Dielectric lens balanced antipodal Vivaldi antenna with low cross-polarisation for ultra-wideband applications

The major deficiency of conventional `balanced antipodal Vivaldi antenna´ (BAVA) is its tilted beam over upper working frequencies. This study reports on a new BAVA to overcome this defect. By applying a dielectric lens in front of the antenna´s aperture, beam-tilting in E-plane was improved within the ultra-wideband frequency range, as well as higher frequencies. In the new BAVA, the authors have also achieved an acceptable cross-polarisation. Measurements show that the antenna has better than 10 dB return loss within the aforesaid frequency range. The measurements successfully verify the simulation results. Group delay and fidelity factor as time domain characteristics of the proposed antenna have been studied. They have compared performance of the conventional BAVA, with achievements of the new BAVA as hereunder.