This letter presents a dual-sense circularly polarized (CP) microstrip patch antenna with a dual-coupled line. The rectangular patch antenna operating in TM01 mode is utilized as a basic design, and a single-coupled line is introduced to excite the TM10 mode with a phase difference of 90°, generating CP operation. As different polarizations can be obtained by changing the position of the single-coupled line, a dual-coupled line is introduced to the rectangular patch antenna to excite two CP modes with different polarizations. The prototype of the dual-band dual-sense CP antenna is fabricated and measured. The measured results illustrate that the dual-sense CP antenna obtains a wide impedance bandwidth of 7.95% and dual axial ratio (AR) bandwidth of 0.33% for the left-hand circular polarization (LHCP) and 0.72% for the right-hand circular polarization (RHCP). Furthermore, the antenna has a wide 3 dB axial-ratio beamwidth and a small frequency ratio of 1.04.

中文翻译：

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带耦合线的双感圆极化天线

这封信展示了一种带有双耦合线的双感圆极化 (CP) 微带贴片天线。工作在TM01模式的矩形贴片天线作为基本设计，引入单耦合线以90°相位差激发TM10模式，产生CP操作。由于改变单耦合线的位置可以获得不同的极化，因此在矩形贴片天线中引入双耦合线以激发具有不同极化的两种CP模式。制作并测量了双频双感CP天线的样机。测量结果表明，双感CP天线获得了7.95%的宽阻抗带宽和0.33%的左旋圆极化（LHCP）和0的双轴比（AR）带宽。右旋圆极化 (RHCP) 为 72%。此外，该天线具有 3 dB 的宽轴比波束宽度和 1.04 的小频率比。