Recent Advances in Finline Circuits

Detailed studies of transmission properties of the finline coupler have revealed existence of certain phenomena which adversely affect the transmission characteristics. A discussion of the origin and successful elimination of such effects is described. New applications for the finline coupler have been found in the design of hybrid junctions, twists and bends in multimode waveguide, and other polarization selective devices. The paper concludes with a presentation of theoretical and experimental results in the application of finline techniques to low-pass microwave filters.