Performance enhancement for antipodal Vivaldi antenna modulated by a high-permittivity metasurface lens

Abstract

A metasurface unit is designed operating at 2–20 GHz to enhance the gain and radiation performance of an antipodal Vivaldi antenna (AVA). The unit has a simple structure, stable ultra-wideband performance, high permittivity, and can independently modulate two polarization modes electromagnetic waves. We analyze the current distribution on the unit and extract equivalent characteristic parameters to verify the ability of independent modulation on two polarization modes electromagnetic waves. The designed metasurface unit is integrated into the aperture of the AVA and forms the metasurface lens (ML) for guiding the propagation of electromagnetic waves. Two types of ML are proposed and integrated into the AVA to design antennas Ant1 and Ant2. The modulation effect of the lens on the electromagnetic wave is analyzed from the perspective of electric field amplitude and phase, and the final design is obtained. From the optimized design results, the AVA and the proposed Ant2 are fabricated and measured, and the measurement results are in good agreement with the simulation ones. The impedance bandwidth measured by Ant2 basically covers the 2–18 GHz frequency band. Compared with the conventional AVA, the gain of the proposed Ant2 is increased by 0.6–3.7 dB, the sidelobe level is significantly reduced, and the directivity has also been clearly improved.

Keywords

Antipodal Vivaldi antenna (AVA) / Ultra-wideband / High-permittivity / Dual-polarization / Metasurface lens (ML)

RIGHTS & PERMISSIONS

2021 Zhejiang University Press