An Antipodal Vivaldi Antenna with a Lower Cutoff Frequency Based on Spoof Surface Plasmon Polaritons and Corrugated Edges

Abstract

In this paper, an antipodal Vivaldi antenna (AVA) with a lower cutoff frequency is proposed based on spoof surface plasmon polaritons (SSPPs) and corrugated edges. Firstly, the gradient slots are etched on the outer edges of the two radiation arms of the conventional antipodal Vivaldi antenna. As a result, the low cutoff frequency is decreased slightly due to the increased surface current path of the antenna. More importantly, the SSPPs structure with identical units is etched on the inner side of two radiation arms, leading to a significant reduction in the low cutoff frequency due to the larger propagation constant of the SSPPs structure compared to the radiation arms of the conventional antipodal Vivaldi antenna. Additionally, the structure of the SSPPs on the stripline ensures effective momentum and mode matching between the quasi-TEM mode and SSPPs mode. Furthermore, to improve the gain at the high-frequency band, the structure of the SSPPs introduced on the inner side of the two radiation arms is further optimized by varying the depths of the grooves. Experimental results demonstrate that the designed antipodal Vivaldi antenna exhibits excellent radiation performance, with a low cutoff frequency of 2.8 GHz and a maximum gain of 9.3 dBi.