Patent ID: 8047445
Filing Date: 2011-11-01
Classification: G06K,H01Q,H04B,Y10T

Abstract:
1. A wireless IC device comprising: an insulating sheet; a plurality of coil electrodes defining an antenna coil and being arranged so as to sandwich the insulating sheet therebetween and to be connected to one another; wherein the plurality of coil electrodes are superposed with one another so as to define a single ring when viewed in plan from a direction extending perpendicular or substantially perpendicular to a direction in which a main surface of the insulating sheet extends; the insulating sheet includes a plurality of stacked layers and certain ones of the plurality of coil electrodes arranged at both ends in the direction extending perpendicular or substantially perpendicular to the direction in which the main surface of the insulating sheet extends wind through a length of less than one circuit around a coil axis of the antenna coil; a minimum value of a distance between an outer edge of the single ring and outer edges of the insulating sheet is greater than a distance in the direction extending perpendicular or substantially perpendicular to the direction in which the main surface of the insulating sheet extends between the plurality of coil electrodes; and the plurality of coil electrodes and the plurality of stacked layers of the insulating sheet are arranged to prevent leaking of electric force lines generated between the plurality of coil electrodes so as to prevent variations of a resonant frequency of the wireless IC device due to changes of a capacitance generated in the plurality of coil electrodes due to the manner in which the wireless IC device is held.