An inverted-F antenna is provided that has a resonating element arm and a ground element. A shorting branch of the resonating element arm shorts the resonating element arm to the ground element. An antenna feed that receives a transmission line is coupled to the resonating element arm and the ground element. One or more impedance discontinuity structures are formed along the resonating element arm at locations that are between the shorting branch and the antenna feed. The impedance discontinuity structures may include shorting structures and capacitance discontinuity structures. The impedance discontinuity structures may be formed by off-axis vertical conductors such as vias that pass through a dielectric layer separating the antenna resonating element arm from the ground element. Capacitance discontinuity structures may be formed from hollowed portions of the dielectric or other dielectric portions with a dielectric constant that differs from that of the dielectric layer.