What is RFID?

Radio Frequency Identification (RFID) Technology is wireless communication technology that enables users to tag objects and individuals. A RFID system is composed of three basic components: a tag, a reader and a host computer.

RFID tags contain tiny semiconductor chips and miniaturized antennas inside some form of packaging. They can be identified by the reader. When attached to a person or an object, that person or object can be tracked and identified wirelessly. Security management-related RFID applications enable identification, location, tracking, and monitoring of people and objects in all types of environments and facilities.

According to Hunt, Punglia and Punglia (2007), in the coming years, new RFID applications will benefit a wide range of industries and government agencies in ways that no other technologies have ever been able.The American WalMart and DoD (Department of Defense), are the worlds greatest retailer and supply chain operator. RFID technology has begun to attract interest from industry and government agencies.

RFID1. The Tag (also called transponder) is composed of a semiconductor chip, an antenna, and sometimes a battery.

2. The Interrogator (also called a reader or a read/write device) is composed of an antenna, a RF electronics module, and a control electronics module.

3. The Controller (also called a host) is most often a PC (personal computer) or a workstation running database and control software.

The tag and the interrogator communicate information with one another through RF (radio frequency). Radio Frequency Identification (RFID) is able make fast, automatic data acquisition possible, by using magnetic fields or radio waves. This allows for wireless data transfer – including power – between transponder and reader.

RFID can be attached to anything: a person, a product, an object, or a box.

When a tagged object enters a read zone of an interrogator, the interrogator signals the tag to transmit its stored data. Tags can hold many kinds of information about the objects that they are attached to, including serial numbers, time stamps, configuration instructions, and much more. The chip of the tag is a tiny computer that can store information. The chip also has the logic to tell itself what to do when in front of the reader.

The type of communication the exchange of information to happen between the tag and the reader is called backscatter. The reader sends out an electromagnetic wave at one specific frequency. That wave hits the RFID tag and the tag then “scatters back” a wave at a different frequency with the chip’s information encoded in the backscatter waves.

Active RFID tags

An active RFID has a battery or a power source of its own for transmission of data in the same way a mobile phone uses its battery. Active tags can therefore communicate with less powerful interrogators and can transmit information over much longer ranges. Active tags also have larger memories and their batteries can last from 2 to 7 years. Passive tags do not hold much memory and are also less expensive to produce.

RFID and the Frequencies

Both the tags and the readers operate over a very specific frequency. Think of them as radios that have their own specific stations on which they can talk and listen. So in a way, the tags are tuned into the readers, just as your car radio is tuned into a hip-hop station.

Passive tags are operated in the LF (Low Frequency) and HF (High Frequency) bands. Active tags are typically used in the UHF (Ultra High Frequency 860-960 MHZ) and microwave (2,5 GHZ and above) bands.  High Frequency bands pose some health concerns for humans.

Read/Write (RW) or “smart tags”

RW tags can in comparison to Read Only (RO) tags store large amounts of data and have a memory that can be easily changed. Data on such a tag can be erased and rewritten a thousands times. This type of tag can act as a “travelling” database. Information is carried by the tag, rather then by the interrogator. This kind of tag has many applications.

Interference from other Radio Systems

RFID systems are prone to interference from other radio systems. RFID systems operating in the LF band are particulary vulnerable due to the fact that LF frequencies do not experience much path loss, or attenuate very little over short distances, in comparison to the higher frequencies. This means that the radio signals of other communication systems operating at nearly the same LF systems will have high field strength of the antenna of an RFID, which can translate into interference. Microwaves systems are less susceptible to interference and generally a line of sight is required in order for microwave radiators to interfere.

Liquids and metals

The performance of RFID systems will be adversely affected by water or wet surfaces. HF signals due to their long wavelengths are better to penetrate water then UHF and microwave signals.Signals in the High Frequency bands are more likely to be absorbed in liquids.

Metal is an electromagnetic reflector and radio signals cannot penetrate it.  Metal will only obstruct communication if place between an RFID tag and an interrogator. But just the mere presence of metal can have adverse effects on the operation of a system. When metal is placed close to an antenna, something de-tuning can occur. The HF bands are affected by metal more then LF bands. Special precautions must be taken.

RFID and The Future

RFID technology and a global protocol will enable a world we couldn’t even have imagined at this turn of this century. Soon enough if not already RFID will come in 2 flavors.

  1. Cheap dumb readers that only read tags and send the data to a central connection point, which filters and smoothes the data for analyses.
  2. More expensive higher processing smart RFID readers that can preform intelligent operations beyond simple communication.

The cheap and small readers will enable a convergence of parallel technologies:

  1. Mesh networks: Items that communicate and self-reconfigure every time a new node is recognized or removed.
  2. Grid computing: The ability to co-opt computer power.
  3. Dust motes: Tiny sensor networks that can do everything from predicting disasters like tsunamis to recognize chemical warfare, and that can be dropped by a plane by the thousands.
  4. Sensors: To monitor everything from temperature to vibration to nuclear levels attached to this networked world.

The internet of objects will create a world of machine-to-machine communication as all these technologies unite. An object enbedded with an RFID tag will enter the presence of other objects that are similarly enabled and be instantly recognized. Each object will have enough data to reconfigure itself into the geographical network in which it resides. Information about everything will be distributed into these systems. All this will happen wirelessly.

This intelligent, wireless, machine-to-machine communication will grow at a cost of strict regulatory compliance related to our privacy, and freedom if we let one seed germinate that has already been planted – ignorance. …Education and understanding will be the best protection.


RFID: a guide to radio frequency identification, by Daniel Hunt, Albert Puglia, Mike Puglia, 2007

RFID – Systeme (Radio Frequency Identification), Insystems.de

RFID for dummies, by Patrick J. Sweeney,Patrick J. Sweeney (II.) (2005)

Originally posted on: http://targeted-individuals-europe.com/index.php/what-is-rfid-1

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