Design of A Broadband Vertically Polarized Omnidirectional Array Based on Vivaldi Antenna

Using eight Vivaldi elements, a wideband omnidirectional array is proposed in this paper. First, in order to achieve roundness radiation pattern of array in horizontal plane, a Fermi Vivaldi antenna is optimized, which can achieve a 3-dB beam width of 45° (±10°) from 5.5GHz to 7.6GHz. Then, the elements in the H-plane with periodic angle of 45° are employed to build the circular array. Finally, the array is fabricated and its performance is evaluated. Measured result shows the designed array can obtain a bandwidth from 5.5 to 7.6GHz for both omnidirectional radiation pattern and S
₁₁
≤ -10 dB. In addition, this array has a potential application for beam switching with smooth angular variation over a 360° range.