Rigorous theory of rectangular waveguide multiple-slot couplers

A new high efficient quasi-analytical field theory method for the analysis of multiple-slot directional couplers is proposed. The theory is based on one of the versions of the Galerkin's method in which the weighted Gegenbauer polynomials are used as the basis functions explicitly taking into account the edge condition. Another important feature of the presented theory is the separation and analytical transform of the matrix operator static part of the obtained linear algebraic equations set. The results are in good agreement with theoretical and experimental data of other work.