Disclosed is an internal antenna providing impedance matching for a wide band where a feeding patch is placed on a substrate. The disclosed antenna may include: a substrate; an impedance matching/feeding unit including a feeding patch, which is formed on the substrate and electrically connected to a feeding point, and a ground patch, which is electrically connected to a ground and formed above the feeding patch separated at a designated distance from the feeding patch; and a radiator formed extending from the ground patch, where the impedance matching/feeding unit performs impedance matching by way of coupling between the feeding patch and the ground patch, and the radiator receives coupling feeding from the feeding patch. The disclosed antenna has the advantages of overcoming the narrow band problem of a planar inverted-F antenna, and of allowing more efficient utilization of space in an internal antenna for a wide band using coupling matching and coupling feeding.