Installation Manual

OBID i-scan
®
Installation ID ISC.ANT310310-A
FEIG ELECTRONIC GmbH Page 15 of 22 M90401-1e-ID-B.doc
E N G L I S H
Figure 10 The antenna’s impedance in dependence on the frequency
(measured direct at the antenna matching board)
Figure 10 show the diagram of the impedance and phase in dependence of the frequency of the
antenna ID ISC.ANT310/310. If the antenna had been tuned well, the (serial-) resonance point
should be at the minimum of the impedance curve at 13.56MHz, 50 Ω. and a phase angle of 0°.
If metal is brought close to the antenna, the impedance curve shifts to the right and slightly down-
wards. This means that the closer the metal part comes, the impedance value will decrease and
then increase more and more. During this process, the antenna will once again pass the value of
50 Ω. However, this operating point does not lead to optimal reading ranges. The optimal operating
point always lies on the series resonance, which in this case equals the minimum value on the im-
pedance curve.