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In this paper, we present a method for the analysis of lossy substrate-integrated waveguide structures. The analysis is achieved through the cylindrical-wave mode expansion of the field and a mode matching technique to enforce boundary conditions on the post surfaces. We introduce an approximated formulation of the previous exact procedure, valid in the microwave regime, and numerically examine a number of microwave devices using both approximated and exact analyses. These devices include filters, couplers, phase shifter, and so on. Results are presented for the scattering parameters and compared with those obtained with the commercial software in terms of accuracy and computational time. [ABSTRACT FROM PUBLISHER]

We propose a fast and accurate full-wave code capable of analyzing electrically large substrate integrated waveguides consisting of stacked parallel-plate waveguides hosting dielectric or metallic posts and coupling and/or radiating slots. Boundary conditions enforced on posts yield scattering amplitudes, while slots are modeled by equivalent magnetic currents, solved by a method of moments. Substantial accelerations are proposed to exploit various symmetries of the structures and to select the optimal number of modes according to the relevant geometrical and physical parameters. The formulation is validated by full-wave simulations with a commercial software and measurement results. [ABSTRACT FROM PUBLISHER]

A complete set of entire-domain basis functions are introduced for the analysis of scattering from bodies with curved surfaces; they are defined via the application of a generalization of the Shannon sampling theorem. These basis functions are defined for curved patches with arbitrary contours, via a three-step procedure. First, the curved patch is mapped, via Transformation Optics, onto a flat parametric domain surrounded by a virtual anisotropic inhomogeneous space. Next, linear-phase functions are defined on the parametric flat domain; the sufficient and non-redundant number of functions is found by using a spectral domain “completeness relationship” of the delta function. Finally, the back-transformation from flat anisotropic to curved isotropic space yields the basis functions for the curved patch. The number of basis functions so obtained matches the degrees of freedom of the field known in the literature. Numerical results show the effectiveness of the representation for both fields and currents. [ABSTRACT FROM PUBLISHER]

Entire-domain basis functions are introduced for the analysis of scattering from bodies with flat portions, and of radiation from planar apertures; they are defined via the application of the sampling theorem of Shannon. These basis functions are particularly convenient for polygonal contours; however, arbitrary contours can be treated in the same framework with a very minor pre-processing time. A non-redundant set of basis functions is determined a priori by explicit approximate formulas either for currents and for radiated field. Numerical results are presented to shown the accuracy of the method. [ABSTRACT FROM AUTHOR]