低剖面宽波束圆极化天线单元及其宽角扫描阵列设计

Design of low-profile circularly polarized antenna element for wide-angle scanning array

  • 摘要: 针对低轨卫星通信中圆极化相控阵扫描角度窄、剖面高的挑战,设计了一款低剖面、宽波束圆极化天线单元及其宽角扫描阵列。该单元采用双层结构,通过四角微扰与交叉缝隙实现左旋圆极化,并利用上层寄生结构与金属柱基于方向图叠加原理将波束宽度拓展至120°,轴比波束宽度大于175°,剖面高度仅0.07λ0。基于该单元构建的4×4旋转阵列,结合接地板环形开口槽设计,有效抑制了互耦。仿真结果表明,阵列在±60°扫描范围内轴比始终低于2 dB,且增益变化平缓,实现了优异的宽角圆极化扫描性能。

     

    Abstract:
    Background
    With the rapid development of low-Earth orbit (LEO) satellite communications, there is a pressing need for circularly polarized phased arrays that offer wide-angle scanning capability while maintaining a low profile, which remains a significant challenge in current designs.
    Purpose
    This study aims to design a low-profile, wide-beam circularly polarized antenna element and its corresponding wide-angle scanning array to address the limitations of narrow scan angles and high profiles in existing solutions.
    Methods
    A double-layer antenna element was designed, utilizing corner perturbation and cross-slots to achieve left-hand circular polarization, while the beamwidth was broadened via an upper parasitic structure and metallic posts based on pattern superposition. A 4×4 array was constructed by rotating these elements, with annular open slots integrated into the ground plane to suppress mutual coupling.
    Results
    The proposed antenna element exhibits a 3-dB axial ratio beamwidth greater than 175°, a gain beamwidth of 120°, and a profile of only 0.07λ0. Simulations of the 4×4 array demonstrate a scan coverage of ±60°, with axial ratio consistently below 2 dB and a stable gain fluctuation of 3.38 dB throughout the scanning range.
    Conclusions
    The designed antenna and array effectively achieve wide-angle circularly polarized scanning with low profile and stable performance, offering a promising solution for LEO satellite communication terminals and other integrated systems requiring wide spatial coverage.

     

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