Radiation enhanced vivaldi antenna with shaped dielectric cover

Gain curve of the conventional Vivaldi antenna (CVA) decreases at higher frequencies. A dielectric cover is proposed to correct this problem. The detailed analysis, design and discussion for the CVA with shaped dielectrics (SDCVA) have been carried out. Both the CVA and the DSCVA are fabricated and tested. The results show good agreement with the simulated ones. The measured results show that the proposed SDCVA provides a gain variation of 5.2-14.2 dBi in the wide operating range from 3.5 to 16.5 GHz, which corresponds to a gain enhancement of 0.5-6.5 dBi compared to the CVA. In addition, the E-plane half power beamwidths are narrowed significantly at higher frequencies. An average improvement of 3.58 dB is achieved in terms of the front-to-back ratio. The sidelobe levels, on average, are reduced by 5.88 dB and 3.47 dB for E-plane and H-plane, respectively.