Solution of periodically loaded waveguides using the eigenmode projection technique

Waveguides with arbitrary cross-section and periodic loading are analyzed using an eigenmode projection technique. The analysis procedure is based on expanding the fields of the given structure in terms of the solenoidal and irrotational eigenmodes of a canonical waveguide with cross-section enclosing that of the original waveguide. Floquet harmonics are incorporated in the canonical eigenmodes to account for the periodicity. Results obtained using the proposed approach and other techniques are compared and show excellent agreement. The proposed approach has many advantages, namely that the problem reduces to a simple eigenvalue problem and the field distribution is directly given as weighted expansion of the canonical eigenmodes.