In this article, a new broadband circularly polarized (CP) microstrip patch antenna (MPA) with a sequential phase (SP) square‐loop feeding structure is proposed. The presented antenna is composed of a square‐loop feeding structure, four L‐shaped parasitic patches with L‐shaped slots, four parasitic square patches, and a corner‐truncated square patch. At first, a SP square‐loop is designed as a feeding structure. Then, four L‐shaped parasitic patches with L‐shaped slots are utilized to generate one CP mode by a capacitive coupled way. At last, four parasitic square patches and a corner‐truncated square patch are together placed above the SP feeding structure to broaden the circularly polarized bandwidth (CPBW). The presented antenna has a wide 3‐dB axial ratio bandwidth (ARBW) of 16.7% (5.4 GHz, 4.95‐5.85 GHz), and a wide 10‐dB return loss bandwidth of 25.5% (5.5 GHz, 4.8‐6.2 GHz). The proposed antenna features compact structure and broad 3‐AR bandwidth which could completely cover the WLAN (5.725‐5.85GHz) band. Therefore, the proposed antenna is suitable for circular polarization applications in C band.

中文翻译：

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带有寄生元件的紧凑型双层宽带圆极化微带天线

在本文中，提出了一种新的具有连续相位（SP）方环馈电结构的宽带圆极化（CP）微带贴片天线（MPA）。所展示的天线由方环馈电结构，带有L形缝隙的四个L形寄生贴片，四个寄生正方形贴片和一个角截去的正方形贴片组成。首先，将SP方环设计为馈电结构。然后，利用四个带有L形缝隙的L形寄生贴片通过电容耦合方式生成一个CP模式。最后，将四个寄生正方形贴片和一个截角正方形贴片一起放置在SP馈电结构上方，以加宽圆极化带宽（CPBW）。所展示的天线具有16.7％（5.4 GHz，4.95-5.85 GHz）的3dB宽轴比带宽（ARBW），10-dB的宽回波损耗带宽为25.5％（5.5 GHz，4.8-6.2 GHz）。拟议的天线具有紧凑的结构和广泛的3-AR带宽，可以完全覆盖WLAN（5.725-5.85GHz）频段。因此，所提出的天线适用于C波段的圆极化应用。