A broad crossed dipole circularly polarized antenna (CPA) with modified and parasitic elements is presented. The crossed dipole CPA is consisted of a pair of vacant-quarter printed rings as continuous phase feeding structure, four L-shaped strips as radiated patch, four grounded round-metal pillars as parasitic element and a circular ground as a reflector. Note that two deformed trapezoid-microstrip lines as impedance matching element are used to feed the crossed dipole CPA, which is different from the traditional rectangular-microstrip lines. Moreover, the rotated L-shaped strips as radiated patch are used to realize CP radiation, but four rotated grounded round metal pillars as the only parasitic element are arranged at the edge of the L-shaped strips to improve the CP bandwidth. Through making use of these elements, multiple CP resonant modes could be together stimulated, which leads to an increase in the CP bandwidth. The antenna prototype is fabricated and tested to verify the rationality of the design. Finally, the designed crossed dipole CPA features a broad 3-dB axial ratio bandwidth of 78% (1.25-2.85, 2.05 GHz), and a wide −10-dB impedance bandwidth of 107.4% (0.94-3.12, 2.03 GHz), which could include the WiBro (2.3-2.39 GHz) and GPS (L1 1.575 GHz) band. Thus, the presented crossed dipole CPA would be a very promising candidate in the wireless communication systems.

中文翻译：

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具有寄生圆形金属柱的宽带交叉偶极圆极化天线

提出了一种具有修改和寄生元件的宽交叉偶极圆极化天线 (CPA)。交叉偶极子CPA由一对空四分之一印刷环作为连续相位馈电结构，四个L形条作为辐射贴片，四个接地圆形金属柱作为寄生元件和一个圆形接地作为反射器。注意，与传统的矩形微带线不同，使用两条变形梯形微带线作为阻抗匹配元件来馈送交叉偶极子CPA。此外，使用旋转的L形条作为辐射贴片来实现CP辐射，但在L形条的边缘设置了四个旋转接地圆形金属柱作为唯一的寄生元件，以提高CP带宽。通过利用这些元素，多个 CP 谐振模式可以一起激发，这导致 CP 带宽的增加。制作天线样机并进行测试，验证设计的合理性。最后，设计的交叉偶极子 CPA 具有 78% (1.25-2.85, 2.05 GHz) 的宽 3-dB 轴比带宽和 107.4% (0.94-3.12, 2.03 GHz) 的宽 -10-dB 阻抗带宽，其中可能包括 WiBro (2.3-2.39 GHz) 和 GPS (L 1 1.575 GHz) 频带。因此，所提出的交叉偶极子 CPA 将是无线通信系统中非常有前途的候选者。