Enhancement of directional characteristics of circularly polarized dish parabolic Antennas using metallic scatters

Circularly polarized dish antennas are of great importance since they have better immunity to external types of noise compared to linearly polarized ones. Dish parabolic antennas with end-fire helical feeds provide circular polarization, high directivity and relatively low level of side lobs, however, the conducting ground plane of the helical feed results in a blockage of the reflected rays from the reflecting dish which consequently affects negatively the directional characteristics of the entire antenna. In this study, an optimization of the ground plane is considered based on series of FEKO simulations and which lead to a significant reduction of side lobes and an enhancement of the overall antenna performance. In addition, adding metallic scatters to the antenna at specific positions and with specific dimensions would reduce the sidelobe level by about 10dB.