基于渐变折射率超表面的宽带高增益端射天线

Design of a Broadband High-gain End-fire Antenna Based on Gradient-index Metasurface

提出了一种基于渐变折射率调制超表面的紧凑、宽带化、高定向性端射天线。该天线采用阶梯微带线-槽线结构作为馈线、准八木天线作为馈源、所设计渐变折射率超表面作为寄生结构,既可实现天线带宽拓展,又具有增益提升效果。仿真结果表明,天线可以在紧凑化尺寸情况下(尺寸为0.644λ_(0)×0.729λ_(0)×0.017λ_(0),λ_(0)为中心频点所对应的自由空间波长),实现3.66~9.13 GHz频带内的良好阻抗匹配,相对带宽为85.5%,同时,在宽频带范围内,天线的增益浮动在4.78~8.81 dBi,且具有良好稳定的辐射特性。所提出的紧凑、宽带高定向性端射天线可以应用于空间受限的走廊、隧道等平台环境中。

A compact,broadband,high-directivity end-fire antenna based on gradient-index metasurface is proposed.In this design,a stepped impedance microstrip-line-slotline structure is employed as the feeder,a quasi-Yagi structure is used as the feed,and a metasurface consisting of linearly index-modulated patches is utilized for both bandwidth enhancement and gain improvement.The overall dimensions are 0.644λ_(0)×0.729λ_(0)×0.017λ_(0),whereλ_(0) corresponds to the free-space wavelength of the center frequency.The simulation results indicate that the proposed antenna realizes good impedance-matching performance of 85.5%(3.66~9.13 GHz),and a flat gain of 4.78~8.81 dBi over the bandwidth.Meanwhile,the antenna shows good end-fire radiation characteristics across the bandwidth.The proposed compact,broadband,and highly directional end-fire antenna would be quite suitable for space-limited platforms,e.g.,corridors and tunnels.