Abstract: The present invention provides an antenna device comprising a conductive substrate and an antenna element located in the proximity of the conductive substrate, in which a portion of the antenna element is formed of a coil or zigzag conductor and an end of the antenna element is connected to the conductive substrate for grounding. In addition, the coil or zigzag conductor is formed at an end of the antenna element and the coil or zigzag conductor and the other end of the antenna element are connected together on an insulator provided on the conductive substrate.