Design of wideband high-gain circularly polarized Vivaldi antenna array

A circularly polarized (CP) crossed antenna array with 22 elements based on a novel antipodal Vivaldi antenna is proposed. The Vivaldi antenna with tapering serrated structure at the edges, which is a ultra-wideband (UWB) linearly polarized antenna, has a high gain at 4.7-7.0 GHz, and a wide impedance bandwidth of 2.4-11.0 GHz when the reflection coefficient is smaller than -10 dB. The measured data of the antenna array show that the axial ratio is lower than 3 dB between 4.5 GHz and 7.0 GHz. A high antenna gain from 11 dBi to 13 dBi is also achieved at the whole bandwidth of the array. The proposed antenna element and array both own UWB and high-gain characteristics.