Broadband Circularly Polarized Patch Antenna with Low Cross-Polarization Using Artificial Ground Structure
Broadband Circularly Polarized Patch Antenna with Low Cross-Polarization Using Artificial Ground Structure
复制标题
采用人工接地结构的低交叉极化宽带圆极化贴片天线
DOI：
10.1002/mop.31065
复制
发表时间：
2018
影响因子：
1.5
通讯作者：
Y. Kai and T. Fukusako
中科院分区：
文献类型：
--
作者：
丸田一輝;西森健太郎;中山悠;安昌俊;福迫 武;Y. Kai and T. Fukusako
这封信提出了一种圆极化贴片天线，具有 3 dB AR（轴比）和相当恒定的增益特性以及使用 AGS（人工接地结构）覆盖宽带宽的低交叉极化。具有矩形单元的AGS可以扩展CP（圆极化）的3dB轴比和圆极化贴片天线的阻抗特性。为了实现宽带阻抗特性，需要匹配结构以在以大频率比分开的两个并联谐振之间保持足够的阻抗带宽。作为匹配结构，穿过接地面的馈电同轴电缆的外导体延伸至靠近辐射贴片元件。然而，这种匹配结构会在离轴方向产生较大的 XPOL（交叉极化）。在这封信中，延长的同轴结构被替换为曲折探针，用于抑制 XPOL 和匹配阻抗。通过模拟和测量结果讨论了蜿蜒探头的效果。因此，所提出的结构分别实现了约 50% 的 −10 dB S11 带宽和 20% 的 3 dB AR 带宽。在 AR 带宽范围内实现了 7.8 dBic 的平均增益。此外，与之前具有±30°方向扩展同轴结构的结构相比，离轴 XPOL 降低了约 10 dB。
This letter proposes a circularly polarized patch antenna with 3‐dB AR (axial ratio) and reasonably constant gain characteristics and low crosspolarization covering a wide bandwidth using an AGS (artificial ground structure). The AGS with a rectangular unit cell can expand the 3‐dB axial ratio of CP (circular polarization) and impedance characteristics of circularly polarized patch antennas. For achieving the broadband impedance characteristics, a matching structure is required to keep a sufficient impedance bandwidth between the two parallel resonances separated with a large ratio of frequency. As the matching structure, the outer conductor of a feeding coaxial cable passing through the ground plane is extended to be close to the radiating patch element. However, such matching structure yields large XPOL (crosspolarization) in off‐boresight directions. In this letter, the extended coaxial structure is replaced with a meandering probe for suppressing XPOL and matching impedance. The effect of the meandering probe is discussed with simulated and measured results. As a result, the proposed structure achieves a −10‐dB S11bandwidth of around 50% and a 3‐dB AR bandwidth of 20%, respectively. The average gain of 7.8 dBic is achieved covering the AR bandwidth. Furthermore, off‐boresight XPOL decreases by around 10 dB compared to the previous structure with the extended coaxial structure in ±30° directions.