Abstract: This specification discloses a polarization network for selectively converting between linear and circular polarization. The network includes a twistable waveguide having a generally rectangular cross section. Coupled to the twistable rectangular waveguide is a transducer waveguide which acts as an interface between the rectangular waveguide and circular waveguide. A polarizer having a generally circular cross section is coupled to the transducer waveguide and can convert transmitted electromagnetic waves between linear and circular polarization. A coupling means permits relative rotation between the transducer waveguide and the polarizer and selective securing at any of three rotational positions. A first position permits a linearly polarized signal to pass through the polarizer remaining linearly polarized. A second position converts between a linearly polarized signal and a right hand circularly polarized signal.