US Patent 10936931 Antenna device

An antenna device having excellent communication characteristics even when no opening is provided in a conductor. An antenna device including: an antenna coil inductively coupled to an external device (reader/writer) and provided by winding around a conducting wire two dimensionally via an opening; and a conductor provided to be overlapped with the antenna coil at a surface of the antenna coil opposing to the external device, wherein the conductor includes a first slit formed from a region overlapped with the opening of the antenna coil to an end of the conductor, and a second slit connected to the first slit and formed in the region overlapped with the opening of the antenna coil.