A front‐to‐back pattern‐reconfigurable circularly polarized (CP) antenna based on two pairs of planar complementary dipoles with back‐to‐back configuration is presented and implemented. The 8 p‐i‐n diodes are employed into the front and back printed dipole arms. The beam direction can be switched from front‐to‐back, and the left‐right circular polarization can also be changed at each beam direction individually, in which switches are controlled by the dc bias voltage loaded on both ends of the p‐i‐n diode. A prototype operating at 5.8 GHz is then fabricated and measured. Experimental results show that the overlapped bandwidth for 10‐dB return loss and 3‐dB axial ratio of the proposed antenna are from 5.75 to 5.88 (front) and 5.74 to 5.90 GHz (back) for the two pattern states. The presented antenna can be a well choice for ISM systems, which are widely applied in handheld medical terminal and signal detection system.

中文翻译：

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基于两对平面互补偶极子的图案和极化可重构圆极化天线

提出并实现了基于两对具有背对背配置的平面互补偶极子的从前到后模式可重新配置的圆极化（CP）天线。正面和背面印刷偶极子臂中使用了8个p-i-n二极管。光束方向可以前后切换，左右圆极化也可以分别在每个光束方向上改变，其中开关由加载在p-i-两端的直流偏置电压控制。 n二极管。然后制造并测量了在5.8 GHz频率下运行的原型。实验结果表明，对于两种模式状态，拟议天线的10dB回波损耗和3dB轴向比率的重叠带宽为5.75至5.88（正面）和5.74至5.90 GHz（背面）。提出的天线可能是ISM系统的不错选择，