OBID
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Antenna Manual
ID RW24
FEIG ELECTRONIC GmbH
Seite 8 von 15
h80391-1e-ID.doc
3. Elementary antennas
Elementary antennas are subdivided into simple frame antennas and 8-loops.
In the sector of access control for persons, the simple frame antenna is used, since it has a larger
range. 8-loops are more suitable for industrial applications, where the special field alignment of the 8-
loop is very advantageous.
3.1. Simple frame antenna
Figure 3.1-1.b illustrates the field alignment of a simple frame antenna. It is the most simple and most
customary antenna type and is mostly used for access control of persons. The size of this antenna
depends highly on the requirements regarding reading range and on the surroundings.
Figure 3.1-1
In order to maximize the reading range, we recommend dimensions of approx. 50 cm x 70 cm for 22
to 26 turns, when using flat strip cable.
Chart 3.1-1 indicates the expected inductance for the various antenna sizes and the number of turns
of flat strip cable antennas. The surface of the antenna is calculated by multiplying the middle edge
lengths (see also figure 3.1-2). Please notice that the relation of edge length a and b does not ex-
ceed a value of 2:1.
In order to reach a maximum reading range, the number of turns with the highest inductance has to
be choosen.
