Analysis of corrugated waveguides using a Periodic-Asymptotic Boundary Conditions approach

Periodic-Asymptotic Boundary Conditions (PABCs) are introduced to analyze corrugated rectangular waveguide. The obtained dispersion characteristics show that the conventional Asymptotic Corrugation Boundary Conditions (ACBCs) have notable inaccuracies in predicting the dispersion characteristics, especially the left-hand propagation region. The derived expressions extend the validity of asymptotic boundary conditions in cases where the period is comparable to the wavelength and generally, improve the accuracy of the dispersion characteristics as they incorporate the effect of the high-order Floquet harmonics.