In the paper design for the 32-metre Cassegrain type antenna polarizer at the Ventspils International Radio Astronomy Center (VIRAC) is described. A circularly polarized feed horn antenna generating a circularly shaped beam is used for reception from circularly polarized sources in the 6-cm band. For signal recording equipment it is necessary to split real time received signal in two orthogonal polarized components, for example, horizontal and vertical. The polarizer is realized as rectangular waveguide with two cascade sections. In the first section it is realized polarization splitter but in the second – matching network with 50 ohm input impedance. The performance of the polarizer has been simulated and test results are presented in the thesis.