A broadband internal antenna includes a first radiator having a radiation part with one or more coils having different pitch intervals connected in series to each other, and a second radiator having at least one conductive strip line arranged parallel to a longitudinal direction of the first radiator. The antenna further includes a connection part to which an end of the at least one conductive strip line is connected, to which a first end of the first radiator is attached and in which a part for supplying current to the antenna and a part for grounding the antenna are formed, and an attachment pad to which a second end of the first radiator is attached and from which current is drawn. Current flowing through the first radiator and current flowing through the strip lines form current paths in different directions to set a certain broadband using mutual Electromagnetic (EM) coupling.