Abstract: A novel wideband omnidirectioanl planar antenna comprised two back-to-back dipoles printed on a dielectric substrate which use as unit of pattern reconfigurable antenna array is presented. The presented antenna shows a wide impedance bandwidth about 50% (VSWR2), and a stable antenna gain level of about 6.44 dBi, with small variations(2.0 dB) for omnidirectional radiation, is obtained across the used bandwidth. Details of antenna design and experimental results are proposed, and compared with excellent agreement. A constructed prototype is suitable for WiMax(802.16) application fixed and mobile solutions ,as well as base or relay stations for WLAN operation or mobile communications.