Mode analysis in cylindrical waveguide loaded with spoof surface plasmon

Modes in cylindrical waveguides with periodic subwavelength metal grating loaded on the inner surface are analyzed by both theory and simulation. Coupling between spoof surface plasmon mode and traditional waveguide mode provides a robust way to build TM₀₂ single mode operation. Furthermore, a new approach to realize the well-integrated and reciprocal mode conversion between TM₀₁ mode and TM₀₂ mode is proposed.