Patent ID: 8773240

Claim:
A method of detecting an identification object in an area around an antenna device, comprising: initializing the identification object with a fixed threshold value dependent on a received nominal magnetic field, emitting a calibration signal in the direction of the antenna device to determine a setting power only when the antenna device is operating, measuring a current circulating in the antenna device when emitting the calibration signal, comparing a measured current to an initial current, determining, on the basis of a comparison, the setting power to be applied to the antenna device, setting the setting power with an operating voltage having a given duty factor, emitting a functional signal corresponding to the setting power in the direction of the antenna device such that the antenna device emits a predetermined magnetic field, measuring a magnetic field received by the identification object that corresponds to the emitted predetermined magnetic field, comparing the measured magnetic field to the nominal magnetic field, and determining, on the basis of a comparison, whether the identification object is located inside the area around the antenna device.