Dielectric-less quad-ridge adapters for ferrite faraday rotators

This paper presents an adapter between empty and ferrite filled circular waveguides, having quite different cross-sections, based on the use of empty quad-ridge waveguide sections. The absence of dielectrics improves the overall reliability of the device with respect to standard solutions, which employ partially filled waveguide transformers. Measurements of a built Faraday rotator are shown and discussed.