Disclosed is an internal antenna using electromagnetic coupling that supports improved impedance matching. The antenna includes a first conductive member having one end electrically connected with a power feed point; a second conductive member separated from the first conductive member by a particular distance and electrically connected with a ground; a radiator extending from the second conductive member; and a grounding plate joined with the other end of the first conductive member. This antenna provides the advantages of adequately ensuring wide-band and multi-band characteristics while improving impedance matching properties.