A novel design concept to widen axial-ratio (AR)-bandwidth of a single circularly polarized (CP) patch antenna is presented by resonating its TM $_{1/2,0}$ , TM $_{1/2,1}$ , and TM $_{3/2,0}$ modes. First, a set of shorting pins is loaded around the edge of the patch with decreased width, aiming to suppress undesired nonbroadside modes. Second, the far-zone radiated fields of the antenna are theoretically studied by using equivalent magnetic currents (EMCs). The results demonstrate that its broadside $\vert {E}_{\theta }\vert $ , $\vert {E}_{\varphi }\vert $ , and $-\vert {E} _{\theta }\vert $ components of xo z plane radiation patterns could be orthogonally generated under TM $_{1/2,0}$ , TM $_{1/2,1}$ , and TM $_{3/2,0}$ modes, respectively. Most importantly, these three broadside EMCs must be sequentially rotated. Third, the resonant frequencies of these triple radiative modes ( ${f}_{1/2,0}$ , ${f}_{1/2,1}$ , and ${f}_{3/2,0}$ ) are extensively analyzed and reallocated by loading the shorting pins. It proves that the ${f}_{1/2,0}$ and ${f}_{1/2,1}$ could be progressively pushed up to around the ${f}_{3/2,0}$ , resulting in generating the CP radiation as expected. With these arrangements, the AR-bandwidth of the proposed CP antenna is significantly widened under triple-mode resonance. In final, the proposed antenna is fabricated and measured. Simulated and measured results are in good agreement with each other. The measured results depict that the CP antenna has acquired an enhanced AR-bandwidth with two minima poles, covering a fractional bandwidth of about 5% from 3.25 to 3.41 GHz, which is about 3.3 times wider than the traditional counterpart (1.5%). Besides, its profile is kept only about 0.03 free-space wavelength. Particularly, the single-layer, single-fed, single-radiator, and high-efficiency properties are simultaneously maintained for the CP antenna without needing to rely on any extra feeding networks, patches, or resisters.

中文翻译：

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三模谐振下增强AR带宽的单圆极化贴片天线的设计方法

通过谐振其 TM 提出了一种用于加宽单个圆极化 (CP) 贴片天线的轴向比 (AR) 带宽的新颖设计概念 $_{1/2,0}$ ， TM值 $_{1/2,1}$ , 和 TM $_{3/2,0}$ 模式。首先，在贴片边缘加载一组短路引脚，宽度减小，旨在抑制不需要的非宽带模式。其次，通过使用等效磁流 (EMC) 从理论上研究天线的远区辐射场。结果表明，其宽边 $\vert {E}_{\theta }\vert $ , $\vert {E}_{\varphi }\vert $ ， 和 $-\vert {E} _{\theta }\vert $ 的组成部分 xo z平面辐射图可以在TM下正交生成 $_{1/2,0}$ ， TM值 $_{1/2,1}$ , 和 TM $_{3/2,0}$ 模式，分别。最重要的是，这三个横向 EMC 必须按顺序轮换。第三，这些三重辐射模式的谐振频率（ ${f}_{1/2,0}$ , ${f}_{1/2,1}$ ， 和 ${f}_{3/2,0}$ ) 通过加载短路引脚进行广泛分析和重新分配。它证明了 ${f}_{1/2,0}$ 和 ${f}_{1/2,1}$ 可以逐步推高到周围 ${f}_{3/2,0}$ ，导致产生预期的CP辐射。通过这些安排，所提出的 CP 天线的 AR 带宽在三模谐振下显着加宽。最后，建议的天线被制造和测量。模拟和测量结果相互吻合。测量结果表明，CP 天线获得了增强的 AR 带宽，具有两个极小极点，覆盖了从 3.25 到 3.41 GHz 约 5% 的部分带宽，比传统天线 (1.5%) 宽约 3.3 倍。此外，其轮廓仅保持约 0.03 自由空间波长。特别是，CP天线同时保持了单层、单馈、单辐射器和高效率的特性，无需依赖任何额外的馈电网络、贴片或电阻器。