Integration of a Via-Loaded Annular-Ring Reduced-Surface-Wave Antenna and a Branch-Line Coupler
Integration of a Via-Loaded Annular-Ring Reduced-Surface-Wave Antenna and a Branch-Line Coupler
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通孔加载环形减面波天线与支线耦合器的集成
DOI：
10.1109/access.2020.3010061
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发表时间：
2020
期刊：
影响因子：
3.9
通讯作者：
N. Shinohara and T. Mitani
中科院分区：
文献类型：
--
作者：
S. Kojima;N. Shinohara and T. Mitani
本研究提出一种双圆极化缩减表面波天线，其结构紧凑且简单，是将一个通孔加载的圆环（VLAR）-RSW天线与一个分支线耦合器整合在一起。通过仿真详细分析了一种变增益谐振腔天线的基本特性。通常，当元件间隔小时，与传统贴片天线相比，RSW天线之间发生更强的互耦合，因为近的物理距离的效果变得大于表面波抑制的效果。它表明，VLAR天线可以减少相互耦合比传统的天线通过选择适当的半径在每个单元间距，即使当单元间距很小。由于在激励TM 11模式时的高输入阻抗，环形天线通常需要匹配电路。相比之下，对于VLAR-RSW天线，通过调整馈电位置和短路通孔之间的距离，在没有匹配电路的情况下阻抗匹配是可行的。实测结果表明，所研制的双圆极化天线的性能与仿真结果基本一致。在5.8GHz时，两个极化方向的轴比小于0.6dB，端口间的隔离度约为29 dB。此外，它表明，开发的天线减少互耦合比传统的贴片天线，因为抑制表面波的效果。
This study proposes a dual-circularly polarized Reduced-Surface-Wave (RSW) antenna which has a compact and simple structure by the integration of a via-loaded annular-ring (VLAR)-RSW antenna with a branch-line coupler. The fundamental characteristics of a VLAR-RSW antenna are analyzed through simulations in detail. In general, stronger mutual coupling between RSW antennas occurs in comparison with conventional patch antennas when the element spacing is small, since the effect of the close physical distance becomes larger than the effect of surface wave suppression. It is shown that the VLAR antenna can reduce the mutual coupling than the conventional antenna by selecting the appropriate radius at each element spacing, even when the element spacing is small. A matching circuit is generally required for an annular-ring antenna because of the high input impedance when exciting the TM11 mode. In contrast, for the VLAR-RSW antenna, impedance matching is feasible without a matching circuit by adjusting the distance between the feed position and the shorting vias. Measured results show the performance of the developed dual-circularly polarized antenna is in agreement with the simulation. At 5.8GHz, the measured axial ratios of both polarizations are smaller than 0.6dB and the measured isolation between ports is about 29 dB. Moreover, it is shown that the developed antenna reduces mutual coupling than the conventional patch antenna because of the effect of suppressing surface waves.