Microwave Square Waveguide Polarization Converter with Diagonal Corner Diaphragms

In this research we suggest and analyze new type of microwave waveguide polarization converter with application of diagonal corner diaphragms. Recommended technical solution ensures simple integration of developed polarization converter into dual circular polarization antenna systems without any additional transitions between an orthomode transducer and a waveguide polarization transformer. Besides, the manufacturing of the whole feed network, which contains designed waveguide polarization converter, can be realized by modern fast and reliable CNC milling technology. In order to investigate the suggested engineering solution we developed a 3D model of a microwave polarization converter with 5 corner diaphragms in the form of square conducting plates located in the diagonally opposite corners of the square waveguide. Numerical simulations were carried out using efficient finite elements method in the frequency domain. The structure of a polarization converter was developed for the satellite operating frequency band 19-21 GHz. Optimized design of the polarizer provides VSWR less than 1.5 for vertical and horizontal polarizations of fundamental electromagnetic modes. Peak level of numerically simulated cross polarization isolation is less than -30 dB in the whole operating frequency band. Therefore, presented waveguide polarization converter with application of diagonally located corner diaphragms can be integrated in modern antenna horn feed networks for satellite communications, microwave radars, telecommunications and other information systems.