Artificially anisotropic cylinder to convert omnidirectional linear polarization into circular polarization

Circular polarization and omnidirectional radiation are desired characteristics in various mobile communication systems. This paper studies possibilities to convert linear polarization into circular polarization by designing an artificially anisotropic cylinder around the antenna. The design process and simulated results for the cylinder with a half wave dipole antenna at the centre frequency of 2.3 GHz are presented. It is shown that the cylinder has minor effect on the return loss and gain of the antenna and that axial ratio remains below 5dB over the frequency range of 900MHz.