A dual circularly polarized omnidirectional receiver antenna for satellite communication

This study describes about an omnidirectional antenna for satellite communication applications possessing dual circular polarization at almost over the full azimuth plane and wide elevation plane. The antenna does not use any septum polarizer behind it such that the circular polarization is satisfied with a simple rectangular-to-circular waveguide transition and some disks surrounding the circular waveguide with slots. The structure is fed by a rectangular waveguide and a rectangular-to-circular waveguide transition is used. Then, the inclined slots in each section of the circular waveguide supported with radially outward disks are cut in the same slanted way such that +45° slots in the first section gives LHCP and -45° slots in the second section gives RHCP. The realization of the proposed antenna is carried out at Ku-band about 14 GHz. The antenna provides more than 10 dB return loss for 3 percent frequency bandwidth, Besides, the axial ratio for both polarizations is below 3 dB within overall azimuth plane and about 65° beamwidth of elevation plane. The gain variations in the same planes are found to be about 2.5 dBi, which proves omnidirectional property of the antenna.