A Miniaturized and High Gain Double-Slot Vivaldi Antenna Using Wideband Index-Near-Zero Metasurface

• Published in: IEEE access Vol. 6; pp. 72015 - 72024
• Main Authors: Zhu, Shuangshuang, Liu, Haiwen, Wen, Pin, Du, Lixia, Zhou, Jiafeng
• Format: Journal Article
• Language: English
• Published: Piscataway IEEE 2018; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Antennas; Bandwidth; Circuits; Defected ground slot; Design defects; Frequencies; High gain; Impedance; index-near-zero; Metamaterials; metasurface; Metasurfaces; Power dividers; Reflectance; Resonant frequency; Slot antennas; Ultrawideband; Unit cell; Vivaldi antenna; Vivaldi antennas
• ISSN: 2169-3536; 2169-3536
• DOI: 10.1109/ACCESS.2018.2883097

In this paper, a wideband, miniaturized, and high gain double-slot Vivaldi antenna is proposed. First, a corner cutting technique is adopted to broaden the frequency band. Second, a pair of defected ground slots is added to the edges of the antenna to extend the low-end frequency limitation from 2.27 to 1.15 GHz, which provides a great design freedom. Third, a novel unit cell of an index-near-zero metasurface is proposed in our design. The unit cell is a two-stub-loaded split-ring resonator, which has a compact size, a wide frequency band, and a good reflection coefficient. The gain of the double-slot Vivaldi antenna is improved over a wide frequency band by the inclusion of the index-near-zero metasurface in the aperture, without changing the overall dimensions or compromising the whole frequency band performance of the antenna. Finally, to verify the design method, an ultra-wideband double-slot Vivaldi antenna with defected ground slots and metasurface was fabricated and measured. The circuit has an overall size of <inline-formula> <tex-math notation="LaTeX">0.76\,\,\lambda \text{g}\,\,\times0.41\,\,\lambda \text{g}\,\,\times 0.005\,\,\lambda \text{g} </tex-math></inline-formula>. The modified antenna exhibits a measured gain of 0.7-14 dBi over the frequency band of 1.13-12 GHz.