Modeling of waveguide dual-mode bandpass filters over wide frequency range In this paper, we investigate the efficient modeling of waveguide dual-mode bandpass filters over wide frequency range. Analysis of the characteristics of the general scattering matrix (GSM) of each junction of a typical filter structure shows that it is possible to preserve and extract only necessary information without sacrificing model accuracy. The complexity of the electromagnetic (EM) data can therefore be significantly reduced in the construction of the filter model, while maintaining required simulation accuracy. The efficiency of the method is demonstrated using a Ku band dual-mode pseudo-elliptic filter. Responses obtained using the proposed simplified model agree well with full EM simulations and measurement results over 2 GHz frequency range.