Waveguide septum polarizer shaped with Legendre polynomials

This paper presents the design and performance of a waveguide septum polarizer where the longitudinal profile of the septum blade is shaped with Legendre polynomials. A performance comparison with a conventional septum polarizer based on a blade with a stepped profile is performed at Ka-band (27.5-30.0 GHz) to show the merit of the proposed profile shaping. Preliminary results indicate an increase in frequency bandwidth of about 20% combined with a length reduction of 5.5%. This compact 3-port waveguide device can be used to generate either dual-circular or dual-linear tilted polarization.