Broadband Septum Polarizer in Multimode Regime

A method of design of a broadband septum polarizer with a square common port is proposed. It is based on a classical configuration with a longitudinal stepped metal insert. The results of numerical optimization of its profile showed that it makes no sense to use more than four steps in the single-mode regime, since an increase in their number does not lead to an improvement in the characteristics of the device. It is shown that this limitation is absent in the multimode regime, and it is possible to achieve better device characteristics by increasing the number of steps. The design of a broadband septum polarizer with a bandwidth of 46.5% in the multimode regime is presented.