Wideband Circular-Polarization Reconfigurable Antenna with L-Shaped Feeding Probes

A wideband circularly polarized reconfigurable patch antenna with L-shaped feeding probes is presented, which can generate unidirectional radiation performance that is switchable between left-hand circular polarization (LHCP) and right-hand circular polarization (RHCP). To realize this property, an L-probe fed square patch antenna is chosen as the radiator. A compact reconfigurable feeding network is implemented to excite the patch and generate either LHCP or RHCP over a wide operating bandwidth. The proposed antenna achieves the desired radiation patterns and has excellent characteristics, including a wide bandwidth, a compact structure, and a low profile. Measured results exhibit approximately identical performance for both polarization modes. Wide impedance, 31.6% from 1.2 to 1.65 GHz, and axial-ratio, 20.8% from 1.29 to 1.59 GHz, bandwidths are obtained. The gain is very stable across the entire bandwidth with a 6.9-dBic peak value. The reported circular-polarization reconfigurable antenna can mitigate the polarization mismatching problem in multipath wireless environments, increase the channel capacity of the system, and enable polarization coding.