A Dual Band and Dual Circular Polarization Radial Line Slot Antenna

In this letter, the design of a dual band and dual circular polarization RLSA (Radial Line Slot Antenna) fed by a broadband feeding network is presented. The antenna consists of the parallel radial line, slot array on the upper plate and feeding network on the underside of the plate. The antenna works at 12GHz and 14GHz. The feeding network is composed of microstrip line to provide the phase excitation for left-handed circular polarization and right-handed circular polarization. The diameter of the antenna is 100mm. At 12 GHz, the right-handed circular polarization sum gain is 18.02dB. the aperture efficiency is 40.18%; at 14GHz, the left-handed circular polarization circular polarization sum gain is 20.56dB, the aperture efficiency is 53.72%. The axial ratio is lower than 3dB in both bands.