Design of High-gain Antipodal Vivaldi Antenna Using Split Ring Metasurface for Near-field Measurements

Antipodal Vivaldi antenna have been widely used in many fields including near-field measurement due to its low profile and ultra-wideband characteristics. However, it faces the challenge of low gain, as well as patterns distortion. In this paper, a high-gain antipodal Vivaldi antenna based on split ring metasurface (MS) is proposed. By introducing the metasurface composed of split ring elements on the antenna aperture, the gain and radiation stability of the antenna are improved. The simulation results show that at 6-18GHz, the return loss of the designed antenna is below -10 dB and the maximum gain reached 11.5 dBi. Moreover, in the whole frequency band, the 3-dB beam width of the antenna is stable and the radiation pattern is undistorted. Finally, the designed antenna is fabricated and measured, and the measured results are in good agreement with the simulation results.