Patent ID: 8517280

Claim:
A contactless IC card which transmits and receives signals and supplies electric power by electromagnetic induction, the card comprising: a first antenna coil with one end electrically coupled to a first terminal of an IC chip, the coil having a first number of turns and a first winding direction; a second antenna coil with one end electrically coupled to a second terminal of the IC chip, the coil having a second number of turns, different from the first number of turns, and a second winding direction opposite to the first winding direction; a first interconnection substrate on which the first antenna coil is formed; and a second interconnection substrate on which the second antenna coil is formed, wherein one of the first antenna coil and the second antenna coil lies over the other, wherein the IC chip is mounted over either the first interconnection substrate or the second interconnection substrate, wherein the first antenna coil is formed along a periphery of a surface of the first interconnection substrate and the second antenna coil is formed along a periphery of a surface of the second interconnection substrate, and wherein the first and second interconnection substrates are stacked one upon the other between a pair of external sheets and an area which is on a surface of the external sheets and inside the areas of the first and second antenna coils is embossed with a given stamp.