A novel method of designing a wideband series-fed circularly polarized (CP) differential antenna by using crossed open slot pairs is presented in this article. The near-field distributions and input impedance analyses show that the closely spaced open slot-pairs can radiate as the crossed dipoles and have stable radiating resistance with a compact radiator size. Besides, a wideband half-power phase shifter using open slot is proposed and utilized to realize CP radiation. The proposed CP antenna is composed of a wide slot-pair and a narrow slot-pair. In the antenna design, the narrow slot-pair is not only excited as a radiator, but also elaborately loaded to provide wideband half-power output and quadrature phase excitation to the wide slot-pair. Both the proposed half-power phase shifter and CP antenna are illustrated by the corresponding equivalent circuits. Based on these analyses, the proposed antenna is designed, fabricated, and measured. Compared with the simulated traditionally designed counterpart, 2.1 times wider axial ratio (AR) bandwidth is achieved for the proposed antenna. The measured overlapped bandwidth for AR < 3 dB and return loss >10 dB is 1.95–3.45 GHz (55.6%). Also, the antenna gain and radiation patterns are measured, which agree well with the simulated results.

中文翻译：

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一种采用交叉开槽对的宽带串馈圆极化差分天线

本文介绍了一种使用交叉开槽对设计宽带串联馈电圆极化 (CP) 差分天线的新方法。近场分布和输入阻抗分析表明，紧密间隔的开槽对可以作为交叉偶极子辐射，并且具有稳定的辐射电阻和紧凑的辐射器尺寸。此外，提出了一种使用开槽的宽带半功率移相器，并利用它来实现CP辐射。提议的 CP 天线由宽槽对和窄槽对组成。在天线设计中，窄槽对不仅作为辐射体被激励，而且还精心加载，为宽槽对提供宽带半功率输出和正交相位激励。所提出的半功率移相器和 CP 天线都由相应的等效电路说明。基于这些分析，设计、制造和测量了所提议的天线。与模拟的传统设计对应物相比，所提出的天线实现了 2.1 倍宽的轴比 (AR) 带宽。AR < 3 dB 和回波损耗 >10 dB 的测量重叠带宽为 1.95–3.45 GHz (55.6%)。此外，还测量了天线增益和辐射方向图，这与模拟结果非常吻合。3 dB 和回波损耗 >10 dB 为 1.95–3.45 GHz (55.6%)。此外，还测量了天线增益和辐射方向图，这与模拟结果非常吻合。3 dB 和回波损耗 >10 dB 为 1.95–3.45 GHz (55.6%)。此外，还测量了天线增益和辐射方向图，这与模拟结果非常吻合。