Patent ID: 7198198
Filing Date: 2007-04-03
Classification: G06K,H01Q

Abstract:
1. An antenna device that makes data communications with a contactless IC card by electromagnetic-inductive coupling, the device comprising: an asymmetric loop coil means formed from a winding of a conductor in a plane, whose sections opposite to each other across a center of the loop coil are different in interval from each other, the sections including a first section on a first side of the center of the loop coil and a second section on a second side of the center of the loop coil, the first section being wider in interval than the second section; and a lead means for supplying a power to the loop coil means; wherein the loop coil means, when supplied with power from the lead means, generates a magnetic field which is distributed asymmetrically with respect to the center, such that the magnetic field is stronger at the first section than at the second section.