Design, Optimization and Fabrication of a X-Band Septum Polarizer for Satellite Communication

This paper presents the design steps, numerical optimization and fabricated of a 4-stepped septum polarizer. The structure of the septum polarizer consists of a square waveguide, a segment of several steps called the septum, and two rectangular waveguides. The simulated result shows that the proposed structure accomplished return losses of lower than -18 dB, forward transmission characteristics between -3 dB and -3.2 dB, isolation characteristics between -25 dB and -37 dB and the phase difference between two modes is between 89°-90.5° at the target frequency ranging from 7.25 to 8.4 GHz. Based on the obtained results, X-band prototype was manufactured, and its performances were measured. The measurements of the prototype are in good agreement with simulations. The designed and manufactured septum polarizer was used in the feed of the satellite antenna.