Differentiation Features of RFID Systems - RFID: Fundamentals and Applications in Contactless Smart Cards and Identification - page 17

Figure 2.10 Watch with integral transponder in use in a contactless access authorisation system
(reproduced by permission of Junghans Uhren GmbH, Schramberg)
2.2.6 Clocks
This construction format was developed at the beginning of the 1990s by the Austrian
company Ski-Data and was first used in ski passes. These contactless clocks were
also able to gain ground in access control systems (Figure 2.10). The clock contains
a frame antenna with a small number of windings printed onto a thin printed circuit
board, which follows the clock housing as closely as possible to maximise the area
enclosed by the antenna coil — and thus the range.
2.2.7 ID-1 format, contactless smart cards
The ID-1 format familiar from credit cards and telephone cards (85 . 72 mm × 54 . 03 mm
× 0 . 76 mm ± tolerances) is becoming increasingly important for contactless smart
cards in RFID systems (Figure 2.11). One advantage of this format for inductively cou-
pled RFID systems is the large coil area, which increases the range of the smart cards.
Contactless smart cards are produced by the lamination of a transponder between
four PVC foils. The individual foils are baked at high pressure and temperatures above
100 ◦ C to produce a permanent bond (the manufacture of contactless smart cards is
described in detail in Chapter 12).