Design of a Wideband Omnidirectional Circular Polarized Antenna

To realize a wideband omnidirectional circular polarized antenna (OCPA), one omnidirectional antenna using polarizer and metasurface are designed, fabricated and measured. Omnidirectional circular polarized (CP) wave is achieved by the anisotropic dielectric polarizer. Then, the metasurface can compensate the phase difference of orthogonally polarized electromagnetic waves caused by the anisotropic dielectric polarizer as the frequency increasing. The phase difference can maintain in nearly 90° within a broad band. Hence, it can achieve wideband omnidirectional CP radiation. The measured results are consistent with the simulated ones. The measured results show that the proposed OCPA can achieve an impedance bandwidth of more than 70% (11 GHz-25 GHz) and an axial ration (AR) bandwidth of 66.6% (12 GHz - 24 GHz).