Design and Fabrication of a Wide Beam Stepped Choke Ring Antenna for X band Links of LEO Satellites

Choke ring antenna is one of the best options among many types of antennas being used for LEO satellites operating in microwave frequencies. In this paper, a four-ring stepped choke ring antenna with a descending profile has been designed, optimized, fabricated and tested. This cylindrical waveguide fed antenna produces circular polarization by using a septum. The wide radiation pattern of this antenna covers 125 degrees in 10.5 GHz with a gain better than 3dB. To minimize the effects of the satellite body and solar panels on the radiation pattern, the antenna has been mounted on a satellite mock-up whose effects have been fully investigated in simulation and measurement.