Analysis of a coupled waveguide circulator using non-reciprocal attenuation

This paper describes a coupled waveguide circulator in which the secondary waveguide is loaded with distributed non-reciprocal attenuation along the coupling length. In the forward direction of transmission, the difference in the attenuation constants between the two coupled waveguides is large and transmission takes place between the primary waveguide ports. The peak and average power capability for this direction is essentially that of the empty waveguide. In the reverse direction, the difference in the attenuation constants is essentially zero and complete transfer of power takes place between the two waveguides. The insertion loss for this direction of propagation is limited by the back-to-front ratio of the non-reciprocal loss.