Design and Optimization of a Broadband Waveguide Magic-T Using a Stepped Conducting Cone

The design of a broadband waveguide magic-T was accomplished using a genetical swarm optimization (GSO) technique. A multi-stepped, off-centered conducting cone was used to enhance the bandwidth performance of the conventional magic-Ts. The geometrical parameters of the stepped cone were optimized by GSO, and the optimized magic-T for X-band application was fabricated and tested. Measured scattering parameters are shown to be in good agreement with the computed results. The optimized design exhibits -20 dB reflection bandwidth over 20.0% at all waveguide ports.