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The demonstration of the first continuous wave radio generation and transmission of radio signals by Ernst F. W. Alexanderson
in 1906 signalled the beginning of modern radio communication and, subsequently, radio frequency identification (RFID). RFID
is the convergence of radio broadcast technology and radar, although many of its early developments are not widely known due
to the military significance of this technology. Most documented histories of RFID technology trace its development to the
radiobased identification systems from World War II, when the British Air Force used radar to distinguish Allied aircraft
from enemy aircraft.
Commercial development of RFID began in the late 1960s. Arguably the first and most widespread commercial use of RFID was
in the development of electronic article surveillance (EAS) equipment to counter theft. Although this system could only detect
the presence or absence of a tag, the tags themselves could be made cost-effectively and provided an effective anti-theft
measure — an important application in the early commercialisation of the technology.
Research and development by academic institutions, government laboratories and private companies led to applications for animal
tracking, vehicle tracking and automated manufacturing. By the mid 1990s, implantable RFID tags that were initially used to
track laboratory animals were being marketed to veterinarians and animal shelters to identify pets.
RFID is now used for hundreds of applications including theft prevention, personnel access systems, automated parking, traffic
management and library book tracking, along with the monitoring of assets in supply chain management. In fact, many attendees
were focused on finding asset-tracking solutions1 at the recent RFID Journal LIVE! 2010 event in Orlando (Florida, USA). Management of assets using RFID is the key to its
application for pharmaceutical laboratories.
RFID technology fundamentals
RFID systems consist of four main elements: the RFID tags, the RFID reader, the antennas and computer network used to connect
the readers.2 The tag itself is the building block of RFID, each containing an antenna and a small chip that contains a radio receiver
and a modulator to send a signal back to the reader. Tags come in a variety of shapes and sizes allowing them to be implanted
into animals and humans, and they can be powered by the incoming radio signal (passive tags) or by a small battery (active
tags). The advantage of an active tag is that its reading range and reliability is greater than that of a passive tag; however,
passive tags can be much smaller and cheaper to produce and should, in principle, work indefinitely. RFID tags can also either
be promiscuous in that any RFID reader (also known as an interrogator) can communicate with it, or secure where the reader
requires an authentication credential in order for the tag to respond.
RFID readers work by sending a pulse of radio energy, which is measured using oscillation frequency and power, to a tag and
monitoring the tag's response. Certain frequencies require a license to broadcast using this part of the spectrum, though
most RFID systems use the so-called unlicensed spectrum, which does not require a radio license. Low-frequency (LF), high-frequency
(HF) and ultra-high frequency (UHF) bands are used within RFID systems depending on the application. For example, the FDA
has adopted the HF band for RFID systems that are used to monitor prescription drugs. In a simple RFID system, the reader's
energy pulse acts simply as an on-off switch for the tag. In more complex systems, the pulse can include commands to the tag,
such as instructions to read or write memory for more advanced monitoring.
