Miniaturization and performance enhancement of Vivaldi antenna based on ultra-wideband metasurface lens

Abstract In this paper, the gradient elliptical slots (ES) are designed to enhance the operating bandwidth of the Vivaldi antenna (VA) in the relatively low frequency band. The antenna EVA is implemented by integrating the elliptical slots to the edge of the VA, which extends the low frequency operating point from 7.4 GHz to 5.4 GHz while obtaining the miniaturized design of the antenna. To address the problem of the gain deterioration, we design ultra-wideband metasurface lens (ML) and integrate it into the aperture of the EVA. The lens has a simple structure that can perform dual polarization modulation on electromagnetic waves. The propagation path of the electric field at the aperture of the EVA loaded with the ML is extended, and the electric field behaves more planar. We simulate and analyze the conventional VA, EVA, and ML integrated EVA (MLEVA). The VA and the proposed MLEVA are fabricated and measured. The results match those of the simulations. The operating bandwidth of the proposed antenna is 5.4-18 GHz that has been expanded compared with the VA. And the gain has increased by approximately 0.3-3.2 dB without changing the overall antenna sizes. The sidelobe level is significantly reduced at the same time. Generally, miniaturization and performance enhancement of the VA is achieved in the proposed MLEVA.