Generalised asymptotic boundary conditions and their application to composite right/left-handed rectangular waveguide with double-ridge corrugations

A generalised form of the asymptotic corrugation boundary conditions (ACBCs) is presented and employed to analyse a composite right/left-handed rectangular waveguide loaded with double-ridge stubs. Enforcing the ACBCs yields the dispersion relation as well as the field distribution in the main waveguide without the need for any sophisticated modal analysis. The asymptotic solution proves to provide accurate results within a wide frequency band. The effect of the various geometrical parameters and the aspect ratios is investigated to determine the range of validity of the ACBCs. The results compared with the full-wave simulations exhibit very good agreement.