BROADBAND AND HIGH-GAIN PLANAR VIVALDI ANTENNAS BASED ON INHOMOGENEOUS ANISOTROPIC ZERO-INDEX METAMATERIALS

Vivaldi antennas have broad applications in real practice due to the ultra wideband properties. However, their gain and directivity are relatively low. In this paper, a new method is presented to improve the gain and directivity of Vivaldi antennas in a broad band using inhomogeneous and anisotropic...

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Bibliographic Details
Published in:Electromagnetic waves (Cambridge, Mass.) Mass.), 2011-01, Vol.120, p.235-247
Main Authors: Zhou, B, Li, H, Zou, X.Y, Cui, T.J
Format: Article
Language:English
Subjects:
Advanced materials
Anisotropy
Antennas
Antennas (Electronics)
Broadband transmission
Design and construction
Engineering design
Materials
Methods
Technology application
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Summary:Vivaldi antennas have broad applications in real practice due to the ultra wideband properties. However, their gain and directivity are relatively low. In this paper, a new method is presented to improve the gain and directivity of Vivaldi antennas in a broad band using inhomogeneous and anisotropic (IA) zero-index metamaterials (ZIM). ZIM have the ability to enhance the antenna directivity; anisotropic ZIM with only one component of the permittivity or permeability tensor approaching to zero can make impedance match to improve the radiation efficiency; and IA-ZIM can broaden the frequency bandwidth. Single- and multiple-layered planar IA-ZIM have been analyzed, designed, and fabricated, which can be embedded into the original Vivaldi antenna smoothly and compactly. The IAZIM-based Vivaldi antennas have good features of high gain, high directivity, low return loss, and broad bandwidth. Compared to the original Vivaldi antenna, the measurement results show that the gain has been increased by 3dB and the half-power beam width has been decreased by 20 degrees with the reflection coefficient less than -10dB from 9.5 GHz to 12.5 GHz after using IA-ZIM.
ISSN:1559-8985
1070-4698
1559-8985
DOI:10.2528/PIER11072710