| CPC G06K 7/10366 (2013.01) | 12 Claims |

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1. A method for determining a value of an electromagnetic field strength by means of a chip card, comprising the steps of:
providing a chip card having a coil and an integrated circuit;
calibrating the chip card by means of different values of an electromagnetic field strength,
wherein in each case a power of the integrated circuit is determined at a specific value of the electromagnetic field strength;
establishing a correlation of the different values of the electromagnetic field strengths with a respective corresponding power of the integrated circuit;
applying an electromagnetic field strength of unknown value to the chip card;
determining a power of the integrated circuit; and
determining the value of the electromagnetic field strength corresponding to this power by means of the correlation.
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