Introduction - RFID: Fundamentals and Applications in Contactless Smart Cards and Identification - page 7

underlying technical procedure is drawn from the fields of radio and radar engineering.
The abbreviation RFID stands for radio frequency identification, i.e. information car-
ried by radio waves. Due to the numerous advantages of RFID systems compared with
other identification systems, RFID systems are now beginning to conquer new mass
markets. One example is the use of contactless smart cards as tickets for short-distance
public transport.

1.2 A Comparison of Different ID Systems

A comparison between the identification systems described above highlights the
strengths and weakness of RFID in relation to other systems (Table 1.1). Here too, there
is a close relationship between contact-based smart cards and RFID systems; however,
the latter circumvents all the disadvantages related to faulty contacting (sabotage, dirt,
unidirectional insertion, time consuming insertion, etc.).

1.3 Components of an RFID System

An RFID system is always made up of two components (Figure 1.7):

• the transponder , which is located on the object to be identified;

• the interrogator or reader , which, depending upon the design and the technology

used, may be a read or write/read device (in this topic — in accordance with
normal colloquial usage — the data capture device is always referred to as the
reader , regardless of whether it can only read data or is also capable of writing).

A practical example is shown in Figure 1.8.
A reader typically contains a radio frequency module (transmitter and receiver), a
control unit and a coupling element to the transponder. In addition, many readers are
fitted with an additional interface (RS 232, RS 485, etc.) to enable them to forward
the data received to another system (PC, robot control system, etc.).
The transponder, which represents the actual data-carrying device of an RFID sys-
tem, normally consists of a coupling element and an electronic microchip (Figure 1.9).

Data

Contactless
data carrier =
transponder

Clock

RFID reader

Energy

Coupling element
(coil, microwave antenna)

Application

Figure 1.7 The reader and transponder are the main components of every RFID system