Polarization reconfigurable omnidirectional antenna using crossed dipoles

A novel polarization reconfigurable omnidirectional antenna is proposed. The polarization reconfigurable antenna consists of four crossed dipole elements; each element has a left-leaning dipole and a right-leaning dipole. By switching between the left-leaning and right-leaning dipoles, a left-handed circularly polarized (LHCP) or a right-handed circularly polarized (RHCP) omnidirectional radiation pattern can be obtained. It is shown that the polarization reconfigurable omnidirectional antenna achieves a bandwidth of ~18% for return loss >10 dB and ~22% for axial ratio <; 3 dB.