A circularly-polarized-reconfigurable patch antenna based on fluidic control method is proposed in this paper. A liquid dielectric, ethyl acetate, is introduced to change the substrate of a patch antenna from homogeneous to inhomogeneous. Two orthogonal fundamental transverse magnetic (TM) modes are excited with a 90° phase difference in order to produce circularly polarized (CP) radiation. Then, the polarization of the proposed patch antenna is switchable between left-hand circular polarization (LHCP) and right-hand circular polarization (RHCP) through the injection of the liquid dielectric to different channels in the substrate. For demonstration, the proposed antenna is designed at 2.4 GHz for radio frequency identification (RFID) application. According to the measured result, the proposed circular-polarization-reconfigurable patch antenna has a stable circularly polarized (CP) gain of 8 dBic and an efficiency of 90 % across the effective frequency band. Additionally, the measured overlapped impedance bandwidth of two polarization state is from 2.24 to 2.52 GHz which can fully cover the measured overlapped 3-dB axial ratio (AR) bandwidth from 2.38 to 2.43 GHz.

中文翻译：

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具有液体介电的圆极化可重构贴片天线

提出了一种基于流体控制方法的圆极化可重构贴片天线。引入液体电介质乙酸乙酯，以将贴片天线的基板从均质变为不均质。以90°的相位差激发两个正交的基本横向磁（TM）模式，以产生圆极化（CP）辐射。然后，通过向基板中的不同通道注入液体电介质，所提出的贴片天线的极化可在左旋圆极化（LHCP）和右旋圆极化（RHCP）之间切换。为了演示，建议的天线设计为2.4 GHz，用于射频识别（RFID）应用。根据测量结果，所提出的圆极化可重构贴片天线具有8 dBic的稳定圆极化（CP）增益，在整个有效频带上的效率为90％。此外，两个极化状态的测量重叠阻抗带宽为2.24至2.52 GHz，可以完全覆盖2.38至2.43 GHz的测量重叠3-dB轴比（AR）带宽。