This aticle presents a new wideband omnidirectional array antenna that operates at Ku‐band. Each element of the array antenna consists of a modified planar bow‐tie dipoles radiator, a pair of parasitic strips, and a pair of directors. The parasitic strips and directors are designed to enhance the antenna omnidirectional radiating performance. All elements are combined through a double‐sided parallel strip‐line feeding network. A wideband semicircular balun is employed at the feeding port to broaden the impedance bandwidth. Finally, a 2 × 2 prototype is designed, fabricated, and measured. The measured results demonstrate that the proposed array antenna provides 47.3% (11.3‐18.4 GHz) relative impedance bandwidth with 4.1 dBi maximum gain, around 44.8° half‐power beamwidth at 15.0 GHz and less than 2.5 dB unroundness over the whole operating band in xoy plane.