Theoretical design of a metamaterial-based antipodal vivaldi antenna with modifications in radiation slots and feed-line section for wideband applications

Abstract

A key challenge in wideband antenna design is the inherent trade-off between achieving wider bandwidth and maintaining high gain, as well as balancing structural modifications with the overall antenna size. This work presents a simulation-based design and performance analysis of a modified antipodal Vivaldi antenna (AVA) for enhanced performance. A basic AVA is first designed on a low-cost FR-4 epoxy substrate of size 54 mm × 35 mm × 1.6 mm. To enhance bandwidth, cuts are introduced in the radiation slots and the feed-line section. To improve gain and directivity, an “inverted double V” metamaterial unit cell is designed and then incorporated as a 6 × 6 array on the aperture of the modified AVA. The proposed antenna operates over a wide frequency range of 3.4 – 23.7 GHz (S₁₁ < –10 dB), covering the Ultra-wideband (UWB), S-, C-, X-, Ku-, and K-band applications, with a maximum gain of 10.1 dB. Comparative analysis shows that our proposed design outperforms several previously reported designs and provides a valuable simulation-based reference for further experimental and practical implementations. The novelty of this work lies in the integration of a compact AVA structure with a novel metamaterial array and other optimized structural modifications, resulting in improved performance while maintaining low cost and compact size, thereby addressing key challenges in wideband antenna design.