Various embodiments of an antenna structure for mobile devices are described. In one or more embodiments a multi-band antenna includes a grounded parasitic element. In some embodiments, a high band arm is provided, and is fed off-center, so that the resonating arms are not symmetrical in length. In some embodiments, a coupled ground resonator is included to add a differential resonating mode. A ground leg may be included to offer facilitate impedance and inductance matching. The combination of these structures creates four distinct resonance modes for the high band, which creases a wide effective bandwidth for the disclosed antenna. Other embodiments are described and claimed.