On the theory of a circular waveguide with anisotropic impedance surface for gyro-devices: Eigenmodes

Circular waveguides with anisotropic impedance surfaces can be used in gyro-devices in order to improve their performance. Among them are dielectric-loaded metallic waveguides [1–5], axially [6] and azimuthally [7] corrugated waveguides. Their eigenmodes are purely (or nearly) TE and TM modes only in a number of extreme cases. Such cases were considered previously in [1–7]. However, in the general case, when the surface impedance is arbitrary, waveguide modes are hybrid HE and EH waves. Derivation of the boundary-value problem for such waves is the main aim of the study.