Conclusion

Several approaches for calculating waveguide performance have been presented. This performance is primarily characterized by attenuation, the dispersion diagram relating the linear phase shift β to the angular frequency ω (or frequency), and the cutoff frequency of the propagated modes. First, a general formulation, based on a perturbation approach, for calculating the attenuation of a mode in a uniform waveguide was derived, and several examples were presented. For general structures, the use of numerical approaches is necessary. To this end, the main methods—first approximate, then rigorous—were presented in the application dedicated to waveguides. The exact methods are primarily transformed into a transverse problem involving eigenvalues associated with points on the mode dispersion diagram. The eigenvectors are related to the configuration of the associated mode fields. The presentation...