An electromagnetic model for post-wall waveguide building blocks

Abstract

Abstract-During the past five years, dielectric and metallic post-wall waveguides (PWWGs) have been analyzed at TNO Defence, Security and Safety, using both an integral equation approach and a modal approach. The model developed focuses on TEn0 modes facilitating the analysis of infinitelylong, straight PWWGs as well as finite PWWGs with arbitrary post positioning. Quite recently, we introduced an alternative approach for dealing with complex propagation constants, so that PWWG losses, and the scattering matrices of PWWG sections can be computed. These sections are represented by 'current matrices' that relate the 'incoming' electric and magnetic surface currents on predefined ports to the 'outgoing' surface currents. The derivation of the current matrices is based on Lorentz's reciprocity and Love's equivalence theorems. Both the 'incoming' and 'outgoing' surface currents are represented by rooftop bases. The scattering parameters of a PWWG section are determined by expressing waveguide modes in terms of these bases. Finally, the corresponding software code can be integrated in a circuit simulator, a familiar platform for microwave designers.

A current‐matrix model for metallic and dielectric postwall waveguides

“…Following Coenen [2010] and Coenen et al [2010], we present in this paper a model for PWWG building blocks that is based on the same principles as those of Van de Water et al [2005], in particular Lorentz's reciprocity theorem. However we characterize the PWWG building block entirely in terms of electric and magnetic input and output surface currents at predefined port interfaces, as in the BI‐RME and Arnieri and Amendola [2008].…”