A simple yet practical antenna structure composed of a regular half-wavelength dipole with coupling arms is presented. Adjustment of the amount of coupling to the main dipole through physical dimensions enables operation in either dual-band or wideband mode. Omni-directional radiation patterns can be achieved for both operation modes. The proposed antenna has been implemented for mid- and upper-bands of a WiMAX system. Good agreement between the simulation and measurement results has been observed.