the power of the reader and interference from objects (containing metal or liquid) or other RF devices. Low-frequency tags are normally read from 30cm or less. High frequency tags have a range of about one metre and UHF tags can be read from 3 to 7 metres. Active RFID tags, which use batteries to boost read ranges, can be read from up to 40 metres away.
What is an Electronic Product Code?
The Electronic Product Code (EPC) is a universal numbering scheme which is being used to identify products as they move through the global supply chain. EPCs are used to store information efficiently on an RFID tag.
Are there any standards for RFID?
The EPCglobal Tag Data standard defines the structure of the unique identification number used in RFID tags. EPCglobal was set-up as a GS1 initiative to develop industry-driven standards to support the world-wide adoption of Electronic Product Codes and RFID. This is an open standard and available for download from the GS1 website (http://www.gs1.org/epc-rfid).
Some additional standards have been adopted for some specific applications.