Improvements in a 4-Element High Gain Directional UWB Antenna Array

In this paper, a novel serrated structure at the edges of the antipodal Vivaldi antenna is introduced. Compared with the Vivaldi antenna without serrated structure, the novel structure antenna has a better Front-to-Back ratio (F/B ratio). Additionally, when building a 4-element array with mirror image elements placed alternately along the H plane, the cross-polarization level at the boresight is reduced a lot compared to conventional array configuration. The design of the novel 4-element Vivaldi antenna array with mirror image elements described in this paper experimentally produces a gain with a range of 9∼15 dBi, F/B ratio more than 15 dB, and cross-polarization level at the boresight is reduced more than 10 dB from 3.5 GHz to more than 10.6 GHz with –10 dB return loss. The novel antenna array can be used for directional UWB systems.